How about the AtoZ of ' In or on the water'? How does that sound?
aircraft carrier
able seaman
clipper
corsair
canoe
cruiser
Halibut, just for
Hermaphrodite brig
mariner
mackerel
mussels
marlin
merchant ship
piranha
passenger ship
pirates/pirate ship
pleasure boat
patrol boats
porgies
pike
Queen Mary ... ocean liner