Dyneema running rigging

LadyInBed

LadyInBed

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Me - Zumerzet Boat - Wareham
montymariner.co.uk
When replacing running rigging, is Dyneema worth the extra cost on a cruising boat wrt longevity, UV resistant and ware / chafe?
I know it's a lot stronger so smaller diameters​ can be used, but how much smaller considering that a lot of my running rigging is 14 and 12mm?
Does the diameter reduction make the cost more viable?
 
I use some 5mm dyneema spliced into the jib sheets, more to do with weight reduction on the clew and easy clearing the inner forestay than anything else. Works well though. Smaller diameters wouldn't really work very well on the winches.

The sheets last forever anyway, so might not be much point on that respect.
 
I doubt if there is one answer to this question, which applies to all situations.

Probably the smaller the yacht and/or the less hard you sail it, the less you will care about the advantages you can have from dyneema.

Speaking of my own case, one data point, on my boat (Moody 54 with carbon sails, sailed hard and long distances), dyneema running rigging has brought simply huge advantages.

The boat was originally delivered in 2001 with dyneema running backstays, outhaul, and staysail sheet.

I have gradually replaced the rest of it with dyneema.

I replaced 16mm polyester double braid jib sheets with 14mm racing dyneema, one of the best things I ever did to the boat. Less stretch means the jib can be sheeted more accurately at high tensions with no panting. 14mm dyneema weighs about half of what 16mm polyester weights, so a dramatic improvement in handling the sheets. The smaller diameter, more flexible cordage is also much more flexible and handles much better on winches. It cost somewhat more than polyester, but the difference is reduced by going down one size in diameter.

I replaced 14mm polyester double braid main sheet with 12mm racing dyneema. The main sheet is extremely long -- something like 50 meters if I remember right -- so was very hard to handle. The new mainsheet weighs about half and has far less bulk, and is far easier to deal with. Being far more flexible it works far better in the multiple purchase boom end sheeting arrangement. I don't notice the difference in stretch in this particular application, but the difference in handling is just night and day. I would never go back to polyester for this, ever!

I replaced my 12mm polyester furling lines with 10mm racing dyneema. I don't use either of my headsails reefed odwn so the difference in stretch is not important, but as with the case of the mainsheet, the improvement in handling is dramatic. The smaller furling lines fit far better on the furling drums and being far more flexible, don't wrap or get bulked up on the drum. The smaller and more flexible ends of the furling lines are far more pleasant to handle and easier to store. I would never go back to polyester!

I replaced all my wire halyards, with racing dyneema. Now here I'm not sure that this was actually better. The loose cover has caused me some problems in the jammers, holding the halyards at high tension for long passages.


Last advantage: dyneema, even double braid, is far easier to splice. The cover of double braid dyneema cordage is not load bearing, it's just a protective tube, so splicing it is far simpler and reliable.

Only downside besides cost (and that is moderated in some cases be being able to reduce the diameter), is that dyneema doesn't like knots. So you need to splice loops into the ends of all of your dyneema lines. But this isn't such a big downside, considering how easy it is to do, and especially, considering how much stronger and neater splices are, compared to knots.

I also use a ton of single braid dyneema (and now an excellent dyneema equivalent, Timm Amundsen Acera, which is just as good at 1/3 the cost) on board, for all kinds of things. Davit falls, lifting strops, low friction eye strops, soft shackles, leaders, a million other things. Ropework in single braid is a doddle, so opens up all kinds of things to do with cordage, which was not really practical in the pre-dyneema era.

All this is just one data point -- YMMV!! But in my narrow subjective view, dyneema cordage is one of the best technological developments for sailing, ever!
 
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I have replaced the main halyard on my boat with dyneema as a trial, using the same dia, 10mm. It is very noticeable how little the sail shape changes under load. It's also noticeable how stiff and unwieldy the dyneema is. It needs an extra turn on the winch. The core is inclined to pull away from the outer, and creep out, or the outer creeps up, I'm not sure which. I need gloves on to grip it, as it's quite slippery.
I did expect it to bed in a bit, and it has done a season, which included a summer trip of 2300miles.
In this period the cruising dyneema I tried before had gone hairy, and was showing signs of wear, this isn't and looks almost new.
I know I'm not answering about the dia reduction because I have no experience with that, but the wear reduction is substantial. Handling is not so nice.

Mike
 
Just a point to bear in mind; I recently replaced an old dyneema main halyard with a new one in cruising dyneema. The new one is quite slippery and I found it was creeping back through the clutch at working load, rather negating its supposed advantage of not having a sagging luff after an hour or so sailing. The clutch was twenty years old and on stripping it down, both the cam and base plate were quite worn. I have replaced these, full marks to Spinlock for still having the parts available, and this seems to have cured the problem, although I have only been able to try it on the mooring so far.
 
richardbrennan said:
Just a point to bear in mind; I recently replaced an old dyneema main halyard with a new one in cruising dyneema. The new one is quite slippery and I found it was creeping back through the clutch at working load, rather negating its supposed advantage of not having a sagging luff after an hour or so sailing. The clutch was twenty years old and on stripping it down, both the cam and base plate were quite worn. I have replaced these, full marks to Spinlock for still having the parts available, and this seems to have cured the problem, although I have only been able to try it on the mooring so far.
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I've had the same problem. A polyester double braid tail on a wire halyard will be far less susceptible to this problem, because polyester double braid, unlike dyneema, has a load bearing cover which is tightly connected to the core.

I would say this is a definite drawback to dyneema halyards.

I'm going to be doing the same thing to my clutches, that you did.
 
Disagree with the notion that dyneema makes less difference on smaller yachts. Five years ago we replaced all our RR with dyneema. Main halyard went from 12mm to 10mm and single reef lines down to 6mm. We did other things as well: reorientated deck tidys, swapped out for ballraced sheaves, new furlex System, gas kicker, fitted a Teflon mast track, and changed all four winches for huge 35.2 self tailers. And all new laminate sails.

Result was a revelation. I no longer worry about any sail change on any point of sail. No rounding up to reef, reefs pull in easily, sail drops by letting off halyard clutch (even downwind up to around F4).

Point is if you are looking for performance improvement (and there would be no point in changing out lines of you’re not) dyneema is a great starting point but only one part of a holistic system. Look at the whole sail handling setup and kill friction everywhere.

ETA boat is 30ft
 
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bitbaltic said:
Disagree with the notion that dyneema makes less difference on smaller yachts.....
Click to expand...
Absolutely, it made me chuckle.
My dinghy has a 4mm dyneema 2:1 main halyard, nothing else will do the job properly. Vectran might work, kevlar would break at the turn around the shackle, polyester would stretch as soon as the cunningham was used.
Smaller boats can benefit hugely from using dyneema, for example one boat in our club, changing the kite halyard to slightly thinner dyneema and stripping the cover off the sail end has got rid of most of the friction. The kite now goes up and comes down with much less effort and drama.
Spinnaker guys that don't stretch much are a bonus on anything from a Mirror upwards.

Not so sure about main and jib sheets, sometimes a bit of give helps gust response?
 
Creep of the cover of dyneema for halyards is a known issue. In common with many cats we have a 2:1 screecher halyard (similar to a Code Zero). Thee are unstayed sails with a dyneema luff (ours is a 2:1, some are anti torque). Because of slippage off the cover over the Dyneema core of the halyard it is common practice to tension the halyard and leave it on the winch - not relying on the clutch. This does mean that specific winch is then 'lost' as it is dedicated to the screecher.

I crewed on one larger cat and someone took the halyard off the winch, relying on the clutch. The cover failed at the clutch and we had the devil of a job to retrieve the sail. I simply don't recall what clutch were used - but they were not old, the cat was only about 3 year old.

It might be that clutches are not, or were not, designed for the very much higher loads that smaller diameter dyneema can impose. As mentioned above - you cannot simply change the rigging to smaller dyneema and expect everything to work 'the same' . Really you need to go back to basics and look at the complete picture and replace some bits of hardware to suit the smaller diameter cordage, or the higher loads that might be imposed.

Things may have changed with cordage construction - but when we use our screecher we never take the halyard off the winch so do not rely on the clutch.

Virtually all of our running rigging is dyneema, except for the spinnaker halyard.

Jonathan
 
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I've just changed over on our Sadler 32 from wire braided to polyester tails (12mm) to either 8mm or 10mm (sorry can't remember) but there was no issue with the strength! Whilst doing this we've added clutches and are bringing everything back - I've found it an impossible job to do a proper eye splice with the cover in place as milking the cover back over was beyond me no matter how much I tried. In the end I did an uncovered splice which is an absolute doddle and as far as I'm aware Dyneema is pretty UV resistant - but I'll be keeping an eye on it.

as previous posters suggested the smaller line diameters are a joy, albeit it is funny stuff so requires an extra turn on a winch and feels quite stiff (it's new so this might have a bearing).

also replaced the topper with cruising dyneema so i've got a second halyard if needed, and also the kicker line - all works great.

will be doing the reeefing lines soon in 6mm diameter - i'll try single line with blocks.

ebay is your friend when buying this stuff! costwise it's no dearer than wire :)

nick
 
lw395 said:
Absolutely, it made me chuckle.
My dinghy has a 4mm dyneema 2:1 main halyard, nothing else will do the job properly. Vectran might work, kevlar would break at the turn around the shackle, polyester would stretch as soon as the cunningham was used.
Smaller boats can benefit hugely from using dyneema, for example one boat in our club, changing the kite halyard to slightly thinner dyneema and stripping the cover off the sail end has got rid of most of the friction. The kite now goes up and comes down with much less effort and drama.
Spinnaker guys that don't stretch much are a bonus on anything from a Mirror upwards.

Not so sure about main and jib sheets, sometimes a bit of give helps gust response?
Click to expand...

Yes our sheets are not dyneema. They are some lovely-handling thing that the rigger recommended, presumably polyester. You need the sheets to give a little as the sails fill.

Our whole refit was done with a rigger and sailmaker working together on the whole project. As I say the results of this can be exceptional but it is not where most owners go. Mid-way through I was at the boat discussing the furling system with the rigger on a darkening January evening. He laid out the problems with the existing facnor and how it could be kept alive; I said don’t bother just change it for a system that works. He looked at me and said, ‘yeah, you’re right, and now I think I understand what sort of owner you are- but most aren’t like that’.

Easy sail handling is way to achieve but it will always cost, basically.

Couple of years later and a pal with a much bigger boat engaged the same rigger to sort out a knackered facnor but not replace it. Pal was very happy ‘some lube sorted it’ it never worked properly after and he sold the boat. You can imagine the feedback from the rigger.
 
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LadyInBed said:
When replacing running rigging, is Dyneema worth the extra cost on a cruising boat wrt longevity, UV resistant and ware / chafe?
I know it's a lot stronger so smaller diameters​ can be used, but how much smaller considering that a lot of my running rigging is 14 and 12mm?
Does the diameter reduction make the cost more viable?
Click to expand...

I have changed all my running rigging for Dyneema except the jib sheets. I want a little give in the jib when a gust hits. A little give reduces the stresses on the rig, winches and turning blocks. Although when I was racing I had Spectra sails and Dyneema jib sheets also.
 
thinwater said:
Do you? Easing a jibsheet just a few inches in a gust makes the sail go from flat to full, instantly increasing power. Traveler, yes. Spin sheet, maybe. Jib sheet, no.
Click to expand...

Leaving the jib pinned in, it will stall during the gust. Easing the sheet a little allows the top to twist off slightly, opening the slot.
Easing the traveller and keeping the jib in will close the slot if there's any overlap on the jib.

But in hard numbers, a polyester jib sheet is not going to stretch very much in response to a gust. It's not very long and already pre-loaded. My point was more that there is no great value in losing/reducing that stretch, in constrast to a guy or halyard.
Maybe if you've got a cutter, dyneema for the yankee sheet might be nice to save weight.
 
No mention here of a problem experienced with Dyneema , -cover wear ?
I have just replaced the main halyard with such a line and after 3 months the cover has worn badly where the clutch holds it .
I had this happen before and hoped there had been some improvement in the cover but alas , not .
As the last dyneema halyard failed and the cover just ripped then slipped completely half way through the first seasons use ,
, I attached the main 1.2 metres long so the clutch now has "fresh" cover to grip .
no such clutch wear on all other lines after several years use but the dyneema seems to have a weakness here maybe as it does not stretch ?
I am open to suggestions on how to either prevent this cover wear or remedy the existing problem ?
 
There are quite a lot of different 'dyneema' ropes available.
And quite a variety of clutches.
There doesn't seem to be much collated data on which combinations cause problems?

Then there's the fact that a lot of boats have worn clutches, stiff clutches full of dirt etc.
 
thinwater said:
Do you? Easing a jibsheet just a few inches in a gust makes the sail go from flat to full, instantly increasing power. Traveler, yes. Spin sheet, maybe. Jib sheet, no.
Click to expand...

+1

Stretch in jib sheets is very bad! Assuming you have a jib which can be trimmed flat at all -- many of them can't.
 
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