Motor size
Although most sailboats do not specify the maximum motor, what I would recommend is based on experience. First the Tohatsu/Nissan 8 & 9.8 are basically the same block witht the 9.8 given more horsepower. This would be true with the 9.9 and 15 both being the same block but the 15 having more power of course. There are many theories but based on experience, the maximum horsepower would be a 9.9 whether it is 2 or 4 cycle for your boat. Most folks should remember that sailboats are displacement hulls that sit in the water pushing it aside whereas power boats are planning hulls that require for the most part the excess power to get the boat on top of the water in order to move. If you have for example a 15 horsepower on the back of the 25.5, you will see under full power the bow raising up thus plowing through the water and slowing you down. When you reduce power, the bow will lower and if you had a knot meter, it would prove my point. Simply put, 9.9 for your boat would be ideal. Happy sailing
