I spend a lot of my time working on boats and the best advice I can give is:
Make sure that you really thoroughly wrap hoses etc if passing over varnished surfaces
same for teak decks, loads of coverings,
Also, if you can it is sometimes better to try and source a dock plug, so you can plug directly into the dock, they are on trip switches.
and don't do what I saw a competitor do, and forget to tie your machine to the dock / chock the machine, splaaaaash!!!!!!
Bit of an expensive mistake for him!
Simon
Have fun