Vessel Maneuvering and Handling

Environmental forces that affect the motion of a vessel are wind, seas, and current. The coxswain has no control over them and must take the time to observe how the wind, seas, and current, alone and together, affect the vessel. The coxswain should also determine how these forces cause the vessel to drift, and at what speed and angle. Coxswains must use environmental forces to their advantage and use propulsion and steering to overcome the environmental forces. Usually, a good mix of using and overcoming environmental forces results in smooth, safe boat handling.

The wind acts upon any portion of the vessel that is above the waterline. This includes the hull, superstructure, and on smaller boats, the crew. The amount of surface upon which the wind acts is called sail area. The vessel will make “leeway” (drift downwind) at a speed proportional to the wind velocity and the amount of sail area. The “aspect” or angle the vessel takes due to the wind will depend on where the sail area is centered compared to the underwater hull’s center of lateral resistance. A vessel with a high cabin near the bow and low freeboard aft (see Figure 6-1) would tend to ride stern to the wind. If a vessel’s draft were shallower forward than aft, the wind would affect the bow more than the stern. A sudden gust of wind from abeam when mooring a vessel like this might quickly set the bow down on a pier.

Knowledge of how the wind affects a vessel is very important in all close quarters situations, such as mooring, recovery of an object in the water, or maneuvering close aboard another vessel. If maneuvering from a downwind or leeward side of a vessel or pier, the coxswain should look for any wind shadow the vessel or pier makes by blocking the wind (see Figure 6-2). The coxswain should also account for the change in wind by planning maneuvers with this wind shadow in mind.

Seas are a product of the wind acting on the surface of the water. Seas affect boat handling in various ways, depending on their height and direction and the particular vessel’s characteristics. Vessels that readily react to wave motion, particularly pitching, will often expose part of the underwater hull to the wind. In situations such as this, the bow or stern may tend to “fall off” the wind when cresting a wave, as less underwater hull is available to prevent this downwind movement. Relatively large seas have the effect of making a temporary wind shadow for smaller vessels. In the trough between two crests, the wind may be substantially less than the wind at the wave crest. Very small vessels may need to make corrective maneuvers in the trough before approaching the next crest.

Current acts on a vessel’s underwater hull in the same manner as wind pushes on a vessel’s superstructure. The amount of draft a vessel has will determine how much affect current will have. A strong current will easily move a vessel upwind.

NOTE

A one-knot current may affect a vessel to the same degree as a 30-knot wind. The coxswain should learn to look for the signs of current flow so as to be prepared when current affects the vessel, and should be particularly aware of instances where current shear is present. As with wind, a large, stationary object like a breakwater or jetty will cause major changes in the amount and direction of current (see Figure 6-3). Crewmembers should note the amount of current around floating moorings or those with open pile supports. Caution should be used when maneuvering in close quarters to buoys and anchored vessels. Crewmembers should observe the effect of current by looking for current wake or flow patterns around buoys or piers and should watch how currents affect other vessels.

Environmental conditions can range from perfectly calm and absolutely no current to a howling gale and spring tides. Chances are that even if operation does not occur at either extreme, some degree of environmental forces will be in action.

The coxswain should know how the vessel responds to combinations of wind and current, and should determine which one has the greatest effect on the vessel. It may be that up to a certain wind speed, current has more control over a given vessel, but above that certain wind speed, the boat sails like a kite. The coxswain should know what will happen if a sudden gust of wind is encountered; will the boat immediately veer, or will it take a sustained wind to start it turning? When current goes against the wind, the wave patterns will be steeper and closer together. The coxswain should be particularly cautious where current or wind is funneled against the other. Tide rips, breaking bars, or gorge conditions frequently occur in these types of areas and may present a challenge to even the most proficient coxswain. On the other hand, making leeway while drifting down current requires a change in approach to prevent overshooting the landing.

NOTE

Stay constantly aware of conditions, how they may be changing, and how they affect the vessel.

For this discussion of propulsion, the following assumptions are made: (01) If a vessel has a single-shaft motor or drive unit, it is mounted on the vessel’s centreline, (02) When applying thrust to go forward, the propeller turns clockwise (the top to the right or a “right-handed” propeller), viewed from astern, and turns counterclockwise viewed from astern when making thrust to go astern, (03) If twin propulsion is used, the propeller to starboard operates as above (right-hand turning), while the port unit turns counterclockwise when making thrust to go forward when viewed from astern (left-hand turning) (see Figure 6-4), (04) Be aware that some propeller drive units rotate in only one direction, and changing the propeller blade angle of attack controls ahead or astern thrust (controllable pitch propeller).

The key to powered vessel movement is the effective transfer of energy from the source of the power (an internal combustion engine) to the water through a mechanism that turns the engine’s power into thrust. This thrust moves the boat. There must also be an element of directional control, both fore and aft, and from side to side. Propulsion and steering are considered together here for two reasons. Applying thrust has no use if the vessel’s direction cannot be controlled, and often the device providing the propulsion also provides the steering. There are three common methods to transfer power and provide directional control: (01) Rotating shaft and propeller with separate rudder, (02) A movable (steerable) combination as an outboard motor or stern drive, (03) An engine-driven pump mechanism with directional control, called a waterjet. All three arrangements have their advantages and disadvantages from the standpoint of mechanical efficiency, ease of maintenance, and vessel control. Using one type of propulsion instead of another is often a matter of vessel design and use parameters, operating area limitations, life cycle cost and frequently, personal preference. There is no single “best choice” for all applications. Regardless of which type you use, become familiar with how each operates and how the differences in operation affect vessel movement. On almost every boat, propulsion and steering arrangement is designed to operate more efficiently and effectively when going ahead than when going astern. Also, every vessel rotates in a transverse

NOTE

direction about a vertical axis on its pivot point (see Figure 6-5). The fore and aft location of the pivot point varies from boat to boat, but is generally just forward of amidships when the boat is at rest. As a hull moves either ahead or astern, the effective position of the pivot point moves either forward or aft, respectively.

In small craft installations, the propeller shaft usually penetrates the bottom of the hull at an angle to the vessel’s designed waterline and true horizontal. The practical reason for this is because the engine or marine gear must be inside the hull while the diameter of the propeller must be outside and beneath the hull. Additionally, there must be a space between the propeller blade arc of rotation and the bottom of the hull. For single-screw vessels, the shaft is generally aligned to the centerline of the vessel. However, in some installations, a slight offset (approximately 1°) is used to compensate for shaft torque. To finish the installation, the rudder is usually mounted directly astern of the propeller. For twin-screw vessels, both shafts are parallel to the vessel’s centerline (or nearly so), rudders are mounted astern of the propellers, and the rudders turn on vertical rudder posts.

When rotating to move in a forward direction, a propeller draws its supply of water from every direction forward of and around the blades. Each blade’s shape and pitch develop a low-pressure area on the forward face of the blade and a high-pressure area on the after face of the blades, forcing it in a stream toward the stern. This thrust, or dynamic pressure, along the propeller’s rotation axis is transmitted through the shaft, moving the boat ahead as the propeller tries to move into the area of lower pressure.

Regardless of whether the propeller is turning to go ahead or astern, the water flow pattern into the propeller’s arc of rotation is called suction screw current, and the thrust flow pattern out of the propeller is called discharge screw current (see Figure 6-6). The discharge screw current will always be stronger and more concentrated than the suction screw current.

In addition to the thrust along the shaft axis, another effect of propeller rotation is side force. Explanations for side force include: (01) How the propeller reacts to interference from the vessel hull as the hull drags a layer of water along with it (the propeller encounters boundary layer “frictional wake”), (02) How the discharge screw current acts on the rudder, (03) The propeller blade at the top of the arc transfers some energy to the water surface (prop wash) or to the hull (noise) and that the blade at the top of the arc either entrains air or encounters aerated water. Due to the angle of the propeller shaft, the effective pitch angle is different for ascending and descending propeller blades, resulting in an unequal blade thrust. The descending blade has a higher effective pitch angle and causes more thrust. This net effect is sometimes referred to as sideways blade pressure. The important facts to know: for a right-handed propeller turning ahead, the stern will tend to move to starboard (see Figure 6-7), and for a right-handed propeller when backing, the stern will tend to move to port. For a left-handed propeller (normally the port shaft on a twin-screw boat), the action is the opposite. An easy way to remember how side force will push the stern is to think of the propeller as a wheel on the ground. As the wheel rolls clockwise, it moves to the right. As a propeller turns clockwise when viewed from astern, the stern moves to starboard.

Cavitation is the rapid formation and collapse of vapor pockets in a flowing liquid in regions of very low pressure, and is a frequent cause of structural damage to propellers. Cavitation usually occurs when the propeller rotates at very high speed and a partial vacuum forms air bubbles at the tips of the propeller blades. Cavitation can also occur when trying to get a stopped propeller to spin at maximum speed, rapidly going from ahead to astern (or vice-versa), or by operating in aerated water where bubbles are dragged into the propeller flow. Cavitation occurs more readily when backing, as the suction screw current draws water from behind the transom, and air at the waterline mixes with the water and is drawn into the propeller. Cavitation frequently occurs when backing with outboard motors. In this case, through-hub exhaust gas bubbles are also drawn forward into the propeller blade arc.

NOTE

Outboard motors and stern drives will be considered together, as both include a pivoting gear case and propeller drive unit (called a lower unit on an outboard). The differences between these drive arrangements and the shaft/propeller/rudder arrangement is that the screw currents and thrust from an outboard or stern drive can be developed at an angle to the vessel centerline. Also, the point where thrust and steering are developed is usually aft of the vessel hull. The lower unit contains drive gears, a spline connection, and on many set-ups, through-the-propeller hub exhaust. Many lower unit gear housings are over six inches in diameter. Where an inboard engine powers the stern drive attached through the transom to the drive unit (the outdrive) and is commonly referred to as an inboard/outdrive or I/O. The outboard “powerhead” (engine) is mounted directly above the lower unit. Both outboards and stern drives can usually direct thrust at up to 35° to 40° off the vessel centerline. Also, both types generally allow the coxswain some amount of trim control. Trim control adjusts the propeller axis angle with the horizontal or surface of the water. This is done by operating the vessels trim/tilt or trim tab controls. Effectively operating the trim/tilt or trim tabs will reduce the amount of the vessels surface that is actually in contact with the water. Balancing a vessel properly along its axis fore and aft, while keeping it on an even keel is called “trim.” Efficiently operating trim control can improve fuel consumption, increase speed, and reduce the effects of porpoising. Porpoising is a continuous rise and fall of the bow in a rhythmic pattern. Contributing causes of porpoising are weather, load distribution, and power (thrust). Porpoising is a condition more commonly found in faster performance boats. The major difference in operation between the I/O and outboard is that the outboard motor, operating with a vertical crankshaft and driveshaft, develops a certain degree of rotational torque that could cause some degree of “pull” in the steering, usually when accelerating or in a sharp turn to starboard. If caught unaware, the coxswain could have difficulty stopping the turning action. The easiest way to overcome this torque-lock is to immediately reduce RPMs before trying to counter-steer.

Outboards and stern drives have a small steering vane or skeg below the propeller. The housing above the gearcase (below the waterline) is generally foil shaped. Though these features help directional control, particularly at speed, the larger amount of steering force from an outboard or stern drive is based upon the ability to direct the screw discharge current thrust at an angle to the vessel’s centerline (see Figure 6-9).

This directed thrust provides

extremely effective directional control when powering ahead. When making way with no propeller RPMs, the lower unit and skeg are not as effective as a rudder in providing directional control.

The propeller forces discussed above in A.11 Propeller Action also apply to the propellers on

NOTE

outboards or outdrives. However, because these drives can be directed, side force can be countered. The steering vane/skeg angle is usually adjustable, also assisting in countering side force.

When backing, it is possible to direct outboard/outdrive thrust to move the stern to port or starboard. When backing with the unit hard over to port, propeller side force introduces an element of forward motion (Figure 6-10), but can be countered through less helm. When backing to starboard, the side force tends to cause an element of astern motion and also tries to offset the initial starboard movement. Many lower units are fitted with a small vertical vane, slightly offset from centerline, directly above and astern of the propeller. This vane also acts to counter side force, particularly at higher speeds.

Outboards and stern drive usually allow a level of vertical thrust control. Trim controls the angle of attack between the propeller’s axis of rotation and both the vessel waterline and the surface of the water. Vertical thrust control, especially applied aft of the transom, changes the attitude the vessel hull will take to the water (Figure 6-11). Small amounts of trim should be used to offset for extreme loading conditions or to adjust how the vessel goes through chop.

In addition to trim, a vertical component of thrust develops in another situation. Depending on the type of hull, if a vessel is forced into an extremely tight turn with power applied, thrust is directed sideways while the vessel heels, actually trying to force the transom up out of the water, causing a turn to tighten even more.

WARNING

In lightweight or highly buoyant outboard powered boats, use of full power in tight turns can cause loss of control or ejection of crew, coxswain or both. It is mandatory that the helmsmen attach the engine kill switch lanyard to themselves.

Trim tabs consist of two adjustable planes mounted at the bottom edge of the transom where the planning surface meets the water. Controlled by a hydraulic power unit, these tabs can move up and down when adjusted by the vessel operator. They provide lift in order to compensate for changes in speed, weight distribution, and sea conditions.

Trim tabs control the pitch and roll axis of a vessel and have three specific purposes: performance, efficiency, and safety. They provide performance by reducing pounding, correct listing, eliminating porpoising, and offset propeller torque. They increase efficiency by reducing fuel consumption, reducing engine laboring, and eliminate squatting. Furthermore, they increase safety by reducing wake size, improve vessel handling, and reduce stress on the hull.

For the best results from your trim tabs, operate them in short half-second “bursts” and let the boat react before making another adjustment. The amount of time between corrections is influenced by the size of the trim tabs and the boat’s speed. When they are adjusted downward, the water force on the trim tab creates upward pressure (lift), raising the stern and reducing hull resistance (drag). The surface area of the tab, the angle of deflection, and the speed of the boat all contribute to greater lift. Operating your trim tabs in this manner will help avoid over-trimming, which occurs when you have deflected the tabs too far.

WARNING

Over-trimming while operating at high speeds creates unpredictable boat handling, which results in an extremely hazardous condition.

Trim tabs assist in getting the vessel up on plane around the pitch axis (Figure 6-12) as quickly as possible. Once achieved, it easy to maintain the boat’s most economical cruising speed. This is accomplished by simultaneously lowering both trim tabs. The force of the water against them will push the stern up consequently lowering the bow. Trim tabs may also be used to keep the bow up to avoid taking seas over the bow if the water is rough. The trim tabs can be adjusted to keep the bow from digging into waves or prevent launching the boat over waves. The vessel operator would simultaneously raise both trim tabs, causing the stern to lower and the bow to rise.

As a result of uneven weight distribution (e.g. passenger or excess gear), propeller torque or wind, a vessel can run with a list. Running with a list is uncomfortable, as well as unsafe. The port and starboard trim tabs act independently, making them an excellent instrument to provide effective list correction. To do this, adjust the trim tab downward on the listing side using short bursts. The water pressing against the tab as you move will lift that side of the vessel around the roll axis (Figure 6-12) and eliminate your list.

NOTE

Trim tabs will have less effect at slower speed than at high speed.

Power trim can be used to adjust the boat’s pitch axis, but it is highly inefficient. This is because a propeller is designed to force the boat forward. When utilizing your engines power trim, the propeller must not only push the boat forward but raise the stern as well. In this situation, propeller slippage is greatly increased thereby wasting RPMs. Power trim also cannot correct listing, and is ineffective at slower speeds. For increased speed and power, use your trim tabs in conjunction with your engine trim. The trim tabs adjust how your vessel plane, while the power trim adjusts the propeller. The result is optimum performance and efficiency not attainable by the use of the engine power trim alone. To achieve maximum performance: (01) Adjust the trim tabs to achieve a planing efficiency, (02) Then use the engine trim to position the propeller path parallel to the water flow, (03) If necessary, re-adjust the trim tabs to “fine tune”.

For the most comfortable ride, when running into a head sea you want to trim the bow down so the sharp forward sections of the boat do their work splitting the waves. This will bring the “V” of the hull in contact with the waves rather than having the wave’s pound the hull.

For best maneuverability and maximum steering control, trim tabs should be fully raised in a following sea. Keep the trim tabs up so the tide or current won’t push the stern from side to side.

When operating in astern propulsion, both trim tabs should be fully raised. The trim tabs produce drag if they are left down. This puts strain on the tabs as well as affects the boat’s handling. Additionally, if one tab is lowered more than the other while operating astern the boat tends to pivot around the lowered tab.

As speed increases, the bow repeatedly rises out of the water until gravity overcomes lift and the bow bounces down. Trimming down in half second bursts will allow the trim tabs to deflect, thus resulting in the porpoising to subside and your speed should remain the same or increase. Only a slight amount of trim tab adjustment should be necessary.

Jacking plates are used on smaller boats, usually less than 30ft in length, to aid in operating in shallow water. Instead of being mounted directly to the transom, the outboard motors are mounted to the jack plate which can be raised or lowered as needed (Figure 6-13).

Jacking plates, when equipped, can raise the outboard motors allowing you to control the engine draft. By raising the jacking plates and applying throttle, you can get on a plane in shallower water than you could if you were operating without the jacking plates. Once on plane, you can adjust or lower the jack plates as appropriate. Jacking plates can be powered via manual or hydraulic means. When powered by hydraulic means there is usually a control panel on the dash which can be used to raise or lower the outboards and also indicates the jacking plate height. Until you are familiar with jacking plates and their use. Utilize the crawl, walk, run method when operating

CAUTION !

your boat. High speed turns with the jacking plates in the full raised position may result in a loss of control, ejection, or capsizing event.

There are 2 main advantages to using jacking plates: (01) Operate in shallower water than normal, (02) Increased Efficiency. Trimming up your outboard(s) causes the bow to go up and the stern down, increasing your draft. However, jacking the outboards up to the point just before cavitation allows for thrust to be directed directly astern and reduces the increase in draft. This is because once water clears the transom; it flows upward into the propeller and provides sufficient water for the propeller(s) to work. Because the thrust is more efficient, not thrusting up or down by using the engine tilt, it helps to save more fuel.

High speed maneuvers can be more difficult when the jacking plates are fully raised. Additionally, a false sense of bravado may occur when determining operational draft realities. Always use sound risk management principles when operating in shallow water. Usually when getting a plane, boats squat in the stern causing the bow to rise and reducing visibility. When trim tabs are used, they increase visibility by reducing the squatting at the stern and in turn lessening the “bow rise” associated with coming up on a plane. Additionally, the engines do not have to work as hard to get on plane and therefore increased fuel efficiency. The tabs are more effective than engine tilt at controlling the pitch axis when already on a plane where the tabs can be manipulated to keep the bow from digging into waves or prevent launching the boat over waves.

As noted earlier, cavitation frequently occurs when backing with outboard motors. As through-hub exhaust gas bubbles are drawn forward into the propeller blade arc, the aerated water increases the possibility of cavitation. Though outboards and stern-drives are fitted with an anti-cavitation plate above the propeller, the coxswain should always take care to limit cavitation, particularly when backing or maneuvering using large amounts of throttle.

A waterjet (Figure 6-14) is an engine-driven impeller mounted in a housing. The impeller draws water in and forces it out through a nozzle. The suction (intake) side of the waterjet is forward of the nozzle, usually mounted at the deepest draft near the after sections of the hull. The discharge nozzle is mounted low in the hull, exiting through the transom. The cross-sectional area of the inlet is much larger than that of the nozzle. The volume of water entering the inlet is the same as being discharged through the nozzle, so the water flow is much stronger at the nozzle than at the intake. This pump-drive system is strictly a directed-thrust drive arrangement. A waterjet normally has no appendages, nor does it extend below the bottom of the vessel hull, allowing for operation in very shallow water.

[Lettered on the illustration: Bucket Impeller Housing Suction Discharge Intake Steering Nozzle]

Vessel control is through the nozzle-directed thrust (Figure 6-15). To attain forward motion, the thrust exits directly astern. For turning, the nozzle pivots (as a stern drive) to provide a transverse thrust component that moves the stern. For astern motion, a bucket-like deflector drops down behind the nozzle and directs the thrust forward. Some waterjet applications include trim control as with a stern drive or outboard. With this, thrust can be directed slightly upward or downward to offset vessel loading or improve ride.

Since the waterjet impeller is fully enclosed in the pump-drive housing, no propeller side force is generated. The only way to move the stern to port or starboard is by using the directed thrust.

Waterjet impeller blades revolve at an extremely high speed. A much higher degree of cavitation normally occurs than associated with external propellers without a loss of effective thrust. In fact, a telltale indicator of waterjet propulsion is a pronounced aerated, water discharge frequently seen as a rooster tail astern of such craft. As the impeller rotation does not change with thrust direction, frequent shifting from ahead to astern motion does not induce cavitation. However, as the thrust to make astern motion reaches the waterjet inlet, the aerated water is drawn into the jet, causing some reduction of effective thrust. As with all types of propulsion, slowing the impeller until clear of the aerated water reduces cavitation effects.

When stepping up to the controls of any vessel for the first time, the coxswain should immediately become familiar with any physical constraints or limitations of the helm and engine controls. Ideally, controls should be designed and mounted to allow for a wide range of operators of different arm length and hand size, though this is not always so.

The coxswain should determine if anything obstructs hand or arm movement for helm and throttle control. Checks should be made for the following obstructions and hazards: (01) A firm grasp of the wheel through 360°, (02) Anything that prevents use of the spokes, (03) Awkward position of throttle/gear selector, (04) Layout that prevents use of heavy gloves, (05) Inaccessible engine shutdown handles, (06) An easily fouled outboard kill-switch lanyard, (07) Other common sense items. The coxswain should also learn where all the controls are and know their function before snagging a sleeve while maneuvering in close quarters or banging a knee or elbow in choppy seas. Check control operation while moored with engines secured. Some larger vessels require engine

NOTE

operation to operate controls, such as engine-assisted hydraulic steering. If so, check throttle controls with engines secured

The following are some guidelines for determining the helm limits:

The following are some items to check when checking engine control action:

NOTE Perform these steps as part of every getting-underway check.

Joysticks are increasingly replacing legacy helm and throttle controls. In most cases boats will be equipped with two joysticks, one acting as a tiller to adjust heading and the other as the throttle with limited directional control for docking maneuvers. On vessels with jet propulsion, moving the throttle joystick forward will command the jet buckets up and the engines will accelerate, dependent on the amount of joystick forward movement, to increase jet flow for forward motion. Moving the joystick aft will command the buckets down and the engines will accelerate, to increase jet flow for astern motion. Moving the tiller joystick port or starboard will cause the boat to move sideways in the same direction. If wind or current are acting on the boat at an angle, the tiller can be moved slightly to the opposite angle to oppose those forces. The following are some guidelines for determining joystick limits:

Smooth, positive operation of helm and engine controls is absolutely necessary for safe boat

WARNING

operations. Do not accept improper control configuration, mismatched equipment, or improper maintenance as a reason for poorly operating controls. Poor control operation causes unsafe boat operations.

After checking all controls while moored with engines secured, the coxswain should recheck their operation with engines running while securely moored. It may not be safe to apply full ahead to astern throttle, however, a note should be made anytime there is a lag between throttle shift and propulsion, from neutral to ahead, neutral to astern, ahead to astern, and astern to ahead.

CAUTION !

When going from the ahead position to the astern position, and when going from the astern position to the ahead position, pause briefly at the neutral position. When training, an experienced individual should get the vessel underway and into open water before turning control over to anyone not familiar with the particular boat’s operation. Once in open water, control may be turned over to the new coxswain who should recheck helm and engine control operation at clutch speed.

When moving forward in a straight line, throttle should be advanced gradually and firmly. If the vessel is single-screw, outboard, or outdrive, propeller side force will tend to move the stern slightly to starboard (see Figure 6-16). The side force should be offset with slight starboard helm. If twin-engine, throttles should be advanced together. The vessel should not yaw in either direction if power is applied evenly. Engine RPMs should be checked so both engines turn at the same speed. Some vessels have a separate indicator to show if engine RPMs match, but also compare tachometer readings.

NOTE

Do not ram throttles forward when starting up. As the engines try to transfer the excessive power, the stern will squat, raising the bow and decreasing visibility (see Figure 6-17), and propellers or impellers may cavitate.

Small amounts of helm should be used to offset any propeller side force or the effects of winds and seas. Compass course should always be noted and corrected frequently to stay on course. It is important to develop a practiced eye and steer on a geographic point or range such as a point between buoys. Small, early helm corrections should be applied to stay on course, rather than large corrections after becoming well off course. Oversteering, leaving a snake-like path, should be avoided. At low speeds, helm correction will be more frequent and require more rudder than at higher speeds.

For planing or semi-displacement hulls, the boat will gradually gain speed until planing. If fitted with trim control (including trim tabs on inboard boats), slight, bow-down trim may lessen the amount of time needed to get on plane or “on step.”

Running at full speed all of the time should be avoided. This wastes fuel and can cause excessive wear on the boat and crew. Many vessels will not exceed or will only marginally exceed a given speed, regardless of the power applied. At some point, the only effect of applying additional throttle is increased fuel consumption with no speed increase. Finding a speed that offers a comfortable ride as well as allows mission completion is advised.

A margin of power should always be left available for emergencies. The best speed for the vessel should be determined. A good normal operating limit for semi-displacement vessels is usually 80 percent maximum power, allowing the remaining 20 percent for emergency use.

A boat at high speed has a large amount of force. With an untrained operator, this force can be dangerous. The following factors, and those identified in Rule 6 of the Navigation Rules and Regulations Handbook, should be considered to determine safe speed. (01) High seas: Slow down as winds and seas increase; the boat will handle more easily. Pounding or becoming airborne fatigues the hull and could injure the crew or cause them chronic skeletal problems. If it takes tremendous effort just to hang on, the crew will be fatigued and not able to perform their jobs. Minimize taking spray and water on deck,

NOTE

Find the most comfortable, secure location for the entire crew. For many vessels, this means in the immediate vicinity of the helm. (02) Traffic density: Do not use high speed in high traffic density areas. A safe speed allows response to developing situations and minimizes risk of collision, not only with the nearest approaching vessel, but with others around it, (03) Visibility: If conditions make it difficult to see, slow down. Fog, rain, and snow are obvious limits to visibility, but there are others. Geographic features and obstructions (river bends, piers, bridges and causeways), along with heavy vessel traffic, can limit the view of “the big picture.” Darkness or steering directly into the sun lessens ability to see objects or judge distances. Prevent spray on the windscreen (particularly salt spray or freezing spray) as much as possible and clean it regularly. Spray build-up on the windscreen is particularly hazardous in darkness or in glare, (04) Shoal waters: In shallow water, the bottom has an effect on the movement of the vessel. Slow down in shallow water. In extremely shallow water, the vessel’s stern tends to “squat” and actually moves closer to the bottom. Being “on plane” will not allow crossing a shoal that would ground the vessel in the displacement

WARNING

mode. At high planing speed, the stern will squat as it gets in shallow water, possibly grounding at a very damaging speed.

In extremely narrow channels, a vessel moving through the water will cause the “wedge” of water between the bow and the nearer bank to build up higher than on the other side. This bank cushion tends to push the bow away from the edge of the channel. As the stern moves along, screw suction and the movement of water to “fill- in” where the boat was creates bank suction. This causes the stern to move towards the bank. The combined effect of momentary bank cushion and bank suction may cause a sudden shear toward the opposite bank. Bank cushion and bank suction are strongest when the bank of a channel is steep. They are weakest when the edge of the channel shoals gradually and extends in a large shallow area. When possible, a trainee should stay exactly in the center of an extremely narrow channel to avoid these forces (see Figure 6-18). Slower speed also reduces the amount of cushion and suction. Some rudder offset towards the closer bank will help to avoid continuous cushion and suction effects by. Do not overcompensate for bank cushion and bank suction. Too much helm in the direction of the bank

CAUTION !

could cause the bow to veer into the bank. Then, a subsequent large helm movement to turn the bow away from the bank may cause the stern to swing into the bank.

When meeting another vessel close aboard, bow cushion and stern suction occur between the vessels much the same as bank cushion and suction. Helm corrections should be used to compensate. As both vessels move through the water, the combined effect is greater than what a single vessel encounters from bank interaction. Caution should be used so the bow does not veer too far from the intended track and the stern swings into the path of the other vessel. A port-to-port meeting situation is assumed. Before vessels are bow-to-bow, a small amount of right rudder should be used to ensure the bow is clear. The bow cushion will increase separation. As the vessels near bow-to-beam, using left rudder will enable the vessel to keep away from the right-hand bank and to stay parallel to the channel. When the vessels are bow-to-quarter, the bow cushion will be offset by the stern suction, and bank cushion may need to be offset by some right rudder. Finally, as the vessels are quarter-to-quarter, stern suction will predominate, and will require left rudder to keep the sterns apart. The following bow cushion and stern suction considerations apply when meeting another vessel in a narrow channel and when operating near a bank: (01) The deeper the vessel’s draft, the greater the cushion and suction effect, particularly if draft approaches water depth,

NOTE

(02) The closer to a bank or another vessel, the greater the cushion and suction, (03) In very narrow waterways, slow down to decrease cushion and suction effects, but not to the point of losing adequate steerage. When meeting another vessel in a narrow channel, the bow cushion and stern suction effects caused by the other vessel should be balanced with the bank cushion and suction effects due to the channel.

As a vessel proceeds, a combination of bow and stern waves move outward at an angle to the vessel track. The wake height and speed depend on vessel speed and hull type. Relatively large, semi-displacement hulls, proceeding at cruising speed, cause some of the largest wakes. Some lighter craft actually make less wake at top speed in the planing mode rather than at a slower speed. Displacement craft make the largest wake at hull speed. The coxswain should determine how to make the vessel leave the least wake; it might require slowing appreciably. All vessels are responsible for their wake and any injury or damage it might cause. Only an unaware coxswain trails a large wake through a mooring area or shallows, tossing vessels and straining moorings. A large, unnecessary wake, particularly in enclosed waters or near other smaller vessels, ruins the credibility of a professional image.

WARNING

While maneuvering, keep the crew informed of “Coming-up,” turning, or “Coming down,” slowing down. A quick warning shout could prevent injury.

To move in a straight line, small, frequent, momentary helm or tiller inputs adjust the position of the stern and bow to head in the desired direction. To intentionally change the vessel heading, larger, more sustained helm movement should be used.

As noted earlier, the direction of the bow may be changed by moving the stern in the opposite direction. As the stern swings a certain angle, the bow swings the same angle. Depending on the fore and aft position of the pivot point, the stern could swing through a larger distance than the bow, at the same angle. When a hull moves forward through the water, the effective pivot point moves forward. The higher the forward speed, the farther the pivot point moves forward.

Because outboards, stern drives, and waterjets use propulsion thrust for directional control, they can make a much tighter turn (using helm alone) with a given hull shape than if the same hull had shaft, propeller, and rudder. With extended outboard mounting brackets, the directed, lower-unit thrust is farthest aft of the pivot point compared to the other configurations. Some brackets move the thrust three to four feet aft of the hull. The location aft of the pivot point, along with the amount of directed thrust determines how much the stern will kick away from the direction of the turn. With directed thrust, the stern will usually skid outward more than with shaft, propeller and rudder, making the bow describe a very tight arc (see Figure 6-19).

When proceeding on a steady heading, putting the helm or tiller over to one side or the other, begins to turn the boat. Up to the time the boat turns through 90°, the boat has continued to advance in the original direction. By the time the boat has turned through 90°, it is well off to the side of the original track. This distance is transfer. As the boat continues through 180°, its path has defined its tactical diameter. If the vessel holds the turn through 360°, the distance it takes to reach the point where it first put the helm or tiller is referred to as its final diameter. For a particular vessel, these values vary for speed and rudder angle (see Figure 6-20). Developing a working knowledge of the vessel’s turning characteristics will enable decision-making such as whether to make a particular maneuver in a certain space solely with the helm or whether other maneuvering tactics are needed. Learning when to ease the helm will help to prevent oversteering a course.

Some planing hulls and most semi-displacement craft will slow appreciably when turning at high speeds. As the boat heels into a turn, the hull provides less buoyancy to keep the vessel on plane at a given speed. Also, as the aft part of the hull skids across the water while in a heel, it presents a flat shape in the original direction of movement and pushes water outward, thus causing the vessel to slow down. With light-displacement, high-powered craft, maximum helm at high speed will quickly stop a boat’s progress in the original direction of movement. Though such a turning action is effective to avoid contact with an immediate hazard, the violent motion could eject unsuspecting crewmembers. Use this

WARNING

technique only as an emergency maneuver. Do not use this maneuver to demonstrate the boat’s capability.

Bank suction, bank cushion (see B.11. Bank Cushion and Bank Suction above), and currents will all affect a boat navigating a sharp bend in a narrow channel. Where natural waterways have bends or turns, the water is always deepest and the current is always strongest on the outside of the bend. This is true for 15° jogs in a tidal estuary and for the “s” shaped meanders on the Mississippi River. This happens because the water flow has a great degree of momentum and resists having its direction changed. As it strikes the outside of the bank, it erodes the earth and carries the particles with it. The particles fall out farther downstream in areas of less current (the inside of a turn or bend) and cause shoaling. In some turns or bends, there may be circular currents (eddies) in either the deep outside of the bend or the shallow inside. Back currents also sometimes occur near eddies on the inside of the bend. When eddies or back currents occur, those near the shallows are much weaker than eddies or main current flow at the outside of the bend. Because bank cushion and suction are strongest when the bank of a channel is steep and weakest when the edge of the channel shoals gradually, bank effect is stronger on the outside of bends or turns. The coxswain should be aware of the mix of current and bank effect and use these forces to the fullest extent.

The effect of a head current is minimized by steering along the inside quarter of the channel, making sure to avoid shoaling. If the bow gets into the area of greater current, it may begin to sheer towards the outside of the bend. It can be countered through helm towards the inside of the bend and by getting the stern directly down current from the bow. The vessel can then be gradually worked back to the inside quarter of the channel. If the starting point is the outside of the bend, the full force of the current will be encountered. Bank cushion should keep the bow from the outside edge, but the stern is limited in its movement by bank suction. Initial helm towards the inside of the turn may allow the current to cause the bow to rapidly sheer away from the outside, but this is immediately offset with power and helm to keep the bow pointed upstream. Gradual helm with constant power should be used to get out of the main force of the current, and work across to the inside quarter of the channel.

The turn on a course should be approached just to the outside of the middle of the channel. This will avoid the strongest currents at the outside edge while still getting a reasonable push. While turning, the strongest current will accentuate the swing of the stern quarter to the outside of the channel. Because of this, and because the following current tends to carry the boat toward the outside, the turn should begin early in the bend. The amount of sideways movement or if the boat tends to “crab” in the channel should be constantly monitored. If the boat starts to move too close to the outside of a bend, more helm and power should be constantly monitored to maneuver the boat back into the middle. Once through the turn, the vessel can be gradually worked back to the inside quarter of the channel. (01) If the boat stays too far to the outside of the bend, timing the turn is difficult. Turning too early with stern suction on one quarter with the strongest current on the other quarter may cause an extreme veer to the inside of the turn. Any bow cushion will accentuate the sheer. Turning too late with stern suction and the quartering current could cause grounding. (02) If trying to hug the inside of the turn, both current and bank effect will be lessened. Use a small amount of rudder toward the inside bank to enter the turn. As the channel begins to bend, use less rudder while the boat starts to move from the inside bank. Use caution as the current under the quarter affects the stern, giving it an increase in sheer towards the inside bank. Slack water or an eddy down current on the inside will increase this sheer while bow cushion may not be enough to prevent grounding.

Pulling back the throttle to neutral will cause the vessel to begin to lose forward motion. For a heavy-displacement vessel, once propulsion is stopped, the vessel will continue to move forward for some distance. The vessel carries its momentum without propulsion. For a semi-displacement hull or planing hull, reducing power will cause the boat to quickly come off plane. As the vessel reverts to displacement mode, the resistance of the hull going through the water instead of on top of the water slows the boat. The vessel still carries some way, but at only a fraction of the original speed. The coxswain should experiment with the vessel and see how rapidly the boat slows after going from cruising speed to neutral throttle. Knowing the distance the vessel will travel when stopping (also known as head reach) from different speeds is very important when maneuvering.

Slowing the vessel’s forward movement is not always enough. In an emergency situation, a complete and quick stop to dead-in-the-water or crash stop may be required. This is done by applying astern propulsion while still making forward way. The first step is to slow the vessel by placing the throttles in the clutch astern position. After the vessel begins to lose way, astern propulsion should be applied firmly and forcefully. Power must be higher than that available at clutch speed to prevent engine stall. On a single- screw vessel, the stern will want to swing to port. After all way is off, the throttle should be placed in neutral. At low forward speeds, astern propulsion is frequently used to maneuver, both to check forward way and to gain sternway. Though many vessels are tested and capable of immediately going from full speed ahead to full reverse throttle, this crash stop technique is extremely harsh on the drive train and may cause engine stall. Though much of the power goes to propeller cavitation, this technique can be effective in an emergency. With a waterjet, reverse thrust is immediate. There is no marine gear or drive unit that requires the shaft and propeller to change rotation directions. The clamshell or bucket-shaped deflector plate drops down and redirects thrust forward. The crash stop is an emergency maneuver. It may damage the drive train and stall the engine(s). In

WARNING

most cases, with high levels of crew professionalism, skill, and situational awareness, it is not necessary.

When stopping vessels with outboard engines making forward way, the coxswain should follow the below procedures.

WARNING

The crash stop is an emergency maneuver or an advanced tactical technique. It may damage the lower unit or stall the engine(s) if performed incorrectly. If engines are stalled place throttles into the neutral position and restart the engine(s). It is important to

NOTE

remember that some platforms may require the operator to return the key switch(s) to the off position before allowing the engines to restart.

As noted above, with light-displacement, high-powered craft, maximum helm at high speed will quickly stop a boat’s progress in the original direction of movement. To fully stop, the throttle should be placed down to neutral after entering the skid. If done properly, no astern propulsion is required. With a jet drive, no directional control will be available without thrust. The boat must be in a skid

NOTE

before reducing power. If thrust is reduced before trying to turn, the boat will slow on the original heading. Do not back in a way that allows water to ship over the transom. Be careful with boats of very low

CAUTION !

freeboard aft. Outboard powered vessels, with low cut-out for motor mounting and a large portion of weight aft are susceptible to shipping water while backing, particularly in a chop. If shipped water does not immediately drain, it jeopardizes stability. Most inboard engines exhaust through the transom. Outboard motors exhaust astern. Backing could

CAUTION !

subject the crew and cabin spaces to a large amount of exhaust fumes. Limit exposure to exhaust fumes. If training, frequently change vessel aspect to the wind to clear fumes. After backing, ventilate interior spaces.

Control while making sternway is essential. Because vessels are designed to go forward, many vessels do not easily back in a straight line. Due to higher freeboard and superstructure forward (increased sail area), many vessels back into the wind. Knowledge of how environmental forces affect a boat is critical when backing. Besides watching where the stern goes, the coxswain should keep track of the bow. The stern will move one direction and the bow the other direction around the pivot point. As a vessel develops sternway, the apparent pivot point moves aft and the bow may swing through a greater distance. Firm control of the helm should be maintained to prevent the rudder or drive from swinging to a hard-over angle.

While backing, the rudders have less water flowing over them, due to the propeller being directly forward of the rudders, therefore there is less directional control of the boat. Because steering control comes from water flow across the rudder, the more sternway the vessel has, the greater water flow across the rudder leads to more control.

Propeller side force presents a major obstacle to backing in the direction desired. The rudder does not have much effect until sternway occurs, and even then, many boats will back into the wind despite a best effort to do otherwise. If backing to the wind, the coxswain should know at what wind speed the boat will back into the wind without backing to port. (01) Before starting to back, apply right full rudder to get any advantage available. (02) A quick burst of power astern will cause the stern to swing to port, but use it to get the boat moving. (03) Once moving, reduce power somewhat to reduce propeller side force and steer with the rudder. As sternway increases, less rudder will be needed to maintain a straight track astern. (04) If more sternway is needed to improve steerage, increase power gradually. A strong burst astern will quickly swing the stern to port. (05) If stern swing to port cannot be controlled by the rudder alone, use a burst of power ahead for propeller side force to swing the stern to starboard. Do not apply so much power as to stop sternway or to set up a propeller discharge current that would cause the stern to swing farther to port. (As the vessel backs, it uses sternway water flow across the rudder to steer). (06) If this fails, use a larger burst of power ahead, with helm to port. Sternway will probably stop, but propeller side force and discharge current across the shifted rudder will move the stern to starboard. Now try backing, again.

Both engines should be backed evenly to offset propeller side force. Using asymmetric power (one engine at higher RPM than the other) will help steer the stern. Asymmetric power will also give unequal propeller side force that will help steer. (01) Apply astern power evenly, keeping rudders amidships. (02) If the stern tends to one side, first try to control direction with slight helm adjustment. If not effective, either increase backing power on the side toward the direction of veer or decrease power on the opposite side.

The coxswain shall use the directed thrust to pull the stern to one side or the other. As the power is applied aft of the transom he/she should, use care to keep the bow from falling off course due to winds, avoiding cavitation that can easily occur when backing with a lower unit. Propeller side force is present, but is offset through helm. A lower unit that is not providing thrust is not efficient when trying to steer while backing. It is better to keep steady, slow RPMs than to vary between high power and neutral.

For single-outboard/outdrive, propeller side force is offset by turning the helm slightly to the right. Astern power is then applied gradually, but care should be taken not to cause propeller cavitation.

If astern power is matched, propeller side forces will cancel. As with twin inboards, offsetting any stern swing with helm should be attempted before using asymmetric power. If less thrust than that provided by both drives at clutch speed is needed, one motor or engine should be used. This will keep speed low but will keep thrust available for steering, rather than shifting one or both engines from reverse to neutral. If using one unit, compensate with helm for propeller side force and the increased, off-centered drag caused by the other lower unit.

Waterjets draw water in through an inlet grate in the hull, accelerated by means of an impeller, and thrust it out the transom in a small, high-velocity stream through a steerable nozzle. This nozzle is fitted with a reversing bucket, the deflector that drops down and deflects water forward to stop or reverse the boat. There is no propeller side force and thrust is directed as with an outboard. Going from forward to reverse thrust has no marine gear or drive train to slow things. Thrust is simply redirected with the “bucket.” Unless thrust is applied and being directed, there is no directional control at all. The power must be on and applied to steer either forward or in reverse. Bursts of power astern when backing should be avoided. Bursts of power when making astern thrust will excessively aerate the waterjet intake flow ahead of the transom.

Asymmetric propulsion while backing was covered in previous paragraphs. The techniques presented here are additional methods of maneuvering that capitalize on twin-engine vessel capability to differ the amount or direction of thrust produced by the two engines. Any difference in thrust affects the boat’s heading. The amount of this difference can vary from that needed to hold a course at cruising speed to turning a boat 360° in its own length by opposing propulsion (splitting throttles). The concept of asymmetric or opposed propulsion can be likened to “twisting” the boat, but the forces and fundamentals discussed earlier still apply and affect vessel response. Pivot point, propeller side force, and turning characteristics remain important. Because the drives are offset from vessel centerline on a twin-engine vessel, they apply a turning moment to the hull. Twin outboard motors on a bracket apply this twist aft of the hull (and well aft of the hull pivot point), while twin inboards apply most of this twist to the hull at the first thrust-bearing member of the drive train (usually the reduction gear or v-drive, much closer to the pivot point). With inboards, propeller side force is transferred through a strut and stern tube to the hull. Up to a point, the greater the difference in RPMs, the greater the effect on the change in heading. Above that point, specific for each boat, type of propulsion, sea conditions and operating speed, cavitation or aeration will occur, and propulsion efficiency will decrease, at least on one drive.

NOTE

As with all boat handling techniques, learn these first in calm weather, in open water, and at low speeds.

Depending on a vessel’s topside profile, wind conditions might make the bow continually fall off to leeward. Though the helmsman can compensate for this by steering with constant pressure to hold desired course, a less taxing way is to adjust the throttles so the leeward engine turns at more RPMs than the windward engine. The difference in RPMs can be fine-tuned until pressure is off the helm.

The following techniques cause a faster change in heading by increasing both skid and kick, reducing advance and transfer, and if the heading change is held long enough, the overall tactical diameter.

Rotating about the pivot point is a low-speed maneuver. It is important because situations will occur when the boat’s heading needs to be changed (to the weather or another vessel) or the bow or stern moved in a limited area. The engines should be opposed to turn in an extremely tight space. This maneuver is first performed at clutch speed in calm conditions to learn how the vessel reacts and what type of arcs the bow and stern describe. With no way on, there is no initial advance and transfer, so depending on the boat; this maneuver might yield a tactical diameter of zero if the heading is changed 360° (rotating the vessel in its own length). The forces involved should be considered. Vessels with propellers will develop side force from both drives during this maneuver. The rudder, where equipped, can use propeller discharge current from the ahead engine to help pivot the stern. Because boats operate more efficiently ahead, some headway may develop.

With helm amidships, perform the following procedures:

Put the helm or tiller over hard-to-port by performing the following procedures:

All crewmembers must pay close attention to throttle changes and vessel movements. Firmly hold

CAUTION !

onto the vessel during these maneuvers.

With the basic skill in hand, practice controlling the amount of swing by performing the following procedures:

Experiment with the vessel.

Though turning should help increase the rate of swing, the increase in turn rate might not be worth the workload increase (stop-to-stop helm/tiller use). Due to swing rate, full helm/tiller use NOTE may not be as effective as leaving the helm centered. At some level of power for each vessel and drive train arrangement, cavitation will occur with split throttles. Know at what throttle settings cavitation occurs. More power will not increase turning ability and might cause temporary loss of maneuverability until cavitation subsides. In critical situations, loss of effective power could leave a vessel vulnerable.

An emergency maneuver at cruising speed may require a turn with reduced tactical diameter.

An effective technique for a twin-propeller boat is to have one propeller act as a brake. This creates drag on the side with that propeller and reduces the turning diameter.

Do not put throttle to neutral position. In neutral, the propeller will “free-wheel” and rotate without

NOTE

any resistance. Keeping the engine in clutch ahead will keep the propeller from spinning freely and start “braking” the vessel on the inboard side.

This practice is also more effective with shaft, propeller, and rudder arrangement than with directed thrust drives. One propeller will still be providing forward thrust while the other will be backing. As with opposing thrust in low speed maneuvering, propeller side force is multiplied. Cavitation will be pronounced on the backing propeller, but the vessel’s forward motion keeps advancing this propeller into relatively undisturbed (or non-aerated) water.

WARNING

As with the crash stop, this maneuver is extremely hard on the engine and drive train. The backing engine’s power must be higher than that available at clutch speed to prevent engine stall.

Basic maneuvering techniques should be applied in combination with a single propeller at low speed to further boat handling skills. Practice these maneuvers in calm, no-current situations before learning to overcome environmental forces. A single-screw vessel never has the ability to use asymmetric or opposed propulsion, and its coxswain must develop boat handling skills with this in mind. The operator of a twin-engine vessel could easily become limited to use of one drive due to engine failure or fouling a propeller, and must also become a proficient, single-screw boat handler. For the discussion here, the case of a single-engine propeller vessel with right- hand turning propeller is used. When maneuvering a twin-engine vessel on one drive, the coxswain must account for the propeller rotation and side force for the particular drive used (normally starboard: right-hand turning, port: left- hand turning), and the offset of the drive from centerline.

The back and fill technique, also known as casting, provides a method to turn any vessel in little more than its own length. At some point, anyone who operates a single-screw vessel will need to rely on these concepts when they operate a boat, particularly in close-quarters maneuvering. To back and fill, the coxswain should rely on the tendency of a vessel to back to port, and then use the rudder to direct thrust when powering ahead to starboard. The coxswain should also decide the radius of the circle in which to keep the vessel (at most, 25 to 35 percent larger than the vessel’s overall length), and the intended change in direction (usually no more than 180°) before starting. For initial training, the vessel should be turned through at least 360°. From dead-in-the-water position, perform the following procedures to back and fill:

(01) A firm grasp of the vessel’s maneuvering characteristics is necessary to know whether to back and fill rather than just maneuver at full rudder. (02) The amount of steps used will depend on size of the turning area and the desired change in heading. The smaller the area, the more backing and filling required. (03) Winds will play a factor in casting. If the vessel’s bow is easily blown off course, the vessel

NOTE

probably has a tendency to back into the wind. Set up the maneuver (including direction of turn) to take advantage of this in getting the bow to change direction. Strong winds will offset both propeller side force and any rudder effect. (04) A quick helm hand is a prerequisite for casting with an outboard or stern drive. To get full advantage of the lower unit’s directed thrust, fully shift the helm before applying propulsion. (05) With helm at left full, the propeller side force when backing will have an element that tries to move the stern “forward” around the pivot point.

When operating a duel waterjet platform both waterjets work in tandem unless placed in docking mode. The pictures below show only one waterjets. The reader should be conscious that the second waterjet is performing the same functions simultaneously of the waterjet pictured.

Zero Thrust

Coxswains must learn to manage the effects of environmental forces by using power and helm to maintain their position next to an object. Station keeping is defined as maintaining distance, position and aspect to or from an object. With twin propulsion, coxswains need to develop the skills required to maintain any aspect to an object during most conditions. Though many single- drive boats are thought to be less maneuverable, coxswains should fully develop single-drive station keeping skills should the need arise. Station keeping should be practiced during various levels of wind, seas, and current.

NOTE

All coxswains of twin-drive vessels must frequently train for single-drive operation. This includes station keeping.

Each situation requires a safe maneuvering zone to reach an optimum position near the object so an evolution can safely occur and can be done effectively (e.g., equipment transfer, object recovery, surveillance, etc.). Staying in the maneuvering zone keeps you out of the danger zone and gives you a way out if you encounter problems while station keeping. Before station keeping perform the following procedures to determine a safe and effective maneuvering zone: When station keeping, always have a safe escape route to get clear of the object or any hazard. While

CAUTION !

station keeping, ensure the escape route stays clear. This may require changing position to establish a new escape route.

The coxswain should station keep close enough to complete a mission or evolution, yet far enough to prevent collision or allision. Minimum safe distance to the object will probably vary around the object or along its length. Environmental conditions and boat maneuverability play a major role in determining distance. The coxswain should perform the following procedures:

Station keeping will usually require frequent to near-continuous applications of power and helm to stay in the safe maneuvering zone. While station keeping and trying to stay within the maneuvering zone limits, adjusting for one of the parameters (distance, position, aspect) will almost always involve a change to one or both of the other two. While using power and helm to compensate for and to overcome wind and current, the wind and current should be used to the fullest extent.

To stem the forces means to keep the current or wind directly on the bow or stern and hold position by setting boat speed to equally oppose the speed of drift.

To crab the boat sideways, environmental forces should be used to move the boat at a right angle to the forces. The coxswain should put the bow at a shallow angle (20° to 30°) to the prevailing force and use propulsion and helm to keep from getting set backward, while staying at the shallow angle to the prevailing environmental force.

Make a vessel “open” and “close” the distance on the object at various angles, both to leeward and to weather. With an object on the bow or stern, directly up-drift or down-drift from you, opening and closing requires only to compensate for the fore and aft drift rate and to maintain a steady heading. A combination of control and environmental forces should be used: (01) Side force, (02) Ahead and astern thrust, (03) Rudder force, (04) Leeway, (05) Current, (06) Drift. The more difficult scenario is opening or closing distance abeam.

Differences in objects determine the maneuvering situation. Coxswains should become fully capable of station keeping in a variety of situations with both different types of objects and environmental conditions.

Object type and size ranges from small items floating in the water to other vessels. No two items will drift at the same speed through the water. Free- drifting objects will present a different drift rate from the vessel. The coxswain should develop station keeping techniques by first comparing your drift rate to the object, and then overcoming the difference. The following are procedures for station keeping on a free-drifting object:

Station keeping on an anchored object limits much of the object’s movement due to wind and current, but the object will often surge and swing. A vessel will react freely to the wind and current. The object will ride with its moored end into the strongest environmental force affecting it, while the combination of forces on a vessel may cause it to take a different aspect. Station keeping on an anchored object helps determine where to and where not to maneuver. The following are procedures for station keeping on an anchored object:

When determining approach, the following conditions should be considered: (01) Prevailing weather, (02) Currents, (03) Location, (04) Vessel conditions, (05) Vessel sizes, (06) Traffic density. The coxswain should discuss intentions with the other vessel’s master.

CAUTION !

Do not approach from leeward if it will put the vessel and crew in jeopardy, whether from shoal water or obstructions farther to leeward, or from smoke or hazardous fumes. If going alongside a disabled vessel or one that is underway but dead-in-the water, compare relative drift rates. When approaching a larger vessel with a low drift rate, approach from leeward. If

NOTE

approaching a smaller vessel, determine if vessel makes a wind shadow that will slow the other vessel’s drift. In this case, an approach from windward may be better, and the smaller vessel will then be protected from winds and waves by the larger vessel. See Reference (b) for more information.

If possible and prudent, the vessel should maintain a course and speed to make the approach as smooth as possible for both vessels.

Most large vessels will not be able to alter course significantly in a limited area to provide ideal alongside conditions. If it is not practical for the large vessel to change course, the coxswain should request that it reduce speed so the effects of bow and stern waves are reduced.

Small vessels do not ride well when not making way in any kind of winds or seas. Unless the weather is perfectly calm or the vessel is disabled, a small vessel should maintain a course and speed that makes for safe, comfortable navigation while allowing mission completion. Speed should be slow enough to safely come alongside, but fast enough for both vessels to maintain steerageway when alongside one another.

Many sailing vessels are much more stable while under sail than when powering or drifting. The coxswain should consider coming alongside while the other vessel is under sail, but should ensure that spars, standing or running rigging, or control lines do not foul either vessel. The situation should be discussed with the other vessel’s master.

CAUTION !

Make sure the other vessel does not change course while approaching or coming alongside. If this happens, break off and start the approach over again once the other vessel is on a steady course. Inform the master to maintain course and speed until the transfer is complete.

A large vessel will create a wind shadow and block most of the seas allowing a smoother approach on the leeward side of a vessel. Coxswains should take advantage of this as in mooring to the leeward side of a pier. When approaching smaller vessels, the coxswain should first determine the smaller vessel’s rate of drift. The coxswain can then determine if an approach on the leeward side (better control over approach) or windward side (a wind shadow will be created) would be better. If an approach from leeward is not possible (due to sea room or other condition like smoke or

NOTE

hazardous vapors), use caution during a windward approach to prevent being pinned up against the side of another vessel. If approaching on the windward side is a must, a bow-in approach might provide the most maneuverability.

Lines and fenders should be rigged as needed. Remember that with fenders, too many is much better than too few.

After completing approach preparations, the coxswain should go alongside and determine where to make contact on both vessels. Perform the following procedures to close in on another vessel:

WARNING

If initial heading was parallel to the other vessel, increase speed slightly when starting to close at an angle.

NOTE

Pick a contact point well clear of a larger vessel’s propeller (including in the area of suction screw current), rudder, and quarter wave. Forces from these could cause loss of control.

In some instances, a sea painter may be used in coming alongside a larger vessel underway. The sea painter is a line used to sheer a boat clear of a ship’s side when underway or to hold a boat in position under shipboard hoisting davits and occasionally to hold the boat alongside a ship in order to embark or disembark personnel. It leads from the larger vessel’s deck well forward of where the boat will come alongside. Perform the following procedures when securing a sea painter to the boat:

As both the boat and ship have headway, the pressure of water on the boat’s bow will cause it to sheer away from the ship. The coxswain should use this force by a touch of the helm to control sheer, in or out or, by catching the current on one side of the bow or the other. Riding a sea painter helps maintain position and control of the boat.

NOTE

When sheering in or out, apply rudder slowly and be prepared to counteract the tendency of the boat to close or open quickly. Perform the following procedures if using a sea painter:

If approaching a vessel anchored in a strong current, the sea painter can be used to provide a means to

NOTE

lie alongside. Procedures are the same as if the vessel is making way. Approach from leeward, against the current.

Perform the following procedures to make and hold contact with a vessel:

When alongside and conducting the intended missions, the coxswain should:

Getting set toward the side or stern of the vessel should be avoided. Perform the following procedures to clear the side of a vessel:

CAUTION !

Never back down when clearing alongside. Always pull away parallel to the other vessel that is making way. If on a sea painter, use enough speed to get slack in the line, then cast off once clear. Ensure the sea painter is hauled back aboard the larger vessel immediately to prevent it from catching in the screws.

NOTE

If operating a twin-screw boat, go ahead slowly on the inboard engine. This also helps to keep the boat clear of the ship’s side.

In heavy weather, the motion of the boat rolling, pitching, and yawing affect handling of the boat. If these motions become excessive or combine, they may become uncomfortable or even dangerous. High winds affect boat handling and may amplify control problems.

Rolling occurs when the boat is running beam to the seas. If the course requires running or turning broadside to heavy seas, the boat will roll heavily, possibly dangerously. In these conditions, it may be best to run in a series of tacks like a sailboat, changing course to take the wind and seas at a 45° angle. Sea breaks can exert considerable pressure on the side of the boat, which is resisted by the water on the lee side. This can produce a turning moment which if greater than the initial righting moment will result in a knockdown or rollover. To turn sharply while exposing the boat to a beam sea for the least amount of time, the coxswain should slow down for a few seconds, then turn the helm hard over and apply power. This can be done effectively with a twin-screw boat by using the split-throttle maneuver or in the case of jet drive boat, turn the tiller hard over and drop the bucket until the boat is square with the wave.

Pitching occurs when the boat is running bow into the waves. The bow of the boat rises over the wave and then drops rapidly into the trough. If the seas become too steep, speed should be decreased. This will allow the bow to rise, meeting the swell, instead of being driven hard into it. Changing course may be the better option to reduce stress on the crew and boat. Again, 45° off the swell may give better control and a better ride. If conditions become too hazardous, slow until the boat is making bare steerageway and meets the seas on the bow. Again, power should be used to negotiate the wave without sending the boat launching off the back of the seas.

Yawing occurs when the boat is operating in following seas. The boat sheers off to port or starboard due to the action of the waves. The boat surfs down the face of the wave, slowing as the bow digs into the trough. The rudder loses control and the sea takes charge of the stern. At this stage, the boat may yaw so badly as to broach (to be thrown broadside out of control) into the trough. Once the wave clears the stern, it lifts the bow of the boat and the stern begins to slide down the backside of the wave, allowing better rudder control causing the boat to straighten out. Jet drive boats have no rudders and little protruding below the hull. This allows for excellent sea-keeping ability when running stern to the seas. As with propellers, adjust speed to maintain position on the back of the wave. Severe yawing may result in a knockdown, pitch pole, or rollover. Extreme care must be taken when operating in a large following sea, constantly watching behind the boat. Slowing speed or changing course may reduce yawing.

High winds can amplify conditions discussed in the previous sections. It can make routine operations such as towing approaches extremely difficult. Overcoming the affect of wind requires practice and experience on the boat.

Awareness of the position of your throttles at all times is of paramount importance when operating in heavy weather. All throttle inputs should be timely and deliberate. Every effort to familiarize yourself with the operation of the throttles should be made. A lack of throttle awareness will prove to be a severe hindrance when attempting complex maneuvers, especially in a heavy weather environment.

Coxswains/operators should always keep one hand constantly on the throttle control(s) to manage their engine propulsion.

Use the following procedures when managing the power of heavier vessels:

Use the following procedures when managing the power of lighter vessels:

“Flying through” the crest should be avoided at all costs. If a large vessel becomes airborne at the top of a wave, the crew is threatened with serious injury and could damage the vessel when it lands. With lighter craft, ensure the after sections stay in contact with the water, but do not let the bow sections get too high. If the bow sections get too high while going through a crest, the apparent wind or the break can carry the bow over backward. On the other hand, if forward way is lost with the stern at the crest, the bow might fall downward, requiring to redeveloping speed and bow-up attitude before the next wave approaches.

Station keeping is maintaining a given position in heavy weather. Station keeping is necessary to hold position while waiting for a window or lull, or holding position prior to and during recovery of a PIW. Environmental factors such as the seas, wind or currents can make station keeping difficult. Therefore, good backing skills and proper application of power are essential. The following are guidelines for station keeping: (01) Use only enough power to maintain position and counteract the force of the oncoming wave. On smaller waves, keeping the bow square with neutral throttles may be all that is needed, while larger waves may require a great deal of power to counteract, (02) If needed while operating the Response Boat – Medium (RB-M), increase the idle by adjusting the knob. This can increase maneuverability and sea keeping power on demand, (03) Using too much power will set the boat out of position and/or launch the boat. Too little power will cause the boat to be set backwards, or broach the boat, (04) Keep the bow as square to the seas as possible, (05) If the boat is being set towards the seas by current or wind, it may be necessary to back down frequently to hold position, only applying forward power to meet oncoming waves. Wait until a wave crest passes and back down once on the backside. Do not back down on the face of a wave, (06) By adjusting power, it may be possible to safely allow a wave to set the boat back to regain position. This technique requires practice, and the operator must maintain control of the maneuver at all times, (07) It is possible to move laterally while station keeping by allowing the bow to fall slightly to the desired side and then using the throttles and helm to straighten out as the wave pushes the bow. For example, to crab sideways to port, allow the bow to fall slightly to port and as the wave pushes the bow, apply power and steer to starboard, finishing the maneuver with the bow once again square to the seas. This maneuver must not be attempted on large waves, and it is important not to allow the bow to falloff so far that the safety and control of the boat are compromised. Using docking mode in open waters is not recommended. It was designed for close-quarters situations

NOTE

near a dock or berth. Use standard open and close techniques to maintain position in heavy weather. An increase in idle also increases the amount of suction drawn into the waterjets. Crews must be aware

NOTE

of all lines and gear being passed to a disabled vessel to ensure it does not get sucked into the waterjet intakes.

Making fast and effective turns requires knowledge of the boat’s capabilities and skill in handling. A full power, full rudder, 180-degree turn takes over 20 seconds to complete. For this reason, splitting the throttles and pivoting may be your preferred method in certain conditions.

The

technique for performing this split throttle turn is outlined below:

NOTE

In certain situations (i.e. turning 180° but not wanting to stop the boat) this maneuver may be executed without the backing throttle. The steps described in the “split throttle” turn are designed to achieve a faster turning speed while

CAUTION!

reducing the wear and tear on the entire propulsion system. This maneuver should be used only in the most extreme of circumstances.

CAUTION!

Initiating a Heavy Weather (Split Throttle) turn on the face of a steep wave can result in a knockdown/ rollover and should be avoided.

Due to the maneuverability and speed of Heavy weather / Surf platforms it is capable of avoiding waves when running outbound.

Wave avoidance is

preferable no matter what situation you are in. However, if you do not make prudent decisions while driving, such as maneuvering to shoulders and low sides of waves, the lifeboat may be unintentionally launched out of the water. This can cause severe injury to your crew, damage to certain vessel systems and may potentially disable the vessel when the sortie has just begun.

Heavy weather / Surf platforms ride well at full speed in open head seas up to 6'. Head seas over 6' may require that the speed be reduced, as necessary, to soften the ride. Increased sea states may dictate further speed reductions for the benefit of crew safety. Relatively smaller, but steeper seas (steep chop) may require that the speed be reduced in lesser sea states. Large open ocean ground swells typically pose no problem, however, and speeds can be increased and adjusted to accommodate crew comfort. The coxswain must find a safe and comfortable speed, avoid launching the boat and avoid burying the bow in a wave.

Taking larger head seas slightly off of either bow can create a more comfortable ride, as the boat may proceed more gently off the back of the wave instead of slamming violently. The speed and angle of approach will have to be adjusted as needed for the optimum ride. This is sometimes referred to as quartering the seas, which is not to be confused with taking a following sea on the quarter.

An effective method of transiting through head seas while staying in the power-band of the engines and preserving built up momentum is often referred to as the “Turn and Drag” method. This method prevents launching while simultaneously avoiding the high-side of the wave. The procedures of the turn and drag is below:

Whenever possible, you should avoid steering a course parallel (broadside) to heavy swells. Tack across the swells at an angle (30 to 40 degrees). If necessary, steer a zigzag course, making each leg as long as possible, and adjust the boat speed for a safe and comfortable ride. Seas directly off the beam of the boat can cause adverse rolling conditions. When transiting parallel to the seas, the boat will tend to ride the contour of the wave surface. This means that the boat’s vertical axis will remain perpendicular to the surface on which the boat is operated. A wave face of 20 degrees will cause a 20-degree heel.

If you must take up a course which places the boat beam-to the seas, it is vital to remain vigilant against the incoming waves. If at any point you see a swell which can possibly steepen up or even break, you should not hesitate to square up. Putting the bow of the boat into threatening seas is the best way to ensure total control of your vessel and should never be viewed as the “wrong” course of action.

Following open seas can be negotiated at full speed as long as the boat remains stable as it travels down the front of the swell. However, large following seas may require a reduction in speed to maintain stability and avoid injury to the crew.

While running inbound in waves over ten feet, position the boat on the back of a wave and adjust the speed so the boat will ride in on the back of the wave. You must also watch astern to remain aware of if and when you’ll be overtaken by another wave. While riding on the back of a wave in heavy weather, monitor the boat’s speed closely to avoid overtaking the wave as its speed toward shore decreases. On the 47 MLB utilizing a slow turn back and forth (S-Turning) or quickly “Sallying” your rudder full right and full left may help you avoid this occurrence. In some situations (aerated water, face of a wave)

NOTE

reducing the engine RPM is not advised as a means to slow the boat as the propellers can provide needed “screw-suction” in a precarious situation.

While operating the 47FT MLB stern to the seas >6’ and RPMs >1800, the boat is prone to being caught on the hard chine. Being caught on the hard chine is best described as the boat suddenly heeling over 50-80 degrees on a false keel. In short, this condition is caused by the speed of the MLB and its relative angle to the swell.

The coxswain’s corrective action shall be to immediately reduce power to return the boat onto the true keel Due to the uncertain effectiveness of the previous method, many operators have grown to rely upon the following techniques as a means of correcting Hard Chine Lockup: (01) Quickly reducing (200-300 revs) and increasing the engine R.P.M.’s on the throttle away from the heel of the boat, also known as the “high side” throttle. Care must be exercised to ensure this reduction in shaft RPM is not so extreme or prolonged that it affects the screw suction of the high side propeller,

NOTE

(02) Turning the helm fully in the direction of the heel and then immediately back to amidships (center). This violent and athletic maneuver has the effect of rocking the MLB off of its false keel while simultaneously helping the boat take up a more square, down-swell heading (removing the angle from the speed and angle equation). This “turn-in, turn-out” method should be vigorously employed until the lockup is corrected.

When transiting harbor entrances, inlets, or river entrances in rough weather, there will be times when the vessel must either leave or enter port in challenging conditions. Though certain locations have extreme conditions much more often than others, learning how rough weather affects the various harbors and entrances throughout the local area is essential. Methods covered above for maneuvering in head, following, and beam seas still apply, but the entrance areas add additional consideration.

Though mentioned above, local knowledge is key. Knowing as much as possible before transiting an entrance in rough weather will help guard against potential problems. Utilize the following procedures and considerations to assess entrances areas:

Transiting when the current opposed the seas presents the most challenging situation near an entrance. In opposition to the seas, a current has the effect of shortening the wavelength, and increasing the wave height. This makes waves much more unstable and much closer together. Utilize the following procedures and considerations to transit when the current opposes the seas:

In a situation of transiting when current and seas coincide, a current has the effect of lengthening the waves. Longer waves are more stable, with the crests farther apart, but caution is still needed. Utilize the following procedures and considerations to transit when current and seas collide:

Though preceding discussions dealt with encountering severe wave action, high winds do not always accompany large swells. Also, there will be instances when extreme winds occur without sufficient duration to make large waves. Much of the time, though, high winds and building seas will coincide.

Depending on the vessel’s sail area, it may be necessary to steadily apply helm or asymmetric propulsion to hold a course in high winds. Coxswains should learn to “read” the water for stronger gusts. The amount of chop on the surface will increase in gusts, and extremely powerful gusts may even blow the tops off waves. The effect of a gust should be anticipated before it hits the vessel. Utilize the following procedures and considerations when crabbing through steady winds:

A knockdown or rollover is never routine, but always possible. These unpleasant events must be considered and planned for. Training and experience will give a crewmember the edge, but it can still happen simply because of the severe environment he or she is operating in. The following risk management practices should be followed: (01) All crewmembers must be properly outfitted in PPE, (02) All crewmembers should be familiar with the causes of a knockdown, rollover or pitch poling, as well as how to recognize an impending event, and what to expect, (03) All crewmembers should be well-trained in the procedures to be followed for a knockdown, rollover and involuntary beaching. Crewmembers must be familiar with the procedures for emergency anchoring and drogue deployment as well as the location of necessary equipment. Always brief the crew prior to entering a surf zone, (04) Crewmembers should be prepared to take control of the boat should the operator be injured, incapacitated or lost overboard. The crewmember should also have the skills to maneuver the vessel to recover the man overboard, (05) A backup surf capable resource or aircraft should be standing by whenever possible, positioned where it can observe the boat working in the surf, (06) Backup communications (handheld VHF) should be aboard the boat in case the antennas are lost, or the main radio is damaged. The risks versus the potential benefits should always be assessed. A sense of urgency must not cloud judgment or cause the loss of situational awareness.

The following procedures apply in a knockdown/rollover:

Do not unfasten safety belt or consider swimming to the surface. It is likely the propellers will still be WARNING turning, and the boat is designed to right itself in a few seconds. When the boat rights itself it may strike you in the process.

After damage and injuries have been assessed, the coxswain must determine whether to continue with the mission or return to the unit. The following factors should be considered: (01) Condition of crewmembers, (02) Overall material and operating condition of engines and boat structure, (03) Condition of electronics, particularly communications, (04) Urgency of mission, and availability of backup resources, (05) Likelihood of another rollover if continuing on mission and how it will impact crew, boat and mission outcome. Remember that after a rollover has occurred, there remains the possibility of another rollover, since it is likely that similar conditions still exist. Upon returning to the Station, post-knockdown/rollover procedures must be taken in accordance with the specific Boat Operator’s Handbook.

Prior to entering the surf, a complete round must be made of the boat as follows:

A Coast Guard Surfman is a highly trained, highly skilled boat handler who understands surf behavior and characteristics. Since surf is not characterized by height, but rather by several waves or swells of the sea breaking on the shore, shoal, reef, bar, or inlet. The Coast Guard requires a qualified surfman, in a surf capable boat, to operate in a surf zone when the surf exceeds 8 feet, when the CO/OIC deems it’s necessary, or if there is doubt from the coxswain as to the present conditions.

Breaking waves cause aerated water in the surf zone. As the wave breaks, it combines with air, creating whitewater on the face of the breaker. As the breaker moves through the surf zone it leaves a trail of pale or white aerated water behind it which takes some time to dissipate. This air-water mix can create changes in a boat’s handling, which must be taken into account while maneuvering.

A boat’s propeller(s) will not create as much thrust when operating in heavily aerated water. The boat’s response may be greatly slowed. This effect can be recognized by: (01) Poor acceleration and/or apparently slow throttle response, (02) Cavitation and/or excessive engine RPM for a given throttle, (03) Poor turning performance, particularly on a twin propeller boat.

A boat’s rudder(s) will not direct the propeller force as effectively in aerated water, nor will it have as much steering affect while moving through aerated water. This affect can be recognized by: (01) Poor turning response, (02) Reduced steering effort, or “light rudders”.

Waterjet drives will have a reduction in thrust when operating in aerated water. This is caused by the aerated water being drawn into the intakes and being discharged at high speed through the jet nozzle. While not quite as pronounced, think of the way a garden hose that has been sitting in the sun and how it sputters when you first turn it. The normal stream that is used to maneuver the boat is not as effective because of the aerated water . This will cause: (01) Decreased acceleration, (02) Increased engine RPMs, (03) Poor turning performance.

Operation in very shallow water can be complicated by a serious effect on a boat’s maneuverability. This effect, caused by resistance to the bow wave as it contacts the bottom, and drag due to the closeness of the bottom to the boat’s hull, propellers, and rudders, can be recognized by: (01) Reduced speed over ground, (02) Reduced engine RPM for a given throttle position, (03) Sluggish response to throttle and steering inputs, leading to poor acceleration and poor turning ability, (04) Larger wake than normal, (05) Jet intakes may be fouled by sand or other debris limiting maneuverability, (06) Change in trim caused by the bow riding up on its pressure wave, and stern squat caused by propeller suction. This change in trim can lead to grounding of the stern if the water is shallow enough. The effects of operating in aerated or shallow water are similar to the symptoms of serious engine,

NOTE

reduction gear, or steering problems. Any indication of systems trouble must be investigated as soon as possible once safely clear of the surf zone.

Changes in center of gravity or trim can lead to dramatic affects on the stability and handling of a boat in the surf. These changes are caused by either external or internal forces, and can vary widely depending on condition, type of boat, and other factors.

The primary external force for surf operations is the surf itself. A boat’s position, speed and heading relative to a wave will dictate the effects on stability and handling. These effects are numerous and will not be covered entirely, but a description of the most significant effects is provided.

As an approaching wave reaches the stern, the stern will rise and the center of gravity and the pivot point are shifted forward. As this process develops, the trim of the boat changes and may reach a point where the waterjets/propellers and rudders are no longer deep enough to be effective. This can cause a severe reduction in maneuverability or complete loss of control as the stern picks up and falls to either side in a broach. This effect is most common on very steep swells or breakers. It can be greatly amplified if the operator reduces power, which causes an even greater shift in the center of gravity.

As the approaching wave reaches the boat, it will cause it to heel over and shift the center of gravity to the low side of the boat. This may lead to a reduction in effectiveness of the waterjet/propeller and rudder on the high side, which will cause reduced maneuverability.

As the approaching wave picks up the bow, the center of gravity and pivot point will shift aft. If the boat does not have enough way on, and the bow is not sufficiently square to the wave, it may cause the bow to fall to one side or the other as the force of the wave pushes it around the new pivot point.

There are numerous internal forces that affect the stability and handling of a boat, many of which are permanent aspects of the boat’s design. It is the responsibility of the operator to be familiar with the characteristics of the specific boat in question. The following is a description of those factors that are subject to change, or are under the direct control of the operator.

Loose equipment can be tossed to one side and affect the boat’s stability by placing weight off center. Loose equipment may also result in loss of watertight integrity by breaking windows or damaging watertight fittings.

Generally, a rapid reduction in power will result in a forward shift of the center of gravity, while an increase in power will have the opposite effect. Large steering inputs will cause a boat to heel over, shifting the center of gravity to the low side.

A pitch pole is when a boat is inverted end-over-end. This can occur when a boat is traveling stern-to a very steep breaker or large wave. As the stern is picked up, the boat begins to surf down the face of the wave. This will cause the center of gravity to shift forward. If the stern rises high enough, the bow will begin to dig deeply into the trough of the wave, and the resistance created will cause the boat to trip over itself, tumbling end-over-end. A reverse pitch pole is also possible if a boat is surfed backwards while bow-to a large breaker. Pitch poles are rare, but are possible, particularly for a relatively boat. More often, an impending pitch pole will turn into a broach and knockdown/rollover. The operator must avoid those situations that could lead to a pitch pole since they are violently destructive to the boat and its crew. Broaching and a resulting knockdown/rollover are preferable to pitch poling.

The following description of techniques has been organized to follow the sequences of an actual operational situation, such as entering a beach surf zone to recover persons in the water, or crossing a bar or inlet.

General procedures for entering a beach zone or transiting inbound a bar or inlet with surf on stern are outlined as follows:

It is preferable to transit the surf during any lull period that may exist. The operator should wait until the last big wave in a series has passed and proceed in closely behind it, at maximum safe speed. This reduces the relative speed at which the waves overtake, gives the operator more time to react and gets you through the zone as quickly as possible. It may also provide the best maneuverability for some boats. The operator should attempt to work through the surf zone by driving through windows and wave saddles, thus avoiding the majority of the breakers. Some boats may be fast enough to avoid breakers by maintaining position on the backside of a swell while others will be overtaken by approaching waves. If operating in an area of limiting maneuverability, such as a narrow inlet or bar, the operator may have to rely strictly on timing the waves and make the transit during lull periods. To deal with an overtaking breaker or peaking swell, there are a number of techniques, which vary in success and safety based on conditions and type of boat. An operator must understand the effectiveness and safety of a technique for the specific boat, which is gained from training experience. These techniques are listed in descending order of preference and safety: (01) Maneuver left or right (lateral) to avoid the breaker completely, by using windows and saddles, (02) Come about in sufficient time to meet the breaker bow-on, (03) Reduce speed before a steep, peaking (not breaking) swell reaches the boat, allowing the swell to pass and break ahead, and then immediately increase speed to follow it in, (04) As a wave approaches, begin backing square into it. Gain sternway and climb the wave before it breaks. Never allow the boat to be caught under a breaker. If it is necessary to back through the whitewater of a breaker, gain sternway before the whitewater reaches the propellers and rudders. Move smoothly into the wave as it lifts the stem, using only enough power to maintain sternway. The momentum of the boat will break it through the wave. Once the stern breaks through, ease off the throttles and prepare to resume the course ahead, (05) If the boat is overtaken by the white water of a breaker, the last resort is to try to get off the wave by applying full throttle, and steering for the “low side” of the wave, hopefully coming out the backside. Do not attempt to ride it out by maintaining course. Something must be done. Never forget to drive the boat, (06) A final option may be to back into the surf zone or across the bar, keeping the bow into the seas. This will be very difficult and time consuming. Excellent backing skills are mandatory. Strong opposing currents in the area may make backing impractical. Also, great care must be taken in shallow water, as the propellers and rudders will hit first if the boat strikes bottom.

WARNING

Reducing speed after the wave has already picked up the boat will likely result in a loss of control and/or broach. Speed must be reduced before the wave arrives.

NOTE

If there is no discernible lull, it is prudent to remain at sea while waiting for bar conditions to improve (i.e., flood current).

General procedures for transiting with surf on a beam are outlined as follows.

WARNING

This maneuver is safe only in small conditions and must not be attempted if the operator has any doubts. Wave avoidance is still the preferred technique.

It is preferable to make a beam transit during a lull, when the seas may be smaller. Wait for the last big series of waves to pass and commence the run. In the absence of lulls, great care and patience must be exercised, because the boat is very vulnerable with the nearly constant beam surf. The operator should use maximum comfortable speed to minimize exposure to beam seas. Speed may be reduced to allow waves to pass ahead of the boat, or increased to avoid a breaker. Good timing, and ability to read several waves back are critical. Any significant waves, which cannot be avoided, must be taken bow-on. There are several techniques to deal with breaking seas on the beam. The suitability of a technique is dependent on the boat type and present conditions. The operator must have an understanding of the boat’s capabilities, as some maneuvers may not be safe or effective in all cases. The following techniques are listed in descending order of preference and safety: (01) When it is apparent that the boat is about to be overtaken by a breaker, retain or increase speed and turn to meet it square with the bow. Once square to the wave, the helm must then be returned to amidships and throttles decreased to avoid launching through the crest. Station keep if necessary, and prepare to return to original course. (02) If a breaker is approaching from ahead of the boat, decrease speed to allow it to pass ahead. Time the maneuver to reach the back shoulder of the wave just as it passes in front. This timing will allow quickly getting behind the wave and continuing the transit, and hopefully avoid the next wave altogether. The crew must be alert for other waves building off the beam. (03) If a wave is some distance off the beam, it may be possible to outrun it by increasing speed. If there is any chance of not beating the wave, turn to meet it or run away from it if space and time permit. (04) In some instances, there may be time and room available to find a window by running away from a breaker by placing it on the stern or quarter. This carries all the risks associated with running stern-to, and will also set the boat off the original track line or range, as well as being time consuming. It is not the most efficient means of transiting, but may be a valuable safety maneuver depending on the circumstances. When transiting very small surf relative to the size of the boat, it may be possible to maintain or slightly reduce speed and simply turn towards a small breaker at about a 45° angle, resuming course behind it after crossing the crest.

WARNING

Do not get surprised by a breaker on the beam while watching ahead, as there is a good chance of a knockdown/rollover if hit on the beam at slow speed.

Station keeping is maintaining a given position in the surf. Station keeping is necessary to hold position while waiting for a window or lull, or holding position prior to and during recovery of a PIW. Environmental factors such as the surf, wind or currents can make station keeping difficult. Therefore, good backing skills and proper application of power are essential. The following are guidelines for station keeping: (01) Use only enough power to maintain position and counteract the force of the oncoming wave. On smaller waves, keeping the bow square with neutral throttles may be all that is needed, while larger waves may require a great deal of power to counteract, (02) Using too much power will set the boat out of position and/or launch the boat. Too little power will cause the boat to be set backwards, or broach the boat, (03) Keep the bow as square to the seas as possible, (04) If the boat is being set towards the seas by current or wind, it may be necessary to back down frequently to hold position, only applying forward power to meet oncoming waves. Wait until a wave crest passes and back down once on the backside. Do not back down on the face of a wave, (05) By adjusting power, it may be possible to safely allow a wave to set the boat back to regain position. This technique requires practice, and the operator must maintain control of the maneuver at all times, (06) It is possible to move laterally while station keeping by allowing the bow to fall slightly to the desired side and then using the throttles and helm to straighten out as the wave pushes the bow. For example, to crab sideways to port, allow the bow to fall slightly to port and as the wave pushes the bow, apply power and steer to starboard, finishing the maneuver with the bow once again square to the seas. This maneuver must not be attempted on large waves, and it is important not to allow the bow to fall off so far that the safety and control of the boat are compromised.

An outbound transit of the surf may be necessary in crossing a bar/inlet or departing a surf zone. The operator should practice wave avoidance by picking a course through the windows and saddles, if available, minimizing risk to the boat and crew. The transit should be made at maximum comfortable speed adjusting to avoid launching over the waves or avoiding them entirely. The following guidelines apply to an outbound transit: (01) Choose a course through windows as much as possible, zigzagging as necessary to avoid breakers. Stay close to the shoulders of the waves to take advantage of any window that may open up behind the wave as it passes, (02) If a breaker cannot be avoided, try to go through the wave at the saddle, where it may not be breaking yet, or the force may be less. If both ends of the wave are breaking towards the saddle, the boat may be caught in a closeout. Get through the saddle before it closes, or slow down to let it closeout well in front of the boat. Any breakers that cannot be avoided should be taken bow-on. Slow down and allow momentum to carry the boat through. Do not meet breakers at high speed or the boat may plow into the face, or launch off the back, risking injuries or boat damage. Do not allow a wave to break over the bow while transiting outbound. If it appears that this may

WARNING

happen, either reach the top before it breaks, or slow down/stop letting it break in front of the boat and then regaining headway in time to meet the whitewater.

See Section G Knockdown and Rollover Causes.

If the boat is disabled

either by mechanical failure or after a

knockdown/rollover in or near the surf, it will be driven into the shore. If not already aware or on scene, a backup resource must be notified immediately. The best chance for survival is to remain with the boat but the decision on where to ride out the breakers, either in a survivors compartment or strapped in on deck, is one you should consider before being in this situation. Some factors to consider are: (01) Size and type of breaker – While on deck the boat may survive repeated rolls in 20ft breakers but a crewmember on deck may not, (02) Wave Period – do you have enough time to get into a survivors compartment, (03) Location of your boat with respect to grounding hazards such as wash rocks, jetties and other hard grounding areas that have potential to hole the boat increasing risk if in a survivor’s compartment. The chances of a knockdown/rollover or crew injuries can be reduced by taking the following actions:

WARNING

Do not expose crewmembers to the likelihood of serious injury or loss overboard by sending them to the bow in surf. It may be safer to sustain a roll while waiting for a lull. This is a judgment call.

Bank cushion occurs only when operating in close proximity to the bank and refers to a boat being pushed away from the nearest riverbank. As the boat moves ahead in the river, the water between the bow and the near riverbank builds up high on the side of the boat, causing the bow to move away from the bank. The bank cushion affect is especially prevalent if the draft of the boat is nearly equal to the depth of the water, or in narrow channels with steep banks.

Bank suction refers to the stern of a boat being pulled toward the bank. As the boat moves ahead while near the riverbank, the unbalanced pressure of water on the aft quarter lowers the water level between the boat and the bank, forcing the stern to move toward the bank. This suction effect occurs most notably with a twin-screw boat.

The combined effect of bank cushion and bank suction may cause a boat to suddenly veer toward the opposite bank (see Figure 6-27).

A single-screw boat going at a very slow speed with its port side near the left bank may lose control if veer occurs. Increasing speed and adding a small amount of left rudder will bring the boat under control.

A twin-screw boat, with its port side near the left bank, usually recovers from this sudden veer by increasing speed on the starboard engine, and adding left rudder.

Current is the horizontal flow or movement of water in a river. Maximum current occurs during runoff and/or high water and the greatest velocity is in the area of the channel. Restricted or narrow channels tend to have a venturi effect, in that rushing water squeezes into a passage and accelerates. Current in a bend will tend to flow away from the inside point (to the outside), creating eddies, counter currents, and slack water immediately past the point. This effect will build shoals at the point or inside a bend. The prudent operator will be alert to the changing current within a waterway.

In extremely narrow channels where bank cushion and bank suction are expected, the coxswain should proceed at a very slow speed, keeping near the middle of the channel and passing other boats closer than normal. In a meeting situation in a narrow channel, headway should be reduced but not enough to lose steerage. On approaching the boat, a small amount of right rudder should be applied to head slightly toward the bank. Shortly after passing the other boat, the coxswain should reverse the rudder and straighten up. A little right rudder may be needed to hold course against the bank cushion effect. Because of wash from passing boats, extreme caution should be used.

Bank suction, bank cushion, currents and wind are factors that affect a boat’s turn in a sharp bend in a narrow channel. Bank cushion and bank suction are strongest when the bank of a channel is steep. They are weakest when the edge of a channel shoals gradually and extends into a large area. Bank suction and bank cushion increase with the boat’s speed. Channel currents are usually strongest in the bend with eddies or counter-currents and shoaling on the lee side of the point. Speed of the current is greater in deeper water than in shallow water.

In a following current, the boat makes good speed with little help from the engines. When making a sharp turn with a following current, it is possible to make the following maneuvers: (01) Hugging the point, (02) Staying in the bend, (03) Proceeding on the bend side, middle of the channel. An experienced operator can accomplish any of the three; however, the third choice, called the “bend side, middle of the channel,” is the safest, and therefore, the preferred choice.

The operator makes a small turn toward the near bank to steer a straight course. As the channel begins to bend and the boat moves from the bank, less of a turn will be necessary. This condition is a signal that it is time to begin a full turn. However, slack water or eddies may be around the bend, making it difficult to prevent the vessel from steering towards the near bank, especially in shallow water. The current under the quarter may affect the stern and vessel steering (see Figure 6-28). To correct for this, the coxswain should apply additional power and helm/tiller to steer back towards the center of the channel, keeping the stern in the middle of the channel.

Staying in the bend is a turn in the bend away from the point that takes precise timing. If done too late, the boat may ground on the bank in the bend. If done too soon, there is extreme danger that a strong and sudden sheer will occur. The bank suction on one quarter combines with the current on the other quarter to give the boat the sheer. Also, the bank cushion under the bow will increase the sheer (see Figure 6-29). Again, to correct for this situation, additional power and helm/tiller should be applied to steer back towards the center of the channel.

Approaching the turn steering a course toward the bend side of the middle of the channel is the safest method when the current is following. By doing this, the boat avoids any eddies under the point and the increase in currents in the bend. The operator can also use the force of the current against the quarter to help in the turn. A following current will force a boat toward the bend side; consequently, the turn should be commenced early in the bend. Additional power and helm/tiller should be applied as needed to stay in the middle of the channel (see Figure 6-30).

It is always easier to pilot the vessel into the current rather than have the current off the stern. When making a turn into a head current, the coxswain should apply power and helm/tiller as needed to stay in the middle of the channel. Caution should be used when starting a turn. If started too soon, the head current could catch the bow and force the vessel down on the point side of the channel. If this happens, the coxswain should apply power and steer back towards the center of the channel and wait until later in the bend to commence the turn. Care should be taken not to wait too long before starting the turn. If the turn is started too late, the current could catch the bow and push the vessel towards the bend side of the channel. The stern should always be kept in the middle of the channel (see Figure 6-31).

As with any profession or skill, there are special terms that mariners use. Many of these terms have a fascinating history. Fellow mariners will expect that these terms will be used in routine conversation. Many of these words will be discussed within this Chapter. The following are common terms used for location, position and direction aboard a boat. Figure 3-1 provides a diagram of a boat with the more common terms noted.

The front end of a boat is the bow. Moving toward the bow is going forward; when the boat moves forward, it is going ahead. When facing the bow, the front right side is the starboard bow, and the front left side is the port bow.

The central or middle area of a boat is amidships. The right center side is the starboard beam, and the left center side is the port beam.

The rear of a boat is the stern. Moving toward the stern is going aft. When the boat moves backwards, it is going astern. Standing at the stern looking forward, the right rear section is the starboard quarter and the left rear section is the port quarter.

Starboard is the entire right side of a boat, from bow to stern.

Port is the entire left side of a boat, from bow to stern.

A line, or anything else, running parallel to the centerline of a boat is fore and aft.

A line or anything else running from side to side is athwartships.

Outboard is from the centerline of the boat toward either port or starboard side.

Inboard is from either side of the boat toward the centerline. However, there is a variation in the use of outboard and inboard when a boat is tied up alongside something (e.g., pier or another vessel). In this example, the side tied up is inboard; the side away is outboard.

Going topside is moving from a lower deck to a weather deck or upper deck.

Going below is moving from an upper deck to a lower deck.

Going aloft is going up into the boat’s rigging.

The weather deck is the deck exposed to the elements (weather).

Lifelines or railings, erected around the edge of weather decks, are all technically called lifelines, although they may have different proper names.

Windward is moving in the direction from which the wind is blowing; toward the wind.

Leeward is the opposite point from which the wind is blowing; away from the wind. The term is pronounced “loo-urd”.

The hull is the main body of a boat. It consists of a structural framework and a skin or shell plating. The hull may be constructed of many different materials, the most common being metal or fiberglass. A metal skin is usually welded to the structural framework, although riveting is sometimes used. A vessel could be monohull or multi-hull, such as catamarans and trimarans. The three basic types of hull forms based on vessels speed are: (01) Displacement hull, (02) Planing hull, (03) Semi-displacement hull.

Many factors influence hull shapes and affect the boat’s buoyancy (its ability to float) and stability (its ability to remain upright). Factors that influence hull shapes are discussed as follows:

Displacement is the weight of a boat and is measured in long tons (2,240 lbs) or pounds.

A gross ton is the entire cubic capacity of a boat expressed in tons of 100 cubic feet.

A net ton is the carrying capacity of a boat expressed in tons of 100 cubic feet. It is calculated by measuring the cubic content of the cargo and passenger spaces.

Deadweight is the difference between the light displacement and the maximum loaded displacement of a boat and is expressed in long tons or pounds.

Light displacement is the weight of the boat excluding fuel, water, outfit, cargo, crew, and passengers.

Loaded displacement is the weight of the boat including fuel, water, outfit, cargo, crew, and passengers.

A displacement hull boat pushes away (displaces) water allowing the hull to settle down into the water. Underway, the hull pushes out this water, creating waves (see Figure 3-3). The water separates at the bow and closes at the stern. Tremendous forces work against a displacement hull as the power pushing it and the boat’s speed both increase. At maximum displacement speed, there is a distinct bow and stern wave. The length of these waves depends upon the boat’s length and speed. (The longer the boat, the longer the wave length.) The bow and the stern ride lower in the water while increasing speed, and the water level alongside, amidships becomes lower than that of the surrounding water. This lower water level is caused by the increase in the velocity of the water flowing under the boat and its interaction with the bow and stern wave. As the boat travels along, it rides in a depression created by its own passage. The displacement hull vessel’s maximum speed is determined by the vessel’s waterline length. Heavy displacement hulls cannot exceed a speed of 1.34 times the square root of their waterline length without requiring excessive power. This speed is known as critical speed. For details on towing displacement hulls, see Reference (b).

CAUTION !

When towing a vessel, be careful not to tow beyond the vessel’s design speed.

At rest, the planing hull and the displacement hull both displace the water around them. The planing hull reacts nearly the same as a displacement hull when it initially gets underway - it takes considerable power to produce a small increase in speed. However, at a certain point, external forces acting on the shape cause an interesting effect - the hull is lifted up onto the surface of the water (see Figure 3-4). The planing hull skims along the surface of the water whereas the displacement hull always forces water around it. This is called planing. Once “on-plane,” the power/speed ratio is considerably altered-very little power increase results in a large increase in speed. Crewmembers must apply or reduce power gradually when going from the displacement mode to the planing mode or from the planing mode to the displacement mode. When the power is decreased gradually, the hull makes an even, steady transition, like slowly moving the hand from above the water’s surface, through it, and into the liquid below. However, if power is rapidly decreased, the transition will be a rough one, for the hull will slap the surface of the water like the slap resulting by hitting a liquid surface with the hand.

Additionally, the rapid “re-entry” into the displacement mode from above the surface, through the surface, and back into the water causes rapid deceleration as the forces in the water exert pressure against the hull. The effect is like rapidly braking an automobile.

The semi-displacement hull is a combination of characteristics of the displacement hull and the planing hull. This means that up to a certain power level and speed (power/speed ratio), the hull remains in the displacement mode. Beyond this point, the hull is raised to a partial plane. Essentially, the semi-displacement hull, like the displacement hull, always remains in the water; it never gets “on-plane.” When in the displacement mode, the power/speed ratio is similar to the power/speed ratio described above for the displacement hull. When in the semi-planing mode, it is affected by a combination of forces for the displacement mode and some for the planing mode. Thus, while a small power increase will increase speed, the amount of resulting speed will not be as great as the same power increase would produce for a planing hull.

The keel is literally the backbone of the boat. It runs fore and aft along the center bottom of the boat.

The following are all integral parts of the keel: (01) Frames, (02) Stem, (03) Sternpost.

Frames are attached to the keel, which extend athwartships (from side to side). The skin of the boat is attached to the frames. The keel and the frames strengthen the hull to resist external forces and distribute the boat’s weight.

The stem is an extension of the forward end of the keel. Although there are a number of common stem shapes, all are normally slanted forward (raked) at an upward angle to reduce water friction.

The sternpost is a vertical extension of the aft end of the keel.

There are many types of keels. However, in metal boats, there are two types of particular interest: (01) Bar keel, (02) Flat plate keel.

The bar keel is popular because its stiffeners (vertical or upright members which increase strength) protect the boat’s hull plating if the boat grounds on a hard bottom. It also reduces rolling. A disadvantage of the bar keel is that it increases the boat’s draft, because it extends below the bottom of the boat.

The flat plate keel has a plate that is perpendicular to the centerline of the hull. A vertical center keel that runs internal to the hull at the centerline typically supports the flat plate keel. The vertical center keel is often provided with a flange top so that when combined with the flat plate keel the section resembles an “I” beam.

The shape of a boat’s bow, its profile, form, and construction determine hull resistance as the boat advances through the water. Hull resistance develops from friction and from the wave the hull makes as it moves in the water. Wave- making resistance depends on the boat’s speed. The bow of a boat must be designed with enough buoyancy so it lifts with the waves and does not cut through them. The bow flare provides this buoyancy. Boats intended for operation in rough seas and heavy weather have “full” bows. The bow increases the buoyancy of the forward part of a boat and deflects water and spray. When a boat is heading into a wave, the bow will initially start to cut into the wave. It may be immersed momentarily if the seas are rough. As the bow flare cuts into the wave, it causes the water to fall away from a boat’s stern, shifting the center of buoyancy to move forward from the center of gravity. The bow lifts with the wave and the wave passes under the boat, shifting the center of buoyancy aft. This action causes the bow to drop back down and the vessel achieves a level attitude.

The shape of the stern affects the speed, resistance, and performance of the boat. It also affects the way water is forced to the propellers. The design of the stern is critical in following seas where the stern is the first part of a boat to meet the waves. If the following waves lift the stern too high, the bow may be buried in the sea. The force of the wave will push the stern causing it to pivot around toward the bow. If this is not controlled, the result can be that a boat broaches or pitch poles.

The rounded, cruiser-type stern presents less flat surface area for a following sea to push upon and tends to split the waves of a following sea, allowing it to pass forward along each side of the boat. Thus, the wave has minimum impact on the attitude of the vessel and provides additional buoyancy for the stern. Crewmembers should always steer into any sideways movement of the stern. For example, when the stern slips to starboard, turn to starboard. It is particularly important that these corrections be made quickly and accurately in short, choppy following seas (see Figure 3-5).

The transom stern provides a larger surface area for the seas to push upon and should not be exposed to heavy following seas or surf conditions (see Figure 3-6).

The rudder controls the direction of the boat and may vary widely in size, design, and method of construction. The shape of the stern, the number of propellers, and the characteristics of the boat determine the type of rudder. The following rudder types are shown in Figure 3-7: (01) Balanced: blade about half forward and half aft of the rudder post, (02) Semi-balanced: more than half of the blade aft of the rudder post, (03) Unbalanced: blade entirely aft of the rudder post.

Most boats are driven by one or more propellers, which move in spirals somewhat like the threads on a screw. That is why the propeller is commonly referred to as a screw. The most common propellers are built with three and four blades. The propeller on a single-screw boat typically turns in a clockwise direction (looking from aft forward) as the boat moves forward. Such propellers are referred to as right-handed. On twin-screw boats, the propellers turn in opposite directions, rotating outward from the centerline of the boat. The port propeller is left-handed and turns counterclockwise. The starboard propeller is right-handed and turns clockwise.

A propeller consists of blades and a hub. The area of the blade down at the hub is called the root, and its outer edge is called the tip (see Figure 3-8).

The edge of the blade that strikes the water first is the leading edge; the opposite is the trailing edge. The diameter of the propeller, the circle made by its tips and its circumference, is called the tip circle. Each blade has a degree of twist from root to tip called pitch (see Figure 3-8).

Pitch is the distance a propeller advances in one revolution with no slip (see Figure 3-8). Generally, less pitch in the same diameter propeller makes it easier for the engine to reach its preferred maximum RPM; thus, like putting a car in first gear, more power, and sometimes more speed, is available. Similarly, like third gear in a car, more pitch may give more speed, but lower RPMs gives less power. Optimum performance is obtained when pitch is matched to the optimum design speed (RPM) of the engine.

As previously stated, it is the framing that gives the hull its strength. Frames are of two types: (01) Transverse, (02) Longitudinal.

Watertight bulkheads or web frames are located at certain points in the hull to further increase the strength of the hull. Just as the keel is the backbone of the hull, transverse frames are often referred to as ribs. Transverse frames extend athwartships and are perpendicular (vertical or upright) to the keel and are spaced at specified distances (see Figure 3-9). They vary in size from the bow to the stern giving the boat hull its distinct shape when the skin is attached. They are usually numbered from the bow to the stern to help quickly identify a particular location in the interior and, in the event of damage to the hull, to isolate the area of damage.

Longitudinal frames provide hull strength along the length of the hull (fore and aft) (see Figure 3-10). They run parallel to the keel and at right angles to the transverse frames. In addition to strengthening the hull, the top longitudinal frames provide a skeletal structure over which deck plating is laid.

A deck is a seagoing floor and provides strength to the hull by reinforcing the transverse frames and deck beams. The top deck of a boat is called the weather deck because it is exposed to the elements and is watertight. In general, decks have a slight downward slope from the bow. The slope makes any water taken aboard run aft. A deck also has a rounded, athwartship curve called camber. The two low points of this curve are on the port and starboard sides of the boat where the weather deck meets the hull. Water that runs aft down the sheer line is forced to the port or starboard side of the boat by the camber. When the water reaches one of the sides, it flows overboard through holes, or scuppers, in the side railings.

In order for a deck with a hatch in it to be watertight, the hatch must be watertight. A weather deck hatch is made watertight by sealing it into a raised framework called a coaming. Hatches operate with quick-acting devices such as wheels or handles, or they may be secured with individual dogs (see Figure 3-11).

Scuttles are small openings. A scuttle cover, fitted with a gasket and dogs, is used to secure the scuttle. A tool called a “T-handle wrench” is used to tighten down the scuttle cover dogs.

Watertight doors are designed to resist as much pressure as the bulkheads through which they provide access. Some doors have dogs that must be individually closed and opened; others, called “quick-acting watertight doors” have handwheels or a handle, which operate all dogs at once.

Rubber gaskets form tight seals on most watertight closure devices. These gaskets, mounted on the covering surface of the closure device (e.g., door, hatch, scuttle cover), are pressed into a groove around the covering. The gaskets are sealed tight by pressing against a fixed position “knife edge.”

CAUTION !

Scuttles must be secured at all times to maintain watertight integrity except when they are open for inspection, cleaning, or painting. They must never be left open overnight or when crewmembers are not actually working or passing through them.

Watertight closures must have clean, bright, unpainted, smooth knife edges for the gaskets to press against. A well-fitted watertight closure device with new gaskets will still leak if knife edges are not properly maintained. On some boats, some of the watertight closures have a sealing surface instead of a knife edge.

The interior of a boat is compartmentalized by bulkheads, decks, and hatches. With the doors and hatches closed, the space between them becomes watertight and is called a watertight compartment (see Figure 3-12). These watertight compartments are extremely important. Without them, the boat has no watertight integrity and a hole anywhere in the hull will cause it to sink. By dividing the hull into several watertight compartments, the watertight integrity of the boat is significantly increased. One or more of these compartments may flood without causing the boat to sink. A boat could be made unsinkable if its hull could be divided into enough watertight compartments. Unfortunately, excessive compartmentation would interfere with the engineering spaces and restrict movement in the interior spaces.

The Navy uses thousands of boats, ranging in size from dinghies to landing craft. These boats are powered by diesels and by outboard motors. Most of them are built of steel, aluminum, or fiber glass. The term boat refers to small craft that are limited in use by their size. Usually, they are not capable of making regular, independent voyages of any length on the high seas.

This chapter is important because you, very early in your career, may be assigned as a member of a boat crew and later on as a coxswain.

To assume the duties of a coxswain, you must know the following:

Who is responsible for each task

What the duties of other crew members are, and be able to carry them out in an emergency

The purpose of each piece of boat equipment

How to read signal flags, so you can return to your ship if recalled

Small boats carried aboard a ship, which are lowered to perform various tasks, are known as the ship's boats.

The distinction between a ship and a boat is largely one of size; boats are carried by ships.

Boat seamanship encompasses more than a knowledge of the kinds of boats in operation in the Navy. Since boat crews are responsible for the upkeep and maintenance of their craft, they must receive training in a number of other areas. Some of the techniques to be mastered require considerable practice and experience before a boat crew member can become accomplished in this work. Included in these skills are the following: Hoisting, lowering, and securing methods Operating boats properly under all conditions, including a knowledge of the Rules of the Road Knowledge of buoy systems Boat etiquette

LEARNING OBJECTIVES: Define boat nomenclature. List the parts of a boat and explain boat construction. As used in this text, nomenclature refers to the names given to the various parts or fittings of a boat. Most boats in service in today's Navy are of molded fiber glass or of metal skeletons to which metal plates have been attached to form a hull. Figure 5-1 gives you an idea of how a boat is constructed. The backbone of the skeleton is called a keel, and its ribs are the frames. Bilges are the inner parts of the hull on either side of the keel up to where the sides begin.

The most forward part of the boat is the stem. The outboard part of the stem that is below the surface is called the cutwater. Starting just abaft the stem and running fore and aft on both sides, there is usually a half-rounded fender, called the beading. Abaft the stem is a ring (hoisting eye) and cleats, used for securing the boat's painter (which is the line used to make the boat fast by the bow. A similar line in the stern is called a stern fast.) At the after end is the sternpost.

Somewhere in the bilges forward and aft, adjacent to the keelson (inside upper edge of the keel), every boat has a couple of screw plugs, which permit water to be drained out when the boat is out of the water. Each Navy boat has a set of strong hoisting eyes for attaching slings or boat falls when hoisting. (Large craft have several sets of hoisting padeyes and multiple slings or a rigid for single point pickups.)

All boats are equipped with a rudder for steering when underway. A rudder blade is attached to the rudder stock, which enters the hull through a stuffing box. The rudder is turned by a steering wheel attached to a system of ropes, push-pull cables, or a mechanically or hydraulically operated arm attached to the rudder stock.

Most boats 50 feet long or under are made of plastic or fiber glass.

[An illustration in the course, not reproduced here: Figure 5-1.–Names of boat parts.]

LEARNING OBJECTIVE: Identify the different types of boats used in the U.S. Navy.

There are a number of types of boats used in the Navy today. We briefly describe a few of the boats most commonly seen, although you will surely see many others during your naval career.

Landing craft (called boats) are carried by various amphibious ships and are referred to by designation. They are designed to transport personnel and/or cargo from ship to shore. Figure 5-2, view A is a line drawing of an LCP(L); view B is a line drawing of an LCM.

The following amphibious ships carries landing craft for the movement of personnel and cargo from the ship to shore.

General-purpose assault ships (LHAs)

Multipurpose assault ships (LHDs)

Cargo ships (LKAs)

Landing ships (LSDs)

Tank landing ships (LSTs)

[An illustration in the course, not reproduced here: Figure 5-2.–Landing craft; (A) 36-foot LCP(L), (B) 74-foot LCM.]

Personnel boats (fig. 5-3) are heavy-duty, square-sterned boats in various lengths from 26 to 40 feet. They are used to transport officer personnel from ship to shore, act as the ship mail carrier, and to ferry cargo as needed. The larger personnel boats are divided into four spaces: the cockpit, the engine compartment, and the fore-and-aft passenger compartments. The smaller personnel boat has no fwd passenger compartment. A canopy may be installed over the cockpit during adverse weather conditions. MOTOR WHALEBOATS (MWBs)

Motor whaleboats (MWBs) are round-bottomed, diesel-powered boats used as lifeboats and shipboard utility boats.

Some ships use MWBs as gigs and officers' boats, in which case they have canvas or herculite canopies. MWBs should never be overcrowded. The Mk 10 MWB (fig. 5-4) is divided into the forward, engine, and after compartments.

[An illustration in the course, not reproduced here: Figure 5-3.–33-foot personnel boat.]

Punts are open square-ended boats 10 or 14 feet long. They are rowed (sculled) and are generally used by side cleaners and paint crews. See figure 5-5.

Utility boats (UBs), 22 to 50 feet long, are generally used as cargo and personnel carriers (fig. 5-6) or as heavy-duty workboats. Many Ubs are modified for other operations.

[An illustration in the course, not reproduced here: Figure 5-4.–Mk 10 motor whaleboat.]

[An illustration in the course, not reproduced here: Figure 5-5.–14-foot punt.]

[An illustration in the course, not reproduced here: Figure 5-6.–33-foot utility boat.]

LEARNING OBJECTIVES: List the standard boat equipment. Explain the upkeep, maintenance and care of small boat equipment.

Every Navy boat in active service is required to have a complete outfit of equipment as designated by the Naval Sea Systems Command (NAVSEASYSCOM), Naval Ships' Technical Manual, Chapter 583, “Boats and Small Craft”, OPNAVINST 3120.32 B and applicable publications.

The Coordinated Shipboard Allowance List (COSAL) lists all the items required with the boat on the ship (items furnished with the boat) and the items that must be requisitioned. The equipment furnished with each boat, called portable parts, generally consists of the following items:

Anchor, 30-pound LWT (lightweight)

Bucket

Life rings, 24-inch

Fenders

Grapnel, No. 4 with 6 feet of 1/4-inch close-link chain

Boat hook, 8-foot

Line, anchor, 25 fathoms of 2 1/4-inch line

Line, grapnel, 15 fathoms of 21-thread line

Bow, painter, 5 fathoms of 3-inch line

Stern fast, 5 fathoms of 3-inch line

Fire extinguisher, 15-pound CO2 portable type

During active service, every effort should be made to provide thorough ventilation and drainage and to prevent water leakage. Standing water and oil in the bilges, even in small amounts, is hazardous; therefore, seams must be carefully caulked and maintained watertight. In fair weather, hatches and deck plates of boats afloat should be opened to increase air circulation. Wet dunnage, line, and life jackets in lockers should be removed and aired out. Boat crews should be alert for leaks beneath the covering board and deckhouse area.

When boats are removed from the water, propellers and sea suction should be checked and all deficiencies corrected. Engine oil should be changed after every 100 hours of running time, or as required by the Planned Maintenance System (PMS). Gear housings, steering mechanisms, and all moving parts must be kept well lubricated. Avoid spillage of fuel or oil; fumes from these are especially dangerous. The loads supported by gripe pads should be distributed as evenly as possible, to prevent hull deformation/damage.

LEARNING OBJECTIVE: List and explain the duties of the boat crew.

All members of a boat crew must know their duties and be qualified second-class swimmers to ensure safe handling of the boat. This section covers the duties of the coxswain, the bow hook, the stern hook, the boat keeper, the boat engineer and the boat officer. The duties of the boat engineer are outlined in the latest Fireman TRAMAN. The duties and responsibilities for boat operation are outlined in the Ship's Boat Bill. The coxswain must know the bill and its contents.

As the coxswain of a boat, you must assume many duties and responsibilities. It is your duty to be familiar with all details relating to the care and handling of your boat. As a coxswain, you must know the boat’s physical characteristics, draft, and cargo and passenger capabilities in both fair weather and foul. These capacities are stamped on the boat label. It is important that the limits not be exceeded. Subject to the orders of the officer of the deck (OOD) and the commanding officer, you, as the coxswain, will have full charge of the boat and its crew.

WARNING

Boat crews entering or leaving the boat via the boat boom must wear inherently buoyant

(kapok) life jackets.

The coxswain is responsible for making sure the boat crew and personnel embarked comply with all safety regulations. (Passengers, regardless of rating, must obey the coxswain's orders if they concern the operation of the boat or the safety of personnel aboard) All boat passengers and crew must wear life jackets when weather conditions are hazardous.

Before operating the boat, the coxswain must inventory the personnel safety equipment and other equipage in the boat equipment to make sure it is all on board.

The coxswain must record courses and en route times, in the appropriate log, to all landings visited under various conditions of tide. The compass course and navigation aids, upon entry to a port, are verified in company with the navigator and/or quartermaster during the first boat run.

The coxswain is responsible to the OOD and the division officer for the boat's cleanliness and readiness for service. Coxswains and boat crews are representatives of the ship and should take pride in their appearance and in the image presented by their boat. The ship's regulations frequently require, for example, that crew members wear clean white sneakers. This is primarily a safety factor, but also aids in keeping boats looking neat.

Supplying oilskins or rain clothes for the boat's crew is the coxswain's responsibility. The gear should be all of one type, if possible, and should be kept in the boat when not in use. Wearing foul weather gear is strictly prohibited for boat crews unless severe weather requires its use. Usually, the senior officer present afloat (SOPA) issues instructions that set the uniform for boat crews. If you are not familiar with these instructions, check with the OOD before reporting for boat duty. Then inform your crew of the proper uniform so that all crew members will be dressed correctly before being called away.

When called away, man your boat promptly. In the absence of a boat officer, the coxswain receives orders from the OOD.

When the boat is underway, the coxswain should station the bow hook in the forward part of the boat to act as a bow lookout. This requirement is of major importance in boats such as LCMs, where the coxswain's vision is severely limited.

A boat coxswain must see that the crew and passengers sit in their proper places and that the crew outside the canopy conduct themselves in a military manner when salutes are exchanged.

Coxswains of powerboats should pay particular attention to canopy curtains. When curtains are not required, they should be rolled and stopped up. When in use, they should be stopped down to the washboard. It is not “shipshape” to stop down only one comer of a side curtain. When running bow into the sea, it is sufficient to haul down the curtains on the weather side, leaving them furled on the lee side. Under all circumstances, the curtains must be stowed neatly in place. For safety, a ready exit from the boat is essential, and curtain stops should be broken easily from inside.

Coxswains of powerboats must require the stern hook to pay particular attention to the appearance of the boat's stern sheets. Cushion covers must be kept neat and clean. The boat flag, when not in use, should be rolled neatly on its flagstaff and triced up overhead. When a boat is called for the use of commissioned officers, the stern hook should spread the boat cloth neatly in the stern sheets of the boat. The stern hook must see that the foot cloths (or ladder if used) are on the proper side of the boat; that is, the side on which the passengers are expected to enter.

Officers of the deck (OOD) are responsible for the appearance of the ship; and, because they cannot see the ship as it appears from a distance, most will appreciate it if the coxswain quietly informs them of any irregularities noticed about the ship. Some examples are items hanging over the sides, loose gun and gun director covers, and Irish pennants. The coxswain should make it a habit to notice such things when returning to the ship. After the coxswain returns from a run and reports to the OOD, the coxswain, when ordered, properly secures the boat to the boat boom, comes aboard, and waits for the next run (see fig. 5-7).

The crew must never be allowed to be absent from the boat without proper authority while it is at a landing.

The coxswain never permits smoking in boats. When boats are ordered to secure, they are reported as secured to the OOD by the coxswain. The coxswain must know the capacity of the boat in good and bad weather conditions, as the boat will not safety carry the same number of people in bad weather as it will carry in good weather.

[An illustration in the course, not reproduced here: Figure 5-7.–Securing a boat to a boom.]

Bow hooks and stern hooks must acquire all the knowledge necessary to operate the boat in the event that one of them should be required to relieve the coxswain in an emergency. When the boat is in operation, the bow hook should always be forward acting as a lookout, keeping watch for any floating object or hazard that might damage the boat or result in a collision. Both bow hooks and stern hooks should be ready at all times to fend off the boat from contact with other boats, the gangway, or the landing. Bow Hook

On approaching the landing, the bow hook should be ready to spring ashore smartly with the bow line and take a turn on the nearest cleat. Also, the bow hook should be ready in the bow with the boat hook when approaching a ship's gangway, to snag the boat line and make fast. The bow hook should always have a fender ready to drop over at the proper spot if a bump becomes unavoidable. Stern Hook

The stern hook, likewise, should be ready to jump ashore at once to make the stern fast. Both the bow hook and stern hook must be at their lines, ready to cast off and jump aboard, when the boat is about to get underway. They should never cast off, however, without orders from the coxswain. The coxswain frequently has to go ahead or back down on one of the lines to clear the landing. Lines should be kept neatly flemish down and the fenders rigged in when not in use.

Personnel assigned as boat keepers assume responsibility for care of the boat in the absence of the crew.

The boat engineer performs maintenance on the engine as needed. Only the boat engineer should work on the engine. The boat engineer must ensure that the engine and the engine components are in good condition and ready to run. The boat engineer also performs duty as a stern hook on most boats.

During heavy weather and other times as deemed necessary, an officer (sometimes a chief petty officer [CPO]) is assigned to a boat as the boat officer.

A boat officer naturally has authority over the coxswain. However, the boat officer does not assume the coxswain's responsibilities nor relieve the coxswain of his normal duties. The coxswain and the boat officer are jointly responsible for the boat and the safety and of the crew and the passengers. The situation is somewhat like the relationship between the OOD and the commanding officer on the bridge.

LEARNING OBJECTIVE: Describe the basic principles of boat operations.

One of the duties you may experience as a Seaman is as a member of a boat crew. You may be assigned as bow hook, stern hook, or perhaps even coxswain. You must know the nomenclature, characteristics, and handling of small boats.

The process of hoisting and lowering boats with a crane primarily entails handling the slings by the safety runner (fig. 5-8). The safety runner, a short wire pendant, is attached to the bill of the hook on a boat crane and is connected to a tripping line. A pull on the tripping line causes the safety runner to dump the ring of the boat slings off the hook.

When a boat comes alongside a ship underway to be hoisted in, it first secures to the end of the sea painter–a strong line that hangs over the side of the ship and is located forward of the spot where the boat will be hoisted. The shipboard end of the line is bent securely to a cleat or a set of bitts. The eye of the sea painter is lowered to the boat and tended by means of a light line called a lizard line. The bow hook secures the eye to the inboard bow cleat, the cleat nearest the side of the ship.

NOTE

The sea painter is never secured to the boat's stern or to the side of the bow away from the ship. To do so would cause the boat to dive against the side of the ship when the boat begins to ride the painter, and it would probably capsize. It is important that the sea painter be adjusted properly and that the boat be allowed to drop back on it so that the boat's attachment point will be directly under the crane before lifting. Otherwise, it may broach to and capsize as it starts to leave the water.

Once it rides to the painter, and the slings are attached, the boat is lifted out of the water and the engine is secured. Steadying lines should be secured to the cleats on the outboard side of the boat and brought back on deck to hold the boat steady as it rises. The bow hooks and stern hooks must fend it off the side. When the boat is clear of the water, the engine is secured, and the plugs should be removed (so that the bilges will drain before the boat reaches the deck).

In operating with davits, the boat attaches to the sea painter and the steadying lines in the same manner, and must take the same precautions against broaching when lifted. The falls are lowered to the boat and the bow hook hooks the forward Raymond release hook first (hook pointing aft). The bow hook must rotate the block until all the twists are out of the falls before hooking on; otherwise, a dangerous jam will occur as the blocks draw together. Once the forward block is hooked on, the stern hook removes the twists in the after fall and then attaches the after Raymond release hook (hook pointing forward). Both then secure the releasing hooks closed by their lanyards using three figure-eights and a half hitch. Manropes (monkey lines) are suspended from the strongback/span wire to the boat, and each person aboard must support part of his or her weight on the line as the boat rises, to be ready in any emergency.

Hard hats with chin straps and inherently buoyant life preservers must be worn by personnel when they are being hoisted or lowered in a boat.

[An illustration in the course, not reproduced here: Figure 5-8.–Safety runner.]

In operating a boat, the most important point to remember is that the stern, not the bow, goes off track first when the rudder is turned; the boat reacts to the rudder much faster at high speed than at low speed. Often, when you see that you did not allow yourself enough room for a turn, gunning of the engine will bring it around in time. You will have to make a judgment call on that.

All single-screw boats have right-handed screws turning in a clockwise direction going ahead, when viewed from astern. For this reason, the side force of the screw, when going ahead, tends to walk the stern to starboard when the boat is gathering headway. This screw action means that your boat always makes a faster turn to port than to starboard when gathering headway.

When backing, however, the stern tends to walk to port, no matter how much rudder you put on to the right. If you have to back a long stretch in a straight line, back with a hard right rudder until you start to curve to port. Then shift your rudder and gun your engine ahead fast. The boat straightens itself in a second, without losing sternway.

One of the first pointers you must learn about your boat is how fast it will backdown. It is next to impossible to back a boat in a straight line. You must use your rudder and, at times, shift your engine to back your boat because of the effect on the screw and rudder.

It is always easier to go alongside port-side-to than starboard-side-to. See figure 5-9. The reason: When you put your port bow alongside and start to back, the side force of the backing screw on the stern will walk your stern alongside. If you have to go starboard-side-to, remember that you must come alongside much straighter, because the backing screw will walk your stern away from the landing. Make a starboard-side-to landing at slow speed, and work your engine and rudder to get the boat alongside.

When tying up to a ship's gangway in a tideway or stream, always secure the boat line to the ship side of the bow, and set the rudder a little away from the ship, so that the boat will ride clear. Tie up to a deck or landing, bow-on to the stream whenever possible, so you can set your rudder to hold it off in the same manner as just described. If the wind tends to throw the boat onto the landing, use less rudder and speed, and use your fenders to keep from chafing the boat against the pilings. Tie up with a bow line leading forward and stern line leading aft. Never have both lines leading in the same direction.

In getting underway from a starboard-side-to landing, usually it is best to back until the stern has walked itself away from the dock, because a single-screw boat will back to port. If you have no room astern, hold the bow by the bow line and go ahead slowly with a hard right rudder. When your stern is well out, cast off, back with a hard left rudder, and your stern will walk out without difficulty.

CAUTION

When you are shoving a boat away from the pier, the bow and the stern could fall in the water.

[An illustration in the course, not reproduced here: Figure 5-9.–Effect of backing propeller.]

With normal sea conditions, steering a powerboat is much the same as handling a single-screw ship, although the reactions of the boat to the engines and rudder are more pronounced. Too much weight forward may cause the bow of the boat to plunge into the waves.

Some hints on handling powerboats under special circumstances are given here as an aid to a boat crew that, having mastered the elements of its work, is ready to operate in more complicating situations.

When handling boats in a moderate or a rough sea, you must exercise caution, good judgment, and seamanship. Each member of the boat crew must know and perform all duties well to ensure the safe operation of the boat at all times.

One of the most risky situation arises when a powerboat is running before a sea. When the hull is lifted by the stern, there is danger that steerageway and power may be lost when the screw and rudder are clear of the water. The boat may then swing around broadside to the seas. The coxswain must rely on skill and training in the use of the rudder to keep the stern to the mountains of water. It is helpful to reduce speed and to allow large swells to roll by. In extreme cases, a drogue or sea anchor (fig. 5-10) may be used.

Running into a sea is less hazardous, but not without danger. Reduced speed lessens the strain on both engine and hull. To this end, the throttle should be adjusted so that the bow rises with oncoming waves instead of driving into them. Taking the seas on either port or starboard bow is sound seamanship, too, because some of the pitch is lessened by this method.

Avoid the trough, except in an emergency. When moving broadside to waves, turn the wheel momentarily, so as to take larger wave crests on the windward bow, and return to the course when conditions permit.

The coxswain must keep the screw rotating sufficiently to maintain steerageway and then keep the bow facing the seas at an angle on either the port or starboard bow.

A drogue or sea anchor is a cone-shaped canvas bag about 2 feet wide at the mouth and approximately 4 1/2 feet long. It is towed open-end forward so as to offer resistance. The towline is made fast to the open end of a sea anchor, and a tripping line is secured to the pointed end. The drogue fills with water and tends to slow down the forward movement of a boat. The most important use of the drogue is in keeping a boat at right angles to a sea. The bow of a small boat can be kept toward the seas by rigging the drogue line and allowing the drogue's resistance to the water to hold the boat in position to the sea.

If the drogue is no longer needed, the towline is slacked and the tripping line is heaved on. This action causes the sea anchor to lose its resistance and enables the crew to haul it aboard.

[An illustration in the course, not reproduced here: Figure 5-10.–Sea anchor or drogue.]

Boats are secured for sea when they are gripped down in the chocks, with plugs out and boat covers stoppered down securely.

The ready lifeboat, usually a motor whaleboat, is secured for sea in the davits, and, on some ships, swung out ready for lowering. As a safety measure, wire preventers connected to the davit heads may be attached to the boat's hoisting eyes, and the preventers must be cast off before lowering. They are equipped with pelican hooks, which can be tripped to transfer the boat's weight back to the falls.

The lifeboat has its sea painter and steadying lines already rigged, and the manropes from the span are coiled down clear for running. To keep it from swinging, the lifeboat is gripped against a pair of soft paddings on a heavy spar called a strongback, securely lashed between the davits. Canvas-covered lines running in a V-shape from the strongback around the boat to the deck are the gripes in this instance. They are brought down hard to the deck by means of a turnbuckle, with a pelican hook for quick releasing. The strongback is not always used. A set of inboard gripes, similar to those outboard, is used instead.

At the start of each watch, the Boatswain's Mate of the watch (BMOW) checks the ready lifeboat and reports the ready lifeboat condition to the OOD. It should have a full tank of fuel and fuel oil reservoir. The bilge should be clean and dry with the boat plug in place. Life jackets and safety helmets should be ready nearby or in the boat so the crew may don them before lowering away.

LEARNING OBJECTIVE: Explain proper etiquette procedures for a member of a small boat crew, including saluting, loading and off loading passengers.

Early in this chapter you were told that a ship is often judged by its boats and their crews. Clean boats and sharp crews draw favorable comments from superiors. An essential element for a smart crew is proper, seamanlike conduct. Following are a few rules of boat etiquette, established by custom and regulations, to serve as your guide to proper conduct when in boats. Observe them closely, and insist that others in your boat do likewise.

When there is no officer, petty officer, or acting petty officer in a boat lying at a landing, gangway, or boom, the personnel seated in the boat rise and salute all officers passing near. When an officer, a petty officer, or an acting petty officer is in charge, that person alone renders the salute.

Coxswains in charge of boats rise and salute when officers enter or leave their boats unless the safety of the boat would be imperiled.

When boats with embarked officers or officials in view pass each other, hand salutes are rendered by the coxswain and the senior officer embarked. The engine of the junior boat is idled during the salute. After the officer returns the salute, speed is resumed. Coxswains must rise while saluting unless it is dangerous or impractical to do so.

When a powerboat salutes another boat in passing, crew members outside the canopy stand at attention facing the other boat.

If a powerboat is carrying an officer or official for whom a gun salute is being fired, the engines are slowed and clutches are disengaged on the first gun, and the boat is headed parallel to the saluting ship. During the salute, only the person honored rises and salutes.

Enlisted personnel who are passengers in the stern sheets of a boat always rise and salute when a commissioned officer enters or leaves.

Boat keepers and all other personnel in boats not underway and not carrying an officer, a petty officer, or an acting petty officer in charge, stand and salute when an officer comes alongside, leaves the side, or passes near them. They should remain standing until the boat passes or reaches the ship's side.

Personnel working on the ship's side or aboard a boat do not salute unless ATTENTION is sounded.

Salutes aboard powerboats should be extended to foreign military and naval officers.

During morning or evening colors, powerboats should be stopped. The coxswain stands at attention and salutes. All others sit at attention.

No junior should overhaul and pass a senior without permission. The junior always salutes first, and the salute is returned by the senior. If doubt exists about the rank of an officer in a boat, it is better to salute than risk neglecting to salute one entitled to that courtesy.

Subject to the requirements of the rules for preventing collisions, junior boats must avoid crowding or embarrassing senior boats. At landings and gangways, juniors should give way to seniors. Juniors should show deference to their seniors at all times by refraining from crossing the bows of their boats or ignoring their presence.

Juniors precede seniors into a boat but leave after their seniors unless the senior officer in the boat gives orders to the contrary. As a general rule, seats farthest aft are reserved for senior officers. In personnel boats and motor whaleboats with no officers embarked, the stern sheets usually are reserved for chief petty officers.

Officers seated in boats do not rise in rendering salutes except when a senior enters or leaves the boat.

The position of attention in a boat is sitting erect.

Enlisted personnel who are passengers in running boats with officers maintain silence under ordinary circumstances.

Boats transporting seniors to a landing should be given first opportunity to land.

Except when excused by proper authority, boats should stand clear of shore landings and ship's gangways while waiting, and crews should not leave their boats. If a long wait is probable during bad weather or at night, permission may be requested to make fast to a boom and for the crew to come aboard.

When a visiting party is alongside, the petty officer in charge should go aboard and obtain permission before allowing any of the visiting party to leave the boat.

LEARNING OBJECTIVE: Describe the proper display of the national ensign, personal flags and pennants, bow insignia, and flagstaff ornaments on small boats.

This section discusses the proper display of the national ensign and personal flags and pennants from boats of naval vessels.

The national ensign is displayed from naval vessels at the following times:

When in port or at anchorage, the national ensign and the union jack are displayed from 0800 until sunset from the flagstaff and the jackstaff respectively. A ship that enters port at night, when appropriate, displays the national ensign from the gaff at daylight for a time sufficient to establish the ship’s nationality; it is customary for other ships of war to display their national ensigns in return.

During daylight, when underway in a foreign port.

When required to be in full dress.

When going alongside a foreign vessel.

When an officer or official is embarked on an official occasion.

When a flag or general officer, a unit commander, a commanding officer, or a chief of staff, in uniform, is embarked in a boat of his or her command or in one assigned to him or her for personal use.

At such times as may be prescribed by the senior officer present afloat (SOPA).

Personal flags and pennants are displayed from naval vessels at the following times:

An officer in command, or a chief of staff when acting for that officer, when embarked in a boat of the naval service on official occasions, displays from the bow the command officer's personal flag or command pennant or, if not entitled to either, a commission pennant.

An officer entitled to the display of a personal flag or command pennant may display a miniature of such flag or pennant in the vicinity of the coxwain's station when embarked on other than official occasions in a boat of the naval service.

A boat regularly assigned to an officer for personal use carries insignia on each bow as follows:

For a flag or general officer, the stars as arranged in his or her flag

For a unit commander not a flag officer, a replica of the command pennant

For a commanding officer, or a chief of staff not a flag officer, an arrow

Staffs for the ensign, and for the personal flag or pennant in a boat assigned to the personal use of a flag or general officer, unit commander, chief of staff, or commanding officer, or in which a civil official is embarked are fitted at the peak with devices (shown in fig. 5-11) as follows:

A spread eagle for an official or officer whose official salute is 19 or more guns. The head of the spread eagle must face forward.

A halberd for a flag or general officer whose official salute is less than 19 guns or for a civil official whose official salute is 11 or more guns but less than 19 guns. The cutting edge of the halberd must face forward.

A ball for an officer of the grade, or relative grade, of captain in the Navy or for a career minister, a counselor or first secretary of an embassy or legation, of a consul.

A star for an officer of the grade, or relative grade, of commander in the Navy. The points of the star must face fore and aft.

A flat truck for an officer below the grade, or relative grade, of commander in the Navy or for a civil official not listed above, and for whom honors are prescribed for an official visit.

[An illustration in the course, not reproduced here: Figure 5-11.–Flagstaff insignia.]

LEARNING OBJECTIVES: Explain the procedures for challenging an approaching small boat. List and identify boat hails and their replies.

When a boat approaches a ship, the officer of the deck must know the rank of the senior officer embarked so that a proper reception with the appropriate ceremonies may be extended. During daylight hours, the officer of the deck (OOD) questions the boat coxswain to ascertain the rank of the senior officer by raising an arm straight up, fist clenched. The coxswain replies by showing fingers equal to the number of side boys the officer rates. Fleet admirals, admirals, and vice admirals rate eight side boys. Rear Admirals, upper and lower, rate six side boys. Captains and commanders rate four side boys, and all other commissioned officers rate two. Officers of other services rate the same number of side boys as their equivalents in rank. If there are no passengers in the boat who rate side boys, the coxswain gives the OOD a wave off. At night the OOD hails a boat with “Boat ahoy,” and the coxswain answers, according to the senior embarked, as indicated in table 5-1.

LEARNING OBJECTIVE: List and explain the recall signals for small boats including the Admiral's barge and the Captain's gig. Occasionally it is necessary to recall personnel and boats by means of a flaghoist. The PAPA flag is the general recall when shown in port. It is flown from the foretruck, or where seen best, and means: All PERSONNEL BELONGING TO THIS SHIP RETURN IMMEDIATELY.

QUEBEC, while flying, means: ALL BOATS BELONGING TO THIS SHIP (OR BOATS ADDRESSED) RETURN TO THE SHIP IMMEDIATELY. If for any reason it is desired to call a particular boat, a hoist is flown as follows: QUEBEC, followed by a numeral pennant, which designates a type of boat, and one or more additional numeral flags to indicate the number of the boat.

The calls for the various types of boats follow:

Calls are usually assigned according to boat numbers.

An example of a call to own ship's boat is Qp52, meaning own ship's powerboat number 2.

To call another ship's boat, the ship's call is placed under the boat call. For example, Qp4Rp6p2 calls the captain's gig of carrier 62.

The general recall for all boats to return to their ships is QUEBEC hoisted singly.

Figure 5-12 illustrates the recall signal for the captain's gig (QUEBEC over PENNANT FOUR).

[An illustration in the course, not reproduced here: Table 5-1.–Coxswain Replies According to Senior Embarked]

Errata #1 (23 Jul 1999), which Errata #2 (22 May 2000) later superseded without repeating its text corrections: Change paragraph 5 to read as follows: “The general call for all boats to return to their ships is QUEBEC hoisted singly.”

LEARNING OBJECTIVES: Describe how to steer a boat by compass. Recognize compass error and describe how to correct compass error.

Standard powerboats and landing boats are always equipped with a compass. The coxswain uses this instrument more than any other device in piloting the craft to its destination.

Both the magnetic compass and the gyroscopic compass were explained in Chapter 2 of this book; hence, they are not discussed here. The rest of this chapter does, however, explain many of the things you must know about steering a boat by compass.

The coxswain must ensure that the compass light is installed and operating for night runs. To follow a compass course, the coxswain leaves the side of the ship, swings around to the bow, and uses either the point where the anchor chain enters the water or, preferably, the anchor buoy as point of departure. The coxswain then steers the previously given compass course. By this method the boat should arrive at its destination with little difficulty if there is no wind or current, if the compass is in good condition, and if no metal objects (such as tools, or a large steel vessel passed en route) cause the compass to deviate.

It is necessary for the coxswain to move approximately 100 yards away from the ship before taking the compass reading. The reason is to prevent the magnetic attraction of the ship's hull from influencing the operation of the boat's compass.

Trust your compass. At times you may swear something has gone wrong with it, but that is probably your imagination, not a faulty compass. It is not a good practice to try to make your way from ship to ship by listening for the ship's bells.

Sound is deceptive in fog. Sound seem to come from everywhere at once. If you should become lost, you may have to listen for bells to try to find the nearest ship. Never leave your ship without knowing which berth the ship is in. Handle your compass with care so that you can rely on it when you need it.

[An illustration in the course, not reproduced here: Figure 5-12.–QUEBEC over Pennant Four.]

Two forces make up compass error. They are variation and deviation. Earth is a huge magnet. The north magnetic pole of Earth is over a thousand miles from the geographic North Pole. A magnetic compass points to magnetic north instead of true north because of Earth's magnetic field. The amount the compass is offset from the true pole is called variation.

Variation differs at various points on Earth's surface, and at many points it increases or decreases by a known annual rate.

Variation for any given locality, together with the amount of increase or decrease, is shown on the compass rose of the chart for that particular locality. On small-scale charts of larger areas, however, variation is shown by lines (isogonic lines) running through points with the same amount of variation.

Along each line or every fifth line (depending upon the type of chart used), variation is printed, and rates of annual changes are shown between the lines.

Figure 5-13 shows a compass rose indicating that in 1968 there was a 26°45' easterly variation in that area and that it was increasing 11' annually. The total amount of variation is found by multiplying the number of years since the year printed in the compass rose by the rate of annual change. The result is either added to or subtracted from the variation given, depending upon whether the error is increasing or decreasing. In this instance, total variation in 1992 would be 24 years x 11' annual increase + 26°45' = 31°09'.

Variation remains the same for any heading of a ship or boat at any given locality. No matter which direction your boat is heading, the magnetic compass, if affected by variation alone, points in the direction of the magnetic pole.

Deviation is caused by the magnetic metallic masses in and on a ship. It is built into a ship and the ship, in effect, becomes another magnet. We do not intend to give a detailed explanation of how this force affects a magnetic compass, but where deviation exists, it must be taken into account. Although it remains a constant amount for each compass heading, it gradually increases, decreases, increases, and decreases again as the ship swings through a complete 360° circle.

Deviation must be considered in correcting compass error, consequently the deviation for any given heading of a ship must be known. Before the ship puts to sea, it is swung through the complete circle from 0° to 360°, and the amount of the compass deviation is noted at every 15° swing. Compass deviation is calculated by various methods, generally by comparison with the gyrocompass, or by reciprocal bearings on a compass on the beach, which would be unaffected by the metal in the ship.

The results are compiled into a table called the deviation table (table 5-2). Every 15° is considered close enough, and in using the table, you should use the deviation for the heading nearest the heading you are checking. In other words, if you look in this table for the amount of deviation for a 17° heading, you would select the deviation for 15°, a deviation of 10°W.

When studying the compass, a coxswain should have the following definitions memorized.

Deviation— The error caused by the magnetic properties of any metal in the immediate vicinity of the compass. Deviation for a particular compass should be shown on the deviation table mounted near the instrument.

Variation— The angular difference between true north and the direction of Earth's magnetic field. Variation is marked on charts because it changes from year to year and from place to place.

Compass error— Deviation and variation together are known as the compass error.

True course— The angle between true north and the path along the ocean floor over which the boat is traveling, measured from true north in a clockwise direction.

Magnetic course—The angle, measured clockwise, from the magnetic meridian to the track. Correcting the magnetic course for variation gives the true course.

Compass course— The reading of a particular boat's compass when the boat is following a definite track. Correcting the compass course for deviation gives the magnetic course.

Correcting— The process by which both deviation and variation corrections are applied in converting a compass course to a true course.

[An illustration in the course, not reproduced here: Figure 5-13.–Combination compass rose.]

The course you take from a chart usually is a true course. You must convert the true course from a magnetic compass to a compass course. To do this, you apply the compass error (variation and deviation) to the true course. Changing a true course to a compass course is called UNCORRECTING, and changing a magnetic course to a true course is CORRECTING. You can remember this easily if you think of something that is TRUE as being CORRECT or already corrected. Another handy memory aid, CAN DEAD MEN VOTE TWICE, gives the key to the problem of changing from one to the other. Each word in our memory aid represents a word in our problem, as follows:

COMPASS

CAN

DEAD DEVIATION

MAGNETIC

MEN

VOTE VARIATION

TWICE TRUE

Variation and deviation are always given as EASTERLY or WESTERLY errors, and when CORRECTING (converting from compass to true), ADD easterly errors, and SUBTRACT westerly errors. When UNCORRECTING (converting from true to compass), SUBTRACT easterly errors, and ADD westerly errors.

Suppose the true course, taken from a chart, is 095°; variation, taken from the same chart, is 2° westerly; and deviation, taken from the deviation table, is 3° westerly. Now work the problem. Put down the things you know as follows:

Do not forget the W (for westerly) or E (for easterly); otherwise you will not know whether to add or subtract the error. Now, true course was given, and we want to find compass course. We are uncorrecting; therefore, we add westerly errors and subtract easterly errors. Both errors are westerly, so we add them both.

Compass course is 100°.

Let us now set up a problem converting compass course to true course. We have given compass 193°, variation 7° easterly, and deviation 2° westerly.

This time we are correcting; therefore, we add easterly and subtract westerly errors.

After a little practice, you can work these problems in your head. Because it is compass course or true course you are interested in, find the algebraic sum of the two errors. An algebraic sum is obtained by adding the two errors if they are in the same direction, or subtracting the smaller error from the larger error if they are in opposite directions. The total error then is added to, or subtracted from, whichever course is given.

In many boats, deviation is very small or nonexistent; and when this is true, merely apply variation and you have your answer. In some boats, however, the motor and the other metal objects do cause deviation. These boats must be swung, deviation tables made out, and the date used when correcting the compasses.

[An illustration in the course, not reproduced here: Table 5-2.–Typical Deviation Table]

LEARNING OBJECTIVES: List and explain the basic Rules of the Road. Identify and list sound signals.

International Rules of the Road are specific rules for all vessels while on the high seas and in connecting waters that are navigable by seagoing vessels. The Inland Rules apply to all vessels operating on the inland waters of the United States, and to vessels of the United States operating on the Canadian waters of the Great Lakes (to the extent that there is no conflict with Canadian law).

As a Seaman, you will need a basic knowledge of the Rules of the Road for boat operation.

The International Rules were formalized at the convention on the International Regulations for Preventing Collisions at Sea, 1972. These rules are commonly called 72 COLREGS.

The Inland Rules discussed in this chapter replace the old Inland Rules, Western River Rules, Great Lakes Rules, their respective pilot rules, and parts of the Motorboat Act of 1940. Many of the old navigation rules were enacted in the last century. Occasionally, provisions were added to cope with the increasing complexities of water transportation. Eventually, the navigation rules for the United States inland waterways became such a confusing patchwork of requirements that in the 1960s several unsuccessful attempts were made to revise and simplify them. Following the signing of the 72 COLREGS, a new effort was made to unify and update the various Inland Rules. This effort was also aimed at making the Inland Rules as similar as possible to the 72 COLREGS. The Navigation Rules, International-Inland, COMDTINST M16672.2B now in effect, is the result.

Inland Rules vary from International Rules primarily because of the addition of certain extra precautions. In our discussion of basic rules, each rule stated is the same for both international and inland waters unless a distinction was pointed out. When the term power-driven vessel was mentioned, for example, it meant in both International and Inland, any vessel propelled by machinery as distinguished from a sailing vessel.

The basic rules concerning displays of navigational lights were given in chapter 2.

Errata #1 (23 Jul 1999), which Errata #2 (22 May 2000) later superseded without repeating its text corrections: Anywhere “COMDTINST M16672.2B” appears in your training manual, change it to read “COMDTINST M16672.2c.”

You must understand the steering and sailing rules and be able to apply them to various traffic situations. Although all Rules of the Road are important, the steering and sailing rules are the most essential to know to avoid collision. The risk of collision can be considered to exist if the bearing of an approaching vessel does not appreciably change.

NOTE

When you are approaching a very large vessel, or when you are in close quarters, a bearing change alone does not necessarily mean that a collision cannot happen.

We will illustrate the three situations in which the danger of collision might exist: head-on, crossing, and overtaking. The illustrations and the following summary will help you learn the rules and appropriate actions to be taken in each situation. Meeting (Head-On) Situation

When two ships meet head on, or nearly so (fig. 5-14), each ship must change course to starboard and pass port to port. In international waters, a whistle signal is sounded only when a course change is actually made. If the meeting ships are already far enough off each other to pass clear on their present courses, no signal is sounded. Crossing Situation

When two power-driven vessels are crossing so as to involve risk of collision (fig. 5-15), the vessel having the other to starboard is the give way vessel and must avoid the stand on vessel.

A sailing vessel has the right-of-way over power-driven vessels except when the sailing vessel is overtaking and the power-driven vessel is engaged in fishing, is not under command, or is restricted in its ability to maneuver. Overtaking Situation

Any vessel overtaking another must keep clear of the overtaken vessel. An overtaking vessel is one that is approaching another vessel from any direction more than 22.5° abaft its beam (fig. 5-16). When in doubt, assume you are overtaking and act accordingly.

[An illustration in the course, not reproduced here: Figure 5-14.–Meeting (head-on) situation.]

[An illustration in the course, not reproduced here: Figure 5-15.–Crossing situation.]

Before we continue with our discussion of basic rules of the road, you must first understand the terms we will use. They are as follows:

Vessel includes every description of watercraft, including nondisplacement craft and seaplanes used, or capable of being used, as a means of transportation on water.

Power-driven vessel means any vessel propelled by machinery.

Sailing vessel means any vessel under sail, provided that propelling machinery, if fitted, is not being used.

Give-way vessel refers to a power-driven vessel underway having another vessel to starboard, thus “giving-way” or allowing the other vessel to pass in an overtaking situation.

Stand-on vessel refers to any power-driven vessel in a crossing situation close enough to involve risk of collision; the vessel having the other to starboard must keep out of the way, or “stand-on,” not crossing ahead of the other vessel.

Vessel engaged in fishing means any vessel fishing with nets, lines, trawls, or other fishing apparatus that restricts maneuverability, but does not include a vessel fishing with trolling lines or other fishing apparatus that does not restrict maneuverability.

Seaplane includes any aircraft designed to maneuver on the water.

Vessel not under command means a vessel that, through some exceptional circumstance, is unable to maneuver as required by these rules and is, therefore, unable to keep out of the way of another vessel.

Vessel restricted in its ability to maneuver means a vessel that, from the nature of its work, is restricted in its ability to maneuver as required by these rules and is, therefore, unable to keep out of the way of another vessel.

Vessel constrained by its draft means a power-driven vessel that, because of its draft in relation to the available depth of water, is severely restricted in its ability to deviate from the course it is following (International Rules only).

Underway means that a vessel is not at anchor, made fast to the shore, or aground.

Length and breadth of a vessel mean its length overall, and greatest beam or width.

In sight means vessels are deemed to be in sight of one another only when one can be seen from the other.

Restricted visibility means any condition in which visibility is restricted by fog, mist, falling snow, heavy rainstorms, sandstorms, or any other similar causes.

Inland waters means the navigable waters of the United States shoreward of the navigational demarcation lines dividing the high seas from harbors, rivers, and other such bodies of waters of the United States, and the waters of the Great Lakes of the United States' side of the international boundary.

Demarcation lines means the lines delineating those waters upon which mariners must comply with the 72 COLREGS and those waters upon which mariners must comply with the Inland Navigation Rules. (The boundaries for the demarcation lines are listed in the back of the Coast Guard publication Navigation Rules, International-Inland.)

Whistle means any sound-signaling appliance that is capable of producing the prescribed blast and that complies with the specifications in Annex III of the International and Inland Rules. (When your ship was built and the whistle was installed, all the specifications listed in Annex III were considered.)

Short blast means a blast about l-second long.

Prolonged blast means a blast from 4-seconds to 6-seconds duration.

Meeting (or head-on) situation defines a situation in which, by day, the masts of each vessel, when viewed from the other, are in a line.

Crossing situation defines the situation where each vessel has the other any place forward of 22.5° abaft of either beam.

Overtaking situation describes the situation where one vessel approaches the other from anyplace more than 22.5° abaft of either beam.

[An illustration in the course, not reproduced here: Figure 5-16.–Overtaking situation.]

Errata #1 (23 Jul 1999), which Errata #2 (22 May 2000) later superseded without repeating its text corrections: Change paragraph 1 to read as follows: “Stand-on vessel refers to any power-driven vessel in a crossing situation close enough to involve risk of collision; the vessel being on the starboard side of another vessel is the “stand-on” vessel, the vessel should maintain course and speed.”

Since there are major differences between the International and the Inland maneuvering and warning signals, they will be presented separately, and the differences will be noted on the inland version. International

When vessels are in sight of one another, a power-driven vessel underway, when maneuvering as authorized or required by these rules, must indicate that maneuver by the following signals on the whistle:

One short blast— I AM ALTERING MY COURSE

TO STARBOARD

Two short blasts— I AM ALTERING MY COURSE

TO PORT

Three short blasts— I AM OPERATING ASTERN

PROPULSION

Any vessel may supplement the whistle signals prescribed above by light signals, repeated as appropriate while the maneuver is being carried out. These light signals will have the following significance:

One flash— I AM ALTERING MY COURSE TO

STARBOARD

Two flashes— I AM ALTERING MY COURSE TO

PORT

Three flashes-I AM OPERATING ASTERN

PROPULSION

The duration of each flash will be is about 1 second; the interval between flashes must be about 1 second; and the interval between successive signals must be not less than 10 seconds. The light used for this signal will be, if fitted, an all-around white light visible at a minimum range of 5 miles, and must comply with the provisions of Annex I that pertain to the International Rules.

When in sight of another in a narrow channel or fairway, and action is required by the vessel being overtaken, the vessel intending to overtake another must indicate its intention by the following signals on the whistle:

Two prolonged blasts followed by one short blast— I

INTEND TO OVERTAKE YOU ON YOUR

STARBOARD SIDE

Two prolonged blasts followed by two short blasts— I

INTEND TO OVERTAKE YOU ON YOUR PORT

SIDE

The vessel about to be overtaken will indicate agreement by the following signal on the whistle:

One prolonged, one short, one prolonged, and one short blast, in that order

When vessels in sight of one another are approaching each other and either vessel fails to understand the intentions or actions of the other, or is in doubt whether sufficient action is being taken by the other to avoid collision, the vessel in doubt must immediately indicate such doubt by giving at least five short, rapid blasts on the whistle. Such signal may be supplemented by a light signal of at least five short, rapid flashes.

A vessel nearing a bend or an area of a channel or fairway where other vessels may be obscured by an intervening obstruction must sound one prolonged blast. Such signal must be answered with a prolonged blast by any approaching vessel that may be within hearing around the bend or behind the intervening obstruction.

If whistles are fitted farther apart than 100 meters on a vessel, only one of the whistles will be used for giving maneuvering and warning signals.

These last three paragraphs apply to Inland Rules as well as International Rules. Inland When power-driven vessels are in sight of one another and meeting or crossing at a distance within half a mile of each other, each vessel underway, when maneuvering as authorized or required by the Inland Rules, must indicate that maneuver by the following signals on the whistle: one short blast to mean I INTEND TO LEAVE YOU ON MY PORT SIDE two short blasts to mean I INTEND TO LEAVE YOU ON MY STARBOARD SIDE three short blasts to mean I AM OPERATING ASTERN PROPULSION.

NOTE

The International Rules do not specify a distance for sounding signals. The International Rules read I AM, and the

Inland Rules read I INTEND TO. The one- and two-short-blast signals in the Inland Rules signify an intention of passage with one other vessel. Upon hearing the one- or two-blast signal of the other, the vessel must, if in agreement, sound the same whistle signal and take the steps necessary to effect a safe passing. If, however, the vessel doubts the safety of the proposed maneuver, the vessel must sound the danger signal of at least five short, rapid blasts of the whistle. Each vessel will then take appropriate precautionary action until a safe passing agreement is made. A vessel may supplement those signals with light signals. Light signals must have the following significance: one flash to mean I INTEND TO LEAVE YOU ON MY PORT SIDE two flashes to mean I INTEND TO LEAVE YOU ON MY STARBOARD SIDE three flashes to mean I AM OPERATING ASTERN PROPULSION. The duration of each flash must be about 1 second, and the light used for this signal, if fitted, must be one all-around white or yellow light visible at a minimum range of 2 miles, synchronized with the whistle, and must comply with the provisions of Annex I to the Inland Rules.

NOTE

The Inland Rules do not specify an interval between flashes or an interval between successive signals. The International Rules do not allow a yellow light to be used for light signals. The minimum visible range for light is 2 miles for Inland Rules and 5 miles for International Rules. The Inland Rules require that light signals and sound signals be given at the same time (synchronized). When in sight of another, a power-driven vessel intending to overtake another power-driven vessel must indicate its intention by the following signals on the whistle: one short blast to mean I INTEND TO OVERTAKE YOU ON YOUR STARBOARD SIDE; and two short blasts to mean I INTEND TO OVERTAKE YOU ON YOUR PORT SIDE.

NOTE

The Inland Rules require signals for overtaking vessels when in sight of another in a narrow channel or fairway. The International Rules require two prolonged blasts preceding the short blast required by the Inland Rules. In both International and Inland Rules, overtaking signals are signals of intention only and must be answered by the vessel that is being overtaken. The power-driven vessel about to be overtaken will, if in agreement, sound a similar sound signal. If in doubt, the vessel must sound the danger signal of at least five short, rapid blasts.

NOTE

The Inland Rules require the vessel being overtaken, if it agrees, to answer with a signal similar to the one sounded by the overtaking vessel. The International Rules require the vessel being overtaken, if it agrees, to sound one prolonged, one short, one prolonged, and one short blast, in that order. The Inland Rules for overtaking vessels apply only to power-driven vessels; the International Rules apply to all vessels.

A vessel that reaches agreement with another vessel in a meeting, crossing, or overtaking situation by using the radiotelephone, as prescribed by the Bridge-to-Bridge Radiotelephone Act (85 Stat. 165; 33 U.S.C. 1207), is not obligated to sound the whistle signals prescribed by this rule, but may do so. If agreement is not reached, then whistle signals must be exchanged in a timely manner and will prevail.

Conduct of Vessels in Restricted Visibility, Rule 20C, of both Inland and International Rules states that the lights prescribed by the rules are to be exhibited in restricted visibility. Rule 35 of both Inland and International Rules states that the required sound signals are to be sounded in or near an area of restricted visibility. Inland and International Rule 19 applies to vessels not in sight of one another when navigating in or near an area of restricted visibility. Fog Signals

Before radar, the regulations depended almost solely on the fog signal; vessels in fog sounded fog signals and when other vessels heard them, they stopped. The increasing use of radar today has resulted in a supplementation to the existing regulations.

In 1960, a radar annex was appended to the International Rules; it was ultimately incorporated in 1972.

In 1980, the word fog was discarded and replaced by the term restricted visibility. The International Rules today make it clear that vessels must maintain a proper lookout.

The rules make it obvious that radar is NOT a substitute for a proper lookout. The courts have ruled that dependable radar equipment must be turned on and intelligent use made of it.

Rule 19E requires a vessel hearing a fog signal of another vessel to reduce its speed, to bare steerageway, and to proceed with caution.

No defined distance has been established regarding visibility for sounding fog signals. Three miles has been recommended for all vessels over 50 meters long. The rules prescribe three types of devices: a whistle (for vessels underway), and a bell and a gong (for vessels anchored or aground). A whistle requires either a prolonged blast of 4-6 seconds or one short blast. A bell requires a 5-second rapid ringing. And a gong requires a 5-second rapid sounding. International Rules require a 2-minute interval between warning signals.

The fog signals for inland and international waters (COLREGs) are very similar but there are two exceptions. First, the Inland Rules do not provide for a vessel constrained by draft; and second, they do not require small vessels in specifically designated anchorages to sound fog signals.

Small boats, as well as larger vessels, are required to signal. A boat coxswain must have a foghorn in the boat at all times. Motorboats must be outfitted with an efficient whistle, horn, or other sound-producing device.

It should be noted that because a boat is exempt from some specific requirement of the rules, it is not excused from complying with the rules in all other respects. Sound Signals

The sound signals in restricted visibility for the International and Inland Rules are very similar. In this part of the text, only the Inland Rules will be presented. Any differences between the International and Inland Rules will be noted.

In or near an area of restricted visibility, whether by day or night, the signals prescribed in this rule will be used as follows:

A power-driven vessel making way through the water must sound at intervals of not more than 2 minutes one prolonged blast.

A power-driven vessel underway, but stopped and making no way through the water, will sound at intervals of not more than 2 minutes two prolonged blasts in succession with an interval of about 2 seconds between them.

A vessel not under command; a vessel restricted in ability to maneuver, whether underway or at anchor; a sailing vessel; a vessel engaged in fishing, whether underway or at anchor; and a vessel engaged in towing or pushing another vessel will sound at intervals of not more than 2 minutes, three blasts in succession; namely, one prolonged followed by two short blasts.

NOTE

In the Inland Rules, no provisions are made for a vessel constrained by its draft. The International Rules address vessels engaged in fishing while at anchor and vessels restricted in their ability to maneuver when carrying out work at anchor separately.

The required sound signals for these situations are the same as those addressed for the same situation in the Inland.

A vessel towed (or if more than one vessel is towed, the last vessel of the tow), if it is manned will, at intervals of not more than 2 minutes, sound four blasts in succession; namely, one prolonged blast followed by three short blasts. When practical, this signal must be made immediately after the signal made by the towing vessel.

When a pushing vessel and a vessel being pushed ahead are rigidly connected in a composite unit, they will be regarded as a power-driven vessel and give the signals prescribed earlier for a power-driven vessel making way through the water or a vessel underway but stopped and making no way through the water.

A vessel at anchor must, at intervals of not more than 1 minute, ring the bell rapidly for about 5 seconds. In a vessel of 100 meters or more in length, the bell must be sounded in the forepart of the vessel; and immediately after the ringing of the bell, the gong must be sounded rapidly for about 5 seconds in the afterpart of the vessel. A vessel at anchor may, in addition, sound three blasts in succession; namely, one short, one prolonged, and one short blast to give warning of its position and of the possibility of collision to an approaching vessel.

In addition to giving the bell signal and, if required, the gong signal prescribed above, a vessel aground must give three separate and distinct strokes on the bell immediately before and after the rapid ringing of the bell. A vessel aground may, in addition, sound an appropriate whistle signal.

A vessel of less than 12 meters in length is not obliged to give the above-mentioned signals but, if it does not, the vessel will make some other efficient sound signal at intervals of not more than 2 minutes.

A pilot vessel, when engaged on pilotage duty, may, in addition to the signals prescribed for a power-driven vessel underway making way through the water; underway but stopped and not making way through the water; or at anchor; sound an identity signal consisting of four short blasts.

[An illustration in the course, not reproduced here: Figure 5-17.–International/inland distress signals.]

The International and Inland Rules on signals to attract attention are almost identical. They are as follows:

If necessary to attract the attention of another vessel, any vessel may make light or sound signals that cannot be mistaken for any signal authorized elsewhere in these rules, or may direct the beam of its searchlight in the direction of the danger in such a way as not to embarrass any vessel.

NOTE

The following paragraph from the International Rules is not included in the Inland Rules: “Any light to attract the attention of another vessel will be such that it cannot be mistaken for any aid to navigation. For that reason, the use of high-intensity intermittent or revolving lights, such as strobe lights, must be avoided”. There is no basis in the Rules of the Road for the popular notion that the national ensign hoisted upside down is a recognized signal of distress. No man-of-war would ever subject the colors to this indignity. But if you should see a private craft with the ensign hoisted upside down, it is probably in distress. See figure 5-17 for distress signals under the International and Inland Rules. The signals in figure 5-17 may be used or exhibited either together or separately, to indicate distress and need of assistance.

NOTE

There is no provision in the International Rules for the distress signal shown in figure 5-18.

The International and Inland Rules contain the following supplemental information:

Except for indicating distress and need of assistance, the use or exhibition of any of the foregoing distress signals and the use of other signals that may be confused with any of the those signals is prohibited.

Note the relevant sections of the International Code of Signals, Pub. 102, the Merchant Ship Search and Rescue Manual, and the following signals:

A piece of orange-colored canvas with either a black square and circle or other appropriate symbol (for identification from the air) (fig. 5-17), or a dye marker (fig. 5-17).

The following signals, although not part of the Rules of the Road, are prescribed for submerged submarines in emergency situations involving rising to periscope depth or surfacing:

A white or yellow smoke flare fired into the air from a submarine indicates the submarine is coming to periscope depth to carry out surfacing procedures. Ships should clear the immediate vicinity but should not stop propellers.

A red smoke flare fired into the air from a submarine is a signal that the submarine is in serious trouble and will surface immediately if possible. Smoke flares of any color, fired into the air at short intervals, mean the submarine requires assistance. All ships in the area should clear the immediate vicinity but stand by to give aid.

[An illustration in the course, not reproduced here: Figure 5-18.–A high-intensity white light flashing at regular intervals from 50 to 70 times per minute.]

LEARNING OBJECTIVES: Define buoys.

Recognize the International Buoyage Regions.

Describe the IALA Maritime Buoyage System including buoy types, buoy colors, and buoy markings.

Buoys are moored floating markers placed so as to guide ships in and out of channels, warn them away from hidden dangers, and lead them to anchorage areas, and so forth. Buoys may be of various sizes and shapes. Regardless of their shapes, however, their distinctive coloring is the chief indication of their purposes.

Large automatic navigational buoys (LANBYs) are major aids to navigation, and they provide light, sound signal, and radio beacon service. The LANBY is an all steel disk-shaped hull 40 feet in diameter. The light, sound signal, and radio beacon are located on the mast.

Although buoys are valuable aids to navigation, they must never be depended upon exclusively. Buoys frequently drag their moorings in heavy weather, or they may be set adrift when run down by passing vessels. Lights on lighted buoys may go out of commission. Whistles, bells, and gongs actuated by the sea's motions may fail to function in smooth water.

To reach agreement with all maritime countries to bring all buoyage into one system with the least amount of money and time expended, two international buoyage regions were established. Figure 5-19 outlines International Buoyage Regions A and B. Navigational charts produced and/or printed after 1983 indicate the buoyage region to which the chart refers.

Until recently, as many as 30 different buoyage systems were in use around the world. In 1982, most of the maritime nations of the world signed an agreement sponsored by the International Association of Lighthouse Authorities (IALA). This agreement adopted a system known as the IALA Maritime Buoyage System. The system provides rules that apply to all fixed and floating marks other than lighthouses, sector lights, range lights, lightships, and large automatic navigational buoys (LANBYs).

The Maritime Buoyage System provides five types of marks that may be used in any combination. The five types of marks are lateral, cardinal, isolated danger, safe water, and special. Each type of mark will be discussed briefly here and in more detail later.

1. Lateral marks–indicate the port and starboard hand sides of channels. Within the Maritime Buoyage System there are two international buoyage regions where lateral marks differ. These buoyage regions and the different lateral marks will be discussed in detail later in this chapter.

2. Cardinal marks–used in conjunction with the compass, indicate that the navigable water lies to the named side of the mark

3. Isolated danger marks–erected on, or moored directly on or over, dangers of limited size.

4. Safe water marks–used to indicate that there is water safe for navigation all around the position (examples: midchannel and fairways).

5. Special marks–call attention to an area or specific feature. Explanation of special marks may be found on the navigational chart you are using, in Sailing Directions, or in Coast Pilots. Distinguishing Marks

The meaning of the mark depends upon one or more of the following features:

1. By day–color, shape, and topmark

2. By night–light color and phase characteristics

COLOR.— The colors used for lateral marks in Region A are red, green, green with one red horizontal band, and red with one green horizontal band.

The colors used for lateral marks in Region B are green, red, red with one green horizontal band, and green with one red horizontal band.

SHAPE.— There are five basic buoy shapes (fig. 5-20): can, nun, spherical, pillar, and spar. With the exception of pillar and spar buoys, the shape of the buoy indicates the correct side on which to pass. Can buoys may sometimes be referred to as cylindrical, and nun buoys referred to as conical. The term pillar is used to describe any buoy that is smaller than a lighthouse buoy but has a tall, central structure on a broad base. Lighted buoys in the United States are referred to as pillar buoys.

TOPMARKS.— The IALA Maritime Buoyage System makes use of can, nun, spherical, and X-shaped topmarks only. Topmarks on pillar and spar buoys are particularly important to indicate the side on which they will be passed and will be used wherever practical.

LIGHTS.— Where marks are lighted, red and green lights are reserved for port and starboard or starboard and port lateral marks. Yellow lights are for special marks, and white lights are used for other types of marks, which will be discussed later in this chapter.

PHASE CHARACTERISTICS.— Lights, when fitted, may have any of the following phase characteristics (or frequency of duration): quick flashing, flashing, long flashing, or group flashing. Lateral Marks

Lateral marks are generally used for well-defined channels. They indicate the route to be followed and are used in conjunction with a “conventional direction of buoyage.” This direction is defined in one of two ways:

Local direction of buoyage—the direction taken by the mariner when approaching a harbor, river estuary, or other waterway from seaward.

General direction of buoyage—in other areas, a direction determined by the buoyage authorities, following a clockwise direction around continental landmasses, given in Sailing Directions, and, if necessary, indicated on charts by a symbol.

The numbering or lettering of buoys is an optional feature. In the United States, fairway and channel buoys are always numbered odd to port and even to starboard, approaching from seaward. Table 5-3 shows the aids used by the United States.

REGION A.— As shown in figure 5-19, International Buoyage Region A covers Europe and Asia with the exception of Japan, the Republic of Korea, and the Republic of the Philippines. The major rule to remember in this region is red to port when returning from seaward. The lateral marks (buoys) used in Region A are as follows:

Port-hand marks (fig. 5-21)

Color: Red

Shape (buoys): Can, pillar, or spar

Topmark (when required): Single red can

Light (when fitted):

Color: Red

Phase Characteristics: Any other than Composite

Group Flashing (2 + 1)

Starboard-hand marks (fig. 5-22)

Color: Green

Shape (buoys): Nun, pillar, or spar Topmark (when required): Single green cone, point upward Light (when fitted): Color: Green Phase Characteristics: Any other than Composite

Group Flashing (2 + 1) When the ship is proceeding in the conventional direction of buoyage, a preferred channel may be indicated by a modified port or starboard lateral mark at the point where a channel divides. Preferred channel to port (fig. 5-23) Color: Green with one broad red horizontal band Shape (buoys): Nun, pillar, or spar Topmark (when required): Single green cone, point upward Light (when fitted): Color: Green Phase Characteristics: Composite Group Flashing

(2 + 1) Preferred channel to starboard (fig. 5-24) Color: Red with one broad green horizontal band Shape (buoys): Can, pillar, or spar Topmark (when required): Single red can Light (when fitted): Color: Red

Characteristics: Composite Group Flashing

(2 + 1) REGION B.— Basically, Region B (refer to fig. 5-19) covers the Western Hemisphere, Japan, the Republic of Korea, and the Philippines. The main rule to remember in this region is red right returning from seaward The lateral marks (buoys) used in Region B are as follows: Port-hand marks (fig. 5-25) Color: Green Shape (buoys): Can, pillar, or spar Topmark (when required): Single green can

Light (when fitted): Color: Green Phase Characteristics: Any other than Composite

Group Flashing (2 + 1) Starboard-hand Lateral Aids: Color: Red Shape: Nun or Lighted Light (when fitted): Red Rhythm: Any, other than Comp Gp Fl (2+ 1) Changes: Lights-from white or red to red only Port-hand Lateral aids: Color: Green Shape: Can or Lighted Light (when fitted): Green Rhythm: Any, other than Comp Gp Fl (2+1) Changes: Color-From black to green Lights-From white or green to green only Preferred Channel to Starboard: Color: Horizontally banded green over red over green Shape: Can or Lighted Light (when fitted): Green Rhythm: Comp Gp Fl (2+1) Changes: Color-From black to green Lights-From white or green to green only Light rhythm-From I Qk Fl to Comp Fl (2+1) Preferred Channel to Port: Color: Horizontally banded red over green over red Shape: Nun or lighted Light (when fitted): Red Rhythm: Comp Gp Fl (2+1) Changes: Color-From black yo green Lights-From white or red to red only Light rhythm-From I Qk Fl to Comp Gp Fl (2+1) Safe Water: Color: Vertically striped red-and-white Shape: Spherical or lighted (if lighted, red topmark) Topmark (when required): Single red sphere Light (when fitted): White Rhythm: Morse A Changes: Color-From black-and-white to red-and-white Shape-Nonspherical buoys will have topmark

Nun and can buoys will not Special Purpose: Color: Yellow Shape: Optional, but not conflicting with navigational mark Light (when fitted): Yellow Rhythm: Any, other than Qk Fl, Gp Qk Fl, Gp Qk & L Fl, V Qk Fl, Gp V Qk Fl, Gp V Qk Fl & L FL, Gp Fl (2) Iso, Occ, L Fl, MO (A), or MO (U) Changes: Color-From various color combinations to yellow All special-purpose aids will be yellow and, when lighted, will use yellow lights Information and Regulatory Markers: No Change Starboard-hand marks (fig. 5-26) Color: Red Shape (buoys): Nun, pillar, or spar Topmark (when required): Single red cone, point upward Light (when fitted): Color: Red Phase Characteristics: Any other than Composite

Group Flashing (2 + 1) Preferred channel to port (fig. 5-27) Color: Red with one broad green horizontal band Shape (buoys): Nun, pillar, or spar Topmark (when required): Single red cone, point upward Light (when fitted): Color: Red Phase Characteristics: Composite Group Flashing

(2 + 1) Preferred channel to starboard (fig. 5-28) Color: Green with one broad red horizontal band Shape (buoys): Can, pillar, or spar Topmark (when required): Single green can Light (when fitted): Color: Green Phase Characteristics: Composite Group Flashing

(2 + 1)

NOTE

In buoyage Regions A and B, if marks at the sides of a channel are numbered or lettered, the numbering or lettering will follow the conventional direction of buoyage. Cardinal Marks Cardinal marks are used in conjunction with the compass to indicate the best navigable water. A cardinal mark is placed in one of the four quadrants (north, east, south, or west) from the best water. A cardinal mark takes its name from the compass point in which it is placed. Figure 5-29 shows the IALA Maritime Buoyage System cardinal marks (buoys).

Mariners are safe if they pass north of a north mark, east of an east mark south of a south mark and west of a west mark. Acardinal mark may be used to accomplish the following:

Indicate that the deepest water is an area on the named side of the mark

Indicate the safe side on which to pass a danger

Draw attention to a feature in a channel, such as a bend, junction, branch, or end of a shoal

TOPMARK.— By day, topmarks are the most important features of cardinal marks. The arrangement of the cones must be memorized. For north, the point of each cone is up. For south, the point of each cone is down. An aid to help you memorize the west topmark is its resemblance to a wine glass. Cardinal marks carry topmarks, whenever practical, with the cones as large as possible and clearly separated.

COLOR.— Black and yellow horizontal bands are used to color cardinal marks. The position of the black band, or bands, is related to the points of the black topmarks. The black and yellow horizontal bands are used as follows:

North—Black band above yellow band

South—Black band below yellow band

West—Black band with yellow bands above and below

East-Black band above and below yellow band

The shape of a cardinal mark is not important, but in the case of a buoy, it will be pillar or spar.

LIGHT CHARACTERISTICS— When lighted, a cardinal mark exhibits a white light. The characteristics are based on a group of quick (Qk) or very quick (Vqk) flashes that distinguish the light as a cardinal mark and indicate its quadrant. The distinguishing quick or very quick flashes are as follows:

North—Very quick flashing (Vqk) or quick flashing (Qk)

East—Very quick flashing every 5 seconds (Vqk [3] 5s) or quick flashing every 10 seconds (Qk [3] 10s)

South—Very quick flashing followed by a long flash every 10 seconds (Vqk FL [6] + LF1 10s) or quick flashing followed by a long flash every 15 seconds (Qk [6] + LF1 15s)

West–Very quick flashing every 10 seconds (Vqk [9] 10s) or quick flashing every 15 seconds (Qk [9] 15s)

As a memory aid, associate the number of flashes in each group with a clock face (3 o'clock–east, 6 o'clock–south, and 9 o'clock–west).

The long flash immediately following the group of flashes of a south cardinal mark is to ensure that its six flashes cannot be mistaken for three or nine.

Quick flashing lights flash at the rate of either 60 or 50 flashes per minute. Very quick flashing lights flash at the rate of either 120 or 100 flashes per minute. It is necessary to have a choice of quick flashing or very quick flashing lights to avoid confusion. Two north buoys that are placed near enough to each other to be mistaken is one example where the quick flashing and very quick flashing lights would be needed. Isolated Danger Marks

Isolated danger marks (fig. 5-30) are erected on, or moored above, an isolated danger of limited extent. The isolated danger mark has navigable water all around it. The extent of the surrounding navigable water is not important. The isolated danger mark, for example, indicates either a shoal that is well offshore or an islet separated by a narrow channel from the coast.

A black double-sphere topmark is, by day, the most important feature of an isolated danger mark. Whenever practical, this topmark will be carried with the spheres as large as possible, mounted vertically, and clearly separated.

Black, with one or more red horizontal bands, is used for isolated danger marks. The shape of an isolated danger mark is not significant, but, in the case of a buoy, it will be a pillar or spar.

When lighted, a white flashing light showing a group of two flashes (F1 [2]) is used to denote an isolated danger mark. The association of two flashes and two spheres in the topmark may be a help in remembering these characteristics. Safe Water Marks

Safe water marks (fig. 5-31) are used to indicate that there is navigable water all around the mark. Such a mark may be used as a centerline, midchannel, or landfall buoy.

Red and white vertical stripes are used for safe water marks. The vertical stripes are used to distinguish them from the black-banded danger marks. Spherical, pillar, or spar buoys may be used as safe water marks. Whenever practical, a pillar or spar buoy used as a safe water mark will carry a single red sphere topmark.

When lighted, a safe water mark exhibits a white light. The phase characteristics of the light will be occulting, equal interval (isophase), one long flash every 10 seconds, or Morse A. The association of a single flash and a single sphere in the topmark may help to remember these characteristics. Special Marks

Special marks (fig. 5-32) may be used to indicate a special area or feature. The nature of the special area or feature may be found by consulting the navigational chart being used.

Notice to Mariners. The uses of a special mark include the following:

Ocean Data Acquisition System (ODAS), buoys carrying oceanographic or meteorological sensors

Traffic separation marks

Spoil ground marks

Military exercise zone marks

Cable or pipeline marks, including outfall pipes

Recreation zone marks

Another function of a special mark is to define a channel within a channel (for example, a channel for deep-draft vessels in a wide approach area where the limits of the channel for normal navigation are marked by red and green lateral buoys).

Yellow is the color used for special marks. The shape of a special mark is optional, but it must not conflict with a lateral or a safe water mark. For example, an outfall buoy on the port-hand side of a channel could be can shaped but not conical.

When a topmark is carried, it takes the form of a single yellow X. When a light is exhibited, it is yellow. The phase characteristics may be any, other than those used for the white lights of cardinal, isolated danger, and safe water marks. Daymarks

Unlighted aids to navigation (except unlighted buoys) are called daymarks (fig. 5-33). A daymark may consist of a single piling with a mark on top, a spar supporting a cask, a slate or masonry tower, or any of several structures.

Daymarks, like lighthouses, are usually colored to distinguish them from their surroundings and make them easy to identify. Daymarks marking channels are colored and numbered like channel buoys. Many are fitted with reflectors that show the same colors that a lighted buoy would show at night in the same position. Intracoastal Waterway

The Intracoastal Waterway, called the inland waterway, is a channel in which a light-draft vessel can navigate coastwise from the Chesapeake Bay almost to the Mexican border, remaining inside the natural or artificial breakwaters for almost the entire length of the trip.

Every buoy, daymark, or light structure along the Intracoastal Waterway has part of its surface painted yellow, the distinctive coloring adopted for this waterway. Somewhere on a lighted buoy is a band or a border of yellow.

Red buoys and daymarks are to the right, green to the left, as you proceed from the Chesapeake Bay toward Mexico. As in other channels, red buoys have even numbers; green buoys, odd numbers. Because the numbers would increase excessively in such a long line of buoys, they are numbered in groups that usually contain no more than 200 buoys. At certain natural dividing points, numbering begins again at 1.

Lights on buoys in the Intracoastal Waterway follow the standard system of red lights on red buoys and green lights on green buoys. Lights on other lighted aids agree with the standard rules for lights on aids to navigation. Ranges

Two day beacons, located some distance apart on a specific true bearing, constitute a day beacon range. When a ship reaches a position where the two lights (or beacons) are seen exactly in line, it is “on the range.” Ranges are especially valuable for guiding ships along the approaches to or through narrow channels. Much of the steering through the Panama Canal is accomplished on ranges. Other examples of successive straight reaches marked by ranges are the channel entrances to the St. Johns River (on the Atlantic coast) and the Columbia River (on the Pacific coast).

Lights on ranges may show any of the four standard colors, and they may be fixed, flashing, or occulting. Most range lights appear to lose intensity rapidly as a ship diverges from the range line of bearing.

When steering on a range, it is highly important that you ascertain the limit beyond which the range line of bearing cannot be followed safely. This information is available on the navigation chart being used. Fog Signals

Most lighthouses and LANBYS are equipped with fog-signaling apparatus, ordinarily sounded automatically by mechanical and electrical means. For identification purposes, each station has its own assigned number of blasts, recurring at specified intervals. A definite time is required for each station to sound its entire series of blasts; this timing provides another means of identification.

The various types of apparatus produce corresponding variance of pitch and tone, thus giving your ear a chance to compare the sound of a station with its description in the Light Lists, published by the U.S. Coast Guard. A thorough knowledge of the lights and buoyage system is important because you will be, at one time or another, assigned to lookout duties as a bridge watchstander, or as a boat crew where knowledge of the buoy system is used extensively.

[An illustration in the course, not reproduced here: Figure 5-19.–IALA Maritime Buoyage System, Buoyage Regions A and B.]

[An illustration in the course, not reproduced here: Figure 5-20.–Basic buoy shapes.]

[An illustration in the course, not reproduced here: Figure 5-21.–IALA Maritime Buoyage System, International Buoyage Region A port-hand marks (buoys).]

[An illustration in the course, not reproduced here: Figure 5-22.–IALA Maritime Buoyage System, International Buoyage Region A starboard-hand marks (buoys).]

[An illustration in the course, not reproduced here: Figure 5-23.–IALA Maritime Buoyage System, International Buoyage Region A preferred channel to port.]

[An illustration in the course, not reproduced here: Figure 5-24.–IALA Maritime Buoyage System, International Buoyage Region A preferred channel to starboard.]

[An illustration in the course, not reproduced here: Table 5-3.–Markings from the IALA Maritime Buoyage Systems incorporated into the U.S. Aids to Navigation]

[An illustration in the course, not reproduced here: Figure 5-25.–IALA Maritime Buoyage System, International Buoyage Region B port-hand marks (buoys).]

[An illustration in the course, not reproduced here: Figure 5-26.–IALA Maritime Buoyage System, International Buoyage Region B starboard-hand marks (buoys).]

[An illustration in the course, not reproduced here: Figure 5-27.–IALA Maritime Buoyage System, International Buoyage Region B preferred channel to port.]

[An illustration in the course, not reproduced here: Figure 5-28.–IALA Maritime Buoyage System, International Buoyage Region B preferred channel to starboard.]

[An illustration in the course, not reproduced here: Figure 5-29.–IALA Maritime Buoyage System cardinal marks.]

[An illustration in the course, not reproduced here: Figure 5-30.–IALA Maritime Buoyage System isolated danger marks.]

[An illustration in the course, not reproduced here: Figure 5-31.–IALA Maritime Buoyage System safe water marks.]

[An illustration in the course, not reproduced here: Figure 5-32.— IALA Maritime Buoyage System special marks.]

[An illustration in the course, not reproduced here: Figure 5-33.–IALA Maritime Buoyage System lateral daymarks.]

The knowledge and experience you acquire as a Seaman today will help you to do whatever job you are assigned to the utmost of your ability in the future.

As a Seaman you may he assigned to any of the numerous vessels of the U.S. fleet. Aboard most ships, your job will most likely be different from the job you left. With “hands-on” training indoctrination, you should be performing your assigned duties as well as any other Seaman.

This chapter has covered many knowledge factors relating to boat handling, including a basic knowledge of the Rules of the Road and the buoy system. You can be assured that your time at sea will be challenging and rewarding.

It is clear that the conditions under which work of this kind is to be done may vary almost indefinitely and that the methods used must be varied correspondingly. It would be hopeless to attempt to illustrate all or even any considerable number of the situations which arise in practice, but it is not so difficult to analyze in a general way the various factors involved, and to show their application to a few special cases.

The factors are: lines, helm, screw, headway or sternway of the ship, current, wind.

We begin by considering the use of lines, first alone, then in combination with other factors.

CASE I.

If the ship is lying dead in the water abreast of a dock, as in Fig. 1, Plate 138, with a bow line leading to the dock, hauling on this line will turn the bow in, of course, but it will also throw the stern out, the ship pivoting about the center of gravity. It should be noted, however, that the stern does not go out quite as much as the bow comes in; for, since the ship is not held rigidly at the pivoting point, the mass as a whole will respond more or less to the force acting on the bow, and the resultant motion will be like that shown in the figure.

If the stern is held by a line to the dock, as in Fig. 2, Plate 138, the pivot is transferred to the stern and the whole length of the ship comes in as shown. This requires much greater effort than to turn the ship about her natural pivoting point as in Fig. 1.

If the bow and stern lines are hauled on at the same time, the ship may be breasted in bodily, but at an even greater expenditure of work than in the preceding case.

If either of the lines described above leads off at an angle from the beam, it constitutes a "spring," which may be defined as a line diagonal to the keel and exerting a force, when power is applied to it, both in the direction of the keel and at right angles to that direction.

¹ See also Chapter XXI, "The Handling of Destroyers."

[An illustration in the book, not reproduced here: Plate No. 139. Handling Steamers Around a Dock.]

A spring is used, therefore, for moving the ship ahead or astern and breasting her in at the same time.

CASE 2.

If the ship has way, either ahead or astern, her momentum enters into the problem of her behavior. We have here another application of a spring, the power involved in this case being furnished by the ship itself.

In Fig. 3, Plate 138, suppose that the steamer shown is moving parallel to the face of the dock with engines stopped and helm amidships, and that the stern spring A K is taut. Disregarding the resistance of the water, which is inconsiderable, the motion of the ship will be that resulting from her momentum along the original course and the tension along A K. The tension on A K may be resolved into two components; one retarding the ship along the line of her öoriginal course and thus directly opposing the momentum, the other hauling her in toward the dock and tending at the same time to turn her about the center of gravity, drawing the stern in and throwing the bow out. It is important to note, however, that the momentum, which is concentrated at the center of gravity, forward of the pivot, opposes the turning and tends to keep the ship straight. Thus as a matter of fact the ship does not turn much in cases of this kind, but comes in nearly parallel to the dock (Fig. 4, Plate 138).

CASE 3. (Figs. 1 and 2, Plate 139.)

If the vessel is moving as before, but with a spring from the bow instead of from the stern, the forces acting are similar to those in the preceding case, but with an important difference. In the present case, the momentum acts to increase the turning effect of the spring, instead of opposing it. This will become clear if Fig. 2, Plate 139, and Fig. 4, Plate 138, are compared.

The result of this difference is that the bow of a ship moving ahead on a bow-spring turns sharply in toward the dock, whereas the stern is turned in very little, if at all, by a stern-spring.

If the ship is moving astern, instead of ahead, the conditions are of course reversed, a stern-spring turning the stern in sharply, while a bow-spring has little effect.

Evidently, in both of the preceding cases, the turning moment is greatest when the line is made fast at the extreme bow or stern. If it is made fast at the center of gravity, the ship should (theoretically) spring in without turning, provided her draft of water is the same forward and aft. We shall presently see that if the helm is to be used (as in practice it always is) the maximum control of the ship will be obtained when the line is made fast at some point intermediate between the end of the ship and the center of gravity.

CASE 4.

Suppose that the vessel of Case 2 (Figs. 3 and 4, Plate 138) puts her helm to starboard with a view to throwing her head in. Since the steering effect of the rudder is chiefly a matter of moving the stern of the ship, and since the stern cannot be thrown off to starboard because it is held by the spring, it follows that starboard helm can here have comparatively little turning effect. This assumes, of course, that the line is made fast over the rudder. Port helm, on the other hand, will help materially to throw the stern in.

If in Case 3 (Figs. 1 and 2, Plate 139) the helm is put to starboard, it will throw the stern off and greatly increase the rapidity with which the bow turns in. If put to port, it will oppose the turning, but not enough to overcome it.

If in any case we make fast the line at the center of gravity while the ship is working ahead, we shall spring the ship in bodily but can at the same time steer her by putting the helm over, throwing the stern to either side as desired; the ship swinging on a pivot under the influence of the helm, while coming bodily in on the spring.

If the line, instead of being made fast amidships, is taken to a chock between the midship point and the stern, say midway between, we gain a considerable steering power, without entirely sacrificing the turning tendency of the spring. In practice, the spring is usually taken to this point—or to the corresponding one between the midship point and the bow—and this is found to give a convenient balance of forces and to admit of working in with the ship under good control (Fig. 3, Plate 139).

CASE 5.

If we add to the factors already considered, the effect of the screw, going ahead or backing, we have the conditions of actual practice in cases where the tide is not strong enough to be considered.

So long as the screw is turning ahead it has a powerful steering effect through the action of the discharge current against the rudder, driving the stern off to the side to which the helm is put, the bow being held in by a spring. In backing, its effect may be utilized to throw the stern to one side, but not to the other. If it is right handed, it will throw the stern to port and cannot be prevented from this even by hard over port helm. It is for this reason that single-screw steamers (right handed) are most easily put alongside with the port side to the dock. They can run in at a considerable angle, then stop and back and so straighten up parallel to the dock, whereas with the starboard side in, backing would throw the stern further off.

Vessels with twin-screws have the same advantage in working around a dock that they have in manœuvring elsewhere; that is to say, the screws can be utilized to turn the ship even when she has no steerage-way, and when, therefore, the rudder has little effect. This use of twin-screws-going ahead on one and backing the other—is obvious enough; but there is another application which can be made of them which is often overlooked. As noted above (and as explained at considerable length in the chapter on "The Steering of Steamers"), a right-handed screw, in backing, throws the stern to port, while a left-handed screw throws it to starboard. In a single-screw steamer we have, in this action of the backing screw, a powerful force acting to one side, which may be utilized with great advantage if we wish to throw the stern to that side. If it happens that we wish to throw the stern to the other side while backing, or to hold it steady, then this action of the screw is a disadvantage, and often a serious embarrassment. But in a twin-screw steamer we have both a right-handed and a left-handed screw, so that we may, in backing, throw the stern to either side by using the proper screw. It is the general practice to put the right-handed screw to starboard and the left-handed screw to port. If, therefore, we wish to throw the stern to port while backing, we back with the starboard screw alone; and it should be noted that not only does the direct action of the screw throw the stern to port, but the leverage due to the position of the screw (to starboard of the center of gravity) acts in the same direction. Similarly, if we wish to throw the stern to starboard, we back on the port screw alone.

In considering the handling of a steamer around a dock, a distinction must be made between the case in which she uses her own power alone and that in which she is assisted by one or more tugs. All very large vessels are now handled by tugs and it would be the height of imprudence to attempt to dispense with them. But vessels which would formerly have been considered very large are constantly worked in and out with their own resources alone. Such are the splendid vessels of the Sound and Bay Lines of the United States, some of which are side-wheelers and others propellers. These vessels run on schedule time and without reference to tides. They are brought alongside their piers often under the most unfavorable conditions, and rarely meet with an accident. It should be noted, however, that these vessels are especially designed for this business of docking under all conditions of wind and tide. Most of them have guards extending much farther out from their sides than any of the projections which might interfere with docking.

The Marine Superintendent of one of the large Atlantic steamship companies writes to the author on this subject as follows:

"In my opinion, the great secret in handling either a twin-screw or single-screw steamer in approaching a pier, is not to have too much way on the ship; the engines should be slowed and the way off the ship so that she can be kept well in hand at such a distance from the pier, that if it should be necessary to go ahead in order to cant the ship's head either one way or the other by the use of the rudder, it can be done without the ship's overrunning the place where she is required to land. The ship should be kept thus in command until she gets into a position where she can be stopped entirely by moving the engines astern, without risk of her bows striking the pier, or of her getting out of position by her head canting off by the action of the propeller moving half or full speed astern. If the pier is approached in this manner, after a little practice it is astonishing how close even the largest vessels can be brought to the pier without danger of colliding. Large steam vessels should always approach a pier against the tide, and as near parallel with the direction of the tide, or trend of the river, as possible. The practice of heading a ship from the river between two piers is a very doubtful and frequently dangerous operation; for, although the tide may be slack on the surface it may be running smartly either flood or ebb for a few feet below."