Hi, this was the boat I had as a kid... she worked rather well back then on the original Graupner motor and prop system with the then modern vario.

Now as she has stood up to the time rather well I am looking to get her back on the water, this time for my kids.

So I'm going to gut her and replace the broken rudder system by an aluminium prop/rudder a flex shaft, new prop, brushless motor (water cooled) and probably powered by a 3s lipo.

My question is what kv and prop to pick so I have a decent speed and a good run time.

PS the mah of the lipo battery will depend on the space I have left to fit the battery in the boat which will then also determine the run time.

Any advice welcome.

The boat is a Graupner Hydrospeed 60cm long.