They are still acting as captains, mind you, it's just that they are a:
- Parrot. Looks at you with their head swung to the side, one eye open the other closed. Panoramic vision makes brain hurt. Gathers gossip, intelligence from seagulls.
- Swarm of rats. Can't speak, but masters of cartography. Several will pause to stare disapprovingly if you make a rat joke.
- Ship. Wheel turns on its own and crew scurry to keep up. Gives orders once a night at midnight answering yes/no questions. Silence means yes, horrible creaking means no.
- Collective memory. The old crew can still hear a voice barking orders just over their shoulder. Spend enough time around them and you start feeling the stare of dead eyes.
- Tarot deck. The more ways to deal a deck you know the more complex the conversations you can have. Afraid of being transformed back and losing powers of foresight.
- Figurehead. Has had self removed from prow and set into back of wheel. Old enough to know basically everything about the sea.
- Elaborate wig. Grows roots into anyone wearing them and gradually takes control. First thing they instill is a phobia of open flames.
- Bank of fog. Can't go up on deck during high wind. Impossible to otherwise kill. Insists they are still a real person despite overwhelming evidence to the contrary.
- Coral reef. Their fleet is anchored around them. Commandeered ships of no use scuttled, added to mass beneath the waves. Communicates semaphore-style with schools of colourful fish.
- Barrel of Rum. Drinking more strengthens the urge to sail to a specific place and rob specific people, working oddly well as a team with all these people you just met tonight. Watering down the barrel does not diminish the effect.
- Orangutan. Hates sound of own voice and does not speak. Evocative with sign language. Could already kill with bare hands before transformation, but enjoys improved climbing ability.
- Sea monster. Mash-up of Davey Jones, the monster from The Host and the swarm demon from the Constantine movie, but all fish obviously.
Don't even TELL me this isn't super usable. Grab your faves and tell your PC's they have to turn them all back. Introduce one as a cute side character/source/fence/villain. Introduce two as fighting over a potential cure. Just think about the seahag that cursed them all!