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 https://www.youtube.com/watch?v=tGEZApd9MMk
-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 adjust, both shape and weight, compared to steel plates)
-captain (thanks everyone for pointing out this obvious missing part :))

The submarine specs:
Displacement: 2.7 kg (6.0 lb)
Test depth: 1.5 m (4.9 ft)
Hull: glass food container (IKEA 365+ 1.8l), plastic lid
Motors: 3x Lego XL-motor (8882-1)
Magnetic couplings: K&J Magnetics R844-N52 neodymium magnet, TapeCase 423-5 UHMW Tape
Propellers: Lego propeller blade (2952), Lego liftarms
Radio control: 27 MHz controller dissembled from a toy submarine (Zantec Mini RC U Boot), L298 H-bridge to drive motors
Power supply: 9V Lego battery box for the motors, 3.7V Li-Po for the RC
Onboard camera: Faironly Firefly Q6
Pressure sensor: Jolly Logic Altimeter One

Link to the magnets used in the couplings:
https://www.kjmagnetics.com/pr....oddetail.asp?prod=R8

Music:
Tommy Baynen - Laminar Flow [Colorize]
https://colorize.ffm.to/encolor222
https://www.youtube.com/watch?v=UPdR8lh4a1o
https://soundcloud.com/tommybaynen