Using dyneema on a Nonsuch

[jonlewit (Jon Lewit - N26C #115 - Inua - Kingston, NY)]

Dyneema Overview - generic uses

On a sailboat, Dyneema is primarily used for its high strength and low weight, making it ideal for replacing traditional lines like halyards, sheets, and lifelines, resulting in a lighter boat with improved performance and reduced chafe, especially when compared to heavier steel wire options; however, proper sizing and consideration of UV exposure are crucial due to its susceptibility to damage from sunlight.

Key benefits of using Dyneema on a sailboat:

** Lightweight:*

Dyneema is significantly lighter than steel wire, reducing the overall weight of the boat, which can improve performance and maneuverability.

** High Strength:*

Despite its lightweight nature, Dyneema possesses exceptional tensile strength, allowing for smaller diameter lines while maintaining high load capacity.

** Low Stretch:*

Dyneema has minimal stretch, providing precise control over sail adjustments.

** Chafe Resistant:*

When properly protected, Dyneema can be highly resistant to chafe, a common issue with traditional lines rubbing against deck hardware.

Where to use Dyneema on a sailboat:

** Halyards:*

Using Dyneema for halyards allows for easier hoisting and lowering of sails due to its light weight and low friction.

** Sheets:*

Dyneema sheets can provide improved control and responsiveness, especially on larger sails.

** Lifelines:*

Dyneema lifelines are lighter and more comfortable to grip while maintaining high safety standards.

Important considerations when using Dyneema:

** UV Protection:*

Dyneema can degrade when exposed to prolonged UV radiation, so consider using a UV-resistant coating or sleeve for exposed lines.

** Chafe Management:*

Although chafe resistant, proper chafe protection is still necessary at high-wear points like around deck hardware.

** Proper Sizing:*

Selecting the right diameter of Dyneema is critical to ensure sufficient strength for the intended application.

** Splicing Techniques:*

Due to its unique properties, Dyneema requires specific splicing techniques to ensure proper load distribution.

Some Previous Posts Mentioning Dyneema

A search through the Google conversations found these comments:

Tying Blocks with Dyneema

There were several posts what mentioned tying blocks using short lengths of dyneema.

Boom Track

Thor (26C Brentwood Bay BC)

Oct 20, 2024, 4:07:59 PM

Not surprisingly my clew attachment point has worn a bit to the degree there is now some looseness with the shackle pin. I replaced the shackle with some dyneema and it works but wears due to the sharp edge of the hole in the casting.

I was thinking I could remediate the by using something like JB Weld. as a bushing. I can just leave the shackle in place and use dyneema to connect it to the sial. Since both surfaces are smooth wear should be minor.

Other ideas involve a pad eye but the load would in the lateral. I did look at a Wichard eye and welding a stainless ring to the head of a bolt. Both would require a bushing in the hole as well.

Would smoothing the ridge on the casting hole be enough to mitigate the dyneema line wear??

Bob Neches (Me Gusta, Nonsuch 26U #233)

rtneches@gmail.com

Oct 20, 2024, 5:07:06 PM

My current boat came with the clew attachment point enlarged and a stainless steel bushing inserted (I’m guessing somehow press-fitted) that fills the enlarged hole and protects the aluminum boom end casting from the shackle pin wear.

My previous boat had a similar problem, and I dealt with that by using a long length of dyneema to do a lashing which wrapped around the end casting on both sides of the fastenings for the topping lift and mainsheet block. I don’t have a picture of that, but here’s a picture of a similar lashing that was done for the choker block on the forward end of the boom.

Tom Schoenhofer 26C#28 North Star Penetanguishene

tschoenhofer@gmail.com

Oct 21, 2024, 12:36:23 AM

Dyneema doesn’t like any sharp corners or or corners of any kind. I rounded the hole edges to a large radius and polished the hole smooth. The Dyneema soft shackle at the clew has so far lasted two seasons. It looks flat and squished where it contacts the casting and also the sail eye but doesn’t look cut or frayed. A soft shackle is just a loop and is easy to move so a different part of the line is contacting the casting.

I guess you could use a thimble to protect the Dyneema from the casting edges but then the casting will continue to wear. In this case you might as well just use a steel shackle.

The soft shackle I made is about 6 inches long (uses 24 inches of line) so replacing if it becomes worn is no problem. Much easier than fixing the casting.

Replacing the Topping Lift

Doug Farrand, NS30U, Toronto

douglas.farrand@gmail.com

Oct 8, 2024, 1:15:12 PM

I replaced the topping lift wire for my NS30 with Amsteel dyneema. It was an easy splicing project when the mast was down last winter and I was very pleased with the results this sailing season.

Doug Farrand, Corbeau NS30U 386

RCYC, Toronto

Tom Schoenhofer 26C#28 North Star Penetanguishene

tschoenhofer@gmail.com

Oct 8, 2024, 4:55:48 PM

I did the same as Doug. Replaced the heavy rusty coated wire topping lift two years ago with Dyneema. Very easy to splice and setup. No problems with the line.

Tom

26C #28 Penetana

Mark Powers La Reina 26C Vancouver, B.C.

rmp@shaw.ca

Oct 11, 2024, 3:41:39 AM

Bert, one issue with Dyneema is UV damage. Dyneema is fairly UV resistant however the degradation is not fully predictable. The company that makes Dyneema indicates 50 % loss of strength over 10 years however a boat in our area had some Dyneema rigging fail after 3 years. Practical Sailor has found that the U.S. only penetrates so far into the line however with the small size you would be using the U.S. could go all the way through. You can buy Dyneema with a polyester cover however that is much harder to splice.

If you go with Dyneema plan on checking and replacing it regularly.

You don’t want the standing portion of the topping lift failing when the sail is down. I was motoring back into port with the sail down and an inexperienced crew member released the topping lift by mistake. The boom caught me on the shoulder. Based on the pain, I am confident that had it hit my head at best I would have been knocked unconscious.

I that you discuss your options with Mike Quill.

Mark Powers

Brian M. Godfrey

brian@wildbirdshop.com

Oct 11, 2024, 11:13:54 AM

Yes, IV damage is a potential issue. When my mast was re-installed after the move in 2023 the rigger noticed rust seeping through the vinyl coating on the boom hanging cables. He suggested replacing them with Dyneema. I don’t remember the diameter that he recommended, but it was more than adequate for the weight. Still, I had him size it up to the next larger diameter figuring A: it would take longer to degrade to where it was weaker than wire, and B: the outer part created by the extra thickness would intercept most of the UV, leaving an inner part which would last much longer. (Being a woven line that last part might be bogus, but it was in my thinking at the time!) It wasn’t that much more expensive and it gave me more peace of mind.
He also said my topping lift was going to be due for replacement soon and I’ll probably go with Dyneema for that, too. But I will look into the polyester-covered stuff. If it exists then the techniques for splicing it must also exist and a good rigger should be able to do it. I’ll probably still oversize it, though. I think if my boom fell and hit my shoulder it would probably be the last time I ever used that arm. If it hit someone in the head it would kill them. Not worth going cheap on.

–Brian M. Godfrey
Vela, NS33 #77, San Diego

[SVHippo (Colle Bustin)]

Dyneema is a great replacement for most everything, the price difference between traditional polyester double braids and Dyneema core lines is less than ever.

Everything on Hippō is Dyneema or Vectran with either polyester or a combination of a poly and a technora mantle.

Life lines - Amsteel

Topping life - Amsteel with a 4:1 low friction ring set up (will soon become a 2:1, the added friction isn’t worth the gain and loss of travel)

Wishbone hangers - Amsteel

Main sheet, reef lines, flattener (with a 2:1) and choker are all Dyneema cored lines.

The short choker line around the mast is 12mm
Vectran V-100 with an up sized block.

Colle

[SVHippo (Colle Bustin)]

More photos. Life lines etc.

[SVHippo (Colle Bustin)]

New deck organizers are in the works but Antal has had them “in production” since November 2024…

[NS233 (Bob Neches, Me Gusta, Nonsuch e26U #233)]

I’d promised to post about reworking my choker line using dyneema.

Here’s the problem with my original hanging block set-up in the picture below. Note: the lines you’re seeing are all polyester-covered dyneema EnduraBraid, the problem is that the adjustable knots used to hold them have slipped. So-called adjustable knots are effective only if they are continuously loaded. Intermittent loading, e.g., a heavy wishboom banging around, cannot be handled this way. In addition, the cheesy installation of block #1 was wasting a lot of room for boom adjustment. Due to the slippage, the choker line through the block #2 was too low and too far from the mast. This wastes a lot of energy pulling the forward end of the boom down instead of back.

Let’s contrast this with the revised solution using dyneema in a combination of splices and lashings. This solution also takes advantage of the slipperiness of dyneema to use low-friction rings to replace the two turning blocks. This allows pulling them much closer and in-line with where they ideally belong.

Taking a closer look at the ring replacing block #1, you can see that lashing the ring tightly in brought the line a good 6-7" closer to the boom fitting.

Meanwhile, the ring replacing block #2 is now held vertically by a fixed-length of dyneema fastened around the ring. Not shown in the picture is that the other end had an eye-splice, allowing the vertical positioning line to be luggage-tagged to the eye up the mast where the boom hangers terminate. It cannot slip or grow in length. The horizontal positioning of this ring is managed by piece which is looped and lashed, which also is unlikely to slip.

This second turning ring is, I estimate, a good 8-10" closer to the mast. In total, I believe I’ve gained a good 12-18" additional fore-and-aft adjustment range for my boom. This will let me put a longer lashing on my sail clew. That, in turn, will allow me to keep the aft end of the boom further back where it’s less likely to bonk the helmsman, without losing the ability to flatten the sail as much as I please.

These pictures were taken when the choker tackle was quite loose. Just by coincidence, the transition where the choker line’s outer cover was stripped fell right at the ring when this was taken. In ordinary use, the slippery uncovered dyneema would run through the ring, and the higher-friction covered part would end up below the ring. [Correction on 2025-03-17T07:00:00Z: I made a rookie mistake when I wrote these words on Feb 19. Actually, the tackle was tight, the dyneema line going through the friction block had no cover, and I have no explanation for the difference in texture above and below the friction ring.]

I regard this as a nice illustration a number of different points: the advantages that can be gained from slippery dyneema, the use of covered lines for chafe protection, and the when/why of several different techniques of attaching the lines (splices, knots, lashings) that make sense in different circumstances. [And the correction above is a nice illustration of a feature in Discourse not available in the Google Discussion Group.]

The basic plan was mine, except that I’d proposed to use conventional blocks. My rigger’s contribution was pointing out that low-friction rings would work even better. And, of course, he also provided a much higher grade of workmanship than I’m able to deliver.

– Bob
Me Gusta
Nonsuch e26U #233

[SVHippo (Colle Bustin)]

Hello,

I’m interested did your boat not have a check block on the mast for the checker to go through (similar to your #2 block.)? Or did you eliminate it?

Also, a couple of years ago I did some testing of hanger lengths when I replaced them with Dyneema. I opted to actually shorten them by a few inches. This did two things; it add down pull to the chocker that seems to stabilize the front of the wishbone from moving around. (More of a tripod) and since I raised it I get much better sail shape especially when reefed as the wishbone get more “level” at reef 2 and 3.

I’d be interested in others experience, i believe the 324 has a steeper angle on the wishbone. Probably similar to what I have now. Obviously the mast is also taller but was that the only reason for the change?

Thanks again,

Colle

[NS233 (Bob Neches, Me Gusta, Nonsuch e26U #233)]

Colle,

My N26 has a non-standard carbon fiber mast that was installed by a previous owner. He had to replace the original aluminum mast after bending it during a race in San Francisco Bay.

The hanging block arrangement is a result of that change. The new mast didn’t come with a cheekblock on it. I don’t know how this is handled on the newer Nonsuch models which came with carbon fiber as original equipment.

Having dealt with chafe problems from that turning block on my first Nonsuch, I was glad for the change.

I don’t have any data to back my bet on the relative position of the turning block vs. yours. However, my instinct is that positioning the block below the boom effectively turns the boom into a lever where the fulcrum is very close to one end. That would make trying to lift the back of the boom like trying to lift something at the long end of the lever by applying force to the short end – the opposite of how levers work best.

So, my inclination has been to try to position the turning block in line with the boom. My reasoning is that this way, all the effort serves to move the boom fore and aft. To adjust sail shape by changing the boom angle, I instead rely on the four-part purchase of my topping lift.

The 324 may have a steeper angle on the wishbone. Mark Ellis designed all the boat models with the intention that the wishbone angle would be determined by the aspect ratio of the sail. Here’s a picture of the comparative aspect ratios:

It illustrates that N22s, N26s, and N260s have slightly higher ratios than N30s (and thus have slightly sharper angled booms). You’re right about N324s being a bit higher than the N30. N324s are, in turn, also slightly higher than the virtually identical angles shared by N33s, N354s, and N36s.

– Bob
Me Gusta
Nonsuch e26U #233

[SVHippo (Colle Bustin)]

I agree that the down angle is bad if you are thinking of it as a lever and expecting to lift the aft end of the wishbone. It would never do that effectively and that wasn’t my goal.

At least on my sail the clew of each reef is slightly higher than the previous. So every time I put a reef in the wishbone becomes a bit higher and more level and reduces its down force on the sail.

My issue was I wanted more “vang” vs “outhaul” and both are the choker on our boats. With the full main up things were ok but especially with a reef I couldn’t keep enough leach tension. By raising the front it keeps more leach tension in relation to the foot tension. Allowing for better preference especially when I am reefed.

Thanks again,

Colle

[SVHippo (Colle Bustin)]

In a perfect world I’ve considered making the hanger adjustable. That way I could control the outhaul vs vang ratio depending on the point of sail. But, I haven’t came up with a good way of doing this given that one hanger takes more of the load depending on the tack or gybe you are on.

Colle.

[jonlewit (Jon Lewit - N26C #115 - Inua - Kingston, NY)]

(copied from INA Google Group)

Thor Powell, Nonsuch 26, Victoria BC

Here is an interesting discussion of the use of Dyneema . My concern regarding the choker is the lack of stretch. Sailing is a very dynamic thing and some flexibility is necessary to prevent damage from the shock loading. And from the article sun damage can vary exponential with latitude.

For a while it was popular to replace the lever shocks on older British cars with the more modern and reliable tube shocks we see now. Ops not so fast. The body design was not built to withstand the increased loads these tube shocks created .

Standing rigging like topping lifts and boom hangers where wire was used dyneema makes sense with proper precautions.

When Should We Retire Dyneema Stays and Running Rigging? - Practical Sailor

[Rob (Soave - N33 #009 - Westport, CT)]

Bob, Thanks for the post. It took me a bit to visualize your comment about the clew lashing.

Your explanation highlighted how the clew lashing length provides a way to optimize the range of adjustment your choker has on the sail. Probably a handy adjustment as a sail ages. My current sail is pretty old and I was thinking lashing would allow me to secure the clew a few inches closer to the aft wishbone casting. A shorter clew lashing means I wouldn’t need to pull the wishbone as close to the mast when flattening ( and flattening seems to be important for Soave as she develops weather helm.

Many Nonsuch boats including Soave use the original (more prone to wear) method of a clew shackle (which is on my todo list). You’ve inspired me to move this up on my list of things to play with next summer.

I noticed some discoloration near your hanger padeye. Next time your wishbone is down you may want to remove Me Gusta’s pad eyes to inspect the area of the wishbone they cover. On Soave the corrosion was worse under the paddeye. ( I documented what I found in a google album HERE )

Thanks again for your explanation got me thinking about next summer on Soave.
Rob…

[SVHippo (Colle Bustin)]

Out of all the lines on a Nonsuch the chocker is the lest likely to be a shock load concern. Even the topping lift is more likely to take a high load as the wishbone bounce.

Yes, high tech lines can increase loads on other part of the boat… but that’s not a reason not to use them it’s just a reason to consider your other week spots.

Colle.

[jonlewit (Jon Lewit - N26C #115 - Inua - Kingston, NY)]

From Facebook - with a Thank You to Norm Neiderer

Tis is a great article on Dyneema

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.

By

Darrell Nicholson

Published:March 3, 2025

(link not provided to content under copywrite - not sure of the rules - google Practical Sailor Dyneema)