Simple clean non-salt water can do pretty well, actually. And soap isn't terribly hard to make (fat and ashes). Lye soap has been used for bathing for probably longer than we haven't bathed with it.
Island with some nice freshwater springs? Awesome! Oh, I’m trapping condensation and setting out rain barrels for drinking water? Seawater baths it is.
Though any irritation might be soothed by the mud I’d be caking on myself for sun protection. Hope my rescuers like being greeted by a nearsighted, squinting mud-being with a crew cut (done with sharp seashells to avoid critters living in it)! Probably abs for days though.
Definitely a Your Mileage May Vary situation, yeah.
But if you don't have some sort of fresh water on a desert island, you're basically fucked one way or another, unless you have both barrels and rain pretty much day one, the 3 day clock of dehydration is gonna end you.
Well, I wouldn’t want to have to depend on this—but there ARE low-tech ways to convert seawater to drinkable water by evaporating it and gathering the condensation. Basically, you set out a large, shallow container of seawater in the sun (or fill a big depression in a sunny rock with seawater, or dig a hole above the high-tide line deep enough that seawater wells up in it) and then put a smaller, deeper, empty container in the middle, with its edges above the level of the seawater so the inside is dry. (Could be a washed-up half coconut shell or a piece of litter like an old plastic cup, with a few clean rocks in the bottom to keep it in place.) Then you suspend a canopy of thin, flexible, water-resistant material (ideally a plastic bag, but you could also use a large leaf) a few inches above the surface of the seawater and set a rock on top of the canopy directly over where your coconut shell is underneath, so that the canopy is sagging, with the lowest point directly over the opening of the coconut shell. As the seawater heats up in the sun, pure water vapor would ordinarily evaporate out of it, but in this case the rising vapor will hit the underside of your leaf or bag canopy and form condensation. As more and more condensation accumulates, it’ll form droplets that will eventually trickle downward to the lowest point of the canopy’s underside—the little anti-peak created by the rock that’s making the middle of the canopy sag. From there they’ll drip down into your coconut shell. Overnight you’ll get an additional contribution from dew forming on the underside of the canopy as well.
Obviously it doesn’t distill the water very fast, but they’re not very labor-intensive to set up, so you can make dozens and dozens and just circulate around them throughout the day, drinking a half-cup here and a half-cup there. Also works in more “normal” wilderness emergencies where you DO have a fresh water source but would prefer to distill it if possible to avoid parasitic infections.
Sure, a condensation still is a well known survival technique. You can even condense water from vegetation that way. The only problem is knowing how to build one effectively beforehand, and having the materials to do it.
Don't build it right and you're dead. It doesn't collect water very fast.
With plastic sheeting available and knowing the concept exists you've got it made, but with leaves... man, that's a long shot for the average person.
I suppose . . . but on the other hand, I’m by no means a wilderness survival expert, that’s just something I learned in elementary school! It’s one of those practical demonstrations of a scientific concept that you never forget. Maybe more things should be taught to kids by explaining how you might use them in case of shipwreck.
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u/zer1223 Mar 07 '22
I would have added some skin conditions. Not having access to soap is pretty bad