I have never built the boat, so I have to admit I'm not sure, but I would try to get the center of gravity somewhere around 28 to 30% of the length of the boat. That works out to roughly 20 5/32 to 21 5/8 inches from the back of the boat with all hardware, the motor and electronics in the boat.There are an awful lot of variables involved. With a more powerful motor you might need to move the cg forward more and with less power it might need to move back among other things. Doug |