Anchor rope - Nylon vs Polyester

[slug]

Originally Posted by rslifkin

I've thought about it, but I'm not cruising in areas with coral or lots of rocks on the bottom, etc. So I can't see needing more than 75 feet or so of chain for abrasion resistance.

As far as the boat, it's a planing hull powerboat. Putting 350 feet of chain in the bow vs 75 feet + 300 feet of line is an extra 250 lbs. On this boat, that much extra weight up forward is noticeable in terms of performance when running on plane. As in every 150-ish lbs added up forward costs about 0.1 kts at a given engine power setting. So I'd rather not carry around more chain than I need. Of course, if I were cruising in areas with coral, etc. I'd carry more chain because it would be necessary.

Everyone must decide what is best for their situation

A troublesome feature of rope is when anchored in a wind against current scenario

The boat may sail over its loaded anchor rode causing the rode to become tangled on keel, rudder, strut ...always at two in the morning

With chain..catenary ..this never happens

To defend against this , when using rope , many folks use lead core rope ..sink line

I don’t know how this lead core rope behaves on a anchor winch

You might ask around for insight

[Breaking Waves]

Originally Posted by Jim Cate

The chap reporting that dacron felt like chain is delusional IMO.

lol.

I think this is our own Thinwater. Who may be many things but I don't think delusional is one of them.

He does tend to anchor quite shallow (multihull) and uses quite short rode, which means relatively little absolute stretch length. You need more elastic fiber if you are using short length.

Polyester just has different trade-offs vs nylon. It's fine so long as you understand that. It will chafe less, which is a common failure mode for nylon. It does not have the internal heating/strength loss that nylon has, but I have never really known how big a problem that was for our recreational yachts - Samson has told me they think it is only a potential real-world problem for quite big diameter line (like over 25mm). And it does have less elasticity (apples to apples) but if you use enough length it has practically speaking enough absolute elasticity.

I will also comment that if you go to most of the rope manufacturers websites and look at their recreational anchoring line pages . . . . you will see pretty much all nylon options listed ... new england ropes, samson (scroll down to anchoring tab),marlow, yale. It leads one to believe that for our application the manufacturers tend to believe nylon (with plait construction prefered) is the best choice.

This (the mfg material recommendation) does change when you get to ship size anchoring/mooring, and when you get to storm mooring buoy pendants. It those two cases the recomendation shifts dramatically to chafe resistance over elasticity, with uhmw being a top recommendation with polester (and polelfin blends) second (and nylon pretty much bottom on the anchoring/mooring list for ships).

[donradcliffe]

I think that the catenary effect with chain would give about the same damping effects as polyester line stretch. I do know that polyester docklines are a bad idea.

I'm in the all chain camp with Slug. I got to experience a nylon/chain rode wrap around the keel this year at sunset and it wasn't pretty. That case was complicated by a mis-sized gypsy that wouldn't grip the nylon and made the chain jump.

A boat I am mentoring to go RTW (Adventureman Dan) also had a keel wrap last year in a tide against wind situation. Between that and the future coral anchorages he saw the light and is now all chain.

[rslifkin]

Keel wrap is definitely a concern on a sailboat, but not so much for me. I don't have much of a keel and the back end of it is a good 30 feet from the bow roller. Plus, it's shaped in way that it would be unlikely to snag a line anyway (and it's only 3'3" below the surface at its lowest point). The first real snag point is the props, about 35' back from the roller (and 3'8" down).

[Vasco]

Keel wrap can easily be prevented with a weight looped around the rode at a depth below the keel. Use a 5 lb weight ( plastic covered dumbbell is best) tie a 7 ft line to it and a loop around the rode make the line fast to a cleat at slack tide this will keep the rode up and down in the water and clear the keel.

[MJH]

Originally Posted by Tonny9

What fact have I overlooked?
If you read various books and articles, most people prefer nylon anchor ropes instead of polyester.
I consider polyester to be the best anchor rope, except for the stretch.
So, if you could get a polyester rope with stretch like nylon, or almost like nylon, then this would be the best anchor rope.
So far, I think everyone agrees.

In the last book I've read, Rigging modern anchors, by Drew Frye, he writes that he almost experiences polyester rope as a chain, just without the catenary effect.

If I look at Liros anchor rope in polyester, then it extends 15% at max workload.
Their corresponding nylon rope extends 20% at maximum workload.

It's not that big a difference and a stretch of 15% should be plentiful in most cases and certainly don't make the rope feel like a chain without catenary effect.

I am convinced that Drew Frye has experienced what he writes, and I am convinced that the Liros writes is correct.

So, I must ask the question, what facts are I not knowledge of?

Is all polyester rope perhaps pre stretched in the United States? And therefore, with significantly less stretch. Has Liros done something special?

Apparently, there are far more Europeans than Americans who prefer polyester as anchor ropes.
Maybe there's a good reason for that?

Does anyone have an idea why there seems to be this different view?

Don't overthink the options. You want stretch in an anchor rope and nylon gives the most...end discussion.

I moor my boat to a buoy 24/7/365; saves me a lot of money versus the marina. It is a three legged system and each leg is 300' of three strand 3/4" nylon...I get a lot of stretch and that is what I want in 60K winds...I can see the boat move up and back as the wind changes. With time I also get plenty of catenary as you would not believe the amount of sea growth on the lines.

However, on the boat I have 300' all chain...best way to go there.

~ ~ _/) ~ ~ MJH

[roland stockham]

Not sure where your figuers com from but 20% stretch in nnylon rope seems a bit low. Figuers I have seen are more like 30-35%. In anycase using the correct nylon rope will give very much higer shock load performance than any polyester. Normal one for anchoring it 8 plait, chefly because, it handles so well and splices easily. There are core/braid constructed ropes that would work and have very good chafe resistance. Ropes designed for climbing world be fine for small boats but only go up to 11mm. 3st laid rope is a pain for anchor roads, goes very stiff and has to be coiled not flaked so wont store in an anchor locker. Performance is significantly lower than 8 plait as well. The test you should ideally look at is the drop test. You set up a jig that allows a weight to fall twice the sample rope length then record the number of drops before it breaks. Low stretch polester rairly survives 1. High stretch pollyester may be 2 or three. A good nylon will do 8-10. I think his test is far more relevent to the snubbing shock loads you get at anchor than any static break test or stretch measurment as it measure energy absorbtion directly. If you want solid reseach on rope properties have a look at vertical access data. Health and safety ensures there is lots of good quality reasearch.

[Jim Cate]

I think this is our own Thinwater. Who may be many things but I don't think delusional is one of them.

He does tend to anchor quite shallow (multihull) and uses quite short rode, which means relatively little absolute stretch length. You need more elastic fiber if you are using short length.

I don't remember who made the statement, but yes, a reasonable length of rode is needed to supply adequate stretch, and "reasonable" is a bigger number with dacron than with nylon!

I'm not a believer in huge stretch in rode or snubber for the reasons posted upthread. The rubber band effect is real, and in my opinion, can lead to increasing the peak inertial loads on the anchor rather than reducing them.

And FWIW, I've used all chain rode ever since starting serious cruising. Rope is for kedges and short, attended anchoring spells... like lunch stops. And no matter if you think your cruising grounds are free of potential snags and chafe spots. The bottom is littered with debris in lots of places, and some of it is sharp. I remember back in the late 70s when within a short period two boats went on the beach in Monterey, CA when their rope rodes were severed... in a nice sand anchorage. A diver then discovered a bit of steel debris sticking up vertically from the bottom... with a nice sharp edge on it.

I like chain!

Jim

[Don C L]

I admit my better self has told me often to spring for more chain, though the extra weight forward, at least in my little boat, is not an appealing thought. Since I pretty much know what’s below me when I’m anchoring I have reassured myself all is well, and so far I have been right and my nylon has come back up un-chafed ...so far... but Jim’s admonition has inspired me to get off my rear... especially if I want to venture to unfamiliar anchorages...
counting my pennies now for that new chain...
darn you Jim!

Now for that cut in the cabin sole to stow the chain on the keel on the longer stretches....

[SVPP]

I have 400’ of 10mm short link high quality chain and 300’ of 7/8” nylon.


When I have my chain out and no nylon, I use an12’ 7/8” nylon snubber.

My boat is 37’ long and weights 10t

I replaces the 25mm poly with the nylon because the poly floated and the nylon didn’t. The nylon also fits though the deck hole into the chain locker.

Nylon is harder to splice a chain to rope splice as the strands don’t sit back in the grooves of the rope nicely as they tend to not have the memory of the poly which plays nicer. So had to use a simple splice instead

I use the poly now for a tow rope, and the last 300’ for the droge.

I would have put up with the poly but I snagged the nylon new on gumtree for $50 aud.

Works well with my CQR and tigress anchors winch. Never had a problem.

My mooring has poly because of its abrasion resistance properties and it floats. A good thing when someone runs over your bout and you want the rope to pop up.

[CarinaPDX]

There is one application where a low-stretch rope rode is highly desirable: bow-in Med moor, for the stern anchor. If done properly the stern anchor will be some distance back, and the bow will be close to the quay (say a meter or so). In this case stretch can put the bow into the quay with onshore wind (waves are rarely an issue in harbor). All chain is not practicable for a stern anchor, and the catenary would have the same effect anyway. I have a roller with polyester double-braid line at the stern for this and it has served well.

While most modern boats go stern-in my barn door rudder precludes doing that in many cases. The deepest part of Carina is the aft end of the keel, and then the rudder itself, and often there is some fill alongside the quay that prevents her from getting close. Anyway I have found stepping off of the bowsprit is easier than climbing over the stern and rudder, which usually requires a plank.

Greg

[Gaia]

Originally Posted by Jim Cate

I don't remember who made the statement, but yes, a reasonable length of rode is needed to supply adequate stretch, and "reasonable" is a bigger number with dacron than with nylon!

I'm not a believer in huge stretch in rode or snubber for the reasons posted upthread. The rubber band effect is real, and in my opinion, can lead to increasing the peak inertial loads on the anchor rather than reducing them.

And FWIW, I've used all chain rode ever since starting serious cruising. Rope is for kedges and short, attended anchoring spells... like lunch stops. And no matter if you think your cruising grounds are free of potential snags and chafe spots. The bottom is littered with debris in lots of places, and some of it is sharp. I remember back in the late 70s when within a short period two boats went on the beach in Monterey, CA when their rope rodes were severed... in a nice sand anchorage. A diver then discovered a bit of steel debris sticking up vertically from the bottom... with a nice sharp edge on it.

I like chain!

Jim

I think Jim put it best as in the above quote. We favour and only use chain. 3/8 inch. Great caternary. In the Marquesas, French Polynesia, we set a rarely used stern anchor in an all sand anchorage and nearly chafed through its brand new 5/8 inch nylon rode on we know not what. Just as in Jim's tale. Likely debris. Thankfully the main anchor, a Spade, was on all chain as always.

Jim SV GAIA

[Siberian Sea]

Although I use all chain, the question was poly or nylon. Given consideration for working load limits only either one will do is you choose the correct line but my personal experience lends me to lean towards the nylon because I like my anchor line to sink, the overall greater elasticity to absorb any shocks but most of all nylons much better ability to withstand harmful UV rays. No matter, like I said either one shall work.

[rslifkin]

There seems to be some confusion here between Polyester and Polypropylene rope. Polyester is more UV resistant than Nylon and sinks like Nylon. Polypropylene is the (much weaker) stuff that floats and degrades badly from UV.

[jmschmidt]

You pretty much answered your own questions. If it concerns you further you could use a snubber on the polyester and/or send a weight down the anchor line on a messenger to create a catenary effect. But that won't be the same as a couple 150 feet of chain laying on the bottom.

In my view the more stretch the better. Europe doesn't typically have Cat 5 hurricanes.