Looks like I was a little too enthusiastic about the condition of the boat. For some reason the range of the remote is about 1.5 meters. There is nothing I can see which could be responsible for it, at least no loose wires, but I’m far from being an expert.
The second thing I realized when I opened the box containing the electronics is that there is only one circuit board containing everything. I guess that makes it cheaper producing the boats, but I guess I’ll have to replace everything except the motors.
This box contains everything, the wires are connected to battery, motors, ON/OFF-switch, on the backside is another one to the antenna.
Well, considering that I would have replaced all that stuff anyway I still consider it a pretty good deal.