Protecting Yourself from the Elements
After drowning, the highest danger comes from exposure (cold, wind, heat, sun, salt).
Hypothermia is the main cause of death resulting from exposure to the elements. The body heat loss is 25 times greater in the water than in the air. Even in tropical water, a man immersed (without protection) for an extended period of time will die from hypothermia. (In the 80s a dive boat sunk in the warm water of the Sea of Cortez. The only people who survived were the ones who were able to grab their wetsuits. Survivors still suffered from hypothermia). In cold water, dying from hypothermia might be a matter of minutes.
In the heat of the moment
If you can, grab as much clothing as possible. Polypropylene will protect you even wet. Rain gear will protect you in the raft.
In the water
Try to get off the water as soon as possible. If you can’t, save your energy. Avoid all movements that will increase your blood circulation as it will also increase your body heat loss (it is wrong to believe that moving quickly in very cold water will help you to warm up. It only exhausts you). The original pain you feel in the extremities will quickly disappear, frostbite in the water doesn’t happen before hypothermia, so save your energy (On land in cold climates and mountains, frostbites can often happen before or even without hypothermia).