Any Updates on Synthetic Rigging ?

[Mark Johnson]

Good point Jedi,
I didn't realize that your runners had a protective UV coating on them. Hmmm...
Depending on how complete a UV barrier it is, and how well stuck it remains, it should stop or minimize UV damage in it's tracks!

UV BARRIERS:
Our tri's synthetic netting is now 17 years old, and was used hard in the tropics as well. It is like new! (Twice the average lifespan). We get a couple more quarts of black vinyl dip from "Sunrise Yachts" and apply 4 or 5 more coats on them, every 5 years or so. The old vinyl dip underneath gets fine cracks and a bit chalky, but unlike other vinyl dips I've used, (like what's sold for rope dipping), it never gets hard and brittle.

We coat everything, even the borders, grommets, & lashings that are exposed. It is a lot of work, but far less than replacement of these custom made nets.

I would think that the concept of a UV barrier applies to all synthetics "that they will stick to", and you should know how effective it has been, when you change out your runners and test them.

Mark

[estarzinger]

Originally Posted by s/v Jedi

Yes, but that assumes that every fiber is exposed. I believe that only the outer fibers are exposed and protecting the fibers underneath....

Actually NO, that test is of a test of an actual commercially sold single braid rope, not the separate individual fibers. This rope also, by the way, has a urethane coating on it (as do most single braids).

And in any case, in the typical single braid most all of the fibers come to the surface at some point.

[QUester51]

It doesn't have to be malicious intent to cause damage. What about accidents with any sort of sharp object, or just plain chafe? I have no problems with the strength of the synthetics, I worry about having to replace it much more often than steel due to nicks, cuts, and abrasion that wouldn't have had any effect on steel.

John

I would not worry about chafe so much as here in the Northwest the loggers use dux for dragging logs out of the woods.

[w32honu]

Originally Posted by estarzinger

Some data from DSM (makers of the dyneema fiber) on impact of UV on strength. Higher than I would have guessed.

Attachment 59984

Evans,

Thank you for this post (UV degrade) . I have been waiting for some of the venders to post their test data.

This is very useful….

Curious if this amount of strength degrade is enough to change anyones mind??

50% to 60% loss is a lot.

Tx.

[Jon Hacking]

Originally Posted by w32honu

...Curious if this amount of strength degrade is enough to change anyones mind??

Certainly gave me pause. We've got all the Dux, thimbles, & turnbuckles for our 8 diamond stays, but no covering for the UV. So we'll probably just reuse our rod diamonds until we can get some covering, then replace the stays in pairs...

[w32honu]

Originally Posted by Jon Hacking

Certainly gave me pause. We've got all the Dux, thimbles, & turnbuckles for our 8 diamond stays, but no covering for the UV. So we'll probably just reuse our rod diamonds until we can get some covering, then replace the stays in pairs...

Good idea……

9mm Dux would still have enough breaking strength at 50% reduction to handle our needs. However it seems that one might eat into the "safety margin." Say 2.5 times SWL.

This is where it all becomes grey area for me.

Dux might work well for smaller boats. And ours is not a big boat. But it seems for the bigger boats the size of the Dux to handle UV degrade would have to be fairly large……..

[Gashmore]

If you size properly for creep a 50% loss is still well above a 2.5:1 safety factor. My guess is that after about 4 years you will notice having to re-tune more often. Also diameters larger than 8mm will probably have a somewhat slower curve as statistically individual fibers will have less exposure.

[Stumble]

As a rough number, Dux is typically sized at two to three times the breaking strength of the wire it replaces to control creep. Even a loss of 50% just brings you back to the strength of the wire that was there in the first place. The major cause of concern will be accellerated creep as the line looses strength.

[w32honu]

The dynamics and set up of the rig on a multihull are a bit different than a monohull…..

Is it safe to assume that most folks adopting and converting to synthetic rigging are in the multihull camp?

At the same time the racing fleet has been quick to shift to synthetics.

Anyone have a judgement on whether the run of the mill monohull cruising crowd is moving in this direction?

If so, any comments? Pros and Cons??

Thanks…..

[pbmaise]

I eliminated the "forestay" instead the Dyneema line sewn into my sail acts as the forestay.

Loads on my big tri due to flexing were shock loading windward/leeward until I figured away to introduce a spring.

A standard car spring tugs on a line kind of like plucking the string on a harp. 90% of load is still on mainlines, the plucking lines takes up windward and lee slack. In pounding waves I can seen port and starboard springs alternate.

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[delmarrey]

Springs are a good way to go. Are you compressing or pulling?

Have a mate who used nitrogen cylinders but I'm sure that's a bit more spendy.

[Scot McPherson]

What do the springs do?

[w32honu]

For what it is worth …………

We finally made the decision and re-rigged the boat. Ours is just a simple cruising boat. One of Chuck Paines older designs. So any micro gains in performance, while important, were not at the top of the priority list.

I have replaced the back stay with 9mm Dux. Our lifelines are 5mm Dux. The rest of the rig I decided to continue with 316 SS 1 x 19 wire. I reused our staylocs throughout which is very DIY friendly and tried and true. The expense was comparatively low. The rig is UV and chafe resistant. And I am convinced that it will be relatively long lived.

In the end I could not justify the cost of converting. I just priced the replacement of both running backs which are only 30 feet in length. Two runners plus 4 terminators priced out at $500……just for the runners. The entire rig would have been big dollars to replace with Dux. I will continue with the wire runners as they are in good condition and no cost.

Then there are the continuing questions of UV degradation, chafe problems, temperature related tuning issues that might lead to the mast being out of column or undue loads on individual shrouds…..etc.

I am a big fan of the "idea" of Dux rigging. In my opinion the reality is not entirely convincing. At least not for the average cruising boat. So I will keep a good eye on my Dux backstay. Its a good hands on tester for me while it provides a nice insulated set up for an antenna. In the mean time I will continue to follow the topic. The forum benefits big time from some good technical minds.

Thanks for the input.

[seandepagnier]

Originally Posted by w32honu

For what it is worth …………


In the end I could not justify the cost of converting. I just priced the replacement of both running backs which are only 30 feet in length. Two runners plus 4 terminators priced out at $500……just for the runners. The entire rig would have been big dollars to replace with Dux. I will continue with the wire runners as they are in good condition and no cost.

It cost me $250 to replace the entire rig (9 stays) with 7mm dux 5 years ago and it's still in great condition.

Why do you use their terminators? You can use half inch bronze turnbuckles (I got 10 for $100), or just use lashing with spectra through thimbles. If you wanted you could make deadeyes from ironwood or delrin.

Then there are the continuing questions of UV degradation, chafe problems, temperature related tuning issues that might lead to the mast being out of column or undue loads on individual shrouds…..etc.

All of these are not an issue, the boat sails better with less weight. I think it will last 20 years without a cover, but a uv/chafe cover and dux probably lasts as long as a fiberglass hull.

Compared to stainless I really can't understand why anyone would get more expensive stainless instead of this, but if you are trying to save cost galvanized is already superior to stainless in practically every way as it lasts much longer and is more reliable.

I just met two boats here who lost their mast because they used stainless steel. One of them is stuck here for 4 months waiting for a mast to be shipped.

[s/v Jedi]

The best thing we did was replacing the 4 stainless steel wire runner with Amsteel synthetic. The handling was improved so much!