Just puchased a 1991 18' celebrity bow rider,4.3l mercruiser.was told that it had a 21pitch prop,top end RPMs is in between 4400-4800.Was hitting about 5100.Went and bought a 23pitch, put it on and noticed that the old one was actually only a 19 pitch.So now for the ? is this gonna be that BIG of a deal,or should i take it back and go with a 21? the boat is used only as pleasure occasonally tubing.<br /><br /> thanks 