Using dyneema for rigging - warning

[Robert Sheridan]

We had a go with a dyneema bridle for our Tiki 30 at the suggestion of the rigger as it is hard to make up hard eyes on 6mm wire. The dyneema stretched really badly the first time out, we retightened and it stretched again (to such an extent I had to set up the spinnaker halyard as a forestay) so we are going to go back to wire.

We have since found out that there are forms of dyneema that 'creep' less than others, but it all creeps to some extent.  The stuff we had was apparently from Liros and the supplier is getting back to them.

So.. if you are thinking of using modern braids for rigging check their stretch and uv characteristics  very carefully before buying and also make sure you are supplied something with a cover to protect against abrasion.

[andy solywoda]

Ahoy Ian R,

     I feel it is my duty to say that I have had it with soft rigging.  In my case I was using dynema lashings instead of turnbuckles and I was using ss thimbles instead of the gentler deadeyes.  I had many of these lashings fail.  At first I thought it was U/V and replaced all of them, but in severe conditions it seems anything that slides across the deck can sever the lashings.  I guess you could protect them with an outer covering.  I can't imagine hanks not doing a job on dynema.  It is very strong but you can put it under tension and slice it with a dull knife.  Take the same knife to a ss rigging wire and no problem.  

     In the smaller boats I wouldn't worry about it so much, the mast can't cause as much damage when it comes down.  I'd like to get more information from those who are out in the blue water with soft rigging.  It's not easy to admit I made a rig that fell down, but we have to have detailed information to avoid recurrences and find a way forward.

Mahalo

[Robert Sheridan]

There is a separate thread on soff rigging I think buf: we havie been using covered spectra for our shrouds for the last couple of years on our T3 and have experience a fair bit of stretch which appears to have stopped  now, though we think it is tempreature sensitive.  I asked the rigger for equivalent spectra to our 5mm (I think) shrouds and maybe should have gone up a size.  I also did not get around to fitting them for a couple of years so they may have relaxed.  We used over size thimbles and bow shackles and dyneema lashings which have worked fine (could not justify the colligo prices and plan to try out delrin deadeyes we have madd ourselves when I have time to resplice the shroud ends)  We have noticed more noise from tbe new sbrouds than the original wire ones.  The weight saving is significant.

[boatsmith]

I have used the Dyneema on four boats now and have not had any problems. I do know  that there are several types of dyneema. Some are heat treated and pre-tensioned. This is what is needed for standing rigging. The materialdoesnot like sharp radii. Colligo's parts are pricey. They are very nice. To replicate their quality for a deadeye  is beyond the ability of many of us and to do it at that price would be way beyond my ability. John Franta is the Colligo guy and is a real nice fellow and he loves Wharrams. He will advise you as to sizing and part choices. He will also make up shrouds and other lines for you. Their work is very nice!    http://www.colligomarine.com/contact/

[Ian R]

Thanks for your reply Andy. Unless someone gives me some positive experiences with dyneema forestays I think I will stick with the stainless option.

As Boatsmith says  dyneema doesn't like tight radii and maybe that's why you had trouble with the lashings to your thimbles. I'd be interested to know if there were failures at the thimbles and/or splices and if so what size the thimbles were and what kind of splices. I was planning to use a conventional cord on the lashings, as I also used for my beam lashings. I have only used the dyneema for multiple lashings of deckboards etc where some radii are tight but the strength of the dyneema is way way over what is required for the lashing. I've got dyneema on my rudders, probably will alter that at some time anyway as I'm not happy with them.

Tight lines! (Oh, that's fishing...)

andy solywoda said:

Ahoy Ian R,

     I feel it is my duty to say that I have had it with soft rigging.  In my case I was using dynema lashings instead of turnbuckles and I was using ss thimbles instead of the gentler deadeyes.  I had many of these lashings fail.  At first I thought it was U/V and replaced all of them, but in severe conditions it seems anything that slides across the deck can sever the lashings.  I guess you could protect them with an outer covering.  I can't imagine hanks not doing a job on dynema.  It is very strong but you can put it under tension and slice it with a dull knife.  Take the same knife to a ss rigging wire and no problem.  

     In the smaller boats I wouldn't worry about it so much, the mast can't cause as much damage when it comes down.  I'd like to get more information from those who are out in the blue water with soft rigging.  It's not easy to admit I made a rig that fell down, but we have to have detailed information to avoid recurrences and find a way forward.

Mahalo

[Ian R]

Hello Robert - I'm using Marlow D12 Max SK78, which is prestretched. When I bought it last year it was the only kind of dyneema like this I could find available in the UK. Now I see Jimmy Green Marine is offering a full range of different dyneemas, including the Marlow. Mine is black which isn't my first choice but I was keener to minimise stretch and had to accept "any colour so long as it's black" (Henry Ford).... and I went up an mm from the 5mm which would have been the equivalent to the 5mm wire specified.  I'm using 8mm thimbles for the 6mm Marlow at the alloy masthead only, deadeyes at the bottom of the shrouds.

Robert Sheridan said:

There is a separate thread on soff rigging I think buf: we havie been using covered spectra for our shrouds for the last couple of years on our T3 and have experience a fair bit of stretch which appears to have stopped  now, though we think it is tempreature sensitive.  I asked the rigger for equivalent spectra to our 5mm (I think) shrouds and maybe should have gone up a size.  I also did not get around to fitting them for a couple of years so they may have relaxed.  We used over size thimbles and bow shackles and dyneema lashings which have worked fine (could not justify the colligo prices and plan to try out delrin deadeyes we have madd ourselves when I have time to resplice the shroud ends)  We have noticed more noise from tbe new sbrouds than the original wire ones.  The weight saving is significant.

[andy solywoda]

Ahoy Ian R and Boatsmith,

     My former rig was stainless, just the turnbuckles were replaced with dynema lashings.  I used ss thimbles with multiple loops of dyneema.  My procedure was to put the midpoint of the dyneema in between the thimbles of the shroud and the chainstay, then run the upward half through the shroud eye and half hitch it there.  Then the lower half was looped around the two thimbles until I had the right amount of excess to half hitch it up the lashing to half way.  I then tied off this excess with a half hitch.  Then I began with the upper half of the lashing and looped it around in the same way.  I then took up any slack and then began half hitching down from the upper thimble and up from the lower.  I did double wraps in the half hitch kind of like a rolling hitch.

     My first failure of the lashings resulted after maybe 5 years of service and maybe U/V was the culprit, so I replaced them and also the mast which was originally wood, damaged now, and replaced with aluminum.  I had two shrouds to either aft quarter, plus running backstays that had multiple purchases, no lashings, and two forestays, one roller furling with an integral turnbuckle, and the other inner forestay with a rather long lashing made up like all the others.  All the lashings failed at some point during passage through 3 gales.  Not weather that should cause a problem in a large Wharram.  Fortunately there was a shroud on each side with a hard connection to the chainplate, with no lashing or turnbuckle.

     I was not pussyfooting my boat, I was breaking blocks and complaining to the manufacturers, and the roller furling gear was losing its screws.  Normally SS in aluminum seizes up, doesn't fall out, but I was having that happen.  Even with locktite they ended up falling out and as a result I had a 500 sq ft genoa deploying in a gale while I was trying to reach across Frying Pan Shoals toward Myrtle Beach.

     I had to remove the roller furling gear in Georgetown, SC, with prejudice.  I then had the genoa halyard and the inner forestay supporting the mast forward.  Later off Savannah or Brunswick, the lashing on the inner forestay parted and I had to deal with a 300 sq ft staysail flying out on the stay while downwind in 35 and breaking seas.  I got it in, I had to stabilize the mast which was now boinging on the genoa halyard.  Have you ever been there with a rope taking the place of wire.  I worked really hard and used one of the rolling backstay purchases to take up the slack on the inner forestay.  Now we were more or less stable.

     I think we have a problem with the catamaran rig in heavy conditions.  I know of other rigs that have failed due to the repetitious snapping of the rigging as the rig dances back and forth.  Stainless work hardens and fails due to metal fatigue.  I thought having dyneema lashings would be one step to get away from that.  

     Not many people sail as I do, maybe they can say they have more sense.  I choose Wharram because there is a design philosophy of being able to hold your own in any conditions.  Even if your boat gets dismasted, it is still a large life raft, and in survival conditions it will get you through almost anything better than any other boat.

     I don't think I or Kaimu would still be here if she were any other design.  We went over the St Marys Entrance jetty and both rudders came off, and the skegs.  A leak developed in the starboard hull right in the middle in the galley.  I had lost my electrics, the bilge pumps had no juice, I could bail with a bucket, but a gas powered pump was just the ticket.  When I called the Coast Guard about it, they said they couldn't go out in the conditions, nor could any of the towing services.  I didn't know that the wind had blown off my aerial off the top of the mast, so it was all done on handheld VHF and relayed.  A local police boat actually came out and stood off for a while.  When they saw me up close they said I had to leave the boat and go with them.  I didn't know that my face was streaming blood, but something hit me a while ago on my eyebrow and that made a mess.  I knew better than to argue with them and went along while they left my boat to drift with an anchor that I set out, but wasn't yet at the bottom.  The boat survived, beaching at Fort Clinch St. Park on soft sand.

     I had to somehow rent a car out of the emergency room of the hospital, wearing scrubs and carrying my sodden clothing and a large red sea jacket.

     In the end we were able to self rescue and get to a great boatyard, St Marys Boat Services, in St Marys, Georgia.  I have had to do repairs and a lot of deferred maintenance, we haven't hauled out for ten years, but the relaunch is scheduled for June 28.

     It's kind of like I tried to use dyneema the best way I knew, but now I think I would have to keep any metal object with sharp edges from ever contacting the dyneema.  Using proper deadeyes is a must.  Like I said before, in a smaller boat with a lighter rig, the mast won't cause destruction on its way down.  In a larger boat the mast is heavy and will impact wherever it falls.

     Anyway, there is a certain amount of embarrassment of telling some of my story and also a sense of duty to say what happened and let others know what can happen, if.  I have been on other voyages in the interim and have shown that I am not a johah, I am a good sailor, I have been paid to sail, and I am eager to sail again.

[Ian R]

Hello Andy - many thanks for your very compelling account of your experiences. Up to now I have only done shortish coastal and cross  English Channel passages in Wharrams and your experience is some way beyond mine.

5 years before complete failure of those lashings in that particular location doesn't seem that bad in the normal scale of things though, however critical those failures might be, at the time? Somehow one expects it not to last that long.

While the consensus on deadeyes at the deck level seems fairly clear, what happens at the top of the mast?

I have had to design myself something for my alloy masts to take oversized thimbles for the dyneema. I have just made the prototype in A4, only 3 to go. Boring with cobalt alloy bits,  but what a swine A4 is to work with.  I have just had a price to mirror polish them- £10 each so thanks I won't have to do that myself at least!

My prototype carp tufnol laminate deadeye was about 3 hrs work all told, I think I can cut that down to 2 hours each for the others + painting white with 2 pack.

Tight lines!   Ian

[andy solywoda]

Ahoy Ian R,

     Thank you for the kind words and also your posting of details of your dyneema rigging.  I only used the lashings to replace turnbuckles, did not do any lashing up on the mast.  In all cases when the lashings failed it was in strong winds with the rig vibrating, oscillating, snap snap snap on the lashings.  Then they snapped.  Probably there was sharp metal abrading the dyneema, maybe the SS thimbles, or in the extreme conditions having the dyneema jump out of the thimble, just one loop jumping out would have done it.  

     I did a lot of paid sailing the past two years and covered the Caribbean and the Gulf and some deliveries down from the Chesapeake and Oriental, NC.  I was in a funk until I sailed a sweet C&C 24 offshore from Annapolis down to Fernandina.  I shouldn't have done that, in retrospect.  I think small boats are more fun than large boats.

     Beware, I may be out at sea again on Kaimu the end of June...

[Éric Bouvéron]

Ouch, my English is far to be perfect and I do not understand everything, but it seems that opinions are mitigated about the Dyneema product. I have rigged my Tiki 21 with 5mm, Samson Amsteel Blue Rope, with splices of 50 to 60 cm, and pulled really hard on them, nothing moves, no elongation. Didn't used deadeyes, maybe I should, I just loop a 4mm polyester rope 5 times around the shrouds, and a turnbuckle on the forestay. Boat will be in the water as soon as the Hong Kong Marine Dept. allows me, but I feel the the rig is not as stiff I think it should be. I there a way to know which tension you need on a Tii21 shroud and halyards? Is it normal that the mast moves slightly when you push it? A friend tols me that it will be that sail that will stabilize everything. 

[john james]

I am planning to use dyneema for standing rigging for shrouds. What is this cover you mention preventing abrasion? With roller furling jib I suspect wire rope is necessary.

[Éric Bouvéron]

On my shrouds, at the mast, I put a plastic hose around the dynema before I splce the loop. That's the only protection I used for abrasion. 

[Robert Sheridan]

The rigger I used provided spectra shrouds and they came with a polyester cover as protection.  Thinking about it I am wondering if having a cover is the reason that the shrouds are a bit noisy, other boats I have seen have used  the black uncovered dyneema.  I was keen to have covers because of the gaff rubbing on the shrouds

Robert

john james said:

I am planning to use dyneema for standing rigging for shrouds. What is this cover you mention preventing abrasion? With roller furling jib I suspect wire rope is necessary.