Question:
Distilling is the only way to remove salt from water??? you say? Not soplease review the technology of reverse osmosis, membrane systems, andvacuum separation ( removal from ice), distillation is one possibility butone of several

Answer: The PUR (and others) use reverse osmosis filters, a similar technologythat is used in very large plants to make fresh water from sea orbrackish. The salt water is applied to a semi-permiable membrane thatlets the water molecules through, but doesn't let through much else, includings It requires lots of pressure (the small boat units I'm familiar withoperate at about 800 psig), and lots of energy (although it's fewer btu's/ergs/whatever than distilling). There are hand powered units for liferafts thatproduce about a pint every 8 hours, and larger units that are engine driven.

If this is directed at me...I thought that I said that distilling was the most practical method. Asolar still, for example, takes time but little effort. A 'real' still isfaster, but needs fuel or some such. However, RO takes pressure, and a lotof it. I wouldn't want to have to rely on a pump generating a thousand PSIfor water-that takes a lot of fuel.

Generating a vacuum for vacuum separation (if I'm remembering this right)is no trivial task either.

BTW, has anybody thought of building a still out of a pressure cooker andtubing, but omitting the fire/stove and just painting the pressure cookerblack and leaving it in the sun