i used a 4mm strait shaft on offshoreelectrics. then i used a graupner 4mm to 1/8 flex coupler on offshore or hobby-lobby.com. i used the 36mm on surface drive(this prop is way to big for subsurface drive) i got it under props on offshore in cf props in s series props and it is the 36mm one. this prop was however slightly too big so maybe a 1.4 pitch prop will be better(in 36mm) . surface drive or surface peircing drive i where you have half of the prop in the water and half of it out at all times, its hard to explain. i made my own rudder bracket out of brass tubing a solder. i can use the stock rudder that way. i tore out the reciever box and battery holder tray thing. i also tore out the motor mount and made a new one out of .062 aluminum. i tried this boat on 12cells on an electrifly t-600 and it hauled!! i used a jeti esc but you can use a cheaper intellispeed esc for 22$ at towerhobbies if you would like. the only draw back was the heat problem because of the large cell count. i could do short runs tho. it was uncontrollable!! the turbo vee prolly went 27-30 but i coulndt get it to that speed with out the boat flipping around.