Chiara’s slave
Well-Known Member
I replaced a wire/rope halyard with a rope. A dyneema one of course, with the cover stripped from where it needs to run over the wire width sheave.
New halyard - seems core?
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Well-Known Member
Neeves
Well-Known Member
I replaced a wire/rope halyard, mainsail, with Dyneema. The wire/rope halyard had failed, earlier, and replaced. I abandoned the mixed halyard for one that was all rope. I needed to install a completely new sheave with sheave box as the dyneema with cover was 10mm and wire (don't know, it was 40 years ago, - maybe 3mm. The wire sheave had a 'V; groove much more narrow than the 'plastic' replacement sheave that was shaped for rope. I had to increase the slot, into which the sheave box fitted to accept the halyard size difference from, say, 3mm, to 10mm. To fit the new sheave I took the mast out.
This was in the days when Dyneema was exotic (led by kevlar) and I bought from Bridon, Doncaster. I had to buy a complete reel which meant I had a blue halyard, blue jib sheets and blue Jenny sheets. Later I bought some red dyneema for the spinnaker but shared the reel with a similar yacht.
The other big advantage of dyneema was for the headsail, being able to hoist the sail to a halyard mark allowed precise and tight pointing. Previously I had added a headsail halyard Cunningham - but a dyneema halyard, red, was the answer. There is little point in having a well cut Mylar headsail if the halyard stretches (and I assume the same is true of black sails.
Based on that experience and practice when we had Josepheline built, 25 years ago, I specified dyneema for the running rigging - except for the spinnaker/screacher halyard. Later I replaced the covered wire lifelines with uncovered dyneema.
Dyneema over the 40 years has been downgraded from exotic to pretty standard. The price differential has decreased and the quality of dyneema based cordage has improved - to the point you can buy dyneema - cruising quality.
I wonder why rope makers, say Marlow, make a specific Dyneema based quality for cruising if it has no advantage - they have conned so many of us.
Josepheline was (is) a cruising yacht, 38' cat - I never regretted use of dyneema. But we drove her hard and used all the skills we had learnt on our previous yacht to get the most out of her sails (mylar headsail). You cannot sail a 7t x 38' floating caravan with a crew of 2, stocked for 3 months off grid at an average of 10 knots over 100nm across Bass Strait with baggy sails.
But we are all different and some might not like averaging 10 knots.
In the early days of dyneema it was feared it was susceptible to UV - a phurphy. Removing the outer cover was not a thing. Rothmans removed the outer cover but only for those portions protected (by the mast or boom). How things change
- at least for some of us.
Jonathan
This was in the days when Dyneema was exotic (led by kevlar) and I bought from Bridon, Doncaster. I had to buy a complete reel which meant I had a blue halyard, blue jib sheets and blue Jenny sheets. Later I bought some red dyneema for the spinnaker but shared the reel with a similar yacht.
The other big advantage of dyneema was for the headsail, being able to hoist the sail to a halyard mark allowed precise and tight pointing. Previously I had added a headsail halyard Cunningham - but a dyneema halyard, red, was the answer. There is little point in having a well cut Mylar headsail if the halyard stretches (and I assume the same is true of black sails.
Based on that experience and practice when we had Josepheline built, 25 years ago, I specified dyneema for the running rigging - except for the spinnaker/screacher halyard. Later I replaced the covered wire lifelines with uncovered dyneema.
Dyneema over the 40 years has been downgraded from exotic to pretty standard. The price differential has decreased and the quality of dyneema based cordage has improved - to the point you can buy dyneema - cruising quality.
I wonder why rope makers, say Marlow, make a specific Dyneema based quality for cruising if it has no advantage - they have conned so many of us.
Josepheline was (is) a cruising yacht, 38' cat - I never regretted use of dyneema. But we drove her hard and used all the skills we had learnt on our previous yacht to get the most out of her sails (mylar headsail). You cannot sail a 7t x 38' floating caravan with a crew of 2, stocked for 3 months off grid at an average of 10 knots over 100nm across Bass Strait with baggy sails.
But we are all different and some might not like averaging 10 knots.
In the early days of dyneema it was feared it was susceptible to UV - a phurphy. Removing the outer cover was not a thing. Rothmans removed the outer cover but only for those portions protected (by the mast or boom). How things change
- at least for some of us.Jonathan
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Chiara’s slave
Well-Known Member
Obviously, I agree with all that. The correct use of a marker pen on your dyneema halyards, and reefing lines, makes you faster through the water, point higher and reef quicker. Is there any of that, that is in any way a bad thing?
My findings are that Dacron sails change shape far more than laminate with wind and halyard tension changes. It’s very much worthwhile to have dyneema regardless of your sail material, I’d go so far as to suggest that even a manky old Centuar would point better if it had stable halyard tension.
My findings are that Dacron sails change shape far more than laminate with wind and halyard tension changes. It’s very much worthwhile to have dyneema regardless of your sail material, I’d go so far as to suggest that even a manky old Centuar would point better if it had stable halyard tension.
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Chiara’s slave
Well-Known Member
Here’s some I prepared earlier today
Zing
Well-Known Member
I’d caution strongly against that sort of thinking. Halyards die from lots of causes, like UV damage, heating, tight bending fatigue,etc and to get decades requires an extraordinary amount of TLC. Having had broken sheets and halyards way too early with forces of less than a tenth of their rated strength I’d be very, very cautious and I replace early now.
Chiara’s slave
Well-Known Member
Those there are our single line reefing, reefs 1 and 2. The last remaining original (to us) rope on the boat. They are replacing 6 year old dyneema lines. It’s a 100% critical job.
Neeves
Well-Known Member
UV damage to Dyneema is a phurphy, possibly inherited, incorrectly from Kevlar. No textile should suffer from tight bending - there is something wrong if its there. Heat is an issue, sheets have failed with friction on other ropes - but again this can be planned out if you are observant.
A tight bend, the classic would be a spliced eye - how many people have reported their splices in dyneema have failed. It is now common place for many to attach their sheets to a sail using a syneema soft shackle - how many soft shackles have failed, subject to UV and tight bends.
This is how UV degradation was a major issue with dyneema - people simply extrapolated from Kevlar (which is very susceptible to UV). No-one conducted any tests on dyneema and its UV susceptibility is incorrect and still quoted. Now we use uncovered dyneema without a second thought for UV damage. Dyneema does need a cover - to make it manageable in clutches and on winches and to make it simply comfortable to work with.
We even have 'yellow' covers on dyneema to make it look like hemp for traditional yachts.
AND - its now 40 years old and we are still finding new uses for dyneema.
Jonathan
merjan
Well-Known Member
If the clutch slipping problem persists then you might consider “bumping” the diameter of the rope by inserting a small diameter rope inside the core of the halyard at the section where the clutch is supposed to grip.
Zing
Well-Known Member
No. That is incorrect. I know from my own experience it is untrue, but Dyneema has been reported to be degraded by UV by the maker DSM and others.
I found a useful article for you by I think Thinwater of this parish:
When Should We Retire Dyneema Stays and Running Rigging? - Practical Sailor
Chiara’s slave
Well-Known Member
Dyneema with a braided polyester cover will grip in a clutch, but you have to watch that it doesn’t strip it’s own cover. Heat sealing is not enough. Seal it, sure. But it needs whipping and stitching. With the ends of the cover and core held together like that, they’ll stay gripped together, as any movement between them will tension the cover and decrease it’s internal diameter. I specifically positioned an end in the photo above to show that.
Neeves
Well-Known Member
Semantics.
Nothing, except stainless steel, will be 100% UV resistant - I think 10 years life., if I have read correctly, is close to UV resistant as you will get. Its UV resistance is similar to polyester and no-one worries too much about UV attack of polyester. The article points out that other factors, simple wear, might be the reason to retire naked dyneema - the dyneema goes fuzzy. One of the characteristics of dyneema is that it is wear resistant - but still needs to be protected from wear. Most people over specific dyneema - to make it manageable by hand - the degradation by UV still will leave more than enough core to be safe for a decade - that's good enough for me.
Maybe I should have said
'dyneema is very UV resistant but not totally immune to degradation'.
More important is Chiara's warning about slippage of the cover. If the cover slips the tension is transferred from the combined rope to the polyester cover and the cover will fail, at the clutch. The core will then slip, big time.
I crewed on a fast 50' cat where the cover slipped - it was a nightmare. The core slips big time and the cover jambs up at the slot in the mast. You cannot take in the halyard - you won't have a free winch. Dyneema is impossible to cut unless it is under tension (and the portion still under tension is in the mast. You need a sharp serrated knife and people who understand without explanation what is needed - as when you eventually cut the halyard and free it from the bunched up cover your head sail is flying free. You cannot furl the head sail - it its meant to furl round its own halyard and the luff of the sail (usually also dyneema, sometimes torque resisitant). Once you have retrieved the headsail you now have no halyard.
I never used Chiara's method of whipping and sewing as we had plenty of winches - so cannot comment. I'd use his methodology AND keep the halyard on a winch.
If you replace polyester with dyneema its worth installing too much, too long. Then you can cut the splice off, make a new splice and move the wear points, primarily at the clutch, before they become an issue.
Jonathan
William_H
Well-Known Member
The problem I found in trying to do wire to rope splice is that you must open up the strands of wire to get the ends of polyester through. With what seemed like 1/8 diameter wire it was impossible for me to open up the strands. Yes obviously it had been done previously but I could not do it. Replaced the wire with dyneema easily spliced. to 10mm polyester.
Just re lack of head room between sail top and sheave. I had a steel thimble on the eye splice on the wire. I was short of room . I moved the thimble to the side of the head board and used a bolt through thimble and headboard. Now this gives an unbalanced pull on sail. I made up a ss plate with a key hole type slot that the thimble and swage went thriough then pulled own to a tight fit around the wire. (upstream of swage) this plate then had a hole in it to match the bolt through from thimble so puting pull on both sides of the headboard. Worked well and saved me some distance previously lost with a shackle. (I did later get the sail head cut down a little so not needed) ol'will
Neeves
Well-Known Member
Necessity is the mother of invention - (no mention of fathers?)
It is interesting the things that we make that are, sometimes, one offs but allow a problem to be overcome.
One day when I have less to worry about it might even merit a thread.
Definitely non boats but before we settled in Sydney and had a home in Sandgate (UK - there is at least one in Oz) I bought a radiator brush, it then travelled to Oz, where radiators are in cars, not houses - and 25 years after it was bought it has suddenly become my favourite paint brush....
....... to paint tight spaces in concrete (the rest of the concrete is painted with a roller (using skills honed during anti fouling
)Apologies for the threads drift.
Jonathan
Daydream believer
Well-Known Member
I would not be so certain about those ropes for situations where the cover would move against the core. Some owners of large yachts remove the outer covers, because they can slip & bunch preventing the line from going out of the clutch. Just whipping the end is not so clever because one can just look at how short a length of rope a rigger uses & locks off for making a splice & milking the rope. I only need 8ft & if the cover cn slip 8ft down the line thenjust whipping the end is pointless.
A comment has been made about tight turns. well here is a 14mm rope with dynema core fitted to a cleat Further down the rope it crossed a shackle & the same thing happened
This picture shows how the cover stayed on the cleat, broke & the core slipped out when only 2.5 tones was applied
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Chiara’s slave
Well-Known Member
I'm confident in that. Been doing it for years. It is stitched and whipped, the cover is sewn through the eye of the splice, they don’t move when done like that. Anchoring the end makes the rest of the cover tighten and grip the core under tension
Daydream believer
Well-Known Member
I bet if you got a new rope & stretched it out with the ends fixed you could grip the cover in the middle & slide it back & forth
Chiara’s slave
Well-Known Member
A bit cheap and nasty if so. And the stretching of the cover tightens it up in any case