Lab condensers run a tube carrying the distillate vapor through an outer tube that has tap water running through it for rapid cooling. Moon shiners ran it through long pieces of copper tubing- also in a water bath. Nastier moon shiners ran it through old car radiators, with considerable leaching of lead from the soldered joints. This lead to irritated customers raising the 'shiner's lead level by ballistic means.

A couple of local folk devised a wood fired water heater by tossing a coil of copper tubing into the bottom of their wood stove, attached to a barrel of water located higher than the stove. The water was supposed to circulate by convection. Worked okay until one of them tried to control the process by installing valves in the lines. Turned a sweet little convector into a steam bomb.

What about Watercone?

http://www.sportsmansguide.com/net/cb/cb.aspx?a=415424

Expensive, $799, but the claim is it will do 1 gallon per hour @ 98.4% salt rejection?

I have been doing a lot of experimentation lately with solar salt water stills. I'm 9 blocks from the Pacific Ocean in So Cal, and there are almost no natural fresh water sources here-abouts. I've tried a variety of setups and, by far, the best setup I've achieved is with a thin clear plastic bowl and lid available from the Smart and Final warehouse stores out here. You put the lid, really a big shallow bowl itself, upside down in full sun, sit a tray of some kind full of salt water in the lid, then sit the upside down bowl itself down on top of the whole thing snapping it onto the lid to get an airtight seal. The salt water evaporates and fresh water condenses onto the inside of the upside down bowl and runs down the steeply sloped sides collecting in the lid. Even running 4 of these stills during all the sunny hours (not as much as you might think considering that a part of everyday there's high fog obscuring the sun), I've been lucky to distill out about 8 ounces of fresh water. One thing that helped was to put a pile of black rags as kind of a wick in the salt water. This seemed to increase the surface area available for evaporation and helped improve the output somewhat. I would work further on refining this addition if I spend any more time on this project.

Thanks, sotto, that's pretty interesting. 8 ounces isn't much, but at least it doesn't take time or fuel, once it is set up.

Read "Into a Desert Place" by Graham McIntosh. He walked all the way around Baja California, on the coast. A large part of his drinking water he got by boiling seawater in a plain old tea kettle with a few coils of stainless steel tubing running out of the whistle hole...

He has apparently written three more books on the subject, the most recent titled "Marooned With Very Little Beer." I haven't read any of those yet...

You might also want to consider the new forward osmosis water filters from HTI. They now have a version that will filter seawater, and their entire line to me seems to be the easiest filter system to pack and use. I haven't actually ordered from them yet, but (unless anybody here has negative experience with them) I'm planning on getting their camelback style filter for my BOB.

http://www.htiwater.com/hti.html
http://www.htiwater.com/seapack.html?Vl=5&Tp=2

UPDATE RE ABOVE

Another reason not to use reverse osmosis plant on land.
Such equipment requires several gallons of sea water for each gallon of drinking water produced.
This matters not on a yacht or ship surrounded by infinite supplies of sea water, but would be a serious drawback if had to carry the water from the sea to a coastal home.

Reverse osmosis watermakers take in seawater and produce a small amount of drinking water, and a much larger amount of slightly more concentrated brine, which is returned to the sea.
Engine driven machines also use this water for cooling.

If it gets cold enough the ice that forms is relatively fresh. Repeated freeze/thaw cycles and slow freezing rates increase the purity and ice on top of sea water is often drinkable water.
You can often tell by the colour how good it is. Clearer is better than greyer.
The effect is strong enough that you can have pools of fresh water form on old ocean ice in the arctic.

Another odd feature of some beaches is that fresh water often sits in a layer just inland from the beach and on top of the salt water layer in the ground. (Ghyben-Herzberg lens)
If the salt water has formed a water table the fresh water floats on top and for every foot it is higher than sea level it will be 40 feet deep. It tends to form a lens shape like most other floating liquids, so it can be thin near the edge but quite deep if it covers much area.
So you might find water if you dig a hole on the land side of the beach, especially if it is sandy.

Another point is you can use the seawater for many things you don't need drinking water for.