Bob:
This sounds like a breaker that opened due to over loading or due to age. Then when the breaker opened and after it cooled off, it reconnected and come back. What boat model is this? Is this a factory install or after market? Do you have a wiring diagram? I would trace out all the wires to this bow thruster and find out where it is connected into the 12 volt system. I would expect the thruster would be on its own circuit and with its own breaker. Do you have to flip a breaker to use the thruster?
PS:
Can you add info to your profile here, so we know the boat model and added info, thanks
ipyoa.com/community/profile/edit
Hayden
