Hydro Boat

[Texas Wheelman]

The Traxxas Nitro Vee has a "return to shore" feature... It's a little electric motor that spins the prop so you can bring it back to shore, if the motor stalls... I would imagine something like that could be integrated into the large scale stuff too...
Just a thought.
Trip..

What else I was thinking... That could be done using a one-way bearing or centrifugal clutch. The centrifugal clutch might be the best, since it's a more common setup and less prone to failure. The electric return-to-shore motor could use a clutch and clutch bell, and then a belt drive to the prop shaft. The prop shaft would just spin the clutch bell when driven by the engine, and the motor could engage to the prop shaft when it spins up. I mention that because it may be difficult to get a gear onto a prop shaft. Also, boats without clutches would have to have the electric motor turn the gas engine to get propulsion.

Almost sounds easier and more fun to make a tugboat to go get your gas or nitro boat that stalls.