I assumed the OP was speaking about a powerboat. One thing I should have mentioned is the inverter. Typically, you'll want to install that near the batter(ies), and that really must be a marine-rated, spark-proof unit.
This subject sparked (no pun intended) my curiosity, so I've tried every google search string I could think of, to find out if in fact one of the features of a marine fridge, is spark protection. Can't find a word about that. The only in-depth tutorials center around power consumption efficiency. I'll also note that the major above-deck components of my marine air conditioner, are not spark protected. It's made by Flagship Marine and uses off the shelf relays and transformers, none of which are 'marine rated'.
Anybody else have anything on the subject of marine fridges and spark protection?