I'm not sure if this is the right place for this question but I was wondering about kicker motors. Specifically i'm wondering what size hp I would need for a kicker on a 19.5 fiberglass boat with an I/O motor and drive? The boat weighs about 2500 lbs i'm told. I want something as a backup to get me home from about 4or 5 miles in salt water that can get a bit rough and have tides. Also how important is it that the prop extend below the bottom of the boat. I know ideally it should but is it absolutely necessary?