The World’s Smallest RC Submarine?

YouTuber Peter Sripol is perhaps best known for his aerial exploits, but in this project, he’s exploring the deep — or at least the bottom of fairly large fish tank — with what he boasts to be the “world's smallest micro RC submarine.” The sub itself is indeed extremely tiny, possibly giving credence to his claim. It operates with two motors that pull it down and allow it to steer under differential control, and it floats to the surface automatically when thrust is turned off.

The video below goes through the sub’s development, including about how similar little subs work with a dive motor, a piston, or even just two channel models that only dive when powered. This simple design is how Sripol's sub is eventually brought to life.

Experimentation starts out for the actual build by coating the electronics of a cheap infrared RC helicopter with epoxy, then submerging it to see if it can still “fly.” Amazingly, it still functions, so he then gets to work stripping it down to insert in a custom sub with helicopter controls, and cut down propellers.

The prototype performed well, but wasn't particularly small. His next experiment was to solder the controls into a smaller package, then attach them to a LEGO figure — creating a sort of humanoid submarine. Finally, he stuffed all this in a mini yellow resin-printed sub. This of course took a bit of finagling, but eventually it turned out quite okay!