The handling of small boats in severe weather conditions is a art all by itself, and can only acquired by practical experience. I have had experience of being in the Coast Guard and operating 52' and 44' motor lifeboats off Oregon and Washington coast. The knowledge I gain from this really helped me, even when I got my license and started to operate ships. This won't cover everything but its a start.
Seamen have every opportunity to gain this knowledge through experience and are able to handle boats under the most severe conditions. The sea can be, and often is, unforgiving, however, and even experienced seamen are lost each year by being tempted to take a chance. No boat should confront severe weather or sea conditions unless it is necessary.
The coxswain of a boat is responsible for the lives of those aboard, and it is therefore he who must ensure that the boat is seaworthy and operated in a safe manner. Safe operation is what places the most burden on the coxswain because that feat requires knowledge, skill, practice, and judgment.
To understand the factors that effect the boat is essential. Waves make up the major pressure on the hull, although wind also contributes if a vessel has high freeboard. Waves are caused by wind pressure on the water, and these wind-raised waves depend on several factors. The size and height of a wave depend on the wind speed, the distance over which the wind has blown (known as fetch), and the length of time the wind has been blowing. When the waves pass out of a storm area, they advance as swells. Swells are not regular and are lower in height and longer in length then the waves that produced them. During heavy weather, the many different wave systems give the watersurface a complex and irregular pattern. These wave systems cross each other at angles, producing mountainous seas.
If you are running into a sea, the bow of the boat will be driven into the waves with increasing force, instead of being lifted as is normal. This causes the boat to take a pounding. The propeller is alternately submerged and then out of the water, with the result that the engine is loaded one moment and racing wild the next. The boat comes under extreme stress, and steps must be taken to reduce it. The easiest way to do so is to slow down. This will cause the bow to lift with the waves, as the natural force of buoyance is again allowed to function. The seas should be taken slightly off the bow, preferably at an angle approaching 45 degrees. Doing so will cause the boat to roll and pitch, but the combination is far easier on the boat than the violent motions of pitching alone.
If unable to make headway under these conditions, it is advisable to lay to. Most power-driven vessels left alone turn their stern into the wind. Since this is a highly dangerous position, enough power should be used to keep the bow up into the wind, adjusting the speed so that the boat makes neither headway nor sternway.
The use of a sea anchor would be advisable here, but only if the coxswain knows what he is doing. An improperly used sea anchor could worsen the situation. In all cases, the center of gravity must be held as low as possible by keeping all occupants down, on or near the bottom of the boat. Doing so will make the boat more stable and reduce the chance of capsizing.
Running in a beam sea, or in the trough is acceptable only under conditions of comparative calm. In a beam sea, the waves are acting directly on the vessel's sides and, in rough enough water, could roll it over. If the required course puts you in the trough and the action of the boat becomes excessive, it is best to change course so that the seas are off the bow or quarter. In order to make the desired course, it will be necessary to run a zig-zag course, taking the seas off the bow for awhile and then off the quarter.
A boat is said to be running before the sea when she sails in the same direction that the seas are running. Close attention to the rudder is required, as the turning action of the hull is difficult to control. The force of the water acting on the stern can cause the boat to yaw wildly from side to side. On powerboats, the rudder and propeller can be lifted clear of the water if the stern is picked up by an approaching wave. If the boat is yawing at the time the stern is lifted clear of the water, the boat will go completely out of control and could be thrown broadside into the trough and rolled over by the next wave. This phenomenon is known as broaching and must be avoided at almost any cost.
The secret of avoiding a broach is to keep yawing under control at all times. Sideways motion can be kept to a minimum only when the rudder is in the water. This is precisely why the use of a steering oar is preferable to a rudder in heavy seas. In a power-driven vessel, the rudder can be kept in the water by slowing down as the wave approaches the stern and allowing it to pass under. The power is then increased slightly until the next wave approaches the stern, when it is reduced long enough to let that wave pass under. By careful use of the throttle and the rudder, yawing can be kept to a minimum. (It must be remembered that any yaw can quickly become a broach.
Another danger is pitchpoling, that is, flipping end over end. To prevent it, control of engine speed in a heavy following sea is essential. Unless a boat is slowed down when a giant wave approaches the stern, the boat will be picked up by the wave and find itself racing down the forward face of the wave at a greatly increased speed. While this might seem like good fun, it could become dangerous if the boat races forward and plows into the trough, burying the bow well under. The following wave might well pick up the stern and, with the bow deeply set in the water, flip the boat end over end.
Both broaching or pitchpoling will cause, at the very least, serious injuries to the boat's occupants.
