I'm interested in hearing from those who have used Dyneema life lines on their boats, what the pros and cons are. I know the basics from various articles.
Pros and Cons of Dyneema Lifelines
- Thread starter Project_Mayhem
- Start date
I've primarily used Dyneema for gates, where the greater flexibility is an advantage. I went considerably oversized, so wear is not an issue.
If you hang rail meat, chafe is a major issue and wire is the better bet. If you do NOT lean on the wires, then go oversized, polish all of the stanchion holes, and follow the advice on chafe gear etc. Or stay with wire; it really does last.
If you hang rail meat, chafe is a major issue and wire is the better bet. If you do NOT lean on the wires, then go oversized, polish all of the stanchion holes, and follow the advice on chafe gear etc. Or stay with wire; it really does last.
The only thing hanging off them is fenders. The thought of going oversized ran through my head today. The PO of my boat made some pvc/foam/sunbrella covers for the cockpit. I've become rather accustomed to the extra stiffness as the hooks generally remain at the back of the cockpit when undone. I assume the Dyneema would live happily inside some PVC unlike steel cable which might be prone to crevice corrosion?
I personally prefer stainless steel life lines. Dyneema stretches and I found it to take more fussing with than stainless lines. I also use my life lines for a lot of things and the chafe issue is a concern for the way I sail. Stainless line will also significantly outlast dyneema line. Dyneema is easy to install and replace...
How tight of a tolerance is your PVC over your life line? Depending upon the design, you may get chafe with dyneema inside. You'd have to have a quite tight tolerance on the stainless wire to even begin to have a corrosion problem.
dj
How tight of a tolerance is your PVC over your life line? Depending upon the design, you may get chafe with dyneema inside. You'd have to have a quite tight tolerance on the stainless wire to even begin to have a corrosion problem.
dj
Not a fan of the PVC or vinyl-coated SS lifelines. The sheath eventually cracks and you can't see what corrosion may occur underneath. For lifelines I like a 'naked stainless' 1 x 19 wire, up-sized to the same OD as the coated wires, terminated at one end with a rolled swage and with a Sta-lock fitting at the other end. Never tried Dyneema but it seems ideal for a DIY world cruiser.
jssailem
SBO Weather and Forecasting Forum Jim & John
- Oct 22, 2014
- 24,663
In 2015 I faced this dilemma. The boat came with cracked vinyl wires. I was just starting to use dyneema on the boat. The decision favored stainless steel. Factors were cost about the same. Life span stainless steel. Insurability stainless steel. Open water racing rules “stainless steel required”. Not that I was planning to race the boat, but the rules were developed over years of experience.
11 years later exposed 24/365 to the marine environment, the stainless steel looks like it did when first installed. I did use Dyneema on the port and starboard gates. While it is still strong (over sized to improve hand feel) the surface fibers no longer have that shiny coating. I suspect UV has had its way. The gates are on my list for replacement this year.
11 years later exposed 24/365 to the marine environment, the stainless steel looks like it did when first installed. I did use Dyneema on the port and starboard gates. While it is still strong (over sized to improve hand feel) the surface fibers no longer have that shiny coating. I suspect UV has had its way. The gates are on my list for replacement this year.
jssailem
SBO Weather and Forecasting Forum Jim & John
- Oct 22, 2014
- 24,663
I’m not sure it is now, it was back then. I called a couple of shops and got a quote for the life lines produced using machine swaging, terminals and completed in 48 hours for $600.
The terminals for dyneema, the inserts for the stanchions, and the dyneema in a size to provide a good hand feel was $50 more and I’d do all the labor.
Today it might be different. Dyneema at that time was new to sailing. Just matching the strength need in dyneema, the line was too small a diameter. You pay a lot more for 3/8 than 1/8. Dyneema requires special radius rounded terminals, so that the fibers do not fracture when tensioned. The terminals cost almost as much as the lines.
It might be different today, as there are more source options.
These are “life lines“!
Choose your materials wisely.
The terminals for dyneema, the inserts for the stanchions, and the dyneema in a size to provide a good hand feel was $50 more and I’d do all the labor.
Today it might be different. Dyneema at that time was new to sailing. Just matching the strength need in dyneema, the line was too small a diameter. You pay a lot more for 3/8 than 1/8. Dyneema requires special radius rounded terminals, so that the fibers do not fracture when tensioned. The terminals cost almost as much as the lines.
It might be different today, as there are more source options.
These are “life lines“!
Choose your materials wisely.
You need a 1:1 radius on Dyneema to achieve 100% line strength in an eye. Manufacturer's website--Google it. Any low friction ring or sailmaker's thimble will easily do that, and in many cases, luggage-tagging to an existing 3/16" welded fitting will do that, since the required diameter of the Dyneema is only 3/16" (required size--not 1/8"). If you go larger, for hand feel (your choice--and you would need to compare the 3/8" wire) or chafe in stanchions, it will still be stronger than it needs to be even with the smaller bend, in part because Dyneema flattens out when loaded if not constrained by a pulley).
(The larger bend diameters sometimes quoted are for pre-set, heat-treated Dyneema, which has different properties--not actually a good choice for lifelines, because it's fatigue life bending is lower. It is NOT a magically better material. It is a different material, like hardended steel vs. spring steel. Different.)
The inserts are smart.
I think you inadvertently made the Dyneema project far more expensive than it needed to be. Not sayin' I don't like wire; Dyneema does chafe if given half a chance.
Why would anyone choose to install something that would need to be replaced within a reasonable period of boat ownership rather than with something that would, essentially, last forever?
My vinyl covered lifelines, installed in 1986 OEM, were replaced with bare SS in 2000, and are still going strong.
My vinyl covered lifelines, installed in 1986 OEM, were replaced with bare SS in 2000, and are still going strong.
I used dyneema for my last set of lifelines. I luggage tagged the forward end to the existing loops welded to the bow pulpit and used splice eyes with threaded studs on my existing pelican hooks on the aft end so the studs were my only hardware cost. For chafe I used short lengths of tubular webbing over the dyneema where it goes through the stanchions. My downside is I don't have gate eyes so the full length sags when I release the pelican hook but it has all worked very well for me. I can't remember the diameter of the dyneema but it was the same or close to the full diameter of the coated stainless wire it replaced so I think I have a reasonable safety factor.
Here are a couple of good articles by a well known author about dyneema. I hope it okay to post these here.
www.practical-sailor.com
www.practical-sailor.com
Here are a couple of good articles by a well known author about dyneema. I hope it okay to post these here.
Dyneema Abrasion Test - Practical Sailor
Where minimal stretch and maximum strength are required, heat-set Dyneema from a reputable rope manufacturer is the top choice.
www.practical-sailor.com
When Should We Retire Dyneema Stays and Running Rigging? - Practical Sailor
Since 1974, Practical Sailor’s independent testing has taken the guesswork out of boat and gear buying.
www.practical-sailor.com
