Italian
Using Pirates of the Caribbean as reference:
La Perla Nera (f) (The Black Pearl)
L'Olandese Volante (m) (The Flying Dutchman)
La Silent Mary (f)
La HMS Providence (f)
La HMS Endeavour (f)
La Santiago (f)
They translated the names of the most important boats (the ones whose meaning was important to understand the conversations).
The others were kept in english but treated as feminine, as "nave" (boat, f) is implied.
And as a possible solution: if you really want to translate the boat names, make them female.