Too true Mars,
Also contained in an article I read while researching this topic is a statement to the effect that drowning deaths are often a result of hypothermia since the victim is unable to turn his back to on-coming waves and spray as he becomes weakened from exposure to cold.
Compound the exposure to cold water and cold air....with the lack of effective airborne SAR capability that now exists in the Gulf Of Mexico and you have a potential for disaster.
Middle of the summer, hot , clear sunny day, flat water, calm winds....immersion in the sea does not present nearly the hazard.