[Dafni]

Sure, I see. But I just don't like the idea of wiring the batt directly to the chassis.

Here is what the short manual says (and, yeah, it sounds kinda weird in german, too):

--If you experience interferences from the motor over the controller, please connect a 1.5m2 wire from the motor (screws) to the batt minus, thus the motor is grounded. (often recommended on CF hulls)

The german text is somewhat confusing, too. Really.

DAF