Hybrid standing rigging

[GILow]

Hi all,

I'm replacing the standing rigging on my Kelly Peterson 44. She is currently rigged with Sta-Lok terminals in a combination of 10mm and 8 mm wires where appropriate.

After a lot of reading on the subject I have lots of ideas, but one idea is a little hard to evaluate.

I would like to reduce weight aloft by using as much synthetic rigging as possible, but I do like the idea of having the lower shrouds made from stainless to deal with my concerns about chafing. Likewise the forestay and staysail stay, as they have furlers.

So this would leave me with synthetic rigging for everything else above the lower spreaders, plus the backstay, plus the fore and aft lower stays.

Has anybody tried a similar approach or are you aware of any pitfalls to this approach?

Matt

[wingssail]

Originally Posted by GILow

Hi all,

I'm replacing the standing rigging on my Kelly Peterson 44. She is currently rigged with Sta-Lok terminals in a combination of 10mm and 8 mm wires where appropriate.

After a lot of reading on the subject I have lots of ideas, but one idea is a little hard to evaluate.

I would like to reduce weight aloft by using as much synthetic rigging as possible, but I do like the idea of having the lower shrouds made from stainless to deal with my concerns about chafing. Likewise the forestay and staysail stay, as they have furlers.

So this would leave me with synthetic rigging for everything else above the lower spreaders, plus the backstay, plus the fore and aft lower stays.

Has anybody tried a similar approach or are you aware of any pitfalls to this approach?

Matt

Not exactly. But we have dyneema on the check stays and running back stays (plus halyards, topping lifts, lifelines, and various other working segments). We made this change to dyneema from wire to save weight about three years ago. The weight savings were very significant.

Why didn't we go to dyneema for the standing rigging? When racing boats first started to use dyneema for their standing rigging, with very significant weight savings, I read that they expected to replace it every two years. I was not willing to sign up for a reoccuring cost.

Now I think that the replacement cycle has lengthened, but what is it?

Then a further thing happened which has really affected my thinking, still along the lines of, "I don't want to do it". We've broken three dyneema halyards and one upper lifeline with in two years of installing them. The breaks were sudden and without warning, and there was no external sign of chafe, and nothing nearby which could cause chafe. The breaks all occurred where an eyesplice tail ended. Apparently I didn't taper the eyesplice properly, but who knew?

What else don't we know?

A broken halyard I can live with, but a broken cap shroud I cannot. I'll continue to use dyneema for my running rigging but not for my standing rigging.

[GILow]

Originally Posted by wingssail

Not exactly. But we have dyneema on the check stays and running back stays (plus halyards, topping lifts, lifelines, and various other working segments). We made this change to dyneema from wire to save weight about three years ago. The weight savings were very significant.



Why didn't we go to dyneema for the standing rigging? When racing boats first started to use dyneema for their standing rigging, with very significant weight savings, I read that they expected to replace it every two years. I was not willing to sign up for a reoccuring cost.



Now I think that the replacement cycle has lengthened, but what is it?



Then a further thing happened which has really affected my thinking, still along the lines of, "I don't want to do it". We've broken three dyneema halyards and one upper lifeline with in two years of installing them. The breaks were sudden and without warning, and there was no external sign of chafe, and nothing nearby which could cause chafe. The breaks all occurred where an eyesplice tail ended. Apparently I didn't taper the eyesplice properly, but who knew?



What else don't we know?



A broken halyard I can live with, but a broken cap shroud I cannot. I'll continue to use dyneema for my running rigging but not for my standing rigging.

Sobering experience.

I've only had dyneema running backstays up to this point in time.

What you have experienced has given me pause for thought. I will search around to see how common this sort of thing is.

[Tupaia]

Contact Mike Strong at www.strongrope.com they are in Oz.

Over 15 years experience in this field.

[RaymondR]

I recall wandering around the yard at Fremantle Sailing Club years ago and noticing that all the around the world racers had a section of galvanized wire on the lower ends of their dynema halyards when I asked why I was told they had had failures in the dynema where it went over the sheaves.

Generally not a good idea to mix materials with different moduli of elasticity but it might work with rigging if you manipulate the thicknesses.

[wingssail]

Originally Posted by RaymondR

I recall wandering around the yard at Fremantle Sailing Club years ago and noticing that all the around the world racers had a section of galvanized wire on the lower ends of their dynema halyards when I asked why I was told they had had failures in the dynema where it went over the sheaves.

Generally not a good idea to mix materials with different moduli of elasticity but it might work with rigging if you manipulate the thicknesses.

RaymondR, this is exceptionally interesting information, were they spliced in or how were they connected?

[RaymondR]

Originally Posted by wingssail

RaymondR, this is exceptionally interesting information, were they spliced in or how were they connected?

They were spliced in.

It struck me as being very unusual which is probably why I remember it.

[wingssail]

Originally Posted by RaymondR

They were spliced in.

It struck me as being very unusual which is probably why I remember it.

I've been in contact with Mike Strong, at www.strongrope.com to see if this is standard practice. His answer is:

"No, [and regarding eye splices] if the buried end of the splice is the right length (approx 35cm bury) and the bury has been tapered ( this is also important) if yes to both of these points a rope that breaks at this point is normally a sign of excess loading, ie the rope strength is too low or the rope itself is poor quality." *

Since we used 4mm K78 dyneema from Marlow or Robson with minimum breaking strength of over 1800kg (4000lbs) I think the strength was sufficient. Must have been my splicing. Anyway it gives me doubt about the approach for standing rigging.

BTW, previously (for 30+ years), we used 1/4" stainless steel wire for halyards (and many other applications) and we had no halyard breakages with that, ever. Its working load limit is 1400lbs although the breaking strength is quoted at 7000lbs. It doesn't seem like we overloaded this dyneema.

[tamicatana]

Brion Toss recommends 72x diameter tapered tail as I recall. I’ve been using UHMWPE for rigging for close to 20 years across several boats. I think highly of it.

For standing rigging you should use DynIce Dux and you can easily Google info about it

[wingssail]

Originally Posted by tamicatana

Brion Toss recommends 72x diameter tapered tail as I recall. I’ve been using UHMWPE for rigging for close to 20 years across several boats. I think highly of it.

For standing rigging you should use DynIce Dux and you can easily Google info about it

72x 4mm = 288mm, 11 inches for 4mm dyneema. OK no problem, I'm already doing that, and the taper should be half that, approx 6 inches. Fine, BS. it still broke.

Now, "you should use Dynice Dux..." Please explain why. I don't believe that Dynice Dux is anything better than any other high quality pre stretched SK78 Dyneema, except the mysterious allure of it's exotic name and Icelandic source. BS

[DefinitelyMe]

We have mixed shrouds. After breaking two of our lower shrouds (3/8" 1x19 stainless with Sta-lock terminals) due to fatigue failures (and a structural problem that has now been fixed) we switched to 13mm 2x12 dyneema for the lower shrouds only. That was in New Zealand in 2018. Now we're in Bermuda. Four years in I'm very happy. I intend to use dyneema for all our standing rigging when I re-do the shrouds in about 3 years time. I'm tempted to do destructive testing on our lowers at that time and see how the numbers look.......

[GILow]

Originally Posted by DefinitelyMe

We have mixed shrouds. After breaking two of our lower shrouds (3/8" 1x19 stainless with Sta-lock terminals) due to fatigue failures (and a structural problem that has now been fixed) we switched to 13mm 2x12 dyneema for the lower shrouds only. That was in New Zealand in 2018. Now we're in Bermuda. Four years in I'm very happy. I intend to use dyneema for all our standing rigging when I re-do the shrouds in about 3 years time. I'm tempted to do destructive testing on our lowers at that time and see how the numbers look.......

How are the lower shrouds holding up in terms of chafing? Any issues from the jib sheets?

[fxykty]

Originally Posted by wingssail

I've been in contact with Mike Strong, at www.strongrope.com to see if this is standard practice. His answer is:

"No, [and regarding eye splices] if the buried end of the splice is the right length (approx 35cm bury) and the bury has been tapered ( this is also important) if yes to both of these points a rope that breaks at this point is normally a sign of excess loading, ie the rope strength is too low or the rope itself is poor quality." *

Since we used 4mm K78 dyneema from Marlow or Robson with minimum breaking strength of over 1800kg (4000lbs) I think the strength was sufficient. Must have been my splicing. Anyway it gives me doubt about the approach for standing rigging.



BTW, previously (for 30+ years), we used 1/4" stainless steel wire for halyards (and many other applications) and we had no halyard breakages with that, ever. Its working load limit is 1400lbs although the breaking strength is quoted at 7000lbs. It doesn't seem like we overloaded this dyneema.

Presumably you are using name brand Dyneema that is properly treated for uncovered use in the outdoors? Often chandleries have Hampidjan or DSM Dyneema as their premium lines (SK75, 78, 99) and no name brand Chineemas for cheaper Dyneema lines (generally equivalent to 75, but usually with much worse longevity due to poorer coatings and manufacturing practices).

It’s not just the amount of taper but that the taper is actually done right - you should end up with a single angle cut strand at the end of the taper and the cover should have a smooth transition with no bumps. Each strand you cut should be at an angle, and the best taper cuts each individual strand at a certain interval. Generally the taper is the last 30% of the bury’s length.

The other way that splices can be weakened is by twisting the cover or bury - make sure everything is very straight with minimal distortions.

Finally, working load for standing rigging using Dynice DUX or DSM DM20 (speak to any experienced synthetic rigger, or Mike Strong, to verify) is 1:5 of spliced breaking strength (conservatively take 10% off straight breaking strength to account for the splices). For running rigging 1:2 is often used and is generally fine. That’s how I size our running rigging.

Regarding DUX/DM20, it is not snake oil. It is made via heating and stretching to almost eliminate creep. They are effectively a different (and much more expensive) product from the SK grades.

[DefinitelyMe]

Originally Posted by GILow

How are the lower shrouds holding up in terms of chafing? Any issues from the jib sheets?

No issues. Only the forward lowers contact the jib sheets and those I've covered with some PVC sanitation hose for the lower 6 feet or so. I probably wouldn't want to heave to with the jib backed and the tensioned sheet crossing the shroud for any length of time but then I wouldn't want to do that with steel rigging either.

I'm pretty particular about chafe in general, but have found dyneema to be quite resistant. I used to work on a mooring barge where we used dyneema for the winch cable. It lasted surprisingly well being dragged across the deck, over bits of rusty old chain and shells several times a day.

[wingssail]

Originally Posted by fxykty

...Regarding DUX/DM20, it is not snake oil. It is made via heating and stretching to almost eliminate creep. They are effectively a different (and much more expensive) product from the SK grades.

Yeah, it's snake oil. Most other high end brands also sell a line of dyneema with pre-stretching and a heat setting process, as well as advanced UV resistant coating suitable for standing rigging. I received information directly from Marlow ropes, for example, "Our D12 MAX Dyneema ropes are heat set and pre stretched. D12 MAX..... has also been used for this application in SK75/SK78 and DM20 fibre grades."

And since DSM is the parent company that owns the Dyneema brand and produces the fibres so all Dyneema ropes are produced by DSM Dyneema.

Someone who brags that their Dyneema is better because it has heat setting process and is pre-stretched and coated for UV, is like someone selling apple pie and saying it's better because it has sugar and apples in it. Don't be sucked in by misleading advertising. Everyone else's product does too.

Certainly there are vendors of Dyneema who sell rope which has not been pre-stretched or heat set, but even Chinese manufacturers can perform those steps, and you just have to be careful what you buy. And if it's Dyneema, its from DSM.