Ropes for Single-Line Reefing. Dyneema?

DJE

DJE

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Our new-to-us 39 footer has 33 sq.m. mainsail with single line reefing for reefs 1 & 2 and two lines for reef 3. The single line system is by Selden using sliding blocks inside the boom. It is currently rigged with Liros braid on braid polyester ropes 12mm for reefs 1 and 2 and 10mm for reef 3. This is a lot of rope and it is heavy. I'm not desperately worried about the all-up weight but I think the weight of the rope contributes a lot to the friction in the system which makes for hard work when shaking out a reef.
The boom is currently stripped down in my garage and a few of the sheaves have a lot of play on their shafts so I will be replacing them - also some of the little wheels on the sliding blocks. But I am seriously considering replacing all the rope with smaller sizes in high tech fibres in an attempt to reduce the friction. This is a lot of rope - 44m total for reefs 1 & 2 plus another 43m for reef 3.
If I go down to 10mm dyneema with a polyester cover I get higher strength and about 55% of weight of the current 12mm braid on braid. I can get the same strength as the existing rope from 8mm dyneema at 35% of the current weight but I think that might be a bit small for the stoppers.
There is enough money in the refit budget to do this - particularly if we leave reef 3 for next year. But will we get a noticeable improvement? And how long will fancy rope last?
Has anybody done something similar? And are there any alternatives to polyester covered dyneema that are worth considering?
 
DJE said:
Our new-to-us 39 footer has 33 sq.m. mainsail with single line reefing for reefs 1 & 2 and two lines for reef 3. The single line system is by Selden using sliding blocks inside the boom. It is currently rigged with Liros braid on braid polyester ropes 12mm for reefs 1 and 2 and 10mm for reef 3. This is a lot of rope and it is heavy. I'm not desperately worried about the all-up weight but I think the weight of the rope contributes a lot to the friction in the system which makes for hard work when shaking out a reef.
The boom is currently stripped down in my garage and a few of the sheaves have a lot of play on their shafts so I will be replacing them - also some of the little wheels on the sliding blocks. But I am seriously considering replacing all the rope with smaller sizes in high tech fibres in an attempt to reduce the friction. This is a lot of rope - 44m total for reefs 1 & 2 plus another 43m for reef 3.
If I go down to 10mm dyneema with a polyester cover I get higher strength and about 55% of weight of the current 12mm braid on braid. I can get the same strength as the existing rope from 8mm dyneema at 35% of the current weight but I think that might be a bit small for the stoppers.
There is enough money in the refit budget to do this - particularly if we leave reef 3 for next year. But will we get a noticeable improvement? And how long will fancy rope last?
Has anybody done something similar? And are there any alternatives to polyester covered dyneema that are worth considering?
Click to expand...
The size of the jammers is important because they need to grip effectively. Otherwise there is no reason not to do as you're proposing. Single line reefing is horrendously friction heavy but smaller lines and decent turning blocks will reduce it to a minimum.

It's very unlikely that reefs one and two require the same length of string so it could be worth measuring the necessary lengths from scratch.
 
We have exactly what you have single line Selden reefing for reefs one and two and 2 lines for reef 3. We have replaced reef 2 with Dyneema, one size smaller. We have replaced reef 3 which is not part of the Selden system with 6mm Dyneema with 10mm tails. This reduces rope size, but maintains strength, (it also reduces cost and weight) and allows decent sized ropes for man (or woman) handling. You need to juggle around to find when you need to go from big to small rope - but that's hardly difficult. Our reasoning was the same as yours, to allow the ropes to flow more freely. The reason for not changing reef one, by the time we reef we nearly always put in reef two. Reef one on our Selden system is pretty small, does not make much difference and once we decide we need a reef we need something decent, hence reef two is our first option.

We did our own splicing, so that was not an expense.

It is quite common on racing yachts to strip off the polyester cover to save weight aloft, but leave the tail covered - but that's a bit extreme. The other alternative is to use uncovered Dyneema,, I forget what Liros brand it - but oncovered Dyneema is very slippery and has even less friction (but is impossible to handle so needs a tail of something a bit more user friendly (that also fits the clutch).

Splicing is not as difficult as it seems, though splicing and making it look professional takes a bit of prqctice :( and most of us do not get enough practice. If you do your own splicing - hand oversew with Dyneema braided fishing line - it will add strength and neaten it up.

Jonathan
 
Thanks for the comments. We had two line reefing on the previous boat and it was great. This is an option but I would need to sort out quite a bit more deck gear (even more expensive than fancy rope!) so first choice is to try and get the current system working better.
Tapering the lines is a thought but at first sight it looks like there isn't much rope left in the boom when the reefs are pulled down so nearly all the rope will be tail with a not very long thin section. Also I am a bit nervous about tapers running round blocks hidden away inside the boom. If a bit of cover comes loose and jams a block it could all get very messy. There are fixed length ropes from each sliding block to the luff cringles on the sail. These never come back to the cockpit so I could make them out of uncovered dyneema.
I have done a few braid on braid splices and I would hope to do all the splicing myself. I think I heard somewhere that Dyneema is easier to splice than braid on braid - we'll see.
 
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We have a similar set up, which was originally fitted with 14mm line, a nightmare of friction. We replaced all the lines with 10mm polyester braid, which freed up the rope movement no end. Never thought about weight but I'd say that the savings were not significant enough to consider as a factor. The new lines have been in for three years now with no problems at all.
We did look at dyneema but the cost was such that it didn't make the first round in the budget debate.
 
Firstly there should be a single line for every reef and that will cut friction. Secondly Dynema is very thin compared to braided rope and I wouldn't use it because it's unpleasant to handle particulary if you are pulling hard.
 
nigelmercier said:
I started a similar thread https://forums-secure.ybw.com/forum...cing-12mm-Reefing-Lines-with-10mm-Dyneema-Mix

I was very pleased with the result, but having seen the way the original line was joined to the blocks (machine sewn mainly through the cover with no turns around), I could probably have used parcel string :)

I also think that on a boat smaller than my 47' you could use 10mm polyester braid.
Click to expand...

Thanks Nigel I should have searched first! But the comments on there are all very positive. Rope size seems to be a major factor - does weight matter? :confused:

We have the sewn loops inside the boom with plastic covers on them. No idea why they weren't spliced.
 
KellysEye said:
Firstly there should be a single line for every reef and that will cut friction. Secondly Dynema is very thin compared to braided rope and I wouldn't use it because it's unpleasant to handle particulary if you are pulling hard.
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I think you will find most suggestions on this thread are that any dyneema should be spliced to a larger tail so the idea of rejecting dyneema outright is unnecessary. We have 'tailed' dyneema (for reefing and furling lines) - it works perfectly and has for 5 or so years. It achieves what the OP is looking for - but we are sure their are other options. One nice thing about splicing a tail is that you can actually add a very tactile tail - that you might not want as the working line. I first heard of it on Rothmans (they stripped the outer core off dyneema (when Bridon made ropes for yachts) and left the cover to allow handling) and that was in the late 80's - its hardly a new idea - and well accepted now.

Jonathan
 
Depends on the sewing - but sewing, if done correctly, is as strong. I suspect its also cheaper and quicker (which is why Selden used it) and its not in an application where the sewing would be subject to any abrasion. Personally I find splicing tight eyes difficult - so I would sew (and whip).

If Thinwater is around, and he has done some work on this, he might add comment.

Jonathan
 
Three quick comments:

  1. Do you really want to bother with a single line third reef? Your's is a fairly moderate sized main in comparison to the boat, so I would image your third reef will only be used on rare occasions where ease of getting the thing in is of primary importance.
  2. Get the rope right! Dyneema as you know covers a wide spectrum of rope: some has a largely straight-strand inner & sometimes mid cores and a slim braided exterior designed to minimise weight and stretch (good for halyards); whilst others have say a braided core and a 24 braid thickish sheath which is nicer to handle and goes through pulleys well. Call up a manufacturer to discuss the lingo they use for their particular range and explain the kind of strength/flexibility/handleability and kinkability you are after; then have a feel of the suggested ropes. Whatever you do, you really should not omit this step as a kink-prone, pulley-hating rope would be a truly evil combination to have confined in a boom!
  3. Yes you can probably go smaller again - but it does depend on the rope
Good luck!
 
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It is worth checking the blocks inside the boom to see how much play there is. If you use a very thin line, you don't want it to be able to jump off the block and jam between the cheeks in a place where you can't get at it.
 
DJE said:
Our new-to-us 39 footer has 33 sq.m. mainsail with single line reefing for reefs 1 & 2 and two lines for reef 3. The single line system is by Selden using sliding blocks inside the boom. It is currently rigged with Liros braid on braid polyester ropes 12mm for reefs 1 and 2 and 10mm for reef 3. This is a lot of rope and it is heavy. I'm not desperately worried about the all-up weight but I think the weight of the rope contributes a lot to the friction in the system which makes for hard work when shaking out a reef.
The boom is currently stripped down in my garage and a few of the sheaves have a lot of play on their shafts so I will be replacing them - also some of the little wheels on the sliding blocks. But I am seriously considering replacing all the rope with smaller sizes in high tech fibres in an attempt to reduce the friction. This is a lot of rope - 44m total for reefs 1 & 2 plus another 43m for reef 3.
If I go down to 10mm dyneema with a polyester cover I get higher strength and about 55% of weight of the current 12mm braid on braid. I can get the same strength as the existing rope from 8mm dyneema at 35% of the current weight but I think that might be a bit small for the stoppers.
There is enough money in the refit budget to do this - particularly if we leave reef 3 for next year. But will we get a noticeable improvement? And how long will fancy rope last?
Has anybody done something similar? And are there any alternatives to polyester covered dyneema that are worth considering?
Click to expand...

I downsized to 10mm dyneema on the single-line reefs on my Dehler 35's 31 sq m mainsail about 6 years ago.

I wind a reef in using an electric winch & I often do so without completely dumping the sheet. This must increase the load on reef line. They're plenty strong & run more easily than the originals. No problem with clutch slippage, either.

Go for it!

Hope this helps.
 
To drift a little, I have the same single line two reef system on a Selden boom on a Malo 36, and will downsize to dyneema when replacing reefing lines. The system works fine to reef, but is a little heavy to shake out reefs.
I am interested in how others have rigged the two line third reef. Are you lashing the clew and using the clew outhaul in the Selden boom for the third reef? Presumably the luff reef is brought through a block at the base of the mast and led aft to a clutch ?
It would seem desirable to be able to put the third reef in from the cockpit.
 
To answer Finbar and maybe help the OP -

My description in Post #5 was an earlier version of our final arrangement. When the yacht was built the original design was to reef at the mast (common then on cats), we were having nothing to do with that and had the Selden single line reefs brought back to clutches (and winches) accessible from the cockpit. Cats might sail flat(tish) but in a sea one of the last things you want to do in the middle of the night is go forward to the mast and reef.

We had a third reef (which contradictorily) was at the mast. We thought we would live with that as we did not anticipate using it much. We soon found that we used the 3rd reef frequently, 45 sqm main, 38' cat. We then changed to a system as described in Post #5.


We soon worked out that the 1st reef was not much use, the Selden system produces very small reefs. We now have the first reef at the mast using the Selden system its dyneema but seldom used. Our 2nd reef is now the 2nd Selden reef - its all dyneema it comes back to the cockpit. The 3rd reef is huge, cuts the main down to around 15 sqm. We use the sheaves at the inboard and outboard end of the boom but use a single line conventional slab reef that comes back to the cockpit. Its 6mm dyneema (normal braided outer cover) with a 10mm tail To improve running we go through blocks on the reef points on the sail. The tail is quite long - but its a huge length of rope.

The reason for using single line reefing for the third reef, instead of 2 reef lines, was we only had a deck organiser and clutches for one line. It has worked well and its easy for one person, you just need to take in an awful lot of rope.

The internal ropes on our Selden system were all 12mm - pretty massive, I'm not sure why they were so large. We replaced all of them with 10mm dyneema. We replaced all the external ropes with 10mm dyneema. In fact all our sheets and halyards are 10mm and we do not find them uncomfortable to work with. The 6mm dyneema, or any 6mm rope, is far too thin to work with by hand and needs tails, and we have found 10mm is fine. If we were doing it again - I'd consider everything with 6mm dyneema, it would be plenty strong enough, but have 10mm tails.

Our clutches (that took the original 12mm lines, work perfectly with the 10mm tails (I suspect the clutches might have been undersized to start with).

Our reefs 2 and 3 and the main halyard all come to the same clutch bank and use one common winch. One person can reef.


The comment about choice of dyneema is correct - some is a stiff as a game fishing rod and some is very soft. Some kinks quite easily, others resists twisting. I think the stiffer, kink free dyneema might be more expensive. But you need to take advise. Our halyards are all stiff and kink free (particularly the 2:1 main and screacher (Code Zero)), our sheets, furlers and reefing lines much more tactile.

Jonathan
 
As Neeves said, I did a bit of work sewing and breaking many materials. Without a picture this is difficult to follow, but the main reason to sew Dyneema (other than cost), is that while easy to bury splice, the splices are very long. Short loops around an object are pointlessly tricky, and for a protected location, sewing works.

Sewing strength is hard to gauge with so little information, but as a starting point for Dyneema, stitches x thread strength x 70% = joint strength. And watch out for cafe.

Pictures?

And by the way, be careful with heat shrink over Dyneema. But perhaps there was no other choice?
 
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