I understand prop diameter and pitch, but aren’t their other factors to prop performance?
Yes there are several more calculations, but now we are getting into propeller tuning, alternately described as a nightmare or black art. It is definitely not a subject that you would want to ask Bubba, down at the boat ramp, to help you with. In the above question we dealt only with the boat’s performance relative to speed. In prop tuning we are trying to regulate either bow or stern lift for a given loading situation. A fully tuned prop is achieved by using a combination of propeller rake, cup, pitch and the number of blades, either three or four. At Port Erie we have spent a lot of time on this equation with our prop supplier and even more hours in testing. In addition, we have developed a proprietary device that we call a wave breaker that attaches under the tunnel in front of the engine. The wave breaker regulates the flow of water around the engine and works in conjunction with the water shape in the tunnel. We have developed a different wave breaker for each type of engine and h
