Source: Mariners Learning System, By Captain Bob Figular

When learning to deal with bad weather and rough water it is important to learn how to understand and anticipate the flow and direction of the waves. If a wave looks like it is going to break, your only out may be to back down before the wave gets to the vessel. Stay extremely aware of any wave combinations and avoid spots ahead where they tend to peak. If they peak ahead in the same place, chances are they will peak there when you and your vessel are closer. Do not let a slightly different wave or wave combination catch you by surprise!

In a situation when the current and seas are going in the same direction, current has the effect of lengthening the waves. Longer waves are more stable, with the crests farther apart, with this said… You still need to use caution.

While heading into the seas and current, your boat’s forward speed over the ground (SOG) will be lessened; this in turn will require more time transiting the entrance. Increasing your boat speed may be necessary to maintain forward progress. However, do not increase your boat speed to a point that makes negotiating the waves hazardous. If you have increased your overall boat speed to maintain forward progress you will need to reduce the boat’s speed as you approach each wave crest individually to maintain control.

With following seas and current, your speed over the ground will be increased. Because the waves are farther apart, the effort required to ride the back of the wave ahead should be easier. With following seas the current is coming from behind your vessel, more forward way will be required to maintain steering control. As with all following seas, stay on the back of the wave ahead. Do not allow yourself to be lulled into a false sense of security. With higher speed over the ground and less maneuverability due to the following current, there is not as much time to avoid a situation ahead. Keep a hand on the throttle and adjust power continuously. When entering or exiting port less time will be spent in the inlet, canal, or fairway, stay extremely aware of any spots ahead to avoid. Maneuver early, as the current will carry the boat.

In addition to coping with the current and state of the seas it is also necessary to understand how to deal with high winds and the effects they will have on your boat when transiting harbors, inlets, or rivers.

Depending on your vessels design and sail area, it may be necessary to steadily apply helm to hold acourse in high winds. As a boat operator you should be able to “read” the water to identify 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 your boat. In large waves, the wave crest will block much of the wind when the boat is in the trough. Plan to offset its full force at the crest of the wave. The force of the wind may accentuate a breaking crest, and require steering into the wind when near the crest in head seas. Depending on the vessel, winds may force the bow off to one side while crossing the crest. For light vessels, the force of the wind at the wave crest could easily get under the bow sections (or sponson on a RIB), lift the bow to an unsafe angle, or force it sideways.

Though a light vessel must keep some speed to get over or through the crest of a large wave, do not use so much speed that the vessel clears the crest; most of the bottom is exposed to a high wind. Be particularly cautious in gusty conditions and stay ready for a sudden large gust when clearing a wave. If your boat is fitted with twin-engines, be ready to use asymmetric propulsion to get the bow into or through the wind. Early and steady application of power is much more effective than trying to “catch-up” by applying a burst of power. Vessels with large sail area and superstructures will develop an almost constant heel during high winds. In a gust, sudden heel, at times becoming extreme, may develop. This could cause handling difficulties at the crest of high waves. If the vessel exhibits theses tendencies, exercise extreme caution when cresting waves. Learn to safely balance available power and steering against the effects of winds and waves.