I have a 15' Wilker Galaxie with a 1986 Mercury 75HP engine. Here is the picture of what the boat looks like: <br /> http://www.shipsahoy.biz/boatframes/15FtWilkerGalaxie.html <br /><br />With the current prop I only get 4100RPM, but I am not sure if the tach is reading properly or not. I know from the manual I should be in the 5000-5500 range. Can someone recommend a prop(pitch and diameter) that will get me in this range and have decent whole shot for water sports. The old prop look pretty hacked up anyway. It has no information on it like pitch or diameter, so I am not even sure what it is.