You may want to consider one that you hang over the rail or side.

Like this one: http://www.basspro.com/servlet...sults

I mounted one of the screw on models on my old Skeeter boat and everytime I would come off plane it would throw a rooster tail of water into the boat. Not bad in the summer, but cold in the winter.

This is the one that I used to have:
http://www.basspro.com/servlet...sults