Hi Bob,

As mentioned in other Sea Queen threads, the stock motor and prop will get you going, most likely at scale speed or a little faster.

If you intend to go (much) quicker, you have to look for a more powerful motor that will fit in the same mount as the stock one (a Graupner 900 motor, just to mention one), or make provisions during the build to have the possibility to upgrade to a larger motor with more torque, but not significantly higher ampdraw.

I've added two pics to show what I mean:
The first two motors are surplus copy machine motors, high torque, low ampdrawing motors, about the same size as the fan motor in the next picture.

Source for the fan motor: scrapheap (it doesn't get much cheaper).

I recently replaced the ugly copper cooling coil with a cooling jacket like the one on the 700 motor, to keep the diameter down, I added some pictures of the new jacket.
The motor next to the fan motor is a 900 Johnson, for size comparison.
The fan motor will power my 43" MTB on 12-24 NiMH cells.

You see, these industrial motors are rather big, so you'll have to adapt the motormount during the build, to be able to use one.

Expect runtimes like with the stock motor, but you'll be able to run a much bigger/coarser pitched prop, making the Sea Queen jump on the plane in a matter of feet when you punch the throttle...

A propwash pickup will provide ample flow for motor and (if required) ESC cooling.

Regards, Jan.