Bill Daniels wrote:
Basic need is water. A Katydyn water filter is standard USMC kit. For
glider types, retain a few gallons of ballast water and filter with the
Katydyn before drinking.

What is Katdyn? I haven't heard fo it before.

For water purification, the most interesting thing I've come across is
this.

http://www.miox.com/News/CDI_MIOX_License.html

Expensive ($130 at REI) but elegant.