I’m hoping for some guidance with prop selection. Our story is that we inherited a 21’ RC V Drive 3 years ago. It used to run some horsepower, but just before my Father in Law passed he replaced the engine so that he could just run pump gas and have more of a cruiser of sorts. The boat is used as the family station wagon at a Lakehouse and gets driven more for transportation than for a typical recreation type of mission. A 10 mile ride to and from a restaurant, etc..

As stated just before he passed he did the engine. When I got the boat the Hobbs showed that he had run the new engine less than 30 minutes. I know he ordered a prop trying to run something better suited for a lower horsepower application, but I never got to speak with him about it. I installed the new prop and have run it for 3 years now.

Last month we spent time on a friends pontoon boat on Lake Powell and I realized right off that this gynormous boat was WAY faster than my Schiada. And I mean it would spank it badly.

Today I carried a portable GPS and collected the following numbers on a mirror smooth lake. The boat always feels like it needs a taller gear so to speak with the forward motion not being right for the excess of power that seems to be being wasted for each speed. It feels like it will easily pull a taller gear for lack of a better wording on my part.

Here’s the numbers, and I stopped at 3,600 rpm because it seemed pointless to keep going with this. For each RPM I played with trim to get the highest readout on the GPS FWIW... Also I’m assuming that the old prop is all wrong or he would have not ordered a replacement and stopped driving it after only 20 minutes or so. It’s a big effort to get the trailer off the hill behind the garage and take the boat out of the water repeatedly with me just guessing with the prop. Also, I’m embarrassed to say that I fon’t Know the numbers on either prop. I’m hoping for a good starting place... Thanks in advance for any help..

2,000 rpm = 23 mph

2,200 rpm = 26 mph

2,400 rpm = 30 mph

2,600 rpm = 33 mph

2,800 rpm = 35 mph

3,000 rpm = 36 mph

3,200 rpm = 38 mph

3,400 rpm = 41 mph

3,600 rpm = 43 mph