john44, why are you using 90A ESCs with 35A motors?
Furthermore it's a 5mm shaft, the MS shafts in the kit are 4mm.
I'm building a Slipway Tamar at the moment, with the following options.
Overlander Thumper V2 3548/05 motors, 710w 900kv
Hawk 60A ESCs
40mm 5 bladed brass props
And battery choice currently undecided whether 4S 7200mah is going to be a bit too fast, or just right. Going to spend out for the 4S anyway because extra throttle that I don't use translates itself into longer runtimes.
That's not tested in the water yet, but it's the same setup used by another modeller (pipster I think) on this boat, only with 10 volts I think, so 14.8 volts will be a bit faster again. I'm trying to get the bow up and out of the water like has been seen with a few models.