Dyneema Standing Rigging a 50' Sloop, Questions for those who have made the swap

[CAELESTIS]

https://svvalerosorefitpage.shutterfly.com/499

[out42]

Thanks Greg. Terminology is always such fun but we have to remember it is why lawyers exist, and therefore avoid terminology arguments where possible. That you have to adjust dyneema more often than steel is clear and on that we can agree furiously.

The OP wanted to know whether people who had done the swap found it worthwhile and my answer is 'yes'. The only point I would add is that I retained the turnbuckle setup for this first season but will now move to the colligo deadeye and lashing type of terminal.

As to loading, it is almost unknown now that you will find any big new race boat using steel. They may not be using dyneema because it moves more than say, PBO, but for me the point is that synthetics have passed the test for rigging longevity, stability and strength, and gone way past anything before in terms of lightness and ease of use.

So OP, go for it!

[Snowpetrel]

I seriously considered going for dynice dux, I will use it for my backstay, but not the shrouds.

It was the change of length with temp that worried me most. My rig is pretty high stress with three spreaders, it needs a good tight tune for lateral stability, and if I end up sweeping the spreaders back good tune is even more critical to prevent pumping and instability.

On a simpler inline rig like yours, or one with a carbon or wood mast that expands and contracts much less I'd have no worries.

[WeeJimmy]

I understand sizing the rigging to accommodate the loads and accounting for set and creep, however, I'd be a little concerned about abrasion/cut resistance of the rigging. Things fall, rub, slide and generally move where you don't want them to move on a boat. Does anyone with polyethylene rigging have any experience with failures from impacts or abrasion etc?

[Boatguy30]

This has long been the concern of mine, going thru bridges etc. if the engine fails and shrouds catch the bridge.

Or my boat went thru a 70knot class 1 hurricane earlier this month, would have been easy for a piece of metal roofing to fly off and catch a shroud.

Probably not very likely though.

[Stumble]

Out42,

I wasn't trying to be pedantic, but creep and mechanical stretch are critically different things in this application. Mechanical stretch is what you experienced initially and it can be accounted for in the initial spliced length before the line is pre tensioned. Creep also needs to be accounted for but only when determining how long to make the splices eye to eye.

On abrasion... Even cutting this stuff is hard, it takes a deliberate effort with a sharp knife to cut strands let alone a large diameter rope. Obviously it's possible, but this stuff wears like steel (ok not quite as well as steel). I obviously wouldn't suggest this for shrouds but as an experament we took some line and started sanding it with 100grit sand paper, after the fourth sheet I just gave it up. The line got a little fuzzy, but no real damage was done.

Because the line is sized for creep not strength, you end up with shrouds that are generally at least double the strength of the wire they are replacing. So it takes a massive amount of line loss to be dangerous. Somewhere between 50 and 75% of the line would need to be cut thru before the shrouds are down to the same strength as the wire it replaced.

So while it's possible to damage a shroud by abrasion it would take that plus a massive amount of negligence in not looking at the rig to be dangerous.

It is different any you need to understand how, but on the other hand it eliminates the single most common failure point (swagged fittings), reduces rig weight, and makes the entire rig repairable anywhere with extra line you can store anywhere.

On highly tuned rigs it works fine, as proven by the VOR and Open classes. But these days most of those boats have switched to Carbon rigging. Lighter, thinner, and zero stretch. But the cost is still extremely high even for race boats.

[Emerald Sea]

In addition to calculating for tension, dynamics and creep, a factor needs to applied for ultraviolet degradation. You would be expecting a similar life cycle from your dyneema shrouds that will exposed daily to UV.

We have a cruising friend with a Catana 42 with complete dyneema standing rigging and he had his engineered which included a UV factor. What he explained to me was that whatever was calculated for usage they went up one or two sizes in available diameter.

[Panope]

I wish I had known about synthetic rigging when I rebuilt Panope. It would have been perfect for my "caveman" rig (pipe mast and three pieces of wire). Boat is tender and would really benefit from the reduction in wieght. I would cover the line 100% for UV and abrasion.

Probably keep my humongous, industrial galvanized turnbuckles has they are well outboard and are the first contact point when something is grinding alongside. Those turnbuckles have 12 inches of travel so should be good for a couple centuries of creep

Steve

[Benz]

Another alternative to Dyneema, but far, far cheaper than Carbon or Kevlar, is Vectran. My boat has had all Vectran standing rigging since she was built in 2009, and it is fantastic. You must get the covered sort (Samson's Validator II, for example) but it has lasted well. I don't believe there is any reason to use metal standing rigging now that these plastic alternatives exist.
Ben
zartmancruising.com

[Snowpetrel]

Originally Posted by Stumble

.
On highly tuned rigs it works fine, as proven by the VOR and Open classes. But these days most of those boats have switched to Carbon rigging. Lighter, thinner, and zero stretch. But the cost is still extremely high even for race boats.

I think this is a very different case, the masts of these boats are almost always carbon fibre, with a vastly different thermal expansion coefficient's to aluminium, and much closer to synthetic rigging. They also dont generally use Dyneema for the standing rigging as well, normally it is PBO or carbon with much less stretch and without dyneema's weird negitive thermal expansion rate, ie it gets longer in the cold and shorter in the heat. An aluminium rig with dyice dux rigging has about 4 times the thermal expansion difference than the same rig with stainless, and three times that of Galvanised steel.

This isn't a big issue with an inline rig, it might be more of a problem with a swept spreader rig (without inner forestays, babystays, runners or checkstays)that relys on tension in the leeward shrouds to prevent inversion and pumping.

I think dux is ideal for many low stress cruisers rigs eg simple inline masthead rigs, gaff rigs etc. The expansion issue almost completely goes away with carbon and wood masts.

[Boatguy30]

Yes, but for low tech, why not keep it low tech and just use some 7X7 or 7x19 wire and wood deadeyes. Way cheaper and longer lasting than dyneema.

I have been a rigger for 25 years and when I see most of the boats on the Colligo site I just don't get it. Clearly Brion Tosses margin in the stuff must be a big part of it.

[Stumble]

Originally Posted by Boatguy30

Yes, but for low tech, why not keep it low tech and just use some 7X7 or 7x19 wire and wood deadeyes. Way cheaper and longer lasting than dyneema.

I have been a rigger for 25 years and when I see most of the boats on the Colligo site I just don't get it. Clearly Brion Tosses margin in the stuff must be a big part of it.

Because no one who owns anything but a workboat wants galvanized wire on the boat. Sure it will last, but it also drips rust all over the boat. Weights a ton, and if you want to protect it needs to be served, adding even more weight and windage.

[Stumble]

Originally Posted by Benz

Another alternative to Dyneema, but far, far cheaper than Carbon or Kevlar, is Vectran. My boat has had all Vectran standing rigging since she was built in 2009, and it is fantastic. You must get the covered sort (Samson's Validator II, for example) but it has lasted well. I don't believe there is any reason to use metal standing rigging now that these plastic alternatives exist.
Ben
zartmancruising.com

Vectran has a lot going for it, but I think critically dependent on the UV cover. Any up penetration into the load supporting fibers will end its life in months. It was a well thought of material in the early days of synthetic rigging, but these days it is rarely used.

[andyft]

Well this morning one of my life lines parted where it is swagged so I walked over to the rigging shop for a new one and was informed that I should replace all my shrouds because the rigging is 30 years old, stainless wire on a 37 ft. ketch. Does this sound like something I need to do soon? thanks

[Stumble]

Originally Posted by andyft

Well this morning one of my life lines parted where it is swagged so I walked over to the rigging shop for a new one and was informed that I should replace all my shrouds because the rigging is 30 years old, stainless wire on a 37 ft. ketch. Does this sound like something I need to do soon? thanks

Stainless wire has an industry lifespan of 10 years which assumes annual inspections, and mast down dye penetration tests. So if yours are 30 years old you are well past what I would be comfortable with.