Dr. Kent Benedict gave a talk on cold water shock and drowning at a recent U.S. Sailing Safety at Sea seminar in the Bay Area. Like many of the talks at the seminar, the topic was presented in light of the tragic race drownings in California last year. Dr. Benedict related that all of the Low Speed Chase deaths at the Farallone Islands were caused by drowning, not by trauma or hypothermia. This drowning was probably initiated by cold water shock. When suddenly submerged in cold water, the body will start an uncontrollable gasping reflex for 10 to 30 seconds. If the victim is below water, this gasping can easily induce drowning. Large waves, being caught by gear or inadequate floatation might hold a victim underwater during this period. It is extremely important that boaters wear properly approved PFDs in cold water areas.
The PDF of the presentation can be found here.