As an aside, nearly all cruising boats that I meet have a laptop
aboard.

Bear in mind that with a video output to a monitor and a wireless
keyboard/mouse (or even wired) you get the advantages of the laptop (power
management, size) while still being able to use it as a normal PC.

When you go with a built-in system you're painting yourself into a corner.
Getting parts is bad enough in the islands, getting parts for specialized or
industrial stuff will be even worse.

Chart plotter and most general purpose use doesn't really require much
computational horsepower. It's often more economical to just buy TWO
low-end laptops; keeping one as a spare. Set one of them up, clone the
drive onto the other one and stow it safely away. Rotate it out now and
then to make sure the spare still works OK.

-Bill Kearney