Hi Speed "Cavitation" 4-blade prop?

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Wood Zeppelin

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Joined
Feb 9, 2016
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C Dory Year
1997
C Dory Model
22 Angler
Vessel Name
C-Creature
Yesterday, with my newly tuned up Honda 50 on my 16" Angler, above 4000 RPM at planing speed, I could hear the motor frequently "Revving up" and see the rpm's jump up a bit on the tach. This seemed to happen most when going over the crest of a wave, but I'm pretty sure the prop was NOT coming out of the water.

Anyone know why it's doing that? Does it have something to do with the 4-blade prop as opposed to 3-blade? Or the prop coming too close to the surface?
 
I've had both 3-blade and 4-balde props on my CD25. I never noticed any difference when it came to cavitation.

I don't know much about this stuff, but if I had to guess.....I'd guess your engine was trimmed to high; or if not, then maybe your engine is mounted too high; failing that, perhaps the previous owner had much more weight in the stern and now the engine sits too high.
 
Wood Zeppelin":3kbll1kb said:
Yesterday, with my newly tuned up Honda 50 on my 16" Angler, above 4000 RPM at planing speed, I could hear the motor frequently "Revving up" and see the rpm's jump up a bit on the tach. This seemed to happen most when going over the crest of a wave, but I'm pretty sure the prop was NOT coming out of the water.

Anyone know why it's doing that? Does it have something to do with the 4-blade prop as opposed to 3-blade? Or the prop coming too close to the surface?
Click to expand...

My 25 with a 3blade does that with too much trim (up) :thup
If I bump the trim down a little bit all is well. :beer
 
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