Sounds like a cool dude. Modern systems are far too complex to make in a home workshop, but hydraulics are simple at heart if you can use a little logic.

I’m a hydraulic fitter. I repair and maintain hydraulic systems, primarily on earthmoving equipment.

Ships are much more efficient than cars. Having said that, this wouldn’t have a huge range, nor is it terribly big by container ship standards.

I don’t see anyone say here that under normal circumstances you have to identify yourself to police upon their request. I’m fairly certain this is true for all Australian states. It certainly is here in Queensland.