How long can you survive in ocean water?

When JFK, Jr. crashed his plane in the ocean, commentators said that even if he landed in one piece, he would only have a few hours to live due to hypothermia from the cool ocean water. Mind you, this was in July.

This confuses me because people go swimming or surfing for hours when they visit the beach, but you don’t see bodies washing up on the shore. I even heard of someone who swam all the way around Long Island for charity, and he didn’t die.

What is the Straight Dope on how long you can live in ocean water at summertime temperatures?

40F degree water will kill in a few hours, if that; while 40F free air temperature is survivable indefinitely, basically. It’s all to do with conduction, as water is an excellent conductor of heat relative to the human body.

What’s the temperature of the ocean there during the time period they splashed in?

Dave, here is an great site about ocean hypothermia. I haven’t read it, but just offer it for your use.

The operative thing may be, that you wade out 10-40 yards and the water temp. is fine. But go out hundreds of yards or more and it gets cold fast.

It depends on several factors including water temperature, the amount of body fat on the victim, clothing, and what the victim is doing in water (like swimming, or treading water). Body size is also important. Children succumb much faster than adults. In general a person wearing a life jacket and light clothing in 50F water has a survival time of 2.5 to 3 hours. It’s a curved graph - in water that’s about 32F, you can survive about 1.5 hours. In 60F, survival time is 6 to 7 hours. Even water that is very warm, to within a few degrees of body temperature such as what one might find in tropical rivers can lead to hypothermia because of conduction. People who regularly engage in water activities wear wetsuits to minimize heat loss.

If you find yourself in a survival situation, use the HELP and HUDDLe technique to increase your chances of survival. HELP is the Heat Escape Lessening Posture. Hold your arms tightly to your chest, keep your thighs together and cross yor feet, and bring your knees to your chest. The idea is to reduce your surface area and keep as much of your body out of the water as possible. Of course, it doesn’t work without a life vest, so wear one! If you’re in the water with a few friends, huddle together with children in the middle. These techniques can increase your survival time by as much as 50%.

My information comes from a water survival pamphlet published for boaters in Oregon called “Hypothermia and Cold Water Survival”. Search on “hypothermia” and “cold water survival” for more info.

Yeah, it depends on water temp as to how long you’d last. When I was in Thailand, the water around the estuary was about 30C. Divers or snorklers can swim all day even without wetsuits on tropicals reefs. If you go deeper, it gets colder though. Cold water long-distance swimmers can last quite long in well, cold water. I saw a guy (I’m sure there was more than one) swim from Alcatraz to the shore in just a simple swim suit - took him close to an hour I think. Then again, if you’re salmon fishing off the west coast in BC and you fall in the water more than a few hundred yards from land, I’ve been told you’ll likely freeze to death before you can swim to shore.

Oh yeah, surfers wear wet suits or come out of the water periodically… that’s why they don’t freeze.

The question has to be asked: which sea and what latitude.

I work offshore, in the north sea. The life expectancy of an unprotected person varies from 15 minutes for southern platforms, decreasing as you go further north to under 10 minutes. I was told in offshore survival training that your life expectancy increases if you’re fat (it insulates) or if you’re a smoker (constricted veins retain heat).

[QUOTE]
*Originally posted by Gary Kumquat *
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What an interesting argument for the tobacco industry.
Smoking CAN (theoretically) save lives!

I surf, I can stay in 52 water for 5.5 hours; but by the time Im 50 I want to be able to do it 6 hours. I dunno cause there is barely enough daylight for that.

The skinny surfers don’t last long.

Some lady fell in the ocean where I surf a couple years back & lasted 25 minutes .

BTW, things happen when you get in the cold water. Like once your body temp hits around 95 (?) your memory starts to go, which is why they often ask people if they can remember their name.

handy Do you wear a suit when in that 52 degree water for 5.5 hours? Where do you live that there is barely enought daylight for 6 hours of surfing? If skinny surfers don’t last long, do we assume you are fat? The lady who fell in the ocean where you surf–she “lasted” 25 minutes. Do you mean she died? Was she just that skinny? Sharks? Thanks.

Almost 900 men survived the torpedoing of the U.S.S. Indianapolis. They spent almost five days floating in the Phillippine Sea with almost no food or water, and sharks all around. 316 survived.

Yeah, but Quint couldn’t survive a run-in with a great white shark just outside Amity Island.