Thanks Jeff, Chris, Wayne;
Your opinions have altered my course; I'm looking in the laptop
direction now. One for use and one sealed as a spare. I've always
built my own computers and as you said, a VIA box would be fun to
build but with a critical application (like running navigation
software) you have to be practical. I'm building a 35' steel
pilothouse cutter and haven't calculated my power requirements yet,
but I'm considering a towed generator. The monitor will be housed in
the pilothouse, where it will be dry.

A navigation solution that will work in the cockpit is another issue!

Cheers, Jim