| Hi, welcome.
Two lead acid batteries should be fine, but do you mean 12 volt?
Leave the speed controller until you decide on motor(s).
The best thing would be to build the hull to the point where the prop shafts are to be fitted, this will give you some idea of how much actual space you have for the motor(s), more importantly, it should allow you to measure the likely height of the shaft in-board, as this will partly determine what size motor you can fit. If you want to drive the shaft direct you will need the motor diameter to be small enough so that the motor and prop shafts line up. This could mean too small a motor for the hull size.
The alternative would be to raise the motor(s) and use indirect drive. This could be a gearbox or belt dive, depending upon the space available, it sounds daft, but the available space will be a lot smaller than you would guess from a 7 foot hull, it's all down to the prop-shaft angle.
J. |