Building a Lego-powered Submarine 2.0 - magnetic couplings

This RC sub has magnetic couplings to transmit torque through the walls. No need to drill holes = no leaks. At the end I test it in a swimming pool. Enjoy! Differences to the first sub -rectangular hull (need flat walls for magnetic couplings) -snap-and-lock lid (more reliable, less leakage) -bigger motors, more motors, more propellers -depth control using propellers (IMO more accurate compared to a syringe ballast tank) -lead pellets for ballast (easier to adjus