Like HowStuffWorks on Facebook!

How long can you survive adrift in the ocean?


Surviving the Open Water
Proper attire is important in a survival scenario -- a suit, tie and cardigan wrap will keep you nice and warm.
Proper attire is important in a survival scenario -- a suit, tie and cardigan wrap will keep you nice and warm.
Smari/Getty Images

There are many variables that determine how long you can survive adrift at sea. Aside from the basic scenarios, there are myriad other factors to consider, i­ncluding your physical condition, supplies you might have on hand and good old-fashioned will to live. Posing a theory on how long someone could live is very much dependent on the specifics of the situation. We can talk in generalities though and break it down into the following basic scenarios:

  • Adrift on a disabled boat
  • On a life raft
  • In the drink

Boat: If you have a stash of food, some fishing equipment and some fresh water, you can survive for a long time on a boat. People have been known to survive for months adrift at sea in a boat that's still sound. If it's cold, you have overhead cover that will help keep you dry and blankets to keep you warm at night. This means you should be able to stave off any cold weather illness, like hypothermia. If it's hot out, you can use the same coverage for shade and avoid heat stroke and sunburn. If you don't have much fresh water, you can fashion a rainwater collection system with a tarp or raincoat that runs into a bucket. Or just place buckets out during rainy weather. Drink at least a liter of water a day, fish a little and you can live for a long time adrift at sea. Of course, storms can always capsize or sink your boat, but other than that, just think of it as an extremely slow sailing trip.

Life raft: Being adrift in a life raft is like being in a boat -- you just have a greater chance of sinking. Life rafts can be punctured, ripped, leaky or simply defective. The good news is that modern lift rafts are thoroughly inspected, pretty durable and come with a lot of bells and whistles to help you survive. They can range from smaller two-person rafts to large 16-person models. A top-notch raft comes with any combination of the following:

  • Covered deck
  • Paddles
  • Insulated flooring
  • Bailing buckets
  • Ladders
  • Flares
  • Water collection pouches
  • Signaling mirrors
  • Reflective tape
  • Fishing kits

A good life raft is pricey, with a deluxe four-person model ringing up at about $4,000 -- but it's worth it. As long as the raft stays afloat and you have some luck collecting water, fishing and keeping dry and warm, you can survive adrift in a raft just as well as on a boat.

In the drink: If you're actually in the ocean like the couple from "Open Water," then you have your work cut out for you. Hopefully you have on a wetsuit and an inflatable safety vest. This will keep you floating and somewhat visible to rescuers. But you won't be able to collect water, and drinking sea water will only dehydrate you. Fishing isn't a reality either. If you're in cold water, you have a good chance of getting hypothermia, so pull your knees to your chest and hold them to retain heat. This is called the H.E.L.P. -- Heat Escape Lessening Position. Assuming you're in warm waters and wearing a wetsuit and life vest, you could potentially survive for as many as three to five days, at which point you'll most likely succumb to dehydration. That is, unless a shark gets you first.

Interested in other survival scenarios? You've come to the right place. Feel free to browse the links on the following page.