Lifespan of nylon mooring lines

[eddystone]

I have two 24mm nylon mooring lines with semi-rigid full length plastic sleeves. One is now nearly 6 years old and the other a bit newer (although can't remember which is which!). Should I think of replacing these at specific intervals? I know nylon is vulnerable to UV but we don't get much of that on the River Tamer.

 

[Refueler]

I have simple answer .... If I am questioning a ropes condition or use ........... I don't use it for anything that has consequences.

Nylon - mmmmmm that covers a multitude of ropes and depends on its real make-up. Pure nylon has no place in my inventory.

 

[eddystone]

I have simple answer .... If I am questioning a ropes condition or use ........... I don't use it for anything that has consequences.

Nylon - mmmmmm that covers a multitude of ropes and depends on its real make-up. Pure nylon has no place in my inventory.

Many people regard nylon as the optimum material for swinging moorings because of its strength and high stretch characteristics but it does deteriorate more than polypropylene under UV.

 

[Refueler]

Many people regard nylon as the optimum material for swinging moorings because of its strength and high stretch characteristics but it does deteriorate more than polypropylene under UV.

Trouble is ... "Nylon is a generic designation for a family of synthetic polymers composed of polyamides. Nylon is a silk-like thermoplastic, generally made from petroleum, that can be melt-processed into fibers, films, or shapes. Nylon polymers can be mixed with a wide variety of additives to achieve many property variations. "

Pure nylon without additions falls apart quickly into literal dust when exposed to environment. I remember a guy who had a boat along from mine in UK ... chatting one day - I noticed he had brilliant white lanyards on his fenders .... he calmly said - yes nylon , nice aren't they. I mentioned casually that nylon as that was not so good out in the weather ... we smiled and carried on enjoying Sundowners .....
Number of weeks later - I noted same boat with some different fenders and lanyards ..... spoke to guy .... nylon lanyards have disintegrated and he lost some of the fenders .... He admitted he dismissed the idea that Nylon was in different forms and that nylon as used in anchoring etc. is not just nylon - its a formulated version ...

 

[Motor_Sailor]

The original poster said his mooring lines were 6 years old not 60.

Any manufacturer producing ropes 6 years ago is not going to be using a pure version of nylon whose short coming were known about in the 1940s. The UV susceptibility of nylon ropes is wildly stated but there is very little qualitative guidance as to life span of said ropes subject to UV as the nature of the 'exposure' can be so variable, as well as the thickness and construction of the rope itself.

Ultimately you are left with a risk / cost / benefit analysis.: How much is new rope to buy versus the cost of the vessel and your peace of mind?

 

[Refueler]

Your quote :

Ultimately you are left with a risk / cost / benefit analysis.: How much is new rope to buy versus the cost of the vessel and your peace of mind?

My earlier quote :

I have simple answer .... If I am questioning a ropes condition or use ........... I don't use it for anything that has consequences.

OK ??

 

[johnalison]

Many people regard nylon as the optimum material for swinging moorings because of its strength and high stretch characteristics but it does deteriorate more than polypropylene under UV.

I thought it was polypropylene that was the fastest to deteriorate but polyester that most of us use.

 

[Pye_End]

2 independent lines; reasonable diameter. If you lose one you still have the other attached? Chafe probably more likely to be a line killer - worth having a good look, especially at the ends of the plastic sleeves and attachment to ring. Otherwise, if it helps you sleep at night then replace one or both.

Personally - I use polyester for permanent lines, and nylon for visiting. The spring in the nylon just doesn't last long enough in permanent lines to warrant the benefit.

 

[penberth3]

Your quote :



My earlier quote :



OK ??

OK, but you drifted off into the realms of fantasy.

"Nylon" is a trade name, there are different "nylons" and anything you buy now should be fit for purpose.

 

[Graham376]

I have two 24mm nylon mooring lines with semi-rigid full length plastic sleeves. One is now nearly 6 years old and the other a bit newer (although can't remember which is which!). Should I think of replacing these at specific intervals? I know nylon is vulnerable to UV but we don't get much of that on the River Tamer.

Six years old and you can't see the condition because of the sleeves so I think it's about time to replace. I gave up using nylon years ago and now use 2 x 24mm polysteel which I change about 3 yearly although they still look fine, just to play safe.

 

[James_Calvert]

I have a couple of nylon mooring lines from an erstwhile fore and aft trot mooring arrangement some 30 plus years ago.

Still use them occasionally, last time used one to pull out a tree stump with a Land Rover.

 

[Refueler]

I have a couple of nylon mooring lines from an erstwhile fore and aft trot mooring arrangement some 30 plus years ago.

Still use them occasionally, last time used one to pull out a tree stump with a Land Rover.

We pulled a stump at a Plant Nursery years ago with a rope .... when rope snapped - nearly took head of the tractor driver.

Ship ST Zaphon entering Curacao Wiilemstadt... harbour tug line parted and destroyed half the bulwarks and frames one side of bow.

The power of a rope - particularly synthetic when it parts is unbelievable even in small sizes we use. Its why if I'm pulling a stump or anything other than towing a car already on the road ... I make sure chain is included or used completely. That way chain helps control any 'flyback'.

Just saying.

 

[AngusMcDoon]

I thought it was polypropylene that was the fastest to deteriorate but polyester that most of us use.

It is. It turns to dust in a few years. Polyester lasts outside in our latitude for at least a decade.

 

[James_Calvert]

We pulled a stump at a Plant Nursery years ago with a rope .... when rope snapped - nearly took head of the tractor driver.

Ship ST Zaphon entering Curacao Wiilemstadt... harbour tug line parted and destroyed half the bulwarks and frames one side of bow.

The power of a rope - particularly synthetic when it parts is unbelievable even in small sizes we use. Its why if I'm pulling a stump or anything other than towing a car already on the road ... I make sure chain is included or used completely. That way chain helps control any 'flyback'.

Just saying.

I was a little cautious about where the stump itself might fly....so not a direct pull. Your warning is well made.

 

[thinwater]

Using nylon to pull a stump is rather like using mole grips for a hammer. Wrong tool for the job, no surprise about the outcome.

Dyneema is probably the best bet; less mass to recoil, and is the material of choice in this modern age.

 

[William_H]

Some time back I had a length of I think polypropylene crayfish pot rope 3 strand. (about10mm diameter) I needed it for a temporary anchor on an old fishermans anchor in weed. (small boat)The rope looked lovely if a bit bleached white . It did however part under not much load. In the middle of the night and recovery and re connection was another story. I brought the rope home and tied it to the car and a pillar just to make sure it was not a weak point where it parted. Sure enough i was surprised just how little strength it had. The moral of the story being polypropylene does deteriorate in UV and not just on outside but apparently right through.
If OP is talking swing mooring bow line then just multiply the lines. I use 3. One problem with swing moorings is that another boat can come adrift and end up pressing on your bow lines chafing through. ol'will

 

[Refueler]

People do realise that the main mooring lines used on ships for years were and are Polyprop ?

The use of wires and 'Titan' ropes are additional. Even wires usually have a Polyprop pendant for actual passing over bits ashore

 

[Stemar]

Polysteel is a UV-resistant polyprop which has the elasticity of ordinary polyprop, but lasts a lot longer. I use it for my mooring bridle (twin strops) and I'm more concerned about chafe than UV, but from that PoV, I don't believe it's significantly worse than any other rope.
From a supplier's website:
Polysteel mooring rope is extremely strong. In fact, it’s one of the strongest synthetic ropes currently available to buy. It doesn’t absorb water, but simply floats on its surface, and maintains all of its strength when wet. Despite the rope’s tough construction, it’s a relatively lightweight option and it offers superior handling comfort – gradually softening over time, with use.

It also benefits from:
high tenacity
low elongation
excellent resistance to abrasion and UV rays
resistance to acids, alkalines and oils

As a result of these useful properties, polysteel rope is particularly suited to marine-based applications – including mooring lines, towing lines, mooring pendants and fishing nets.

I used 12mm 3-strand nylon rope as mooring lines for Jissel (24', 3 1/2 tons) for several years - at least 10, and only replaced them because they were getting tatty, which may have been because of UV degradation or it may have been simple wear and tear, but they got to the point where it was obvious they no longer had the strength they had when new. They didn't fail, they were just at the end of their useful life. I'd be perfectly happy to use appropriately sized nylon for mooring lines on my new boat. Its main disadvantage is that it hardens with age.

 

[AngusMcDoon]

People do realise that the main mooring lines used on ships for years were and are Polyprop ?

The UV damage does not extend below the surface much, so a ship's mooring line is less susceptible than a small craft's line. For a (relatively) thin line left outside constantly its life is short, so isn't a suitable choice. Also what proportion of its total life does a ship spend in harbour moored compared to a typical leisure boat? 10% for the ship and 90% for the boat?