Re: help me find props please..!
Is 56mph @4800rpm at wot (wide open throttle)? Your engine has an operating rpm range, you want to stay within that range. I dunno what you know about prop pitch and you haven't posted your current prop size so here is an explanation I hope will help you. A prop's size is measured by diameter (first number) and pitch (second number) so a 15 x 15 prop will be 15" in diameter with a 15 deg pitch. with reguards to pitch, the higher the pitch number the more agressive the angle of the blades and the less rpm you will turn but you will get more "power" but less speed. The lower the ptich number the less agressive the angle of the blades and the higher the rpm you will turn. This will give you more top end speed, but sacrifice power and hole shot. Each degree of pitch is worth approx 400-500rpm so lets say your engine has a rpm range of 5000-6500rpm and the prop you have on it now (lets say a 15 x 15) is turning 5500rpm @ wot. If you drop a degree of pitch making your prop a 15 x 14 you should turn around 5000rpm. If you raised your pitch making it a 15 x 17, you should turn aroun 6000rpm. Cup is another way to gain a bit of pitch. Cupping your prop is worth about 250rpm and can be done to fine tune the prop. Lets say you are turning 6000 rpm with a 15 x 17 prop. Adding cup would put you around 6250 rpm. Bear in mind to that your boats hull, the weight of your boat, and how the weight is distributed around the boat will effect rpm. I recomend a stainless prop, you will get better performance out of them and I strongly recomend that you do not exceed the rpm range for your motor, if fact you should leave a bit of cushion. Hope this helps you and good luck.
Art
