Good morning all! I’m getting ready to replace my vinyl coated lifelines on Tessq with Dyneema. Looking for photos of the same that anyone else has done for inspiration. Thanks in advance.
Rebecca Bray
“Tessa” N30C #11
Watch Hill RI
Hi Rebecca,
Many consider it a close call between Stainless and Dyneema for lifelines. This spring one of the cruising boats at our club had a Dyneema lifeline fail and had a crew go overboard during a race.
After the accident the boat got lots of attention because many cruising boats at our club are also considering moving to dyneema for lifelines. Here are some of the observations :
- The failure occurred where the lifeline passed through a stanchion. The dyneema chafed on the stainless. There are low friction inserts used to reduce chafe but this boat didn’t have them. Dyneema requires more frequent inspection.
- The dyneema had a fair about of UV damage. It was still pretty strong but it had become uncomfortable to the touch because of some outer strands that had become brittle and broke. It was used for 5 seasons.
- Dyneema expands and contracts as the temperature changes. When cold it is longer. If you tension dyneema lifelines in the cold repeatedly you could eventually damage your stanchions because each cycle hot cycle will pull with enough force to flex them and their mounting points on the deck.
- A proper installation requires hardware specific to dyneema. Kits are available or fittings are sold individually… kinda pricey. ( Example )
- Dyneema is fun to work with but there is a bit of a learning curve. If you don’t do your own splices it gets very expensive. Splices are time consuming, it takes me about 30 mins to make a 4" dead-eye with 12 strand dyneema. Lifelines would be an intermediate level project. On a Nonsuch, if you are not already proficient splicing dyneema, I’d start with some dead-eyes to replace stainless shackles on your mast collar or maybe make a dyneema topping lift or safety line for topping lift.
I’m a fan of dyneema and learned a lot from Herb on his Sailing Wisdom youtube channel. He’s also written a lot about Dyneema .
Good luck, please share pictures.
Rob.
I did dyneema lifelines on my previous Nonsuch but haven’t gotten around to making the change on my current one. I’ll look for pictures.
Rob’s covered some key points as far as he went, although I think he makes it sound harder than it needs to be.
Chafe protection through stanchions is important.
I’d be less worried than Rob suggests about expansion and contraction. This is more of an issue for superyachts using highly tensioned dyneema for shrouds than for us mortal folks. According to Dyneema and its Coefficient of Thermal Expansion — Rigging Doctor
Dyneema is a special material because it actually behaves backwards to this common convention. It will contract as it heats and expand as it cools…
According to the same source, the expansion ratio is such that, if there’s a roughly 40C (104F), difference between your hottest and coolest days, rigging installed on the hottest day will grow by 0.5mm per meter which translates to 0.018 inches, i.e., a bit more than 1/64" per yard. Rigging Doctor therefore recommends installing dyneema lifelines on a warm day.
On a N30, if Rigging Doctor and my math are both right, if you installed your dyneema this summer on a 90F day, your lifeline might expand by half an inch in the dead of winter. If you’re willing to accept half an inch of slack when you go sailing in -10F, this will probably be ok.
Dyneema is susceptible to UV, as Rob points out. Practical Sailor has found that the rate is highly dependent on latitude because the amount of sun exposure differs so much.
There are two common solutions to this. Practical Sailor recommends replacing wire with the same size Dyneema. They suggest that it’s so much stronger that, by the time you’d replace it, any strength lost to UV only reduces it to the strength of the wire it replaces. Alternatively, use Dyneema with a nylon core. Splicing an eye in a cored line looks hard, but turns out to be manageable with good instructions.
This does cut into the cost differences between dyneema and wire, but if you’re willing to do your own splicing, then the savings on not having to buy the specialized tools or pay for help is pretty substantial.
Although dyneema splicing does have a learning curve, this can actually be fun rather than a burden. It allows you to make a bunch of things that are handy to have around. There’s a good source of videos and downloadable guides at Splicing Videos and Instructions - Yale Cordage
I found that my time to do splices went waaay down when I found the right tools. I’ve enjoyed having a choice in different situations between two different kinds of fids: D-Splicers ( Where to buy | D-SPLICER ) and Selma Fids (available from lots of places, including Amazon, just search on the words). I don’t know how to make my own Selma Fids, but a clever person could make their own D-Splicers with bent wire coathangers.
It’s better to have “splice line fittings” for the line, but:
- Shop around, Nautos is one of the most expensive places to look
- I’m pretty sure that you only need a few, because if the other end of your existing turnbuckles is attached to a terminal, you may only need to replace the part connected to the wire.
Bob
I have not used Dyneema for lifelines, so I’m not advising for or against, but asking the question that has prevented me from considering them in the past:
Dyneema is much more “limp” than stainless cabling of a similar diameter. I hang my fenders from the lifelines. (You’re welcome to suggest a better way, providing it is something that any novice can remove and attach with zero knowledge.) The stainless lifelines sag a little under the weight, but not a lot. And they stand up well when my fender bumps the dock as I am arriving in the slip. I wonder what to expect of Dyneema in this situation. My intuition is that it would sag a lot more, but maybe I’m not thinking about it correctly. My old lifelines are probably due for replacement sometime soon, so this subject does interest me, too.
Bob,
The point about thermal contraction is exactly as you mention… in cool weather it’s better to live with the slack… don’t try to “fix” it by taking up slack, wait for the weather to warm up.
Creep is a thing to watch with less expensive dyneema, so you may need to seasonally reset lifeline tension. Re-tension on a warm day and you don’t have to worry about putting too much stress on your stanchions.
I agree splicing is fun !
Sail on…
Rob…
Hi Brian,
Soave’s lifelines are also stainless. Replacing them is a low priority because they are relatively new.
The folks I’ve seen with dyneema lifelines tend to hang fenders from stanchions rather than lifelines. Soave’s stanchions are spaced reasonably well for this. Hanging from a stanchion has the added benefit that the fender can’t migrate forward or aft. Boats with perforated toe-rails also use them sometimes for fenders.
The main advantage I see for Dyneema lifelines ( in the context of Nonsuch boats ) is that they are easier for DIY owners to fabricate and install.
Even though I enjoy working with Dyneema, when the time comes I’ll probably stick with stainless.
I often surprise my ( generally progressive self) by leaning towards the tried and true rather than the new and approved when it comes to boat stuff. I just bought a new AGM battery bank.
I enjoy following the new and improved stuff… once I understand it’s advantage I’ll adopt it.
Rob…
I don’t know a good way to use the stanchions. I generally have my “crew” (enthusiastic helpers) or guests (watchers) take in and put out the fenders while I am navigating through the marina. So I have had to make it foolproof. I have three fenders on each side. Each is attached to a stainless carabiner (the kind with the knobby gate latch, not the kind with the toothy gate latch!) The lines are adjusted to the correct length so as long as you put the right one in the right place it is a simple matter of clipping or unclipping them. I mark the fenders on the port side with black cable ties: 1 tie for the bow fender, 2 ties for the mid fender, 3 ties for the aft fender. I do the same on the starboard side, but with white cable ties. I have matching colors/numbers of cable ties on the lifelines. You clip a fender to the location where the cable ties on the line match those on the lifelines. (Yes, they are all right next to a stanchion, now that you mention it.) Pretty much everyone gets it and it is fast and safe. No tying knots or leaning over to look if you’ve got it tied at the correct length. I only have problems when a cable tie breaks off and I use the heavy duty ones so that is unusual.
I clip my fenders directly to the SS loop in the stanchion base flange. I leave them on the deck connected all the time when away from the yard. I do not want to use up valuable storage in the hold for these relatively inexpensive fenders. As I am reading this exchange I realize I should clip my swivel eye snap shackles to a soft shackle to prevent metal to metal erosion on the stanchion loop.