I wonder about the idea of the Apple Mini. It's fanless!!! I really don't intend to switch to a Mac, but you can use BootCamp to run Windows. Also, I hear that similar PC designs will soon be popping up. These little things are pretty powerful proportionally (both in dollars and size), and I think that they would be strong enough to handle all a ship's systems pretty well. Next, choose any screen you want, and any keyboard/mouse combo (wireless?) as well.
I wonder if they're able to power from 12v?