The reason this thread is confusing to some of us is things like this. Sharing a comment from the prop guy is great, but it indicates one thing: the prop guy was either misunderstood or he doesn't know what he's talking about. The fact is that the prop doesn't "know" what engine is turning it, and the engine doesn't "know" what prop it is turning . . . So how can a type of prop be bad or good for a specific
engine? While there might be an acceptable range of props, and of course it has to be useable with your drive, I think that's the point: there is no right or wrong prop for an
engine. And back to the OP's original query, there is no real benefit in knowing what boat speeds others are getting unless we are dealing with the exact same boat and load and of course the same rating of the engine itself. Anecdotal information is fun, and maybe even interesting, but it shouldn't be used to make any decisions.
Soooo, while I understand that the OP wants to build a mini-data base of info regarding other users and 4.3s, what would you do with that? The frustrating thing about boats is that the only boat that we can really compare with his, is . . . uhhhh . . . his. Same hull, same power, same drive, same ratio and even the same load. That's what matters. Yes, some prop types may work better for watersports, and some for fuel, and some for flexibility, but no prop works best for a specific
engine. Engines ultimately do nothing more in a marine application than twist a shaft, and then, unless it is a 1:1 ratio, the actual propeller shaft spins at a different speed. And then a prop is on that. How does the propeller and engine actually "know" or care about each other? And since they can't and don't, how can there be a better or worse prop for an
engine? There kinda can't be.
Props are most about the application, the hull and drive design. And they are less about the lump of metal that makes them spin.
Why do some of us care about this distinction? Because these threads live forever and others will make decisions regarding purchases based on them. And many people make decisions when they hear what they want to hear (read). So if a guy looking at a 25 foot 'toon reads that a a 4.3 pushed an 18 foot runabout to 50 MPH with a four blade 23" flangelrod defibrillating wonkivator, he may figure that's exactly what he needs . . .
If you really want to see how to compare props and power, take a look at Walleyehed's prop test results here:
http://forums.iboats.com/showthread.php?t=218877
What does that mean to the OP? Almost nothing except how hard it is to compare props and power and hulls. Even when all is the same, the results can be very different
