Also consider getting an actual marine chartplotter and a PC interface. Get
a pair of cheap PC laptops (lay in one as a spare) and stick it belowdecks.
Use the PC for it's regular features and chartplotting. Then upload the
routes and download other data from the marine chartplotter. That way you
get at-sea reliability from the 'real' chartplotter but also get the
flexibility of the PC. This is what I do and it works out great. When
looking, check out MapTech's Chart Navigator Pro. It's a repackaging of
Rosepoint's Coastal Explorer in conjuction with ALL of MapTech's US charts
(including contours). Quite a bargain if you buy it online from Boatfix,
and there's a $50 rebate from Maptech running now.

-Bill Kearney