There was a deadly incident this past week in Indonesia involving the sinking of a passenger ferry. The latest official death toll is 28. That's pretty light for Indonesia, because last January a ferry went down and took 335 people with it. And in December 2006, a sinking ferry killed more than 500. Bad weather and overloading of the vessels is the common reason given for these accidents.
But you don't need to go to Indonesia to be at risk of drowning in a boating-related incident. Right here in the good old USA, we lose right around 700 lives per year on the water. As might be expected, the greatest cause of death is drowning, followed by trauma, followed by hypothermia. Let's compare a few statistics — When a life jacket is not being worn, drowning kills more than forty times more than hypothermia. When a life jacket is being worn, the number of deaths by drowning is only seven times greater than deaths by hypothermia. That should tell you something.
Cold water plays a huge role in drowning. Sudden immersion in cold water creates such a shock to the body that you can actually suffer an immediate cardiac arrest. Hitting the cold water will also cause you to involuntarily inhale, and if your face happens to be under water you'll fill your lungs. If you live past that, you'll quickly lose your ability to grasp and hold onto things such as a flotation ring or a line that is tossed to you. Cold Shock Swimming Failure causes you to lose coordination as you flail your arms and legs in a vain attempt to swim. None of this has anything to do with hypothermia. In fact, if you fall overboard in cold water without wearing a life jacket you almost certainly won't live long enough to die from hypothermia, because you'll drown first.
If you're wearing a proper life jacket, you'll float face up so you can breathe and won't have to worry about drowning right away. This is where you need to be concerned about dying of hypothermia. Doesn't take long in cold water.
Personally, I don't like the idea of the life jacket just keeping me afloat long enough to die of hypothermia and give the rescuers a dead body to find. That's why I equipped my life vest with two strobe lights, three flares, a signal mirror, a signal whistle, a waterproof VHF (marine band) radio, and a waterproof GPS. The plan is that if I go overboard, I immediately get on the radio with the Coast Guard or other boaters in the area, and give them my GPS coordinates. If it's night, I fire up the strobe light and/or use the flares. If it's daytime, I use the signal mirror. When a boat is nearby, I use the whistle.
There is no question that a life jacket significantly increases your chance of survival. But if you really want to improve the odds, equip the vest with signaling devices that will help bring rescuers quickly.