{Stus-List} C&C29 autopilot [was Re: Arioso's broken chainplate]

Brent Driedger brentmd at highspeedcrow.ca
Sat Jul 10 12:52:32 EDT 2010


A guy at our club is a millwright and he fixed my 2 blade martec prop  
from my 27. The pin that holds the blades was bent and the body that  
holds all that together had bent out a little on each side which made  
the prop VERY floppy. To repair it he heated the body and carefully  
compressed it straight again. Then instead of replacing the pin he  
made a shaft with a mushroom head on each end, split in the middle and  
machined so it screws together. The mushroom heads are countersunk  
into the body. With this set up the pin not only holds the blades but  
keeps the force of the turning unit from bending the body apart. A  
small tool custom made was given to me as well to take it apart. This  
is year 2 with it and it works great. This setup is superior to the  
original martec unit and it will likely never need service again.
Another thing to be aware of is that there is a left and right blade.  
If reversed the mechanism jams up slightly. There is a marking on the  
blade to show you which is which but right now I can't rememberer  
which or what.

> The Martec 2 blade folding prop that I had on my C&C 27 worked the  
> same way.  It almost always needed a touch on the throttle in  
> reverse to open properly and at low rpm it seemed to flop.  It was  
> pretty badly worn and was due for repair but I sold the boat and the  
> new owner wanted the 2 blade fixed prop installed because it gave  
> him more confidence as a new owner in coming up to his finger dock  
> at the marina. So he carried the old Martec as a spare that he  
> probably never would use.
>
> I sailed a few times with him after doing the prop change and I  
> would say all other things being the same the fixed 2 blade cost him  
> about 0.5 kts in speed at about 5-6 knots ahead under sail and you  
> could really hear a difference…the hull a different sound going  
> through the water which I think was due to the drag of that fixed 2  
> blade prop.
>
> Dwight Veinot
> 1974 C&C 35, Alianna
> Head of St. Margaret's Bay, NS
>
> From: cnc-list-bounces at cnc-list.com [mailto:cnc-list-bounces at cnc-list.com 
> ] On Behalf Of Jack Cornish
> Sent: July 9, 2010 8:20 PM
> To: cnc-list at cnc-list.com
> Subject: Re: {Stus-List} C&C29 autopilot [was Re: Arioso's broken  
> chainplate]
>
> Sounds like the same thing that happens to my Martec folding prop.  
> One blade will come right out while the other holds back. Martec can  
> rebuild the prop at a reasonable cost but first I would have someone  
> go overboard and see how easy or hard it is to move both blades. If  
> you are in salt water, I suspect you might be getting some growth on  
> the blades or in the hub. I have a diver clean the bottom and the  
> prop every three weeks and the problem doesn't show up. The last few  
> seasons, we didn't get in much sailing and the prop when fouled  
> would slow the boat down. Clean we would get 5.5 knots.  Dirty, it  
> would not throw one blade and we got 2.5-3 knots out of the prop  
> with both blades open. If you ever had the Martec apart you'll see  
> there is room for marine growth. If the prop has been on for years  
> with no rebuild, I suggest you take it off and ship it to Martec  
> over the winter. I was going to buy a new prop and THEY suggested  
> that I have it repaired instead.
>
> Jack Cornish
> Moondance C&C 29 MKI
>
> From: secondwindack at comcast.net
> To: cnc-list at cnc-list.com
> Date: Fri, 9 Jul 2010 18:58:50 -0500
> Subject: Re: {Stus-List} C&C29 autopilot [was Re: Arioso's broken  
> chainplate]
>
> I just finished a miserable month trying to find a similar problem  
> with my C & C 29-2. When moving the transmission to forward the  
> entire boat shook like crazy. If I put it in of gear and back to  
> neutral  number of times I could finally get it to smooth out.
> I have a FlexOFold prop which the mechanics at my yard told me was  
> the problem. FlexOFold loaned me a new prop with a full return  
> privilege to test as they did not think the prop was the problem.  
> Turned out the transmission needed to be rebuilt and it is now  
> (finally) in great shape. Suggest you look at the tranny, coupling  
> and alignment. Can’t comment if you have a Martec but FlexOFold  
> props are geared so both blades MUST open at the same time and to  
> the same degree.
>
> Hope this helps. Keep us posted.
>
>
> Paul Waldeck
> “Second Wind”
> C & C29-2
> From: cnc-list-bounces at cnc-list.com [mailto:cnc-list-bounces at cnc-list.com 
> ] On Behalf Of Ron Ander
> Sent: Friday, July 09, 2010 4:18 PM
> To: cnc-list at cnc-list.com
> Subject: Re: {Stus-List} C&C29 autopilot [was Re: Arioso's broken  
> chainplate]
>
> Dear Fellow C&C Owners.
>
> We are having a problem that completely perplexes everybody  
> including my mechanic.
>
> We have a C&C 29 MK 2, 1986.  We’ve just completed a rebuilding of  
> the Yanmar Diesel as well as refitting all the deck hardware and  
> running rigging.
>
> Our problem is when engaging our engine in gear for the first few  
> seconds or in some cases minutes the prop is not pushing us faster  
> than about 1 knot.  Afterwards we hear and feel a “thunk” and prop  
> is working perfectly well and will easily propel us at about 5.5  
> knots.  When we slow our revolutions down while in gear and then try  
> to speed up we have the same problem.  The transmission is working  
> perfectly well and the shaft is a direct drive to the prop.  The  
> shaft spins properly so everybody is trying to figure out what’s  
> causing the problem.  I dove down and checked the prop.  It is  
> solidly in place and is clear of any debris and turns properly.  In  
> neutral it will spin either way, in reverse and in forward only one  
> way as it should.
>
> We are entered in the LO300 race on Saturday, July 17 and would like  
> to fix this problem before the race.
>
> Any ideas?
>
> Ron Ander
> Alchemist
> E.Y.C.
> Toronto
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