I have a 21' K-Kraft V-Hull fiberglass boat, with 240HP OMC I/O. I have the following props, all 3 blade aluminum.<br /><br />14 1/2 X 19<br />15 X 17<br />15 1/2 X 15<br /><br />I was told when I bought the boat, one prop was for "power" (pulling skiers, etc) the others where for speed. I know nothing about these props. Can some one tell me what is what? I'd like to put the speed one on for general use and the "power" one on when I take the family out.