If you want the motor to last, don't run over 7 cells on that 540 motor....and you better water cool it....can and brush cooling. It will run like a bat out of hell on 8 cells, but don't expect that 10 X 2 to last more than a couple of runs before it self destructs.

The more you stop and go, the more heat will build up. While you're running bring the boat in and check for heat often.