Thickening dyneema rope to prevent clutch slipping

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West Coast

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I have 10mm dyneema halyard on my mainsail. This is slipping in the clutch when fully hoisted and tensioned so been looking up ways to cure this. Seems there are 2 options, thicken the core locally to the full hoist position, or fit external braid sleeve. For either option, where can I buy the additional core or external braid?

For those who have done this, thoughts on which way is better?

Cheers
 
I have a similar problem with a clutch on the main halyard. I think the easiest fix is to add a horn cleat after the clutch to wrap the halyard around. Alternatively some people have an additional clutch in series. (more expensive fix). I don't think an additional coat on the halyard will work out very well. (get fouled up) ol'will
 
Common problem, if the winch is spare - then leave the halyard on the winch, we do that with one of our halyards. Introduce a cheap 'V' cleat, or a cam cleat, and located above the clutch, its then a belt and braces solution - we have done this for a spinnaker halyard (as it allows a very quick drop - if you want). If you follow this route - we have found that the cleat positioned slightly out of line is useful - you need to consciously push the halyard into the cleat but the halyard does not lock into it 'accidentally' (when you are reefing or dropping at the end of the day). So - tension halyard, lock clutch, push halyard into 'V' clutch, release tension on winch - while holding halyard into 'V'. To release you need to re-tension the halyard to release the rope in the 'V' cleat - or be quite strong - depends how much tension the halyard was under. Cam cleats are a quicker and easier release - good for spinnaker

Putting a sleeve on will work (we have done this to manage abrasion - but you will need to sew the outer braid on and it might not fit into the clutch, as its now too big. It can be difficult to work the new outer braid onto the halyard - ideally you want it to be a good fit, being a good fit its too tight to work. Finding a cover is easy - simply strip 300mm from an appropriately sized bit of rope. For abrasion we used a dyneema sleeve (Nautilus Braids, NZ), which will not work (as mentioned) for your application as it is too slippery.

As William mentions - add a horn cleat - it takes time to release and any slippage will still develop due to tightening of the turns. We do this for lazy jacks and topping lift - but their tension is not critical.

Most rope makers supply braided sleeve or hollow tape

Best is leave on the winch - but that is unrealistic in most applications. I'd go the cheap 'V' clutch route for a main halyard (we have used plastic recently and aluminium prior). Cam cleat for spin, horn cleat - where tension does not matter - and a new clutch if you are awash with cash :) You might need to add reinforcing under a 'V' cleat (if it is deck mounted) - it will take a lot of load.

Finally - if the problem is the clutch. The main clutch gets all the use (and wear). Consider swapping it for a similarly sized clutch that sees (or will have seen) less use (spin clutch, reefing clutches, 3rd reef) - its an easy and cheap fix - if its possible and works.

There are so many ways to skin a rabbit!

Jonathan
 
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Another option is to coat with Spinlock RP29. It will increase friction a good bit. This is one of its recommended uses.

Personally, I'd splice on a cover if there is room. It's easy. In general, stripping the cover from an inexpensive PDB or Technora remnant is cheaper than buying the cover from a specialty source... And I bet they are just re-selling covers they stripped from tapering halyards and sheets, a service they charge for!!
 
First see if you have the right sized pieces in the clutch ( assuming spinnlock) these can easily be replaced with new ones to suit your rope size.
Another option is to mark the clutch point on the rope & then, with a D splicer draw some lengths of thick wipping twine down inside the outer covering to increase the thickness of the halyard. Do about 4 strands at a time & it will not take long to get quite an increase in size
 
Daydream believer said:
First see if you have the right sized pieces in the clutch ( assuming spinnlock) these can easily be replaced with new ones to suit your rope size.
Another option is to mark the clutch point on the rope & then, with a D splicer draw some lengths of thick wipping twine down inside the outer covering to increase the thickness of the halyard. Do about 4 strands at a time & it will not take long to get quite an increase in size
Click to expand...

This ^.
You can go further and stitch through the rope. This can have the benefit of preventing the core moving in the outer.
The correct clutch is the best answer, but can be ££££.
 
I had this problem when I replaced my main halyard last year. I changed the cam and base plate on the clutch (Spinlock), which were twenty years old and visibly worn, and have had no further issues.
 
Thanks all

The winch serves 5 lines including main outhaul and kicker, so horn cleat after the winch is a no go.
Cam cleat could be an idea - will need to check if there is room. But would rather get the existing setup to work! Will check the existing jammer cam size, but fairly sure it is right size

The halyard came with the boat. Boat new in 2012, but little used til I bought her in 2018.
 
This is what happens when one applies 1 tonne to a dynema rope that has a declared SWL of 5200Kgs
The outer covering was still left on the cleat when the weight that the rope was supporting dropped. A serious accident was averted only by luck.
The core pulled straight out of the outer covering after the outer covering sheared
this happened in 2 places.So one has to be careful about outer coverings as they can slide on the core
DSC_0003 (2) (600 x 329).jpg
 
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Slippage of the dyneema core through the braid is a very common issue. The problem being the clutch holds the braid but not the core, which is slippery. It is a very common multihull issue where huge tensions are developed on unstayed headsails (Code Zero types). Some here will tell you its a fault of the rope, I'm not entirely convinced - there are too many multihulls with the problem and not all of them buy questionable rope. However it maybe that with better manufacture more recent dyneema rope better copes with the problem - but as your halyard is 'oldish' this is not much help.

The solutions I know of are - keep the rope on the winch (which as you indicate is not an option) or add some secondary locking facility, usually a 'V' cleat or cam cleat (the latter are smaller - or take up space differently) or a horn cleat. I have actually not hear of people 'thickening' the rope to get it to hold - maybe I need to get out more.

If the problem is that the core is slipping then one answer is not to thicken but simply sew the core to the outer braid over 'say' a 0.5m length. I don't know if it will work nor how much sewing would be needed. When we do this 'sort' of thing (tidying up splices) we use braided dyneema fishing line which comes fine enough for decent needles.

We have mast based winches for some of our halyards and we have clutches above them, which can slip for our unstayed headsail. We have a 'V' cleat installed. In the past, different yacht, we used a cam cleat. A big 'V' cleat was cheaper than a decent cam cleat. However as we have 'plenty' of winches - we do keep the halyard on the winch (as well).

Jonathan
 
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Finally

I was crewing on a large, 52', new catamaran on delivery and someone had not left the screecher halyard on the winch and it was simply held by the clutch. The core slipped sufficient that the outer braid was taking all the tension. The outer cover failed, cut/broke clean through. The halyard then completely slipped - but the cover simply bunched up and did not 'run out'. We ended up with this huge sail we could not drop, decent seas and 25 knots. We had to cut the halyard to retrieve the sail - which meant we 'lost' the halyard until we got somewhere where we could drop a new halyard down the mast (and who carries enough dyneema for a new halyard?).

Jonathan
 
Thanks all.

Checked a few things last night - jammers are Spinlock CAM 08-14, ie good for 8mm to 14mm rope. When the rope slips in the clutch, you can visibly watch the rope move, ie it is not the core slipping inside the braid, but the whole rope slipping in the clutch.

Googling the problem yielded the ideas of adding internal core material (to bulk the rope) OR external braid - so neither my ideas! Both your, and DB's, experiences show a scary scenario
 
I have successfully tightened the grip of a clutch by inserting a loose aluminium flat underneath the line,with the projecting ends turned down a little so as to trap the insert within the clutch.The aluminium is totally smooth but works to close the gap sufficiently.Probably on a Barton as my ancient Easylocks have the cunning ability to reverse the lever for different line diameters.
A spinlock is a different matter.
 
bluerm166 said:
I have successfully tightened the grip of a clutch by inserting a loose aluminium flat underneath the line,with the projecting ends turned down a little so as to trap the insert within the clutch.The aluminium is totally smooth but works to close the gap sufficiently.Probably on a Barton as my ancient Easylocks have the cunning ability to reverse the lever for different line diameters.
A spinlock is a different matter.
Click to expand...

Now there is a novel idea!

Jonathan
 
West Coast said:
I have 10mm dyneema halyard on my mainsail. This is slipping in the clutch when fully hoisted and tensioned so been looking up ways to cure this. Seems there are 2 options, thicken the core locally to the full hoist position, or fit external braid sleeve. For either option, where can I buy the additional core or external braid?

For those who have done this, thoughts on which way is better?

Cheers
Click to expand...

I have tried both. You can buy cover from any good rigger, last I bought was from Selden agent in Swanwick marina. To bulk up the core any thin (2-3mm ish) polyester braid will work. Bulking the core is easier and neater, stitching on a cover takes time or ££s if you pay a rigger to do it. As mentioned be careful of the type of cover, we had a rigger put a Kevlar cover on once which was more slippy than the uncovered rope. Both methods are much much easier on new rope. I would not even try to bulk the core on old rope. I have successfully stitched on a cover on old rope but it took hours and was a PITA.

Problem with both methods is that if, like us, you routinely move the wear points to make rope last longer by shortening the halyard or reversing it your bulking inevitable ends up in the wrong place. So I rarely bother nowadays.

We have found that careful maintenance of the clutches is more effective. The slightest sign of wear in the teeth of the cam or base compromises rope holding. If you have a bank of clutches on a single winch you will see the wear starts at different parts of the teeth on each clutch, so intelligently swapping the cams and base plates between clutches can extend the life significantly. This or replacing with new cams/baseplates could have a greater effect than bulking the rope (if you have an IRC certificate you get a 25% discount from Spinlock).

We have also found that rope holding is improved if the rope diameter is at the upper end of the clutch range. So for 10mm rope would try the 0610 cam rather than the 0814 (the Spinlock holding charts show this is a minimal effect but our experience is that it makes a real difference).

As others have said, can't beat keeping high load halyards on the winch. We routinely keep the main and genoa halyard on the winch only taking them off temporarily when adjusting another line. If you do need to take them off the winch pushing the cam down with your thumb before loading up the clutch helps reduce the first cm or so of slippage.

Though you said it is not the problem you are trying to solve, zig zag stitching the cover and core 5 or 6 times for a metre either side of the clutch does help prevent cover failure (saves £££s).

Hope this helps
Ckris
 
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