Makers at the YouTube channel CPSdrone took on the challenge of trying to outswim a shark and come out alive. They pictured getting on the Aquadart 770 Extreme, which is supposed to go at a maximum speed of 25 km/h and saw themselves becoming lunch. On a mission to outperform this underwater sea scooter, they started with thrust testing motors in a water tank in their workshop.
They tried the MTI70182 120KV Inrunner Sensorless Brushless Motor, which achieved 50 kg of thrust. They doubled that to get to 100 kg in hopes of beating the 79 kg thrust of the Aquadart scooter. The design started as a jetpack, and they built a scooter configuration alongside it, considering that the thrust from above could sink someone. With a dead man’s switch and a kill cord, a custom 3D-printed throttle mechanism enabled control of speed underwater using a finger. In addition to this, there was a button mounted between two handles that allowed toggling between four speed settings (this was changed later).
Some designing and 3D-printing later, they bought the dhb Hydron Wetsuit 2.0, taking hydrodynamics into account. A custom PCB was designed to connect batteries together, and an ESP32 acts as the brain of the system. After days of building, tweaking and rethinking prior decisions, they began real-world testing in a swimming pool. They reached a speed of 10.8 km/h at speed 3 using the scooter configuration and found the jetpack disappointing. On speed 4, the vehicle failed, unfortunately, but the makers are confident that they know how to fix that and plan on featuring it in a future video.
