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Posts: 280
Location: US | I have a Alumacraft Competitor 205 CS with 200hp yamaha (4 cylinder). It currently has a 14.25" x 17 reliance SS prop. I'm happy with holeshot and it runs 45-46mph at 6000 rpms. However, at 6000 rpms, I still have throttle left. I'm not sure where it tops out at for rpm at WOT, as the manual says 6000 is the limit and it's still under warranty, etc.
I think i should try a 19p prop to get closer to 6000 rpm at WOT. How much rpm drop should i expect going from a 17p to a 19p?
Any other recommendations beside the reliance series props? |
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Posts: 1209
| 200 rpm per 1" of pitch, different models of props may be styled differently so pitch may be less affected or more affected. Only a real prop guy will know. If it were a merc I would say take up to 6000 and feather in till it's to 6200 or stops pulling. Since in a mercury the redline is variable in many ways. Not sure on Yamaha |
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Location: Athens, Ohio | http://www.bbcboards.net/forumdisplay.php?f=10
folks on this site seem to know a lot about such things. m |
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Posts: 3480
Location: Elk River, Minnesota | Hiya,
The reliance propeller is moderately raked so it does a fair job of lifting the bow of the boat and lifting the overall boat together. It is not a vented prop like the older pro-series propellers, but I believe they are of the same basic design
It is correct that switching from one pitch to another in the same exact prop model will roughly be a 200 rpm change with a change of 1" in pitch (In your case, down 400 RPM going to a 19 pitch from a 17 pitch).
If you change prop brands, then the only real way to determine where you are at is with testing. Some dealers have a blue prop (demo prop) program where you can try different brands/models to find the one prop that works best for your liking and intended use. If the dealer you bought from has this option, it may not be a bad idea to see if they will allow you to try some different props or different pitches.
I'm thinking you should be able to see a bit more out of your rig... If the motor is mounted one hole up off the transom (standard for alumacraft), you could very well move that motor up another hole and go with a 19 pitch or even 21 depending on where your top RPMs are on the rig. I'd think you should be in a range of 50 to 53 or so for that rig...
That motor I believe will have a rev limiter on it (tongue in cheek on this one)....take it out and go to full throttle. If it hits the rev limiter, you know you've got even more room to play with pitch.
Steve |
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Posts: 280
Location: US | Thanks guys, all good input! |
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