On Sunday night 2008-March-23 , the 'Spirit of Sooke' was damaged when a large wave broke over the bow in a following sea near the approach to Sooke Harbour. The centre
front windshield was punched out.
Confused Seas
These are among the worst conditions, and don't necessarily have to involve large waves to be dangerous or make life at sea miserable. Confused sea conditions are best avoided since there is no getting around them and nothing one can do to make things better. Confused sea conditions occur as a result of major shifts in wind direction that occur quickly. This causes waves coming from differing directions, resulting in waves that are irregular and unpredictable.
They are mostly an oceanic phenomenon but do occur on large lakes or very large bays during or after thunderstorms, but will die down quickly on smaller bodies of water. But on oceans, confused seas can last for days after major fronts or hurricanes. Even large thunderstorms can have a significant affect on the ocean. Like throwing a rock in a pond, a storm or front can send out waves in different directions from the winds that caused them previously. The waves come together and make the surface very bumpy.
So called rogue waves are caused by two waves from differing directions coming together at oblique (very wide) angles. Like two boat wakes coming together, the net effect is to create a yet higher wave, up to two or more times the height of the originals. These can be downright dangerous due to their unpredictability. The best way to deal with them is to stay tied to the dock.
When caught out in confused seas, one needs to be particularly alert for those big ones that suddenly pop up out of nowhere. With a bit of experience one can come to anticipate them soon enough in advance to take evasive action.
We often hear reports of skippers describing boats "falling off a wave." They don't mean slamming in the ordinary sense, which is avoidable. A situation occurs that is the opposite of a rogue wave; instead of two waves coming together to make a taller wave. it happens that undulations from confused seas can create exceptionally large troughs. The boat hull can be on a hump and suddenly that hump just disappears out from under the boat. What happens is that the undulation moves away, the boat is left with nothing supporting it and it simply drops. Weird but true.
One can observe this very clearly on those days when there are confused swells as opposed to waves. It's very common in the wake of tropical storms.
Rough Water SeamanshipSAR Seamanship Manual
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