The second survived so far. The prop is the cheapest you can get, no name, 180mm diameter, i cut it down to around 160 on a lathe. The other parts are milled, 3D printing could also work. The first motor was hydrodynamical opimized, that was a failure.
Keep the epoxy coating thin. The seconds motor had more space between the windings, so cooling is much more effective. I run it in the mediterrainian sea, very salty.
The incomplete insulation at the interface makes it necessary to insulate anything else with IP68 or better, so there is no current through water where a person could be.
E.g. the so called safety switches have the problem, that they are not really insulated between inside contact and outside ambient, they only have a cheap and ineffective rubber cap, scrap. Tried to find a better one, talked to some experts, no positive feedback so far.
Battery box with BMS ZLA13, TF02N Shunt, Albright Relay, VESC-X and 32Ah 12s mounted in a frame.