Learning to deal with bad weather and rough water
Written by Captain Bob Figular from Mariners Learning System
While operating your boat there will be times when you will need to either exit or enter a port in rough and challenging conditions. Although certain inlets and rivers have extreme conditions much more often than others, learning how rough weather affects the various harbours and entrances throughout your local area is necessary to operate safely.
Knowing as much information as possible prior to entering a harbor, inlet, or river in rough weather will help guard against potential dangers. In these cases local knowledge can make the difference between a safe passage or getting into trouble. When entering a harbor, inlet, or river you will need to pay special attention to the direction of the current and seas.The most challenging condition you can encounter is when the current opposes the seas when operating near an entrance. In this case the current will have the effect of shortening the wavelength, and increasing the wave height. This makes waves much more unstable and closer together. While heading into the oncoming seas, you will find that the current is coming from behind your vessel thus pushing your boat into the seas at a relatively higher speed. You can reduce this effect by slowing your vessel, although the current is coming from behind you will still need to keep enough headway to ensure effective steering. Do not to allow the current to push your boat into any large cresting waves or combined waves that are peaking together.
In addition, it is also necessary to understand how to deal with high winds and the effects they can have on your boat. Depending on your vessel, it may be necessary to steadily apply helm to hold a course 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. 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. Be particularly cautious in gusty conditions and stay ready for a sudden large gust when clearing a wave. If your boat has twin-engines, be ready to use asymmetric propulsion to get the bow into or through the wind. As with all other maneuvers, early and steady application of power is much more effective than a “catch-up” burst of power. Vessels with large sail area and superstructures will develop an almost constant heel during high winds. 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. For more information on Mariners Learning System visit: www.marinerslearningsystem.com
By following these simple procedures and considerations when transiting harbours, inlets, or rivers you be ready to handle even the toughest challenging conditions.
Here are a few things you should be aware:
• Watch where waves break. Know how far out into the channel, whether near jetties or shoals, or directly across the entrance the waves break.
• Pay close attention to how the entrance affects wave patterns. An entrance that has jetties may push waves back across an entrance where they combine with the original waves.
• Some entrances have an outer bar that breaks, and then additional breaks farther in.Others are susceptible to a large, heaving motion that creates a heavy surge.
• Know where the channel actually is. If shoaling has occurred, room to maneuver may be significantly reduced.
• Know the actual depths of the water. Account for any difference between actual and charted depth due to water stage, height of tide, recent rainfall, or atmospheric pressure effects.