Dyneema topping lift failure

[Benz]

Another comment regarding being able to cut rigging with a knife: who cares? ceramic-knife-wielding vandals are in short supply in cruising places, and with all the other cut-able items on a boat that no one worries about, why worry about standing rigging? My anchor snubber, kedge rode, docklines, sheets, halyards, sails, can all be damaged easily by knives. They are not worth stealing, especially when cut, so there's no incentive for anyone to start hacking at them. If someone REALLY wants to bring down a mast, the same amount of effort will loosen or undo the turnbuckles. Do people lock their turnbuckles against wanton vandalism? Not that I've seen.

[EmeraldCoastSailor]

Did you use Dyneema to get smallest line diameter possible since you were replacing 1/8" cable? I have used Dyneema for various things including lifelines but not for topping lifts or halyards.

[thinwater]

Originally Posted by waterman46

A little explanation for your opinion please, unless its solely for weight reasons. We have many folks here claiming that Dyneema has visible UV degradation in 5 to 10 years but our experience is that SS lasts 20 years.

I still can't get over the fact that anyone could cut plastic rigging wire with a knife.

I had a stainless stay fail at 15 years due to hidden mid-wire corrosion. Just sayin'.


The conventional wisdom on Dyneema is to over size 50-100% to allow for UV. It will still be lighter.


I'm not going to say one is better. Like an engineering material, the choice depends on the application, and the engineering needs to match the application and material. For example, my bobstay is Dyneema because it is a cascade tackle, and wire does not hold up to repeated flexing as well. As for standing rigging and life lines, I see it as case-by-case.

[mlydon]

Slight detour...you mentioned changing your topping arrangement......I have the topping lift fixed up top, with a block about 5’ shy of the boom. A line runs from a padeye on the rear boom, through the block, back down to a cheek block on the boom, then through it to an exit near the mast - less total line than up and over, and adjustable at the mast - same rig as slab reefing.

Matt

[dfelsent]

I was wondering if the failures were due to chafe fro a reef crinkle or other hardware on your leech. Or even rough stitching or heat cut and melted Dacron edges.

[charliehows]

Originally Posted by DefinitelyMe

I think that's an unfair conclusion to draw from a not-particularly-thorough discussion on the topic.

Each to his or her own. For my part I will never rig one of my boats with stainless rigging ever again. Dyneema wins hands-down until something better comes along.

Actually my conclusion from this discussion merely reinforces the already sizeable distrust i have formed for the recent fad of using technical ropes as standing rigging. I'm also not a fan of stainless steel except where it gives an advantage in anti-chafe protection - eg. on forestays with hanked on sails. I have dissected 50 year old galvanised steel rigging wires that were completely covered in rust to find they were still 70% solid steel, I doubt whether any technical rope can perform to 1% of that standard. My comments on re-rigging a newly bought boat would as readily apply to stainless steel rigging unless I had reliable evidence that the rigging was fairly newly laid.

I have included some technical rope in my emergency rigging kit - I'll concede it has excellent qualities for that purpose.

[Benz]

Originally Posted by charliehows

Actually my conclusion from this discussion merely reinforces the already sizeable distrust i have formed for the recent fad of using technical ropes as standing rigging. I'm also not a fan of stainless steel except where it gives an advantage in anti-chafe protection - eg. on forestays with hanked on sails. I have dissected 50 year old galvanised steel rigging wires that were completely covered in rust to find they were still 70% solid steel, I doubt whether any technical rope can perform to 1% of that standard. My comments on re-rigging a newly bought boat would as readily apply to stainless steel rigging unless I had reliable evidence that the rigging was fairly newly laid.

I have included some technical rope in my emergency rigging kit - I'll concede it has excellent qualities for that purpose.

The thing is, those 50-year-old galvi wires were probably made with better steel and quality control than what you can find these days--that's the big lament of people trying to use steel lately. It's all foreign junk of dubious quality. If you find a good source of domestic wire with decent documentation, and learn to splice it and care for it, it probably will outlast rope. But all that's easier said than done.

[wingssail]

Originally Posted by Benz

Another comment regarding being able to cut rigging with a knife: who cares? ceramic-knife-wielding vandals are in short supply in cruising places, and with all the other cut-able items on a boat that no one worries about, why worry about standing rigging? My anchor snubber, kedge rode, docklines, sheets, halyards, sails, can all be damaged easily by knives. They are not worth stealing, especially when cut, so there's no incentive for anyone to start hacking at them. If someone REALLY wants to bring down a mast, the same amount of effort will loosen or undo the turnbuckles. Do people lock their turnbuckles against wanton vandalism? Not that I've seen.

That is not the point. Theft or vandalism is not the point. The point is that **** happens and if a sharp object accidentally came in heavy contact with a highly stressed dyneema standing rigging component, I wonder if it would part? I know how a loaded length of polyester or kevlar can part under that scenario, wouldn't dyneema act the same?

Other uses you mentioned have less consequence if they fail or part. For my standing rigging I will take less chances especially since the recent experience I had with a dyneema halyard.

[Benz]

Originally Posted by wingssail

That is not the point. Theft or vandalism is not the point. The point is that **** happens and if a sharp object accidentally came in heavy contact with a highly stressed dyneema standing rigging component, I wonder if it would part? I know how a loaded length of polyester or kevlar can part under that scenario, wouldn't dyneema act the same?

Other uses you mentioned have less consequence if they fail or part. For my standing rigging I will take less chances especially since the recent experience I had with a dyneema halyard.

I've sailed thousands of miles with synthetic rigging and so far not even one sharp thing has come near a tensioned shroud. I can't even imagine what would do so.
But if a shroud were to part, the nice thing about dyneema is that it will not spring violently away from the break and hit things, like wire or like stretchy rope will.
What we have in all these doubts is really just a fear of the unknown: every single material has a potential failure mode; every material has had a freak breakage due to some unknown factor. But understanding the pros and cons of each material, and becoming familiar with them, we can calm our fears somewhat. I'm suspicious of all SS rigging, but I comfortably go to sea on boats with such rigging that I know have been well-maintained. Likewise timber hulls, carbon masts--you name it, just about every sort of everything has failed sometime or other, but not all of each have failed. You had one bad experience with a dyneema halyard. I go up masts on a single dyneema line all the time, and have never had cause for concern. I guess we all decide based on our experiences and phobias and research what we're comfortable with. I just wish more people would try synthetic shrouds before dismissing them because they didn't understand it well, and had never tried it.

[charliehows]

Originally Posted by Benz

The thing is, those 50-year-old galvi wires were probably made with better steel and quality control than what you can find these days--that's the big lament of people trying to use steel lately. It's all foreign junk of dubious quality. If you find a good source of domestic wire with decent documentation, and learn to splice it and care for it, it probably will outlast rope. But all that's easier said than done.

at the risk of having to line up behind a bunch of bloody newbies I'll pass on my simple method for sourcing good quality gal. steel wire - get it from a company that supplies the construction industry with lifting grade wire - these guys have to maintain high standards of certification. Half the wires on my boat have thimbles stamped "not for lifting" because I got them to skip the expensive testing normally required for lifting wires.


As far as longevity is concerned - galv. wire is cheap. I replace it when the amount of visible rust bothers me and still spend about a third what s/s or tech. rope rigging maintenance costs.

[sanibel sailor]

Don't think I am going to galvanized steel topping lift unless my boat grows about 100 feet longer

[Snore]

Just wanted to post an update to this thread. After 4 years my dyneema topping lift failed. The line had some significant striations and fuzz. It had all the symptoms of being overloaded.

After looking at it and thinking about the line, I realized it was prone to “singing in the wind”. I am very convinced that the harmonic vibration caused the failure. I just upgraded from 5/64 to 1/4”.

If anyone else has any experience with a similar failure, please post.

[sanibel sailor]

I switched to 1/4" T-900, Technora/Dyneema core with polyester cover. 4700 lb breaking strength which compares to 7/32" 7x19 SS wire at 5000 lb.

[thinwater]

I wonder....

• It breaks the same place every time, mid-length
• It does it at a time when the boater was not present
• Dyneema can sing and vibrate, and the frequency will be different than polyester or stainless

I'm betting that at some time when the wind is really cranking AND the owner is not there, the TL starts to flap back and forth at high speed, rubbing on a batten tip. Over time, it neatly slices in the same spot, regardless of strength. And it will happen when you are not there.


Snore, respectfully, I doubt it was harmonic vibration that did the damamge, but you are onto something.


Most people don't know what their boat, and specifically halyards and topping lifts do, when it is blowing 40 knots and they are safe at home.

[Sailmonkey]

Originally Posted by thinwater

I wonder....

• It breaks the same place every time, mid-length
• It does it at a time when the boater was not present
• Dyneema can sing and vibrate, and the frequency will be different than polyester or stainless

I'm betting that at some time when the wind is really cranking AND the owner is not there, the TL starts to flap back and forth at high speed, rubbing on a batten tip. Over time, it neatly slices in the same spot, regardless of strength. And it will happen when you are not there.


Snore, respectfully, I doubt it was harmonic vibration that did the damamge, but you are onto something.


Most people don't know what their boat, and specifically halyards and topping lifts do, when it is blowing 40 knots and they are safe at home.

I know if it’s blowing 40kts and I’m safe at home my topping lift isn’t running on a batten!