Cold-water immersion

Dealing with cold water immersion should be at the top of every boater’s safety list, especially during the off-season when fewer people are around to lend assistance.

Icy water can trigger an involuntary gasping reflex, causing a person who takes an unexpected plunge to inhale water and drown. Frigid temperatures can also cause coldwater shock—a sudden increase in heart rate and blood pressure—that can bring about cardiac arrest in those with heart conditions.

If you survive the initial immersion, you may quickly become too numb to aid in your own rescue. Fingers may no longer work; you might not be able to grab a rope, fire a flare or climb into a life raft.

Physical activity, such as thrashing in the water or trying to swim, may only speed up the heat loss and raise the possibility of cold water immersion hypothermia.

Still, prepared boaters can survive in very cold water for a surprisingly long time by taking the following precautions:

Wear a properly fitting, U.S. Coast Guard-approved life jacket at all times to dramatically increase your chances of surviving cold water immersion. Keep a whistle attached to the jacket or on a cord around your wrist to help attract attention.
Wear garments that retain body heat when wet. Layer clothing and consider donning a wet suit under your clothing. Carry a dry change of clothing in a waterproof bag.
Mount a boarding ladder or swim step on the boat or purchase a life sling and practice using it to get another person back onboard. Getting a partially incapacitated person into a boat can be difficult, even with training.

If you do fall into cold water and can’t immediately get out, stay with the boat. Fold your arms across your chest and cross your legs in the Heat Escape Lessening Position (HELP) to minimize heat loss. If another person is in the water with you, put your arms around each other. Float quietly with minimal exertion until help arrives. –U.S. Coast Guard