Power absolutely nothing with your miniature electric engine!
I had one of these as a kid, or at least something very similar. Rubber bands were one of the component parts. Lesson: if your engine contains rubber bands, it’s not worth a damn.
Okay, granted, someone with skills on par with Montgomery Scott’s could perhaps finagle function and propulsion from an engine with such a handicap, but not mere mortals, that’s for sure. It would be a miracle if it worked, much less was able to launch your dinky little model boat across the swimming pool.
“Your friends will envy you.” Doubtful.