He says it "needs only 2w of energy" and I see a label marked 5v so I presume the board draws 400ma which sounds pretty impressive although you have (one has
) still to add a display device and GPS thingy.
There might be some scope with the Raspberry Pi as well. It's a similar sort of thing: credit card sizes, ARM processor ... and only $35 for the posh version, which has 256MB RAM and an ethernet port. It runs Ubuntu Linux, so all that's needed is a port of OpenCPN and the necessary libraries.www.raspberrypi.org