Re rig in Dyneema

[appick]

Winf I know Ronstan say you can use Turnbuckles twice, or about 20 years. I just saw a clip while watching a Delos video and that's what their rigging ronstan guy said.

[Stumble]

I wouldn't worry about 9 year old turnbuckles unless they showed clear evidence of failure. John Frampta at Colligio keeps wanting to switch the world to lashings, and I get the idea. But I don't by it. Dyneema shrouds with turnbuckles are in my eyes the better way to go.

[SF Bay Dude]

Originally Posted by Winf

What is the consensus on replacing the turnbuckles when you re-rig?

Existing rig is coming up on 9 years old. Recently broke a Forestay. Other work needed on and in the mast so it is coming off anyway so figured I do the rigging at the same time.

Visually the turnbuckles look ok. Not out to skimp but don't believe in wasting something that may be perfectly OK either.

Winf

I've got bronze turnbuckles that are almost 40 years old and I will be keeping them. They are in perfectly good condition, and have less than 10k miles on them. Stainless is a bit different, but have a deep look and do what you feel comfortable with per your sailing.

[RWhite]

I'm on an 87 Catalina 34 and I'm going to rig my boat with Colligo hardware. I should have it done within the next month. Send me a message if you have any questions. My experience level is new.

[japtenks]

Originally Posted by Stumble

3) the actual splices just take a bit of practice and attention to detail. The major issue is that you need to know how much the line will shorten as a function of the splices. Because each of the shrouds needs to come out at very close to exactly the same length.

4) finally after making the shrouds you need to tension them. On larger shrouds this can be thousands of pounds of load. This sets the splices, and pretensions them to minimize the amount of constructional stretch. Ideally this is done just before installation. If you can't pre-tension them just expect a lot of constructional stretch initially, it will work itself out over a few weeks, but you have to allow for it.

For point 3, Is there a way to estimate or calculate how much the line will shorten due to the splice? Is it just length of bury + eye size?

For point 4 is the constructional stretch the listed some where. Only stuff I've seen has it at .68% but that is on the west marine site. Am I correct to think that the way to calculate length of stay would be bury x2 + eye x2 + constructional stretch + the middle = the length you need.

Thanks

[Stumble]

Originally Posted by japtenks

For point 3, Is there a way to estimate or calculate how much the line will shorten due to the splice? Is it just length of bury + eye size?

For point 4 is the constructional stretch the listed some where. Only stuff I've seen has it at .68% but that is on the west marine site. Am I correct to think that the way to calculate length of stay would be bury x2 + eye x2 + constructional stretch + the middle = the length you need.

Thanks

I have numbers for amsteel, but not HSR. So you may need to play with it a bit to make sure you get it right.

For amsteel the line will shorten by 8 times the line diameter per splice. So if using 1/4 amsteel, you measure from two marks on the line and they are 10' apart, and those marks are the apex of the eye you should expect... 8 *1/4=2" PER SPLICE or 4 inches total.

Constructional stretch again I have numbers for amsteel not HSR. It comes out to 12" per 50'. I would expect it to be less on HSR, but not critically so. In part it is going to be dependent on the tension on the line when you measure it versus the static load when installed. Higher post installed tension will result in a slightly longer line when bedded in.


On trick to trying to get very accurate length in dyneema splicing is that you can actually finish the splice in place, or resplice it in place very easily. So its not a bad idea to make it a little longer than you think you want it. If it turns out you need to shorten the line, just undo the bottom splice, move the bury up a bit, and redo it.

On a lot of things, like lifelines I just do the splicing in place from a spool, I don't even bother to measure. But I would not recommend this for standing rigging.

[paxfish]

I just built new shrouds for Terrapin. The previous Dyneema shrouds were at least 6 years old, and possibly 10. They honestly looked like they could do another 10, but I replaced them out of an abundance of caution.

I used 9mm SK-75 blue amsteel. This is able to turn a tighter radius around my highly polished Jesus shackle than Dux, which would have required thimbles. This is a bit oversize for my 43 foot mast, but that will (in theory) help with creep over time and negate any negative strength numbers from the very secure Brummels.

I did use Colligo deadeyes, and they made taking up the construction stretch very easy after a couple of 15+ afternoons on the water.

The splices are easy. I built each shroud, put a couple thousand pounds of pressure on it between a tree and my 4wd truck, and let the pressure settle in overnight. I tapped it occasionally down the length with a wooden closet pole.

If you prestretch this way, be sure to put a tarp on the line in case something let's go. You don't want to take a 200 mph block in the nuts!

I did use a turnbuckle on the forestay and have nearly consumed the 4" of adjustment while keeping my 3 degree mast rake. It will likely get a deadeye also.

here are a couple of pix:

[UNCIVILIZED]

What are some of the little tricks used to get, & keep, the splices tight around the thimbles? I ask as I suck at that part when it comes to doing anchor rodes. Albeit for them, the boiling water trick is supposed to work on Nylon, to shrink them down tight.

[sneuman]

I've used it for lifelines and do not like the stuff at all. The UV makes it "fuzzy" very quickly. It "creeps" much more than advertised and, also contrary to popular belief, it is pretty easy to cut with a sharp knife. A heat gun goes through it like butter.

Not impressed.

http://svsymbiosis.blogspot.com/2016...idnt-work.html

[Oceanride007]

I have my new Dyneema rigging, Rigger chose changing the upper part of all turnbuckles & friction ring in triangulated back stay also with HF antenna wire, needed new bolts thru the mast, Material cost about Au $1800, splicing $800, about $970 for hard items, rest was labour all up about Au $3300. Not including forestay. (For the privilege of living in Aus we get use to paying higher import margins)

Now, I did ask him about chafe, with braid covering that should give longevity. but I won't be taking risks here if I can help it, hope not to let main against shrouds. Regarding inner forestay (not done yet) yes, bronze hanks will work but better to use soft shackles. Regarding 'Hove to' as in jib backed, protect the shroud with garden hose fitted over the sheet, extra protection would be PVC tube split and placed over the shroud.

Now he was not the most talkative guy but he certainly pretensioned everything, made a strong point in saying the rig must be slowly 'run in' and adjusted. He may have made a mistake in measuring the backstay as it needed a lot of persuading to fit the turn buckle, I suggested that its probably because my boat is steel doesn't flex so much! Left it overnight with tension on, it was fine, hope I don't end up with weather helm.

Weight loss, huge about 8:1 for the 1 piece that we measured. The diameter comparison to SS he use to do it at 1.1:1 but now uses 1:1. Rigger is a advocate for dyneema in safety lines, but many modern stanchions have sharp edges due to drilled holes, these should be fitted with SS tube.

There should be a image of my side deck here.

[Oceanride007]

My side deck should be here.

[40 South]

Originally Posted by Oceanride007

My side deck should be here.

I suggest you find a new rigger. With sharp bends on the turnbuckles your breaking strain has just dropped by at least 50%!! The turns should be at least 5 times the diameter of the rigging!

It also looks like regular dyneema, not Dux specifically made for rigging which has minimal stretch. If it is regular dyneema be prepared to adjust for stretch regularly! Also it should be sized at least 1 size greater than the S/S wire it replaced to minimise stretch.

Good luck with that lot.

[daletournier]

I met a couple of Peters customers, they seemed to be very happy with the decision to use dyneema, one had a dyneema forestay with furler. Peter is very enthusiastic regarding the use of Dyneema. I also worry about the chafe.

[paxfish]

Originally Posted by 40 South

I suggest you find a new rigger. With sharp bends on the turnbuckles your breaking strain has just dropped by at least 50%!! The turns should be at least 5 times the diameter of the rigging!

It also looks like regular dyneema, not Dux specifically made for rigging which has minimal stretch. If it is regular dyneema be prepared to adjust for stretch regularly! Also it should be sized at least 1 size greater than the S/S wire it replaced to minimise stretch.

Good luck with that lot.

Here is a discussion of some testing on the Dyneema. Dux may have a higher requirement than regular Dyneema.

bend radius with larger diameter dyneema - Gear Anarchy - Sailing Anarchy Forums

As far as "regularly", I am finding majority of stretch happens early in the life of the shroud. A "pre-stretch" as I described above helped a lot. After your first high wind sail, there is quite a bit of adjustment as your splices work themselves in. Then the adjustments diminish in both magnitude and frequency. Thus far, I have taken up about 8 inches of stretch in 33 foot shrouds over the course of 25 daysails, in high and low wind.

I have adjusted once in the last 10 outings.

Mine are 9mm (oversized for sure.)

BTW - for those of you with rotating masts, your iphone has an inclinometer app available that is helpful on my cat - May not be as effective on a mono. I just lay it along the mast on a calm morning to figure out my rake and side-to-side

Note above, I polished my Jesus shackle, where all shrouds converge, to a mirror finish before rigging.

UNCIVILIZED - here is what the eye looks like today after roughly 25 daysails in varying winds:

[UNCIVILIZED]

If you do a bit of reading of J Franta's posts, as well as what's on his website (Colligo Marine), it explains why they use Dux over other types of Dyneema. As well as how to measure your shrouds, & properly prestretch them, so that little in the way of adjustment is needed. Even after some boisterous sails. As evidently a proper prestretching removes the rope's constructional stretch, thus preventing the shrouds from "growing" after they're first installed. There are also a lot of other threads on CF describing this.

Also, from the way I understand it, you want Dyneema standing rigging to be significantly larger in diameter, & much stronger, than a conventional wire shroud. Particularly as Dyneema loses strength over time due to UV, unlike wire.
Plus, Dyneema (& all other cordage) is definitively not fond of sharp turns. Ergo the use of deadeye-thimbles & similar when rigging boats with this stuff.

One head scratcher is why, in the photo, does the shroud closest to the lens makes an extra complete turn around the eye of the turnbuckle before it's spliced? Anyone else see this?

Paxfish, thanks for the pic.

EDIT: Here's an article discussing sizing Dyneema for use as shrouds, info on types of Dyneema & it's suitability for same, info on prestretching, & line creep, etc.
Before Ordering Your Colligo Dux Rigging... — Colligo Marine®