I've got a 2000 Javelin 17 Venom fish 'n' ski with a 115hp Johnson (looper). The engine sports a Raker stainless prop, 13 1/2 x 20. When the boat is fully loaded--with two on board (wife and self), fishing gear (poles, tackle boxes, etc.), ice chest w/16# of ice, and full tank of gas, which is...