Situation: ventilation<br /><br />18 foot cat, yamaha 90, single engine application.<br /><br />current prop, 13 by 17, 3 blade ( solas ), WOT is right at 5500 rpm.<br /><br />New prop, 13 by ???, 4 blade ( solas )<br /><br />anyone that knows about 4 bladed props? ( solas makes a 13 by 13, 15...