You are trapped on an island. How would you desalinate the seawater around you into drinkable water?

Question

You have very limited supplies. Assume you have a fire and basic "island surroundings." Be specific.

Assume you have basic "island surroundings." No supplies except...a knife.
Assume you have the means to make fire.

This is my first question sorry about the repeated details the second time around.

Answer 1

I don't know how basic you intend basic island surroundings to be understood, but, generally, boil water on fire over top of which you have a slanted roof. Boil the water in a coconut half, the steam rises, condenses on the roof, runs down into the other coconut half. Salt remains in the first coconut half since it can't evaporate, therefore the condensate dripping off the "roof" is fresh water.

Answer 2

If you have glass or clear plastic sheeting, build a solar still. It's basically a little greenhouse with a chamber for holding some seawater, and a basin around the edge for catching condesation. The sun warms the seawater and evaporates it. Then the water condenses on the window material (glass or plastic) and drips into the basin. They sell these things and put them in life rafts.

Otherwise, you're probably stuck boiling it and trying to catch the water vapor in some kind of condenser. Reverse osmosis would work also, but your limited supplies may or many not include an appropriate membrane and pump.

Answer 3

You make a cup out of, say, leaves and twigs (eww). You scoop some seawater into the cup, and then you put it over a fire to boil. But before you do that hold some leaves over the cup so that when the freshwater/drinking water boils, (leaving the salt behind) the water vapors condense on the cool surfaces of the leaves and then you should put little cups out to collect the cooled water vapors dripping from the leaves. THAT, is your drinking water.

Answer 4

I would try and build a fire and boil it so that I can capture the vapor drips as distilled water. The biggest problem would be trying to build the fire. Depending on the supplies that you have you may need to get creative with rubbing 2 sticks together or using your glasses as a magnifying glass. Then you have to be able to boil it in something. A pot would be nice, but if you swam ashore, you may need to make due with carved rocks or hollowed out whale bone.

Answer 5

I'd have to figure out a way to capture steam using large leaves, stems and some container (coconut or some large gourd).

Heat rocks in the fire, pour the water on them or put them into water in a container, capture the steam.

Hmm...maybe I'd be pretty dehydrated by the time I got this done...

Answer 6

Evaporation. Cover the salt water and allow the moisture to bleed off and be captured in another cup. The salt will stay at the bottom.
That is, if you can gerry-rig whatever equipment you have to do this.

Otherwise, you will probably dehydrate and die.

Answer 7

42

Answer 8

walk across the island and find a 7-11

Answer 9

Drink rain water. Boil sea water in a coconut shell.

Answer 10

i remember in the boy scouts they said to take three (3) bowls of sand with a hole in the bottom ,each over the next, pour the water through and by the time it gets through the third tray it is salt free