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Chapter 4

Small Boat Handling

Boat handling requires an understanding of the many variable and complex problems of seamanship. The basic principles involved in handling small boats are essentially the same as those used in handling larger craft.


  4-1. Before attempting to handle a boat, it is important to understand the forces that affect a boat under various conditions. A watercraft operator who thoroughly understands these forces can use them to maneuver his boat. Therefore, he will not have to fall back on the often painful, trial-and-error method of learning boat handling. The following vessel characteristics influence the control of single-screw boats having right-hand propellers.
  4-2. The design of a ship includes the size and shape of the hull, draft, trim, weight, and amount of superstructure. Ships with shallow draft, low superstructure, and slim design normally handle more easily than ships with high superstructure, deep draft, and wide beam because they are less affected by wind and current and respond more rapidly to the rudder.
  4-3. Each phase of motive force as it reacts on the vessel has its own peculiarities. No set of rules can be devised to cover all types. Every vessel has its own power characteristics, which the operator must learn to determine their effect upon handling of the vessel.
  4-4. A propeller draws its supply of water from every direction forward and around the blades, forcing it in a powerful stream toward the stern. This moving current which provides the power for propulsion is called "screw current." The water flowing into the propeller is called "suction screw current," that being ejected is called "discharge current." Figure 4-1 shows this water-pressure effect of the suction current vaporizing off the tips of the blades and spiraling back in a helical pattern. The factors that affect propeller action are:
  4-5. The pitch of a propeller (Figure 4-2) is the distance the propeller would advance in one revolution if the water was a solid medium.
  4-6. The difference between the speed of the ship and the speed of the propeller is known as the "slip". Slip is caused by the yield of the water against the propeller thrust. In other words, it is the percentage of distance lost because water is a yielding substance.

Figure 4-1. Propeller Action and Resulting Screw Action

Figure 4-2. Propeller Pitch

  4-7. When the blade-tip speed is excessive for the size and shape of the propeller, the vessel rides high in the water. There is also an unequal pressure on the lower and upper blade surfaces. This condition produces cavities or bubbles around the propeller known as "cavitation." The result is an increase in revolutions per minute without an equivalent increase in thrust. This results in loss of efficiency. When cavitation is fully developed, it limits a vessel's speed regardless of the available engine power.
Rudder Action
  4-8. The rudder acts the same on a large vessel as on a small craft. The rudder is placed directly behind the propeller to use the powerful discharge current to turn the boat. Moving the rudder to the right deflects the discharge current to the right, which forces the stern to the left. This action is reversed when the left rudder is applied. At very slow propeller speed and with very little way on, there may not be enough control over a boat to maneuver it, especially if other forces are acting upon it at the same time. When this condition prevails, the propeller may be speeded up enough to give it a more powerful thrust against the rudder. Using sudden thrusts of power to kick (move) the stern in this manner is one of the fundamental principles of vessel handling. A vessel can often be turned in twice its length by kicking the stern.
  4-9. Wind, tidal, ocean currents (waves or sea), and depth of water must be considered when handling a vessel. Shallow water particularly affects deep draft vessels because of the cushion effect similar to that encountered when navigating in narrow channels.


  4-10. There are some standard steering commands used to give orders to the helmsman. These are described below.
  4-11. "Right rudder" or "left rudder" are orders given for the wheel to be turned to the right or left. When the wheel is turned to the right or left, the rudder and rudder angle indicator must turn to the same side; that is, they must not be rigged reversely.
  4-12. When a command is given to the helmsman, the first part of the order indicates the direction (right or left) for the helmsman to turn the wheel. The second part of the command states the amount of angle. The following are some commonly used steering commands.
  • "Right (or left) full rudder." Full rudder designates a 30° rudder. When the rudder is turned past 30° (usually designated hard right or left), care must be exercised to avoid jamming it against the stops.
  • "Right (or left) 5° , 10° , 15° , and so on." This indicates the angle, in degrees, that the rudder is to be offset.
  • "Right (or left) easy." Usually indicates 2 or 3 degrees of rudder angle in the direction indicated. Some Masters may prefer 5 degrees of rudder angle for this command. This should be understood in the vessels SOP.
  • "Give her more rudder." To increase the rudder angle already on when it is desired to turn the ship more rapidly in the direction in which she is already turning.
  • "Ease the rudder." To decrease the rudder angle which is on. The order may also be: "Ease to (state number) degrees."
  • "Rudder amidships." To place the rudder on the centerline.
  • "Meet her." To check, but not stop, the swing by putting the rudder in the opposite direction. Usually this order is used when it is desired to keep the ship from swinging past her new course.
  • "Steady" or "steady as you go." To steer the present course while the ship is swinging. The course should be noted at the time the order is given and the ship steadied on that course.
  • "Shift the rudder." To change from right to left (or left to right) rudder. Usually given when a ship loses her headway and begins to gather sternway and it is desired to keep her turning in the same direction.
  • "Mind your rudder." To steer more carefully or stand by for an order.
  • "Keep her so." To steer the course just reported, following a request for that course.
  4-13. To assure the watch officer that his orders have been correctly received, the helmsman must always repeat, word for word, any command received. As soon as the command has been executed, the helmsman must also report it to the watch officer. The watch officer confirms that the order is understood by replying, "Very well."


  4-14. Characteristics or factors, such as the power, propeller, rudder, and design of a ship affect handling in various ways. For illustrating the effects of these factors, it will be assumed that the sea is calm, there is neither wind nor current, and the ship has a right-handed propeller.
  4-15. The single-screw vessel has only one propeller. The operation of this vessel is described below.
Vessel and Propeller Going Forward
  4-16. With the ship and propeller going forward and the rudder amidships, the ship tends to move on a straight course. The sidewise pressure of the propeller is offset by the canting of the engine and shaft. When the rudder is put over (either to the right or left) the water through which the ship is moving strikes the rudder face, forcing the stern in the opposite direction. At the same time, discharge current strikes the rudder face and pushes the stern over farther. As a result of these forces, the bow moves in the direction in which the rudder has been thrown.
Vessel With Sternway, Propeller Backing
  4-17. When backing, the sidewise pressure is opposite to that exerted when the ship is moving forward. The discharge current from the propeller reacts against the hull. This current is rotary; therefore, when the propeller is backing, the current strikes the hull high on the starboard side and low on the port side. This current exerts a greater force on the starboard side and tends to throw the stern of the vessel to port (Figure 4-3).
  4-18. With rudder amidships, the vessel will back to port from the force of the sidewise pressure and the discharge current. When the rudder is put over to starboard (Figure 4-4), the action of the suction current against the face of the rudder will tend to throw the stern to starboard. Unless the ship is making sternway, this force will not be strong enough to overcome the effect of the sidewise pressure and the discharge current, and the stern will back to port.
  4-19. When the rudder is put over to port (Figure 4-5), the force of the suction current on the face of the rudder intensifies the effect of the sidewise pressure of the propeller and the discharge current and will force the stern rapidly to port. Because of these forces, all right-handed, single-screw vessels tend to back to port.

Figure 4-3. Vessel With Sternway, Propeller Backing, Rudder Amidships

Figure 4-4. Vessel With Sternway, Propeller Backing, Rudder to Starboard

Figure 4-5. Vessel With Sternway, Propeller Backing, Rudder to Port

Vessel With Headway Propeller Backing
  4-20. With the rudder amidships (Figure 4-6), the stern will go to port because the only active forces are the sidewise pressure of the propeller and the discharge current.

Figure 4-6. Vessel With Headway, Propeller Backing, Rudder Amidships

  4-21. With the rudder to starboard (Figure 4-7), the stern rapidly goes to port but, as headway is lost and the vessel begins to go astern, the effect of the suction current on the face of the rudder slows the swing. However, since a single-screw vessel tends to back to port when moving astern, the stern will tend to port unless the vessel gathers considerable speed astern.

Figure 4-7. Vessel With Headway, Propeller Backing, Rudder to Starboard

  4-22. With the rudder left (Figure 4-8), the normal steering tendency of the rudder will throw the stern to starboard. This starboard motion will occur when the vessel has considerable headway, but as headway is lost, the effect of the sidewise pressure of the propeller and the discharge current, in conjunction with increasing forces of the suction current against the face of the rudder, swings the stern rapidly to port.

Figure 4-8. Vessel With Headway, Propeller Backing, Rudder Left

Vessel With Sternway, Propeller Going Ahead
  4-23. In this situation, the sidewise pressure of the propeller and the discharge current are persistent factors and may offset each other. Therefore, if the rudder is amidships with no forces acting against it (Figure 4-9), the vessel will tend to follow a straight course.

Figure 4-9. Vessel With Sternway, Propeller Going Ahead, Rudder Amidships

  4-24. With the rudder to the right (Figure 4-10), the action of the water on the back face of the rudder as it moves astern will tend to throw the stern to the starboard. The action of the discharge current against the forward face of the rudder tends to throw the stern to port. Direction is determined by the stronger force. However, as the vessel loses sternway, the direct steering effect of the rudder takes over and the stern swings to port.

Figure 4-10. Vessel With Sternway, Propeller Going Ahead, Rudder to Right

  4-25. With the rudder left (Figure 4-11), the action is the same as with the rudder right. In either case, the rudder action is determined by the strength of the forces, and as the rudder loses sternway, the direct steering effect of the rudder takes over and the stern swings rapidly to starboard.

Figure 4-11. Vessel With Sternway, Propeller Going Ahead, Rudder to Left

  4-26. The twin-screw vessel has two propellers -- one on each side of the centerline. These propellers are maneuvered by separate throttle controls. Generally the propellers are outturning; that is, the starboard propeller is right-handed and the port, left-handed. This balances the sidewise pressure of the propellers and makes it possible to keep the ship on a straight course with no rudder. Discounting outside influences, the twin-screw vessel backs with equal facility to port or starboard.
  4-27. The various forces affecting the action of the single-screw ship are still present, but normally a twin-screw vessel is not affected by these forces as much as a single-screw vessel. This is because the forces from one screw balance the forces from the other screw.
  4-28. One powerful force is the momentum of the ship, ahead or astern, acting through the center of gravity. When a twin-screw ship is going ahead and one screw is backed, two opposing forces are set in motion; namely, the force of the backing screw acting in one direction and the weight of the ship acting in the opposite direction. This is in addition to the forces from the action of the pressure on the rudder if it is put over. Other than this force and the turning action accomplished by one engine ahead and the other astern, the vessel handling characteristics of a twin-screw vessel are similar to those explained in the preceding paragraphs for the single-screw vessel.
  4-29. Single-screw vessels can be turned easily in restricted waters. To start the swing, the engine speed is set at full ahead and the rudder is put full right; then the engine is reversed to full astern until way is lost. When way is lost, the rudder is shifted; after sternway has started, the rudder is again shifted and the engine put full ahead. This procedure is repeated until the vessel is on the desired heading. This maneuver makes use of the tendency of right-handed propellers to back to port. In strong winds, it is wise to turn in such a way that the tendency to back into the wind can be used to increase the turn.
  4-30. A twin-screw vessel with a single rudder can be turned by going ahead on one engine and astern on the other, using the rudder only when headway or sternway has been gained. When the vessel is fitted with twin rudders that are directly behind the propellers, the rudder is placed hard over in the direction of the turn before the maneuver is begun and one engine is backed at the speed necessary to prevent headway.


  4-31. In some ports, particularly on the East and Gulf Coasts, individuals frequently referred to as docking pilots or docking masters direct the docking and undocking of vessels. In most cases, these individuals are employees of tug boat companies.
  4-32. The lines used to secure the ship to a wharf or to another ship are called "mooring lines." They must be as light as possible for easy handling and, at the same time, be strong enough to take considerable strain when coming alongside and holding a ship in place. Five- to six-inch nylon line is the customary material for mooring lines on freight supply and other large vessels. Figure 4-12 shows the locations and names of the lines. Lines should be neatly coiled or arranged to prevent fouling, to eliminate hazards, and to keep the working area clear.

Figure 4-12. Names and Locations of Mooring Lines

  4-33. The bow line and the stern line lead well up the wharf to reduce the fore and aft motion of the ship. Breast lines are run at right angles to the keel to prevent a ship from moving away from the wharf. Spring lines leading forward or aft prevent a vessel from moving aft or forward respectively. Two spring lines placed close together and leading in opposite directions act as a breast line from wharf to ship.
  4-34. Lines assist in coming alongside or clearing a wharf. Before a ship comes alongside, the required lines with eye splices in the ends should be led outboard through the chocks, up and over the lifelines and/or rails. Heaving lines (light lines with weighted ends) are used on larger vessels to carry heavier lines to the wharf. With small boats, there is rarely any need to use a heaving line. Generally, a seaman can either step ashore with the mooring line or throw it the short distance required. Heaving lines should be made fast near the splice--not at the end of the bight where they may become jammed when the eye is placed over the bollard. Heaving lines should be passed ashore as soon as possible.
  4-35. If two bights or eye splices are to be placed over the same bollard, the second one must be led up through the eye of the first and then placed over the bollard. This makes it possible for either line to be cast off independently of the other and is called dipping the eye.
  4-36. When a mooring line is taut, it is stopped off with a stopper line (Figure 4-13). The stopper line is secured to the bitts and applied to the mooring line with a half hitch and three or four turns taken in a direction opposite to the one in which the hitch is taken. When the stopper takes the strain, the turns are thrown off the mooring line and it is made fast to the bitts.
  4-37. In securing alongside a wharf, attention must be paid to the tide. When securing at high water, enough slack must be left in the lines to ensure that at low tide they will not part, carry away bollards, or, in extreme cases, list the ship to a dangerous degree or capsize a small vessel.

Figure 4-13. Stopping Off a Mooring Line

  4-38. Wharves and piers may be built on piles that allow a fairly free flow of water under them and in the slips between them. Their underwater construction may be solid, in which case there will be no current inside the slips, but eddies may whirl around them. Warehouses or other buildings may be built on piles, which vary the effect of the wind on the upper works of a vessel when making a landing.
  4-39. Making a landing is more dangerous when the wind and current are at right angles to the wharf than when blowing or running along its face. In coming alongside, as in all ship handling, the wind and current should be observed and if possible, used as an advantage.
  4-40. Making a landing usually involves backing down. For this reason, procedures for landing port-side-to differ from those for a starboard-side-to landing. Let us first consider a port-side-to landing.
  Note: A coxswain should remember that boats do not always respond exactly as theory predicts and that there is no substitute for actual experience.
Port-Side-To Landing
  4-41. Making a port-side-to landing (Figure 4-14) is easier than a starboard-side-to landing because of the factors already discussed. With no wind, tide, or current to contend with, the approach normally should be at an angle of about 20° with the pier. The boat should be headed for a spot slightly forward of the position where you intend to stop. Several feet from that point (to allow for advance), put your rudder to starboard-to, bring your boat parallel to the pier, and simultaneously begin backing. Quickly throw the bow line over. Then, with the line around a cleat to hold the bow in, you can back down until the stern is forced in against the pier.
  4-42. If wind and current are setting the boat off the pier, make the approach at a greater angle and speed. The turn is made closer to the pier. In this situation, it is easier to get the stern alongside by using hard right rudder, kicking ahead, and using the bow line as a spring line. To allow the stern to swing in to the pier, the line must not be snubbed too short.
  4-43. If wind or current is setting the boat down on the pier, make the approach at about the same angle as when being set off the pier. Speed should be about the same or slightly less than when there is no wind or current. The turn must begin farther from the pier because the advance is greater. In this circumstance, the stern can be brought alongside by either of the methods described, or the centerline of the boat can be brought parallel to the pier and the boat will drift down alongside.

Figure 4-14. Port-Side-To Landing

Starboard-Side-To Landing
  4-44. Making a starboard-side-to landing is a bit more difficult than a landing-to port. The angle of approach should always approximate that of a port-side-to landing. Speed however, should be slower to avoid having to back down fast to kill headway, with the resultant swing of the stern to port. Use a spring line when working the stern in alongside the pier. Get the line over, use hard left rudder, and kick ahead. If you cannot use a spring line, time your turn so that when alongside the spot where you intend to swing, your bow is swinging out and your stern is swinging in. When it looks as though the stern will make contact, back down; as you lose way, shift to hard right rudder.
  4-45. If there is a fairly strong current from ahead, get the bow line to the pier, and the current will bring the boat alongside as shown in Figure 4-15 (View 1). If the current is from aft, the same result can be achieved by securing the boat with the stern fast as shown in Figure 4-15 (View 2). Care must be exercised during the approach because an oncoming following current decreases rudder efficiency, and steering may be slightly erratic.

Figure 4-15. Making Use of the Current

  4-46. If heavy winds are forecast (less than 50 knots), make sure storm lines are out fore and aft and additional breast lines are set. The greatest damage to the ship will result from the ship banging against the pier or other nested ships. Make sure all lines are properly set and that adequate fenders are rigged between the ships nested alongside.
  4-47. As when coming alongside, procedures for getting underway depend upon which side of the pier the boat is located, as well as the state of current, wind, and so on.
  4-48. The easiest way to get underway, when starboard-side-to a pier, is to cast off the stern first, hold the bow line, give the boat hard left rudder, and begin backing. When the stern is clear of the pier and any boat or other object astern, cast off the bow line and back out of the slip.
  4-49. The easiest way to clear a port-side-to landing is to use the bow line as a spring line. Cast off the stern line, give the boat left full rudder, and kick ahead until the stern is well clear. Then cast off the spring line and back out of the slip.


  4-50. Grounded vessels can cause physical damage to fragile reefs. The also pose serious pollution threats to the marine environment because fuel and waste oil tanks can be damaged as a result of grounding.
  4-51. If a vessel runs aground, an intelligent and careful estimate of the situation must be made before attempting to move the vessel. The following procedures should be observed:
  • Notify unit HQ to send assistance; establish communication procedure; furnish a relief party; and provide for another vessel or vessels to take off fuel, water, stores, and/or cargo.
  • Stop engines and inspect the double bottoms and bilges to find out the extent of leakage resulting from the initial impact of grounding.
  • Take soundings around the entire vessel to determine the depth of the water and character of the bottom. Send out a boat to take soundings to determine if engines can be maneuvered.
  • Inform the engineer about the condition of the bottom so that he may take precautions to protect the pumps, pipelines, and engine-cooling spaces from damage by sand and mud.
  • Examine the hull to determine the extent of damage. If the shell has been pierced, IMMEDIATELY close watertight doors.
  • Determine whether backing vessel off would be an advantage or would increase damage and whether or not pumps could control flooding compartments if the vessel were floated free.
  • Study tide tables, sailing directions, and charts to determine the time of high tide and tidal current, depths, and type of bottom in the vicinity of the vessel's position. A leadsman should be stationed to take frequent soundings to note any change in tides. If it appears that some time will be required to ready the vessel for floating or to secure outside aid, weather reports should be obtained before planning action.
  4-52. One of the first observations the master should make is whether the vessel is lively, that is, affected by the swells. If so, it may be possible to refloat her at once by sallying ship. Sallying a ship is accomplished by securing a line from another vessel at right angles to the keel and alternately pulling the vessel back and forth in an effort to free the bottom. At the same time, if the propellers are clear, the engines should be backed at full speed and, if another vessel is in the area, a line should be secured to the vessel to exert a pulling force.
  4-53. When the vessel is held fast and is in danger of being pounded by heavy seas, it may be best to flood the compartments with water to prevent the vessel from moving over the bottom and smashing the hull. The water can be pumped out later after the heavy seas have abated.
  4-54. The vessel may be lightened and its draft reduced by discharging some of its liquid ballast. This weight may be enough to decrease the draft and free the vessel. The tanks should not be emptied completely because a certain amount of fuel and water is needed to keep machinery running to deliver the vessel to safety. If the vessel is aground at the bow, the tanks should be pumped from bow to stern; if the stern is aground, the tanks should be pumped from stern to bow. You must keep in mind that intentional dumping of fuel is a criminal offense. If it is necessary to save the ship, a means of transferring the fuel to another vessel should be attempted.
  4-55. When a vessel grounds on a bar or a river bank in quiet water and the engine either is of no assistance or cannot be used, the vessel may be cleared by kedging. Kedging consists of carrying out kedge anchors with sufficient scope and taking a strain on them. If in conjunction with any possible lightening or shifting, a steady strain often will work a vessel free. If the vessel has gone hard on a bar so that she is aground amidships, it is possible that the best means of freeing her may be to go ahead on the engines and shove full across the bar.
  4-56. If the vessel is not aground along the full length of her keel, all weight should be shifted to the part of the vessel still afloat. On a vessel aground by the bow, ballast, fuel, and water may be shifted to the aftermost tanks available and the cargo may be shifted from the forward to the after hatches. When there is no room in the after hatches, as much cargo as is deemed safe may be deck-loaded aft. Such shifting of weight and cargo should not be attempted if it would merely put the full length of the keel on the bottom. However, when there is enough depth (as there often is when grounded on a bar) such operations may be the quickest and simplest means of working free.
  4-57. When a vessel is aground and the master is not sure that he can get it off quickly without damage or when a vessel strands on a beach in open surf, the aid of another vessel should be obtained immediately. The master of the assisting vessel must acquaint himself as fully as possible with the whole situation. This includes knowing the nature of the bottom, prevailing winds, current and tidal data, and any damage to grounded vessel (such as possibility of pierced hull or compartment). He must also confer with the master of the stranded vessel. Procedures are as follows:
In Quiet Seas
  4-58. In quiet seas an assisting vessel may anchor to seaward with a good scope of cable. The lines should be secured to the stern of the stranded vessel and kept taut until the assisting vessel tails in as near the stranded vessel as wind and tide permit. The anchor windlass should be used with full power to keep these lines taut and pick up every inch of slack until the vessel is pulled off. Engines should be used and a good strain kept on anchor cable.
In Heavy Seas
  4-59. If seas are heavy, it is often necessary to pass a light line (messenger line) between the assisting vessel and the stranded vessel. The messenger line is secured to one end of a heavy towing line and is hauled to the stranded vessel by pulling in the messenger line. During towing operations in heavy seas, oil should be poured on the water. This aids in preventing breakers and gives a smoother sea in which to operate. The oil should be poured so that the current and/or wind will cause it to spread over the area around and between the stranded and assisting vessels.
In Strong Current
  4-60. The assisting vessel can use two anchors, but if they drag and the vessel is being set down on the beach, the lines should be cast off immediately. The vessel can then maneuver clear of difficulty, heave up anchors if necessary, and make a fresh attempt.
Towing Vessel--Not Anchored
  4-61. When the towing vessel is not anchored, caution should be used to prevent grounding (Figure 4-16). A stern line must not be used, especially in a cross current or wind, as it would make the rudder useless.
  4-62. It is best to secure a line to a bitt farther forward and then head the vessel slightly forward and across the current, gradually adding strain to the line and using it with the helm to pivot the towing vessel (Figure 4-17).

Figure 4-16. Maneuverability of
Towing Vessel (Non Anchored)

Figure 4-17. Maneuverability of
Towing Vessel (With Secured Line)

Approaching Bow On
  4-63. When the wind is offshore, it is possible for the towing vessel to approach bow on and pass a line forward (Figure 4-18). After taking the line in through a forward bow chock, the towing vessel can back her engines to pull off the stranded vessel, thereby saving time which would have been lost in maneuvering to take a line aft. However, pivoting power will be lost if the line is taken exactly at the bow. Instead, it should be taken through a chock a little farther aft. This procedure may assist in slowing the stranded vessel's stern and thereby causing it to break free.
  4-64. A towing vessel which approaches bow on should come in a little to the windward, drift toward the stern of the stranded vessel, and receive the line in that position (Figure 4-19).

Figure 4-18. Receiving Line Forward

Figure 4-19. Towing Vessel Approaching Bow On

In Packed Sand
  4-65. When a vessel is grounded by the bow on a sandy beach, sand will frequently become packed around the stern. Soundings taken by lead line will show the exact location of this sand. Water jets may be rigged over the side and connected to the fire mains. At the beginning of the high tide during which the vessel is to be pulled off, these pumps and jets should be started. The force of the water will create live sand, which will move away from the bottom and sides of the vessel.
For Jumping a Line
  4-66. Small vessels may be pulled off the beach by a sudden pull under full power. This method is never used on heavy vessels, but is sometimes useful on smaller craft at high tide. The hawser must be securely fastened to towing bitts because no other part of the vessel will stand so great a strain. Care must be taken to keep the hawser away from the propellers and also that personnel stand clear of the hawser.


  4-67. Since vessels vary in design and size and weather conditions vary in severity, so do the measures that need to be performed. The following are some measures you should know in heavy weather.
  • Meet with the crew to explain the situation and reassure them. Make sure that they know what to do, and what not to do, when the extreme weather arrives. Explain such things as keeping low in the boat, not moving around excessively and not going out on deck unless necessary. Give them all an assignment to keep them occupied and keep their minds off the situation.
  • Determine position of storm, wind direction, speed, and estimate time to your location.
  • Secure all hatches and close all ports and windows to keep the water on the outside.
  • Pump bilges dry (into holding tank) and repeat as required. This helps eliminate "free water affect." (Sloshing of water in the bilge as the boat rolls which can effect stability)
  • Secure all loose gear above and below decks. Put away small items and lash down larger ones.
  • Break out PFD's and foul weather gear.
  • Ready emergency equipment that you may need such as hand pumps, bailers, first aid kit, sound signaling device, and so on.
  • Get a good fix of your position and plot it on your chart. Make note of the time, your heading, and speed.
  • Make plans to alter course to sheltered waters if possible.
  • Continue to listen to the VHF radio for updates to severe forecasts.
  • Review abandon ship procedures.
  • Make sure the life raft is ready to be deployed.
  • Make sure emergency food and water are in the life raft.
  • Rig jack lines and/or life lines. Require anyone who must go on deck to wear a safety harness.
  • Make ready your sea anchor or drogue if needed.
  • Turn on navigation lights.
  • Keep away from metal objects.
  • Change to a full fuel tank if possible.
  • Keep a sharp lookout for floating debris and other boats.
  • If you have a choice, do not operate the boat from the flybridge.
  4-68. Before a vessel leaves port and passes the sea buoy, standard precautions are taken to make her secure. All booms are lowered and stowed, movable gear on deck is lashed down, and covers are placed over machinery that may be damaged by saltwater. When a vessel enters a storm area, a check should be made to see that these standard precautions have been taken. Extra lashings should be added where needed to avoid damage to gear or cargo. Hatch coverings should be checked and the battens secured. Ventilators should be trimmed away from the wind and spray or taken down entirely and plugs or tarpaulins should be fitted over the openings. Boat gripes should be inspected and tightened. Watertight doors should be closed securely and dogged, skylights battened, deadlights closed, and, if necessary, lifelines rigged.
Securing Cargo and Gear
  4-69. When stowing or supervising the stowing of cargo, keep in mind that the vessel will be at sea and the cargo will be subjected to the forces constantly generated by the roll and pitch of the vessel. A stiff roll or continuous pitching has an element of impact that tends to loosen cargo. Once the stowage has become loose, it creates an impact of its own. After the damage is done, it is usually too late and too dangerous to attempt to correct. Gear used to handle cargo should always be stowed securely. Booms should be cradled and bolted and guys and pendants should be coiled and lashed. There should be no loose lines on deck while at sea because they jeopardize life and property.
Protection of Deck Cargo
  4-70. The chief advantage of deck cargo is that it is always visible and can be easily checked. All deck cargo should be well lashed and secured. In foul weather, turnbuckles should be tightened and tarpaulins rigged. When they sweep the deck, waves exert an immense hydraulic force, which the deck cargo must withstand.
  4-71. Each oil and sea anchor must be of the type specified by the manufacturer and must be fitted with a shock resistant hawser. They may also be fitted with a tripping line. One anchor must be permanently attached to a vessel in such a way that, when the vessel is waterborne, it will cause the vessel to lie oriented to the wind in the most stable manner. A second oil and sea anchor must be stowed in the vessel as a spare. Military and passenger vessels must have the permanently attached oil or sea anchor arranged to deploy automatically when the vessel floats free. The oil or sea anchor for a rescue boat must be of the type specified by the rescue boat manufacturer, and must have a hawser of adequate strength that is at least 10 meters (33 feet) long.
  4-72. The adherence of water to air allows strong winds to build up one large wave at the expense of others. These waves are dangerous to vessels because of their size, speed, and the amount of water they can deposit on deck. This liaison between water and air can be reduced by spreading oil over a large area of water to decrease the formation of giant waves and deaden the cresting motion of all waves. Preferably, an animal or vegetable oil should be spread windward of the vessel at the rate of approximately 2 gallons an hour. Too much oil is a fire hazard, especially if there is a possibility that boats may be launched. A canvas bag stuffed with oakum, cotton, or waste, soaked with oil, and hung over the side will spread oil slowly and safely.
Sea Anchor
  4-73. Before it becomes impossible to steam either with or against the seas, the vessel must be hove to, that is, headed so she will take the seas most comfortably. It must be remembered that each vessel will heave to in a manner dependent on her design and trim. Some vessels will lay their quarters into the wind and others, their bows. The master, bearing in mind that the most comfortable and safe position for a vessel is with a small angle to the seas, should estimate what position his vessel will assume when lying powerless. Steaming slowly ahead or astern, depending on whether the vessel is laying its bow or quarters into the wind and whether the storm is of average strength, will preserve the desired angle. However, if the storm is so violent that the vessel is unable to proceed at all, a sea anchor may be rigged.
  4-74. A sea anchor (Figure 4-20) is used to create a drag through the water and hold either the bow or the stern into the sea. Small vessels carry a sea anchor, which is a canvas bag to be dropped over the bow or stern and secured with a heavy line. Large vessels can improvise a sea anchor by rigging one from hatch covers or other available material. Oil (to calm the seas) may be used in conjunction with the anchor.

Figure 4-20. Sea Anchor


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