# Dyneema lifelines



## AdamLein (Nov 6, 2007)

Replaced my lifelines (coating cracked every inch or so, lots of rust coming through) with dyneema today. Thought I'd share the experience with others considering the same change.

I used 3/16-inch amsteel-blue, which is single-braid dyneema. I put a Brummel splice in each end. The end that attaches to the pulpit has a nylon thimble and will be lashed to a SS eye on the pulpit; this lashing was supposed to provide 6:1 purchase to get adequate tension in the lifeline. The eye at the other end of the line was left thimble-less; the holes in my stanchions are big enough to fit a thimble-less eye through, so my thinking was that I would take the lifelines out (at the end of the season? after every sail) to prolong their life. The "soft" end was to be connected to the stern rail with a soft shackle of the same dyneema. The lashings are 1/8-inch double braid with a dyneema core. All of the components together were about $70 at WM.

And the results are in!



And here are my thoughts.

First, I realized partway thought that I would not be able to release the lifelines by the soft shackles once tensioned. Oops. This is not a really big deal for me, since the finger dock in my slip doesn't reach the cockpit anyway 

Second, I mis-measured one of the lifelines and had to run it to a more distant eye on the pulpit, and the lashings weren't long enough. I want the lashings to give at least a threefold purchase to tension the lines.

Third, the lines are brand new and yet already look "hairy". This is a bit disconcerting since I understand that hairiness is a sign that the lines are wearing out. They got this way during splicing. I'd love to see photos of other people's single-braid dyneema to see how it looks after some period of time.

Fourth, splicing this stuff is very very easy compared to double-braid. I did one eye splice following the Colligo Marine video and the procedure is now memorized. Ditto for the soft shackle, though I used the measurements from the calculator on l-36.com. On the other hand I have done about half a dozen splices in double-braid so far and I still need to follow instructions. The hardest thing has definitely turned out to be the measurements and planning (especially as I'm totally ignorant of proper rigging techniques). This was a sort of trial run to see what I'd be getting into if I decide to replace the standing rigging with dyneema, and now I have a much better idea.

Anyway if anybody else has done a similar project, I'd love to hear about it; if you're thinking of it, I'd say go for it!


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## Minnewaska (Feb 21, 2010)

Adam, congrats on your project. What's the word on dyneema chafing through the stanchions?


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## chef2sail (Nov 27, 2007)

I have been thinking of doing this the next time I replace lifelines in a few years. How do you prevent chafe at the hole entry exit of the stachion? Does a difference in temp change the length. How abot attaching fenders to them? Keep us updated on this
Dave


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## puddinlegs (Jul 5, 2006)

We use dyneema around the cockpit, but be aware that if you're racing PIYA or ISAF sanctioned events, you cannot use dyneema where people are hiking. Also, where you connect wire to a pulpit, the length of the lashings cannot exceed 4". Can't quite recall the strength that the lashings are required to hold, but it's substantial. I'll look it up if anyone wants to know. For cruising, it doesn't matter and is all good. Just a heads up if it's relevant. Adam, it's certainly a great upgrade from your old covered lifelines!

(Heat has no effect on length)


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## MarkSF (Feb 21, 2011)

If your splicing is causing wear, couldn't you just use bowline knots at the end? That Amsteel Blue is rated 5400lbs so with a bowline you have half the rating, 2700lbs, still sufficient I would think. If not go up a size to 1/4", 8400 lbs or 4200 with the knots. Guess the big question is will it hold a bowline, it's very slippery.

How to avoid wear at the rope to stantion connection is another question.


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## Zanshin (Aug 27, 2006)

I've had my Dyneema lifelines on Zanshin for a year now and there is no wear and tear, but in those places where I didn't clean the stanchions sufficiently I have some rust stains that I haven't really tried to remove as I'm not sure if the chemicals in the usual rust removers might not attack Dyneema.
I retighten the lashings once a season and that's all I need to do.



See the Dyneema lifelines page for a description.


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## AdamLein (Nov 6, 2007)

I haven't even tried a bowline because of how slippery the line is.

As for chafe at the stanchions holes, well, we'll see. The holes are a lot bigger than the line and rounded a bit at the orifices... I'll try to get a photo today.

I'm disinclined to hang fenders off them. Currently my fenders are tied to the stanchion bases, which has its own attendant problems, but the "hairiness" of the line scares me a bit and I want to avoid avoidable chafe.

As for racing rules, well, I have done very little racing. One of the reasons I did the upgrade now is because I'm thinking of entering a singlehanded race in a few weeks and I don't think my own lifelines would have passed inspection, as they were quite saggy with no room left at the turnbuckles to tighten them further.

I'll post again as things change. My next step will be to reinstall the pelican hooks from the old lifelines so that the new lines can be unhooked under tension. This will also shorten up the lashings quite a bit, I think to 2-3 inches, which I'll feel better about.


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## puddinlegs (Jul 5, 2006)

MarkSF said:


> If your splicing is causing wear, couldn't you just use bowline knots at the end? That Amsteel Blue is rated 5400lbs so with a bowline you have half the rating, 2700lbs, still sufficient I would think. If not go up a size to 1/4", 8400 lbs or 4200 with the knots. Guess the big question is will it hold a bowline, it's very slippery.
> 
> How to avoid wear at the rope to stantion connection is another question.


MarkSF, dyneema needs to be spliced. it's too slick for a bowline.


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## AdamLein (Nov 6, 2007)

Got some photos one of the lifelines passing through the stanchion. I picked the one near the bow where it makes a sharper angle.

From the front:


From abaft:


I have been thinking of taking a short bit of cheap double-braid, removing the core, and cutting the cover up into little two-inch-long sections to put over the lifelines at the stanchions.

Also in these photos you can really see the hairiness. I'm wondering if it's because I left the rope coiled in a cloth bag for a week or so in between buying it and installing it. Hm.


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## poopdeckpappy (Jul 25, 2006)

I used amsteel on my last boat ( about 4 yrs ago ) with CS Johnson splice line hardwear, Plan on doing the same on our current boat soon.

You should get 4-5yrs out of it, maybe longer before you should replace it

Looks great BTW


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## Waltthesalt (Sep 22, 2009)

I'm doing amsteel but haven't run the lines yet. I was thinking of using some tubing over the lines at that stanchons for chafe.


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## poopdeckpappy (Jul 25, 2006)

Maybe use one of the tube flare jigs; take a piece of 1/4 x 1" copper tubing as a insert at each stanchion and flare the copper tubing on either side of the stanchion hole, that way you have a sleeve that won't come out, will move with the movement of the lifeline and ya won't have a sharp edge


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## tap (Apr 1, 2009)

For where my lifelines go through the stanchions I have some clear plastic hose. The dyneema goes through the hose. Some tape is wrapped around the bit of hose on either side of the stanchion so it won't slide through anymore.


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## mitiempo (Sep 19, 2008)

You could use electrical heatshrink over the dyneema where it passes through the stanchion.


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## Kiltmadoc (Nov 10, 2009)

This looks interesting!

Does the dyneema need to be covered at all? And, if you do cover it, does it last significantly longer? 

I see that the amsteel at west marine goes for $0.85 per foot. For a 32 foot boat with 2 levels of life lines, I would assume that one would need around 120 feet.

Also, if you use the "zig-zag" pattern on the lower lifelines to keep stuff from rolling between the toerail and the bottom lines, would that chaff the dyneema too much? 

I have also noticed that this stuff comes in various colors; is one color better than another for fading/UV protection?


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## DwayneSpeer (Oct 12, 2003)

*Amsteel*

I've had Amsteel life lines on my boat for quite a few years (8?) and they are holding up well. Did mine very similar to yours. However I read not long ago on the Dyneema web site (I think) that they always recommend that the ends use thimbles since the line doesn't like making sharp bends. It weakens them quite a bit.


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## mitiempo (Sep 19, 2008)

It is an interesting idea but I doubt there will be sufficient strength after 5 or 6 years UV exposure. That is the area where stainless wins hands down.


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## puddinlegs (Jul 5, 2006)

cheaper and stronger than wire though.


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## AdamLein (Nov 6, 2007)

Sharp bends: I read on the Colligo Marine sight someplace that this is the case for Dynex Dux but not so much for Dyneema. Dux is much stiffer.

Heatshrink: Dyneema has a very low melting point, so I'd be hesitant to use heatshrink on it.

Short lifespan: my plan was to set them up in such a way that they could be easily removed and stored. There are plenty of times when I go several weeks without sailing, so there's no reason the lifelines need to absorb UV that whole time. Furthermore, at $70 for the whole boat it's less than half the price of the raw materials for steel, which is supposed to be replaced every ten years (i.e. twice the expected lifespan of dyneema), and which requires professional labor. From a purely financial standpoint it's a no-brainer.

I've heard that there's some research which says that after the initial exposure, Dyneema becomes opaque to UV and so the 5 year rule is a conservative estimate. I'm still perfectly happy to replace mine in 5 years barring more support for this theory, but it's good to keep in mind.


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## mitiempo (Sep 19, 2008)

Adam

Where do you get the 10 year lifespan of stainless from? A local rigger in Victoria figures 15 to 17 years for stainless standing rigging in our climate. The stainless is washed by rain on a regular (too regular?) basis. The same rigger recommends 7 year replacement of wire rigging in tropical waters.

Heatshrink can be put of without too much heat and if done carefully I see no problem with it. You are not looking for a waterproof bond as with wiring connections, just a snug fit for chafe protection.


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## tap (Apr 1, 2009)

From what I've read, one should not cover them. This allows one to see any cuts or areas of significant chafe. 

Most racing regulations, ISFA special offshore, PIYA, etc. now allow dyneema lifelines. Some race boats, like the Melges 24, come from the factory with them and so a decent amount of data is building up about how well they do. Rules typically require one to use single braid uncovered line. Ends must be spliced. The final join can be done with a lashing and typically the length of the lashing must be limited to 4" or less.

AdamLein is right about the low melting point. Head shrink and dyneema don't belong together. UHMWPE line is excellent it most attributes, chafe resistance, UV resistance, strength, but melting point is one place where it's weak.

My tube over the lifeline works very well. You can slit the tube to install it after the lifelines are already in place as the tape holds it together. It allows you to inspect the lifeline at the stanchion while an opaque covering wouldn't. Anything attached to the lifeline tends to get pulled out of position. The tubing isn't attached to the lifeline, the line slides through it, so it stays in position.

3/16 dyneema will rip the pulpits off your boat. You could go up to 1/4 or 5/16 and it would still be lighter and cheaper to install than steel. Even if UV degradation cuts that strength in half after five years (and data suggests it's not anywhere near that significant) the line is still stronger than steel and still strong enough to rip the pulpits and stanchions off the boat.

But talk about line strength ignores the reality of how lines fail. It's not because they aren't strong enough. It's because some weak point in the system fails. For steel, it's usually been rust. In the wire where it enters the swaged fittings. Hidden under a plastic cover (plastic coated steel isn't allowed for racing anymore). Inside the center of an uncovered line, so it wasn't visible to inspection. In a poorly swaged fitting that looked fine but pulled out at a fraction of what the line's breaking strength should have been.


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## pdqaltair (Nov 14, 2008)

I've noticed some sailors simply go oversize (1/4" and even 5/16"). The strength allowence will then forgive a lot of UV and chafe.

3/16 5,400#
1/4 8,600# 
5/16 13,700#

3/16" seems to be cutting it thin, IMHO.

Slide 10 of this study show the UV effect; 65% after 2 years, and then nearly flat. I would guess that the UV only penetrates so deeply, so the diameter of the rope matters, and they were testing 30,000# rope. I'm guessing 50% strength after 2 years is closer for 5/16" Amsteel.

http://www.samsonrope.com/site_files/High_Performance_Synthetic_Ropest.pdf

There is also discussion that after many cycles of heavy work the line can lose ~ 40% of it's strength, and then the loss basically stops.

That being the case, 5/16" Amsteel would last 4-6 years at greater than 5,000# strength ... unless there is visable chafe or some other reasoning. Of course, the SS wire strength requirement has in it anallowance for wear and tear, based upon expereince. I suspect 3,000 pounds is realistic for a well-used (not corroded) SS lifeline. So 1/4" should be good for 4-6 years and 5/6" for 6-10 years. Hard to say. Real-world long-term testing has a lot of variables and is too expensive.

Lacking dating tags, I can see why a race commitee would reject 3/16" Amsteel.


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## AdamLein (Nov 6, 2007)

mitiempo, 10 years is the round number that I read very often for SS rigging. If it lasts longer in the PNW, well, we get less UV here as well, so I would expect dyneema to also last longer. Basically I'm assuming that the lifespan of dyneema is half that of SS wherever you go, so in my head I just double what I'm paying for the dyneema.

I was considering going up in size on my dyneema lifelines to 1/4", but I wanted to be sure that I could install and remove the lines with the splices in them. Probably it would still work with 1/4", so when I next replace the lines I'll probably use 1/4". I am already up 50% in diameter (116% BL) from the minimum required for a 27-ft boat, which is 1/8". The PDF linked above shows that the strength approaches 60% with exposure to sun over time, which means I'm still above the minimum requirement when I replace them after five years.

Edit: dating tags.... what do you think would be a way to do that in such a way as to satisfy a race committee?


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## DwayneSpeer (Oct 12, 2003)

*recommendations*

Check this out for recommendations from Colligo Marine. http://www.colligomarine.com/docs/respecttherope/RTRDyn1.pdf


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## mitiempo (Sep 19, 2008)

Interesting reading on the Colligo site. Dynex definitely makes more sense than regular dyneema or amsteel. And bigger being better makes a lot of sense as well.

Question- why would you want smaller diameter lifelines on a smaller boat? If their purpose is to stop someone from breaking them when falling I think the minimum should be the same for most boats. 1/8" stainless seems weak to me on a 27' boat. I will be replacing the lifelines on my CS27' with 3/16" bare stainless.


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## AdamLein (Nov 6, 2007)

I dunno why you would go small with lifelines. My goals were as follows:
1) Have lifelines that I could respect.
2) Have lifelines that passed a race committee inspection.
3) DIY/low cost.


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## Minnewaska (Feb 21, 2010)

tap said:


> For where my lifelines go through the stanchions I have some clear plastic hose. The dyneema goes through the hose. Some tape is wrapped around the bit of hose on either side of the stanchion so it won't slide through anymore.


I've been told that lines run through non-breathable chafe protection will retain moisture, heat up and wear faster. No experience with that myself.


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## Boasun (Feb 10, 2007)

Why not use leather chaffing gear at each stanchion. No heat require and if pre-punched easy to sew on. Use to use them on bronze life lines when I was in the Navy.


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## mikefossl (Feb 21, 2008)

1/4" Amsteel. I used the same fittings with some suitable replacement with eyes. I also used the existing turnbuckles which had plenty of travel. The hardest part was estimating the construction stretch which I always over estimated.


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## benjmin (Nov 1, 2011)

Mike,
Very clean looking! Good job! Now please come do mine.


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## Boasun (Feb 10, 2007)

benjmin said:


> Mike,
> Very clean looking! Good job! Now please come do mine.


and mine also.......


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## zz4gta (Aug 15, 2007)

I've been using dyneema lifelines for 3 years, in 2011 they stopped a 200 lbs man from going over the side. He hit so hard it drove the stanchion on the pushpit through the deck of the boat. But he stayed onboard. 

Splice dyneema and use a very strong lashing (spiderline). I'll take some pictures of my lifelines after 3 years of use. Very little wear. 

To the OP, I don't think you'll have any trouble with those stanchions. Just keep an eye on it for the first season, if there isn't any chafe, you're probably good for 5+ years. I used 1/4" for a little more meat, they are "life" lines after all. Dyneema is cheap. 

If you want to combat chafe through stanchions, you can use rubber grommets or cut a small length of rubber tube and milk it over the line into the stanchion. You can tape it in place or sew it there so it doesn't move. Most stanchions don't have super sharp edges anyways. I changed out my plastic caps with SS ones as the plastic was weak from UV and breaking under low loads.


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## Leocat66 (Dec 11, 2010)

Have had dyneema 5/16 lifelines for the last 5 years. No chafe, no problems at all.


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## zz4gta (Aug 15, 2007)




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## AdamLein (Nov 6, 2007)

Seems I maybe have chafier hands than other posters in this thread. My lines looked hairy after just splicing them.


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## zz4gta (Aug 15, 2007)

You really shouldn't need to 'work' the line much. Dyneema is slippery and easy to spice. If you run into any resistance at all, then you may have snagged an internal thread. That happened a lot when I started. It will make a lot harder. Also, the more you do, the easier and faster you'll be. Which means you'll handle the line less and it'll be less fuzzy. 

I'm sure yours are just fine. Your using 100% dyneema/spectra right? Not a blend? Only reason I ask is b/c blends tend to fuzz up like crazy aft 10 minutes of messing with it.


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## AdamLein (Nov 6, 2007)

Hm.... I'm pretty sure it's pure dyneema. Got it off the amsteel spool at WM as I recall.


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## zz4gta (Aug 15, 2007)

ok, that should be it.


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## jimgo (Sep 12, 2011)

Adam,
You mentioned that you will be removing the lifelines periodically to avoid UV exposure. How do you plan on doing that? If the lines have large eyes on the end, won't that make it impossible to fit the line through the holes in the stantion base?


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## Squidd (Sep 26, 2011)

I don't know that I'll be removing my lines as I only have a 5 month season and store indoors... but

My lines are removeable by unscrewing pelican clip from eye bolt and passing thru stancions...



And unlooping "luggage tag" on other end....



I also used "chafe tube" secured by shrink tube...(use a heat gun it only needs 150*  )



Whole thing will slide thru stancions and come off if needed...


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## jimgo (Sep 12, 2011)

Wow! So your eye bolt actually fits through the stantions? That's what I couldn't envision in yours or in Adam's. In my mind, all I can envision is that the eye of the splice is about twice the thickness of the line, which means a 1/4" line is closer to 1/2" (not actually 1/2", since it can "spill over" laterally). If you add an eye bolt to that, you've got to be able to fit the eye through, too. I think I need to go find a Unicorn...


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## AdamLein (Nov 6, 2007)

jimgo said:


> Adam,
> You mentioned that you will be removing the lifelines periodically to avoid UV exposure. How do you plan on doing that? If the lines have large eyes on the end, won't that make it impossible to fit the line through the holes in the stantion base?


Er, while I said I was going to do that, I have been a bit lazy (also excessively optimistic as I was planning to continue sailing all winter, and never really did).

However, should I choose to remove them, it would be quick and easy. One end has a thimble, and that end is lashed to the bow pulpit. The aft end is a simple eye with no thimble. The pelican hooks have a toggle with a clevis pin, and I'm just putting that pin through the eye. The eye, being thimble-less, fits through the stanchions easily; that is in fact how I originally installed the lifelines.


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## SVTatia (May 7, 2007)

With SS you can see that the line needs replacing, not so with synthetics as the line could look like new but weak due to UV susceptibility. I guess with Dyneema you must replace regardless, otherwise it could be “tested” (and fail) by a falling crew.
I have read posts with it being used for 5, 8 years. When do you tell yourself to replace them? Would you make a point of replacing after X years after installation, regardless?


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## jimgo (Sep 12, 2011)

Tatia, I think that's the approach you'd probably want to follow with something like lifelines anyway. You can't always see the places where the stainless is corroding/rusting, so it's better to play it safe and replace them periodically, much like standing rigging.


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## AdamLein (Nov 6, 2007)

SVTatia said:


> With SS you can see that the line needs replacing


I disagree. SS lifelines most often fail inside a swege. No way to inspect it without a process that, for most of us, costs more than new lifelines.

And this assumes that you have uncoated lifelines. Lots of people prefer coated lines; these cannot be inspected along their lengths.

Furthermore, if you are willing to pay the premium, you can get dyneema lifelines that are protected from U.V., either by a polyester cover, or a chemical coating.


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## mitiempo (Sep 19, 2008)

I'm replacing my lifelines with stainless - uncoated. True the issue isn't the wire but the swages - you could use mechanical fittings instead though. They can be inspected and don't have the same hidden issues.


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