Dyneema Lifelines

[PaulJacobs]

Has anyone on this forum replaced their lifelines with Dyneema?

The lifelines on Pleiades (1990 C34 MK 1.5, No. 1068, Tall rig, Fin Keel) are now 31 years old and getting rather tired.  There are numerous cracks and splits in the vinyl covers, and more importantly there are rust stains in various locations, even after repeated doses of citric acid.  Primarily for safety reasons, but also for aesthetic reasons as well I think it is time to treat her to new lifelines.  A large person falling against a lifeline can induce a considerable shock load, and the last thing I want to happen is for a rusty lifeline to give way and have the person fall overboard!

I am inclined to go with Dyneema for a number of reasons: (1) Dyneema is very easy to Brummel splice using a fid, (or even the hollow tapered barrel from a ball point pen!), so I can easily do that myself - as opposed to swaging SS lifelines which would require a professional, since I do not have a swaging tool, (2) Dyneema is actually stronger than steel for the same weight, (3) Dyneema absolutely does NOT rust, (4) and Dyneema is less expensive that steel of the same diameter.  It will very gradually degrade over time due to UV exposure, but modern Dyneema fibers are coated with a UV protector, and by the time they need to be replaced again I likely will have gone on to Fiddler's Green.

Mauri-Pro sells white, 6 mm (approx. 1/4" diameter) Dyneema, with a breaking strength of 5600 lbs. for $1.75 per foot.  Allowing a bit extra for splices, and some small amount of waste, I assume I would need 130 feet to do both the upper & lower lifelines, on both starboard & port.  I could use SS thimbles at each end, or if I am feeling a bit more extravagant, those lovely fittings made by S. Johnson with the machine rounded & polished grooves specifically for spliced lifelines.  I intend to use the original SS turnbuckles to tension the lifelines.

I am really curious to know if ANYONE on this thread has done this before, which terminations did you use, and how did you like the final result?

Paul

[ewengstrom]

Paul,
We did this replacement over the winter of 2019/20 and have been very happy with the conversion. We did do the thimble terminations and brummel splice method. The old turnbuckles on our boat were seized and were basically garbage, along with the SS lifelines. I simply terminated the thimble(s) approximately 6" short of the pushpit/pullpit and tensioned the assembly with 1/8" Dyneema pulled thru the thimble and pulpit loop. This provided a nice adjustment as everything settled into place over the first month or so. I'd seen this on another C-34 and a friend also did his on his 88 C-34 so that makes three that I know of.

Embarrassing admission time......I'd finished up the new life lines early last Spring, but I'd forgotten to install the turning blocks for the furler over the stanchions.  (I'd removed all the stanchions on the boat to straighten and re-bed them.) When I realized this I found I had two choices....cut the Dyneema and buy new or attempt to un-splice it, install the turning blocks and re-splice the life lines. Nothing ventured, nothing gained so I went with option #2 and it was EASY....I had them pulled apart in no time and had no problem re-splicing the two connections. I've had zero problems out of them since.
P.S....this entire installation took very little time, once you get the splicing down...it went VERY quickly.
That's my experience, your mileage may vary. I do hope this helps!!!

[PaulJacobs]

Hi Eric,

Thank you for your splendid and speedy response!

I really like your idea of using small diameter - perhaps 1/8" - Dyneema to tension the lifelines rather like lacing.  Could you kindly forward a photograph or two, so I can see how you did that, and how it looks.  Did the "lacing" approach generate adequate lifeline tension?  Also, Dyneema does have a bit of creep, so over time some of the tension may relax.  Was that a problem at all?  I realize that lifelines do not need to be "bar taut" but if they sag too much I think they do not look great, and even more importantly, they might not function properly.  I was planning to use the existing turnbuckles, but as you noted yours were pretty much garbage after all these years. Ours have not been tightened or loosened in YEARS and are probably frozen.

Finally, do you happen to recall how many feet of Dyneema you actually purchased?  I certainly do not want to fall short, but if I use your "small diameter Dyneema lacing" approach even that would not be catastrophic.  I just hate to waste the stuff by ordering way too much.  On the other hand, I suspect I could find some sort of good use for say 10 extra feet of amazingly strong line.

Thanks again for your great response.

Paul

[Admiral_Swellson]

I'd love to see pictures of this as well! I've contemplating changing lifelines as well but hadn't even occurred to me to use Dyneema.

[ewengstrom]

Paul,
I did search my phone for photos and while I usually take shots of all my projects....I didn't that time!!!! 
I'll see what I can do when I go down this weekend....IF I go down this weekend. (I usually do)
The Dyneema may creep a bit at first...and I'd actually expected it to...but it seems to have settled down at this point. I don't pull it bar tight either but do keep a bit of tension on it, just enough that it doesn't sag. The smaller line can be untied and tightened as needed and I also like the look.
I don't have access to my records at this time for the 1/4" line itself, but if you just get a total linear footage of the lines, then add approx. 18" for the splices and turns around the thimbles you'll be VERY close. I do remember originally ordering 30' of the 1/8" Dyneema and then picking up another 10' from West Marine later to finish the job, I did turn this smaller line back upon itself quite a few times so I'm sure I used more than I thought I would for each connection...better too much than too little though. 

[Jim Hardesty]

31 years old and getting rather tired.  There are numerous cracks and splits in the vinyl covers, and more importantly there are rust stains in various locations,

I know it's not dyneema related but FYI some have removed the vinyl cover and use the stainless wire beneath.  Like many new boats.  One advantage is that any corrosion can be seen. 
Only letting you know there are other options,
Jim

[ewengstrom]

Jim,
Before I decided to switch, I did bring the wire home and removed the vinyl cover on the old lines....I found broken wires and meat hooks all over the place....it was super easy decision to replace those things once I dug into them.
By the time you see that corrosion thru the cracks, I'd say that it's MUCH worse inside the cover.

[ewengstrom]

I did find those photos. This isn't my boat but I copied this install almost exactly.

[ewengstrom]

A few more shots.

[PaulJacobs]

 

Wonderful job!  I note you have nice long "buries" on your Dyneema splices.  Way to go! 

I have been thinking about the best way to do the lacing.  As you know, Dyneema is very slippery, so most knots do not work all that well,  I was thinking of using a "safety bowline" (i.e. a conventional bowline with a relatively long tail which then is used to tie two half-hitches onto the standing part),as a means to attach the 1/8" diameter Dyneema lacing to the pulpit's (or pushpit's) little welded SS "loop".  I would then, as you did, pass the small lacing line through the SS thimble, back through SS loop, and do this 4 times - since the strength of four 1/8" lines is about the same as a single 1/4" line.  Then, when all is ready, I would tension the lifeline with the lacing line, and finally tie about 3 or 4 half hitches, and temporarily secure the lacing with rigging tape.

Learning from your experience - where Dyneema does undergo some initial creep, and hence tension relaxation - after about a month I could  undo the tape and the 3 or 4 half hitches, re-tension, put the 3-4 half hitches back in, but then whip the final result to insure the half hitches don't gradually wiggle loose.

I think the final result should be TERRIFIC, will look great, will be MUCH easier than replacing SS wire, will NEVER rust, and will last for many years.  Thanks so very much for your great inputs and the photographs.

Paul

[waughoo]

Very cool idea!  Where does one find those nifty pelican hook replacements?

[Noah]

Try "erigging.com

https://www.e-rigging.com/three-eighths-inch-stainless-pelican-hook

[Jon W]

or Go2marine.com. Sea-Dog and Suncor are two brands that make pelican hooks with the slide. Probably others as well.

[waughoo]

or if I am feeling a bit more extravagant, those lovely fittings made by S. Johnson with the machine rounded & polished grooves specifically for spliced lifelines.

Paul... are these the fittings you were talking about?

End terminal with toggle
https://www.fisheriessupply.com/johnson-marine-splice-line-lifeline-toggle-jaw-terminal/ls-3600

Turnbuckle
https://www.fisheriessupply.com/johnson-marine-splice-line-lifeline-open-turnbuckle/ls-5200

If so, this would make for a VERY tidy installation (making note for possible future installation).

[ewengstrom]

The Pelican hooks are 4" Seadog Pelican Hooks. I was a bit skeptical of that design but I've warmed to it since the install. They do stay connected as long as there is tension holding them in place......all the more reason to keep some tension on the Dyneema life lines.