How about this!?
A Raspberry Pi 4 running OpenCPN on a Cello 12 volt TV. With a wireless keyboard/trackpad.
Obviously lots more to do as I haven’t loaded any charts yet. Nor have I connected a GPS, so it doesn’t know where we are yet. Also not yet got AIS (which automatically shows ships positions, courses and speeds as well as telling them yours so you don’t collide).
Going to be able to add a touchscreen that we can put in the cockpit. All for a tiny fraction of the cost of “proper” chart plotters. Plus it gives me essentially a full power desktop computer running on 12 volts as well as a TV.