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ltgoshen 11-20-2012 08:36 PM

Folding prop help
 
My C&C 30 MK1 has a folding prop " RH 15D X 9P 2"
The will move but not ver fast under power. It dont want to move in reverse at all? It there a better prop that dont cost too much that will work with this boat? My engine is a 2GM 13. Any help would be greatful.
I just dont know what to expect from the sailboat and the little prop?
Thanks again, Here is a link to the photo of it.
http://www.sailnet.com/forums/genera...er-bottom.html

Faster 11-20-2012 08:45 PM

Re: Folding prop help
 
That's your run-of-the-mill Martec flopper - er- folder, it's going to be a bit problematic in reverse always...

The Campbell sailor prop is a middle ground alternative to the folders and has a pretty good reputation.

West by North Enterprises - Campbell Sailer

It has less cross sectional area than a standard michigan wheel, and performs well, much better than a folder with a bit less drag than a ordinary michigan. The blade design is quite effective, and the three blade model especially runs very smooth.

You may even find a used one, or one off a hurricane boat.. checking out East coast craigslists may pay off...

ltgoshen 11-20-2012 09:15 PM

Re: Folding prop help
 
How would I know what pich and all i would need?

Faster 11-20-2012 09:24 PM

Re: Folding prop help
 
Quote:

Originally Posted by ltgoshen (Post 951304)
How would I know what pich and all i would need?

If you contact the distributor and supply details like boat type, displacement, engine, transmission, gear ratios and shaft size they can make a recommendation. As a reference there should have been something like "14x8 RH" or some such stamped on the hub of your folder.. that would be a starting point. Going to a 3 blade would likely modify the recommendation somewhat. If you have a copy of a survey the original prop details may be listed there.

EDIT:.. just reread your OP and you have a 15x9 RH so you know that already....

There are probably a number of other on-line prop estimators available as well, but you'll need good data otherwise garbage in = garbage out.

msmith10 11-20-2012 09:29 PM

Re: Folding prop help
 
You might also post this question on the C&C photo album website, or as Faster recommends.
C&C Resource Center
I have an atomic 4 which swings a much smaller prop, but your diesel certainly has more torque and can swing a larger prop. It seems a little large and high pitched, though.
What kind of speed can you get? Hull speed is somewhere around 6.7-6.8 knots as I recall. You aren't going to get faster than that. Assuming your bottom and prop are clean, also.

ltgoshen 11-20-2012 10:37 PM

Re: Folding prop help
 
My speed is 4.9 to 5.6 Never been over 6 under steem? Not sure.

rugosa 11-20-2012 11:09 PM

Re: Folding prop help
 
C&C Owner's Manual effective October 1980 states -

Yanmar 2QM15 swings a 15" x 9" x 7/8" shaft right hand fixed wheel and same for folding. You have 2 GM15 so there might be a slight difference.

Do you really need a folder? Or will a fixed do the job? Just sayin'

ltgoshen 11-21-2012 08:09 AM

Re: Folding prop help
 
Quote:

Originally Posted by rugosa (Post 951357)
Do you really need a folder? Or will a fixed do the job? Just sayin'

I donít know if I need a folder. The guy that owned this boat before me raced it singled handed. I will not be racing an Iíve been told that a folding prop is a racing prop so maybe it would suite me better to change for a prop I can get some power out of. I need some reverse. It's very hard to move around the dock in close quarters without good reverse. I have a very strong current here sometime its 3 to 4 knots. It is downright dangerous. Itís to the point if the tide is moving I donít leave or berth the boat. I leave it on the face dock till I get a slack in the tide. Thatís the only reason Iím considering changing it. If I change it out will it make that much difference? Will it help me in the fairway? :confused:
Thanks for your help.

chucklesR 11-21-2012 08:27 AM

Re: Folding prop help
 
At 15hp your C&C 30 MK1 is already under-powered - if you are not racing I'd go back to the normal non-folding prop, specifications already given.

Folding props just are not as efficient.

ctl411 11-21-2012 08:52 AM

Re: Folding prop help
 
I have a martec folder on my 37c it works fine, but you need to use more rpm in reverse. Cal them ask what pitch diameter you need. The PO may have bought used and not got the size right. That said 3-4 knots of current with that little horse isn't going to be easy with any prop. You will be using max power with little room for error. Did the PO slip at the same place? How did he get by?


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