At first I tried a 35 mm surface propeller which I got from a friend. This Propeller is more effective than my printed propeller. It needs less motor speed and was hardly to control because it pushes strong even with little throttle. So later I preferred the printed propeller. It is not so wild and makes more noise due to the higher motor speed ;-).
With increasing speed, the bow shoots up and throws a large bow wave which easily can splash water into the boat. To hold the bow low it was necessary to shift the weight forward. In the end even as much as possible.
Sorry for the bad video quality.
I uploaded it twice with different size but it doesn't make any difference. Partly it is highly compressed.
BTW, the ducks were not impressed at all...
The best is, if you print it with spiral vase methode. Then you will get a neat surface without any noses from layer change.
The hull is 3.0 mm thick.
I printed with layer hight: 0.3 mm and width: 0.6 mm.
Anyway, you have to print it hollow with one perimeter otherwise it will not fit inside the interface part.
The interfaces are supposed to put them fifty-fifty in the gap of each hull part. In this way the the hull parts are aligned and easy to glue.
Before gluing you should mask the edges of the hulls with tape to keep them clean from glue.
It is designed for the Roxxy BL-Outrunner http://www.robbe.de/roxxy-bl-outrunner-2834-08.html
3 mm rod 130 mm long with 11 mm M3 thread on one end.
3 heat shrink tubes, one into each other, both about 50 mm long.
I fastened the second one with rubber band to the motor shaft before shrinking the bigger one upon it. It is not necessary on the other side because of the longer contact surface.
This propeller needs an adapter from M4 to M3. Additional it had to be shortened to fit between the rudder and the stern.
The rudder mount now is 2.5 mm longer.