I just bought a 700 bb turbo 8.4 volt to set up direct drive in 28 inch graupner electro vee wondering what prop I should use on it.I now run a gear drive 2 to 1 hydrodrive I also was wondering if the ujoint will hold up with the new motor,will the motor pull the graupner prop that came with the outdrive without overheating or if I will have to change props to match setup I know it is trail & error but I just need a starting point I have talked enough so please help THANKS

Hi Gas,

In that size boat, a 700BB can do very well without gearing.

On a surface piercing drive an 42- 45 mm Graupner K-series is a good starting point.
Subsurface 40-42 mm depending on pitch.

If you want to run the geared down 700 subsurface, you'll have a problem getting the right propsize under the boat (guestimate at least a 65mm X-prop)
Surfacepiercing drive with a geared down 700 means even larger props; 70mm and bigger.

I'd go for a direct drive with a flex-shaft in surfacepiercing mode, the fastest solution.

Regards, Jan.

Thanks for the information I really appreciate that now one other thing can you tell me the difference between the subsurface and surface piercing drive for me I have the graupner hydrodrive with a speed 600 in it now got it from hobby lobby