Hacked Sea Scooter Lives Another Day

The Seadoo GTI Sea Scooter is a simple conveyance, consisting of a DC motor and a big prop in a waterproof casing. By grabbing on and firing the motor, it can be used to propel oneself underwater. However, [ReSearchITEng] had problems with their unit, and did what hackers do best – cracked it open to solve the problem.

Investigation seemed to suggest there were issues with the logic of the motor controller. The original circuit had a single FET, potentially controlled through PWM.  The user interfaced with the controller through a reed switch, which operates magnetically. Using reed switches is very common in these applications as it is a cheap, effective way to make a waterproof switch.

It was decided to simplify things – the original FET was replaced with a higher-rated replacement, and it was switched hard on and off directly by the original reed switch. The logic circuitry was bypassed by cutting traces on the original board. [ReSearchITEng] also goes to the trouble of highlighting potential pitfalls of the repair – if the proper care isn’t taken during the reassembly, the water seals may leak and damage the electronics inside.

Overall it’s a solid repair that could be tackled by any experienced wielder of a soldering iron, and it keeps good hardware out of the landfill. For another take on a modified DC motor controller, check out the scooter project of yours truly.

 

2 thoughts on “Hacked Sea Scooter Lives Another Day

  1. Fun, but I want to see one converted to Otto fuel!
    https://en.wikipedia.org/wiki/Otto_fuel

    Back on topic, what kind of batteries are used, I have been thinking of making one of these since the early 90s, I missed out on a chance to buy a Russian titanium one rated to something ridiculous below 1000m. Not sure how the divers survived or if it was just rated that high to be attached to the hull or airlock.

    1. These things have existed since the start of scuba diving. Jaques Costeau and his diving buddies welded some together running on car batteries and French starter motors just after WW2. They also existed in the 80’s looking almost exactly as the one above, but having the reed control a relay. They are really simple because a prop acts as a soft start and torque converter. No need to ramp up current slowly, a bang on off switch suffice.

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