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post #11 of 41 Old 11-14-2013 Thread Starter
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Re: Confused about prop pitch, variance between prop brands

I think this just shows hard it is to compare and predict prop performance (especially more subtle things like prop-walk and vibrations) between boats. I wish there was a cheaper way to test them on an individual boat.

Edit: I think this is the same as your old 40, a similar (just larger) underwater configuration to my Pearson:

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Last edited by Alex W; 11-14-2013 at 03:24 PM.
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post #12 of 41 Old 11-14-2013
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Re: Confused about prop pitch, variance between prop brands

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Originally Posted by Alex W View Post

Maine Sail has also used both a Flex-O-Fold and Campbell Sailer as noted by his (not successful) experiment in this thread:
Folding Prop Report - SailboatOwners.com

From a little digging his Flex-O-Fold was 16x12 2-blade and his CS was 16x9 3-blade. It sounds like the Flex-O-Fold was underpropped compared to the CS:
"*Slower than 3 blade under power at same RPM"

I'm also considering a Max-Prop. Flex-O-Fold is a little higher on my list due to price (about 30% cheaper), not catching kelp when sailing, and simplicity.

thanks,
alex
Go Max, VariProfile or any of the other good feathering props..

My FOF was not "underproped" at all. Max RPM was very similar to my CS three blade, nearly spot on, however the FOF was a two blade and simply unable to drive the hull as fast. No big secret that a two blade can't do what a three blade can....

Please understand that if you have a long shaft you WILL have more vibration with a two blade folder. I physically swapped out our BRAND NEW FOF a month after installing it. Vibration was astronomically annoying...

We put the three blade CS back on and smooth as glass...This was a NIGHT & DAY DIFFERENCE. No changes were made other than swapping out the FOF for the CS and the difference in lack of vibration with the CS was TREMENDOUS....

Understand that I tolerate ZERO VIBRATION in my drive line and this is likely different from most sailors. I know from lots and lots of sailboats that most sailors tolerate TONS more vibration under power than I do. I don't understand why, and never will....

If you are the type to not notice when your car brakes are pulsating or your tires are out of balance or you have an annoying rattle then the vibration differences may not bother you. I simply won't tolerate it so the FOF was removed and sold a a BIG loss.....

If you want smooth go CS. If you want smooth go three blade. If you want smooth and less drag three blade feathering prop..

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post #13 of 41 Old 11-14-2013 Thread Starter
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Re: Confused about prop pitch, variance between prop brands

Can you quantify "long"?

My prop shaft is about 3'. It is 1" in diameter. The longest unsupported section is under 2' (between the stuffing box and prop support) as shown in the photo above. Those are standard 1" zincs.

As I said there was no noticeable change in vibration when I went from Michigan Sailor 2-blade to CS 3-blade.

Looking at a drawing of the CS 36 T it looks like the prop shaft is setup to be more sensitive to vibration. The V-drive arrangement makes it have two sections of close to equal length, one inside the boat and one outside. The prop shaft is also longer due to the V-drive arrangement, but it is still 1" in diameter.

I understand that the folding prop makes vibration more likely. A feathering prop would for the same reason that you mention. However there are many happy users of both as well.

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Last edited by Alex W; 11-14-2013 at 05:51 PM.
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post #14 of 41 Old 11-14-2013
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Re: Confused about prop pitch, variance between prop brands

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Originally Posted by Alex W View Post
....
Edit: I think this is the same as your old 40, a similar (just larger) underwater configuration to my Pearson:
Ha! looks familiar, allright!

Ron

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post #15 of 41 Old 11-15-2013
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Re: Confused about prop pitch, variance between prop brands

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Originally Posted by Alex W View Post
Can you quantify "long"?

My prop shaft is about 3'. It is 1" in diameter. The longest unsupported section is under 2' (between the stuffing box and prop support) as shown in the photo above. Those are standard 1" zincs.

As I said there was no noticeable change in vibration when I went from Michigan Sailor 2-blade to CS 3-blade.

Looking at a drawing of the CS 36 T it looks like the prop shaft is setup to be more sensitive to vibration. The V-drive arrangement makes it have two sections of close to equal length, one inside the boat and one outside. The prop shaft is also longer due to the V-drive arrangement, but it is still 1" in diameter.

I understand that the folding prop makes vibration more likely. A feathering prop would for the same reason that you mention. However there are many happy users of both as well.
]

Longer than about 3' - 3.5' between bearings.. Mine is about 4'....

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post #16 of 41 Old 11-15-2013
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Re: Confused about prop pitch, variance between prop brands

My three blade is in my opinion smooth and produces minimal prop walk.




That changes after a couple of months in the water.

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Re: Confused about prop pitch, variance between prop brands

Thankfully Puget Sound doesn't have the fouling problems than the Chesapeake does. Hard growth doesn't seem to be a problem here unless the boat is never used.

Is that a Max-Prop with external pitch controls, or some other variety?

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post #18 of 41 Old 11-15-2013
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Re: Confused about prop pitch, variance between prop brands

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Is that a Max-Prop with external pitch controls, or some other variety?
It is the 3-blade Variable Pitch model. Pitch can be adjusted by removing a set-screw and rotating the graduated ring on the forward end of the prop hub.
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post #19 of 41 Old 11-15-2013
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Re: Confused about prop pitch, variance between prop brands

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My three blade is in my opinion smooth and produces minimal prop walk.




That changes after a couple of months in the water.
Whoa!!! Chuck--You need to hire a diver!!! (Or dive the boat monthly yourself!) With that bottom/running gear, that boat must be slower than a herd of turtles after a few months.

You might also have some "PropSpeed" applied to your running gear during the next haul-out, backed up, monthly, with a hand applied film of a product known as "PropGlop". You might also think about a different brand of bottom paint. We're using Trinidad SR and we virtually never develop barnacles on the hull like that, even with 3 years between haul-outs in the waters of southwest Florida.

"It is not so much for its beauty that the sea makes a claim upon men's hearts, as for that subtle something, that quality of air, that emanation from the waves, that so wonderfully renews a weary spirit."
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Re: Confused about prop pitch, variance between prop brands

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Originally Posted by svHyLyte View Post
Whoa!!! Chuck--You need to hire a diver!!!
I didn't want to say anything.

I have had conversations with Chesapeake Bay hull cleaners in the past, and they indicate that this level of fouling is common there, regardless of paint condition. Apparently, using a scraper there is how you get a hull clean (and you can certainly tell by the pic how "clean" that is.)

My question to Chuck is; how old is the paint in that pic and how much time had elapsed since the bottom was last cleaned?
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