Nylon vs Polyester

[estarzinger]

Originally Posted by s/v Jedi

The Sundeer 64's came with 1,000' of 1.25" 8-plait nylon (from Yale cordage) and I'm still using it.

Nick, if you think polyester is better, why are you still using nylon?

Originally Posted by s/v Jedi

-> New England Ropes 3-strand Nylon stretches 11% at 20% of breaking load.

-> New England Ropes plaited (12-strand) Nylon stretches 2% at 20% of breaking load.

Things don't compute.

I believe we have discussed this previously in this thread - I posted some comparable correct numbers from yale and samson. There is an error in some of NER's nylon spec sheets. Someone did a cut and paste job from their polyester spec sheet and then did not correct the numbers.

[Kettlewell]

I still think it comes down to the fact that total energy absorption will be far superior in nylon line, and that is what you want in an anchor rode. You can compensate for some of nylon's deficiencies by getting the right quality, size, and construction. Take a look at this Yale Cordage white paper on why they think nylon brait makes the best anchor rode--it all comes down to energy absorption.

[s/v Jedi]

Originally Posted by estarzinger

Nick, if you think polyester is better, why are you still using nylon?

I'm using the Nylon because it came with the boat; I have it and changing to Polyester will cost me money. The fact that Polyester is better doesn't mean Nylon is bad... it's just not the most optimal choice. I mean, not all of us have Vectran halyards while they are better than what most of us have

Originally Posted by Kettlewell

I still think it comes down to the fact that total energy absorption will be far superior in nylon line, and that is what you want in an anchor rode. [...]. Take a look at this Yale Cordage white paper on why they think nylon brait makes the best anchor rode--it all comes down to energy absorption.

Hmm... I'm afraid you are reading that white paper the wrong way. Yale invented the 8-strand "Yale brait" and the white paper is comparing that vs 3-strand. Yale does produce a polyester version and they do acknowledge it's better. I quote some from the white paper below and used boldface to emphasize parts:

The rope specialists at Yale Cordage have pioneered a new product that radically improves the art and science of anchoring: Yale Brait anchorline. Nylon- and polyester-Brait sets a new standard for anchoring technology.
This paper will review briefly the evolution of anchoring technology, and then detail the superior performance characteristics and advantages of Yale Brait anchorlines.

The above quote shows they review Brait lines... both Nylon and Polyester.

Three-strand nylon line is not without its problems, however. The very act of stretching and retracting over many cycles generates heat within the fibers, which breaks down the physical properties of the rope, ultimately leading to failure.

Here they state that you should replace your 3-strand Nylon lines regularly because they deteriorate by absorbing energy (stretching).

Yale technicians pioneered a unique eight-strand weave. This new line is called Yale Brait. In 2005, Yale introduced a polyester version of Brait which delivers the same strength, plus additional abrasion-resistance.

And here you find that it is the 8-strand Yale Brait that solves much of the problems and the polyester version solves the abrasion resistance too, making it the ultimate choice (after chain that is)

Once the line becomes taut, Brait begins to elongate (stretch), absorbing up to 75% more energy than three-strand nylon line.

While I don't agree with the 75% figure, they do state here that the better energy absorbing figure is due to the Brait construction and not because of being made of Nylon.

They continue their white paper with recommendations for anchor rodes which is pretty worthless imo. They make good rope; I have this Yale Brait and other Yale Cordage products; but they don't know sh*t about anchoring.

In the end.. their white paper points out that a Polyester Yale Brait is the better choice

cheers,
Nick.

[Kettlewell]

That Yale paper mentions the existence of polyester brait, but all of the discussion about anchor rodes, including the charts and tables, refers to the "nylon brait" vs. nylon three-strand.

[estarzinger]

I can't find a Yale polyester brait or plait rope - does anyone have a link to such a rope. I see one is mentioned in their splicing instruction, but I then can't find it anywhere else on their (or any other) website. Did they used to have one and it has been discontinued?

[barnakiel]

Looked at Yale found nothing. No Gleistein representative where you are?

b.

[barnakiel]

Originally Posted by Kettlewell

Barnakiel, that is a product that is not readily available in the USA. Please reiterate (I may have missed it) why you use polyester instead of nylon. Thanks!

??? C'mon - it is the era of the Internet. Click and whatever your eye desires comes flying to you!

We use polyester because it stretches less and is more UV resistant. With our 50/50 system we never had any problem with too little stretch.

b.

[barnakiel]

Originally Posted by Kettlewell

Barnakiel, that is a product that is not readily available in the USA. Please reiterate (I may have missed it) why you use polyester instead of nylon. Thanks!

If US based:

USA

Gleistein Ropes Inc.
Stephen Michael LoPiano
3100 Brandywine Way
Bellingham, WA 98226

Fax: +1 360 230 2382
Mobile: +1 360 255 3667
Email: sales-us@gleistein.com
Not selling, just telling.

b.

[s/v Jedi]

Originally Posted by Kettlewell

I still think it comes down to the fact that total energy absorption will be far superior in nylon line, and that is what you want in an anchor rode. You can compensate for some of nylon's deficiencies by getting the right quality, size, and construction. Take a look at this Yale Cordage white paper on why they think nylon brait makes the best anchor rode--it all comes down to energy absorption.

Originally Posted by Kettlewell

That Yale paper mentions the existence of polyester brait, but all of the discussion about anchor rodes, including the charts and tables, refers to the "nylon brait" vs. nylon three-strand.

Exactly.. the paper compares nylon vs nylon and not nylon vs polyester, like you indicated in the 1st quote above. It shows that nylon Yale Brait has superior energy absorption compared to nylon 3-braid.

This quest for energy absorption.. I don't like it at all, and that's because it comes with a price I'm not willing to pay. Energy is never lost and it isn't absorbed by the rope at all... it is partly converted into a pulling force (like elastic) and the rest into heat which melts the core of the rope if done quickly enough, or it breaks down the integrity over time under easy conditions. With their 8-strand brait construction they might reduce heat by reducing internal chafing (converting more % of energy to pulling force) but it still weakens when it gets wet and is more vulnerable to chafing and UV damage than polyester.

That's why I advocate the use of a snubber. It's shorter and thinner and cheap and easy to replace when it's worn down. Let the snubber be the sacrificial part of your anchoring gear instead the expensive rode itself. It's how all the users of chain do it.. it works.

For ppl trying to find the Yale Brait... it's just right there, not hidden at all: Nylon Brait \ Eight - Strand Plaited Nylon Rope | Yale Cordage

cheers,
Nick.

[estarzinger]

Originally Posted by barnakiel

If US based:

USA

Gleistein Ropes Inc.
Mobile: +1 360 255 3667
Email: sales-us@gleistein.com
.

Thanks B. I think I will call them.

Originally Posted by s/v Jedi

For ppl trying to find the Yale Brait... it's just right there, not hidden at all: Nylon Brait \ Eight - Strand Plaited Nylon Rope | Yale Cordage
.

Nick, That's nylon. I at least am looking for polyester brait/plait.

[Kettlewell]

Yale tells me that the polyester brait for marine use is still being experimented with.

Couple of thoughts on energy absorption. I wouldn't want to jump off a bridge shackled to a chain--bungie jumping is much preferable because the energy of the fall is absorbed by the bungie. Same thing with a boat at anchor in severe conditions--you want that elasticty to absorb the energy rather than having it transmitted to your anchor and your boat. The less transmitted the better, I would think. That's why you use a snubber on your all chain rode, right? That's why you let out more snubber line when the going gets rough, right?

Sure, some of that energy is converted to heat within the line, but most of that rode is completely water cooled. How many of us have ever had a nylon anchor rode snap except maybe where the line had been damaged?

Again, I'm not saying that this heating/failure issue isn't real, just that it appears to be avoidable if you use heavier and longer lines in extreme conditions. In a hurricane always use multiple lines.

[CarinaPDX]

The "more stretch is better" philosophy has its limits. Imagine as your boat is sailing a bit back and forth on its anchor and a large wave hits the weather bow; the stretchier the rode the more the bow will fall off and the more beam exposed to wind and waves - and hence more total force on the boat and gear. Even if yaw is taken out of the equation, the extra movement aft can cause problems for those of us with transom-hung rudders. Just saying, too much of a good thing is not good.

[cfarrar]

It seems like polyester rode is not uncommon outside the U.S.A.

From a certain anchor maker's website:

Nylon

Nylon rope has become very popular since its introduction, and largely displaced many traditional types. It offers good shock absorption and good strength, and makes the ideal snubber. For small boats, it is appropriate as anchor rode if the lengths are not too long.

However, it has a number of disadvantages, particularly for use on larger boats. Its high degree of stretch can be more than is required for shock absorption, and can cause a boat to veer about undesirably. In gusty conditions, a boat can introduce a lot of stretch into the line – then, when the gust dies, the boat is pulled forward by the rope. When the next gust comes through, the boat has drifted up toward its anchor, and has a long distance to accelerate backward, thus increasing the force that the rode must again absorb and transfer to the anchor.

This higher stretch characteristic can also increase wear from chafe, simply because the rope moves more against fairleads and chocks. This also worsens when the rope is not dry – nylon can lose up to half its abrasion resistance when wet.

Finally, when nylon is 'cycled' at a significant fraction of its ultimate strength, high levels of internal heat are generated. This heat severely lowers the rope's physical properties. Moreover, it is worse still when the rope is wet. This is a key reason behind many anchor rode and tow-line rope failures which appear strange at first inspection, if chafe is not an issue and the failures occur well below the rope's rated strength.

Polyester

“ When polyester line is loaded to 20% of its breaking strength, it stretches between 2.2% and 2.9% depending on construction. Double braid nylon, in same situation will stretch 5.3% and three strand nylon 10%. ”
— Dave Strauss, Samson Ropes

For larger boats, or for very long lengths of rope, we recommended polyester over and above nylon, as it (at least partly) addresses many of the disadvantages of nylon.

Furthermore, with larger vessels, while some shock absorption is still required, a bungee cord is not, and too much stretch (particularly in gusty conditions) creates problems with the boat's behavior at anchor. Polyester offers more control of the degree of stretch a given length of rope will introduce to the rode. For more stretch, a longer length of polyester can be used. With nylon, a typical anchor rode is going to quickly introduce too much.

3-strand

Three-strand ropes tend to harden in the marine environment and becomes difficult to handle. They also tend to twist, and knot, under load. For a high quality anchoring system, other lays are preferable.

Multi-braid

Square, 8, or 10 plait rope makes ideal anchor rode. It is easy to handle and stows in less space than 3-strand.

[Kettlewell]

That certain anchor maker's Web site lays out a clear argument for polyester over nylon, though it seems to all be pure speculation. I wonder why then every major US rope manufacturer's Web site recommends nylon? I wonder why then every major book on anchoring and seamanship I own (I have a big library) recommends nylon, and in most cases 3-strand? But, most importantly to me, is I have not found these arguments to exist in the reality of my more than 30 years of cruising.

By the way, I don't know if it is relevant or not, but in the world of protective motorcycle clothing Cordura nylon is considered to be superior to cheaper polyesters because of a higher resistance to abrasion and melting. I have seen tests comparing these fabrics and the progression from best to least is: leather, Kevlar, cordura, polyester. I also notice that there are various melting points for various nylons, with some going higher than the melting points of some polyesters.

[s/v Jedi]

Originally Posted by estarzinger

Nick, That's nylon. I at least am looking for polyester brait/plait.

Ah, just call them then. I have ordered rope that they don't list on their website without problems... the site is more like a showcase, not the complete line of products.

Originally Posted by Kettlewell

Same thing with a boat at anchor in severe conditions--you want that elasticty to absorb the energy rather than having it transmitted to your anchor and your boat. The less transmitted the better, I would think. That's why you use a snubber on your all chain rode, right? That's why you let out more snubber line when the going gets rough, right?

The rope does not absorb the forces placed on your anchor and boat... it only absorbs the shockload and transforms this in a pull forward towards the anchor. Any (no matter how small) stretch in the anchoring system counters this shock load and I argue that a snubber is more than plenty for any size boat.

Sure, some of that energy is converted to heat within the line, but most of that rode is completely water cooled.

And that's the mistake most cruisers make. The water does NOT cool down the core... it makes the problem WORSE by increasing chafe up to 50% or so; a wet nylon rode that cycle loads gets damaged (much) more than a dry rode doing the same test.

Again, I'm not saying that this heating/failure issue isn't real, just that it appears to be avoidable if you use heavier and longer lines in extreme conditions.

If you do that you loose the stretch factor again. What is it that blocks you from using a snubber?! Do you have a reason for not using one? Using nylon during hurricanes is asking for trouble.

Originally Posted by cfarrar

It seems like polyester rode is not uncommon outside the U.S.A.

Exactly and the quote shows the reason that Nylon can increase shockloads which have to be absorbed again etc. I can't understand why people would want to use an anchor rode that gets weakened by using it, just to absorb some shockloads that can be absorbed by a snubber instead.

cheers,
Nick.