Hate to ask a question like this but.... I'm going boat stuff shopping tomorrow. One of the things on my list is a new bow mount yrolling motor. I'm going with a min kota minimum 70 lb thrust, 24v. My question is, how long of a shaft so I need for an 18 ft Starcraft? I've yet to have it in the water so I'm not sure exactly where the water line is. I hate to pass up the deal I've found so I need an idea on the shaft length. I don't plan to be out in rough weather and most boating will be on inland lakes. Any recommendations? Thanks