I am replacing the prop on my 40hp Force which is on a Fishin Barge 21 pontoon . The numbers on my prop are 48-85632-11 which as far as I can determine is a 10 1/2 inch 11 pitch . A friend of mine has a new 10.62inch 12 pitch . How would the increased pitch affect it ?
What is the WOT RPM range for your engine. Usually. it is prefered to select a prop that allows the engine to run in the higher end of that range
A drop in RPMs, slower holedhot. As for top speed, probably slower. If the boat isn't performing like it used to, figure out why. Boats, like people, tend to gain weight as they age, more junk on board, trapped water. Hulls also get distorted, have growths.
If you friend is willing to let you try the prop, then you will be certain as to how it will perform.
In the 47+ years I have been running boats, I have found swapping props, of the same Lineage, usually resulted in a top speed within 1 - 1 1/2 mph of each other, the main differences being holeshot. However, switching to a Higher performing model/lineage of Prop and the changes in engine mounting permitted, did result in higher top speeds. Sometimes the different prop lineage also changed how the boat rode/handles too.
