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26 X Clanking Centerboard
Posted: Thu Mar 02, 2017 1:39 pm
by Dreamcatcher
I have a 2001 X. The centerboard clanks a lot when I am at a mooring or anchored. I am wondering if it's time to replace the bolt. Does it have a bushing that needs replacing too? Also the control pendant that raises and lowers the board is original and probably should be replaced at the same time. Any ideas? Has anyone done this maintenance? How do you access ?
Re: 26 X Clanking Centerboard
Posted: Thu Mar 02, 2017 2:06 pm
by Tomfoolery
Does the CB clunk around when it's retracted all the way?
Re: 26 X Clanking Centerboard
Posted: Thu Mar 02, 2017 2:32 pm
by paul I
When the boat is not moving and there is significant wave action, my board clunks as well. It would also do so when at anchor or moored. It is loosely suspended by a steel pin that holds it in its slot. There is a lot of play. The clunk you hear is probably the board hitting the sides of the slot.
It seldom makes any noise when fully retracted, and it is nearly always retracted unless the boat is moving.
Are you leaving the board down at anchor? If so, why?
The control line simply goes through a hole in the board and ties off on the other side. The knot kind of recesses into the board. The easiest way to replace the line is to "sew" a new one to the old one, pull it through and knot it off. I've heard of guys doing this in the water where they let the board down fully and then swim under to the connection point, pull the old line through, remove the stitching, and tie a knot in the new line. The other way is to raise the boat off the trailer a bit. This gives enough clearance to drop the board. Then you can pull the line through. That's how I changed mine.
Re: 26 X Clanking Centerboard
Posted: Thu Mar 02, 2017 4:03 pm
by paul I
paul I wrote:When the boat is not moving and there is significant wave action, my board clunks as well. It would also do so when at anchor or moored. It is loosely suspended by a steel pin that holds it in its slot. There is a lot of play. The clunk you hear is probably the board hitting the sides of the slot, or bouncing up and down and hitting its stop.
It seldom makes any noise when fully retracted, and it is nearly always retracted unless the boat is moving.
Are you leaving the board down at anchor? If so, why?
The control line simply goes through a hole in the board and ties off on the other side. The knot kind of recesses into the board. The easiest way to replace the line is to "sew" a new one to the old one, pull it through and knot it off. I've heard of guys doing this in the water where they let the board down fully and then swim under to the connection point, pull the old line through, remove the stitching, and tie a knot in the new line. The other way is to raise the boat off the trailer a bit. This gives enough clearance to drop the board. Then you can pull the line through. That's how I changed mine.
Re: 26 X Clanking Centerboard
Posted: Thu Mar 02, 2017 6:59 pm
by Dreamcatcher
Thanks,
I had assumed that I was hearing the board rattling around in its slot. No, I don't leave it down when anchored or moored. I do, however leave one rudder down,where I can see any wear if necessary. This reduces the Mac's tendency to dance around the mooring, it only a little. It does make boarding from my dinghy easier, however.
Re: 26 X Clanking Centerboard
Posted: Thu Mar 02, 2017 7:38 pm
by Don T
Hello,
Here is my solution.
http://www.macgregorsailors.com/modt/index.php?view=390
I like having the board down. It reduces rocking significantly and I like the stability when I'm up on deck or just walking around, way more stable.
Don
Re: 26 X Clanking Centerboard
Posted: Fri Mar 03, 2017 5:24 pm
by My Mistress
Mistress had considerable play in her CB. I solved the issue by boring out rubber grommets so they would slide over the S/S pin on each side of the CB. When the CB moves from side to side, the grommets compress. So far, the clunking is minimized, and the CB raises/lowers normally. The3 only issue I have so far is the life expectancy of the rubber. I would prefer a more durable material.
I had also considered sliding a length of PVC over the S/S pin to hold the CB firmly in place, but that would place all the stress (which can be considerable in a seaway) on the two bolt holes.
Re: 26 X Clanking Centerboard
Posted: Mon Mar 06, 2017 7:08 am
by Retcoastie
IIRC, When I reworked our centerboard, I used a piece of 1/2" copper water pipe as a bushing. I fit exactly and reduced clunking.
Re: 26 X Clanking Centerboard
Posted: Mon Mar 06, 2017 9:08 am
by Tomfoolery
Just be careful if you bush the hole or otherwise take out some of the clearance to the pin. With a loose pin fit, the CB will react the horizontal sailing forces where it touches the inside of the trunk, like a dagger board. If it's a tight fit, the pin will be loaded, potentially quite highly, as the moment arm (distance between the force arrows in the sketch) is very small, and the pin is very small. That makes for high local contact stress, almost certainly enough to deform the CB at the pin hole, and possibly damage the pin or the hanger.
Reacting against the inside of the trunk puts the contact points much farther away from each other (lower forces) and the contact patch is much larger (so much lower compressive stress). More like a dagger board, only it swings when unloaded rather than translating vertically.
Re: 26 X Clanking Centerboard
Posted: Mon Mar 06, 2017 4:26 pm
by My Mistress
Tomfoolery wrote: If it's a tight fit, the pin will be loaded, potentially quite highly, as the moment arm (distance between the force arrows in the sketch) is very small, and the pin is very small.
Those were my thoughts when I opted for the rubber bushings that will compress, but retain enough flexibility to reduce the clunking while at anchor.
Re: 26 X Clanking Centerboard
Posted: Tue Mar 07, 2017 4:29 am
by Cougar
My Mistress wrote:
Those were my thoughts when I opted for the rubber bushings that will compress, but retain enough flexibility to reduce the clunking while at anchor.
I figure rubber bushings will last quite a while, since they're not exposed to UV.