I have a friend that repairs
clocks and watches and will check with him. I've asked him in the past about one of the electric
powered clocks in our house and his recommendation was just buy a new movement. The old ones are difficult or impossible to repair a new one is cheap
However the regular movements do not include a way to drive the fourth hand for tides on your ship's clock. I'll ask if he has a source for a movement that will include that function. If not you might have to go with a replacement that only has hour, minute and second hands.