Lines slipping through clutches

KompetentKrew

KompetentKrew

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Hello,

A quick video to illustrate the problem, sorry for all the umming and ahhing:


Actually, I have at least two lines that slip back like this, the mainsail halliard as well as the vang - hence it's impossible to get proper sail tightness right now.

What I omitted to say in the video is that both lines slip back a few inches - they catch again one they have done so. It's almost like they get thinner under sufficient load. I already tried switching the vang line over the other way around, but it made no difference.

Thanks in advance for any advice you can offer.
 
On the face of it it appears to be the clutch that is failing. You could test this by threading a different line through and trying that. At any rate, its efficiency will be marginal. It is only four months until Christmas.
 
Yes lines do flatten especially if the same part of the line is always that which is clamped.
Some older clutches (like mine) have two different cam pivot holes which allow you to invert the lever to accomodate different line thicknesses.Looks like these are asssembled with circlips so maybe these do.
I wonder if the winch alignment is holding the line up and away from the correct exit line from the clutch so that when the line is initially very taut the cam is not actually clamping the line to the base.
Have resolved slippage on heavy lifting keel clutch by adding a loose anodised aluminium flat strip,with downturned ends,which is trapped loose under the line in the clutch.Maybe you can build up the base of the clutch by this or another method.
 
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All my clutches are Lewmar which never slip - came out best in a PBO test some years ago. The rope is held in domino system over a longer distance, unlike other makes which don't have such a long distance. Perhaps shortening the rope so it grabs in a different position?
 
we had something similar recently the clutch just needed some silcone grease on the cam as it was catching a little bit preventing it from latching properly, it stays in that top position where it hardly touches the rope--- that makes less sense now i've typed but check your cam movement and make sure its engaging correctly
 
Take the clutches apart, clean them, re-grease them with silicone grease, and then see if that sorts the problem out.

I bet it will.
 
I had a similar problem after renewing my main halyard. Although the new one was the same diameter as the old one, Dyneema can be slippery stuff and it was slipping although not quite as spectacularly as in your clip.

It was a Spinlock clutch, and in spite of being twenty years old, spares were still available. I replaced the cam and the base plate, both of which were visibly worn, and this has resolved the problem.

If you're taking the clutch apart in anycase, I would look at these components.
 
Increase the purchase in the vang so there is less load on the rope at the clutch
get a needle or wire fid and thick twine and sew the twine down inside the core of the rope several times so it effectively thickens the halyard for a distance of 18 inches where the clutch grips. Worked on my dynema halyard
new clutch inserts would also help if worn- check they are for the size rope you are using
 
Our boat we bought from Kiel, in 2017 has two spinlock clutches IN SERIES for both the main and genoa halyards. I have replaced the 8-14 Cam inserts to help with the issue. 42ft boat, part laminate sails and batten cars. Quite a hoist.
 
To me the failure mode is key to identifying the issue.
It isn't a slow gradual creep, which slippery or thin ropes typically cause.
The fact that it seems to run free then stop with a bang suggests very seriously gunged up mechanism, or I suspect the earlier poster may have nailed it. The angle of rope from the winch is too high (relative to the base of the cam, not the deck), so the cam cannot close till the winch load released.
 
My spinlock clutches get dust build up from the lines running through them. Take them apart and blow away the rope dust and re assemble takes two minutes (if you put them together the right way the first time:(). They then work as good as new
 
It's very gratifying to read all your replies and I regret I won't have time to disassemble these clutches, which I think must be my first step, for at least a day or two.

dunedin said:
The fact that it seems to run free then stop with a bang suggests … I suspect the earlier poster may have nailed it. The angle of rope from the winch is too high (relative to the base of the cam, not the deck), so the cam cannot close till the winch load released.
Click to expand...
I do hope you're wrong.

I'm optimistic you're mistaken because, if it were the angle then that would surely mean that the it has never been possible to winch the vang, and surely the PO would have addressed that in his 25 years of ownership.

As I wrote in my original comment, the mainsail halyard also slips similarly, and that is at a different angle - it is a different brand of clutch (I wonder why?) but the rope enters it very slightly downwards and to one side, relative to the plate. The angle of neither looks very big in person, when you look at it end on.

I am hoping that it is merely that the cams are stiff, and will move more freely after the clutches have been disassembled and cleaned.

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johnalison said:
It is only four months until Christmas.
Click to expand...
Every week is Christmas week as far as my boat is concerned!
 
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