By: Captain Bill Jennings
When you head out for a casual day cruise in the family boat the last thing you expect to happen is to get violently tossed out of the boat. Yet this happens far more frequently than people realize, even with regular runabouts. Here is how and why it happens and what you can do to avoid it.
The common denominator in all boater extractions is the surprise factor. You are riding along one minute and then, in a split second, you are in the air before smacking onto the surface of the water. Any physical injury you experience in the process of leaving the boat adds to your difficulty in the water.
There are two common situations that account for such unexpected departures. The first is the 'wave flip.' This can happen in rough water, but also when you cross large boat wakes. You may slow down for an approaching large wave but before you hit the wave your boat often dips into a pre-wave trough. As it rides up the following wave, it lifts your body in an upward direction. If the lift is strong and your boat quickly drops over the top of the next wave, your body will want to continue upward. It's like a pancake being flipped in a frying pan. Most of us have experienced this action. It lifts you off your seat. But if the momentum is just right, you could lift clear your seat and while suspended, have the boat drive out from under you. Splash!
To prevent a 'wave flip' when driving you should judge the approaching wave as potentially dangerous and quickly throttle back in order to climb the wave at a much reduced speed. Surprisingly, in some circumstances, you can reduce the flip effect by accelerating, but be aware that while this may reduce flip effect it will result in some serious air time, along with a heavy landing.
The second most common cause of passenger ejections is the boat 'hook.' In any turn, the boat and everything in it wants to continue in a straight line.
If while making a tight turn, the forward portion of your keel might hook-up with the water while the stern portion of the boat doesn't. This can result in a sharp turning motion or 'hook.' If a passenger is not expecting this, they may find themselves proceeding in a straight line right out the side of the boat. These departures often result in a severe bruises or worse.
If your boat hooks while travelling between 35 and 40 mph a passenger will have to overcome a directional momentum change equal to their own weight in order to remain in their seat --- providing they have the time to react at all. At higher speeds, the likelihood of ejection increases exponentially. That's why there are lots of videos of boaters flying sideways out of their performance boat. Even in situations where a sudden force on a passenger is not violent, bruises or worse can result from striking objects within the boat. Interestingly, passengers are more likely to encounter ejection problems than the driver. This is because the driver has a steering wheel to hold onto and is usually more aware of a pending problem.
If you find yourself tossed out of a moving boat, you can expect an unpleasant water entry. Since water does not compress, the force of the impact will surprise you, and you never know which part of you will strike the water first. Your first line of defense is to wear a life jacket. Also, keep your hand close to a grab handle. Smaller and/or faster boats have grab handles close to every seat for a reason.
All boats are subject to applying varying forces to their passengers. Remain aware of this when boating and you can avoid any unscheduled visits into the water.