Building and Testing a Lego-powered Submarine

Making a radio-controlled submarine with Lego and other materials. At the end I test it in a lake. Enjoy! The submarine specs: Length: 22 cm (8.7 in) Displacement: 1880 grams (66 oz) Speed: 0.2 knots (10 cm/s) Operating depth: 3 m (10 ft) - ballast tank will fail after that Hull: 1.5 liter lemonade pitcher (Orthex) Forward: Lego m-motor runs two 9-length propellers (2952) Turn: Lego m-motor runs a geared-up (0.67:1) small 3-blade propeller (6041) Ballast tank: Lego m-motor runs a Lego linear actuator connected to a 60 ml syringe (Eotia marinade injector). Active range 20 ml 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 battery for the radio controller The yellow toy submarine at 6:00 is this one: https://www.amazon.de/Zantec-Schiff-Fernbedienung-Elektrische-Spielzeug/dp/B07CKD2Y7T