Yes I would add fuse(s). As with all electrical equipment protection from over current is the fuse's responsibility.
While most fuse insertion at or near the source, we prefer to fuse near the unit itself to eliminate any shorts from interfering with source.
A 3 amp fuse should be used and the best is the in-line bayonet and socket type. Salt water can have a creeping effect so make sure the fuse is dry and protected from any water influence.
Not sure why the units shipped without a fuse. Were these new out of the box from dealer or supplier. Or bought elsewhere?
Chuck