Estimating remaining strength of poly anchor line

[Mako]

Is there a table for estimating the remaining strength of poly line that is beginning to degrade? My line is one year old (exposed to sun and in shade, both) and now has a chalky finish to it.

 

[siestakey]

My guess would there is no good way to estimate

plenty of engineering labs here in the states that do sample testing ( Driggers engineering in the Tampa bay area)

to do this they normally want want 3 18" section ( of course now line is shorter)

they will do a test on all 3 and give you the results

 

[RickB]

UV degraded poly(ethylene if that is what you mean) line is hardly worth keeping. It forms little needles that pierce the skin and can cause infections when handled.

Why even bother with it since it is the cheapest line you can get aside from the stuff made of old shopping bags and cellophane.

 

[caltexflanc]

Agree with Rick; nothing good can happen from here on out... get rid of that stuff.

 

[Mako]

Here in the middle east, and in southeast Asia, it's just about all that's available. Nylon is hard to find and is way expensive.

I have to admit that I like floating my line off the sharp limestone rocks and outcroppings in this area. Of couse I compensate with an anchor double the normal weight plus a short length of heavy chain. Has worked fine for me up to 30 knots.

 

[CPseudonym]

Here in the middle east, and in southeast Asia, it's just about all that's available. Nylon is hard to find and is way expensive.



I have to admit that I like floating my line off the sharp limestone rocks and outcroppings in this area. Of couse I compensate with an anchor double the normal weight plus a short length of heavy chain. Has worked fine for me up to 30 knots.

I've heard similar stories from a couple of members who cruise the Philippines. I wonder why nylon is so hard to find and expensive when you do in those regions?

BoatGM is a screen name to search past posts for in the "advanced search" function. Believe he posted some info about a rule of thumb for judging strength in older polyethylene anchor line once. There is another member with either AK or Alaska in his screen name that also cruises the Philippines and may have posted that information.

 

[Mako]

The line is chalking but not "splintering" yet. I suppose I'll just keep an eye on it and when it degrades more then just will cut that section of line out.

 

[Mako]

I've heard similar stories from a couple of members who cruise the Philippines. I wonder why nylon is so hard to find and expensive when you do in those regions?

I don't know the answer about availability except to say "that's just the way it is." Bad answer, I know.

I just returned from Vietnam and chartered a 100 footer. All the boats of this size, which anchor every single night, are setup:

• Manual drum winch reel;
• Big admiralty anchor of (estimating) 150-200 lbs;
• No chain at all;
• 1 inch+ diameter poly, usually in poor shape.

Seems to work ok for them.

 

[psneeld]

Really depends on the "poly".....

Tow Bridles | Towing Lines | Mooring Lines and Hawsers

 

[Mako]

To clarify, I'm referring to good ole fashioned polypropylene.

 

[Ski in NC]

Figure out a way to load the line and see how it holds. Of course take precautions to prevent damage should it part...

 

[psneeld]

Not sure I would trust poly for other than towing a lightweight dingy.

The standards to which it is made would need some investigation in my mind. I have seen large diameter poly used in some commercial applicstions...but it is always new and probably checked regularly. I think the local clamp boats use it on their hydraulic dredges, and that is definitely a pull test.

But......

I watched a tug of war between cub scouts, 50 or so on a team, part poly that was 4 inches or so in diameter. I melted through at the parting point...looked like it had been cut by a hot knife.

A factory flaw maybe? As I have a hard time believing there was that much pull on it as kids were sliding, slipping, falling, etc all along each side....

Thus my distrust in even checking a small porion as it may have a flaw in the middle...

 

[Mako]

I realize that polyprop isn't much respected as an anchor line for so many reasons, but I really prefer a floating line. Are there other materials out there that might fill the need better?

 

[psneeld]

Nylon with floats...but you say nylon is not really a choice.

How do you deal with stretch/shock absoption? Many synthetics have limited stretch....so pick you poison with that in mind to.

 

[Capt.Bill11]

Is there a table for estimating the remaining strength of poly line that is beginning to degrade? My line is one year old (exposed to sun and in shade, both) and now has a chalky finish to it.

It's so cheap to replace I would think nobody would bother creating a table like that.

 

[Mako]

It's so cheap to replace I would think nobody would bother creating a table like that.

At this point I agree with you and will give up on trying for a "technical solution." I suppose it's the engineer in me trying to overthink things.

 

[FF]

Find a sailor and give him a gift.

Polly line makes great BAGGYWRINKLE.

 

[Mako]

Find a sailor and give him a gift.

Polly line makes great BAGGYWRINKLE.

I always thought manila was best.

 

[RickB]

Find a sailor and give him a gift.

Polly line makes great BAGGYWRINKLE.

Anything but poly line ... if nothing else in that application it has more surface area exposed to the sun to turn into rotten needles and dust.

 

[FF]

For many sailors, FREE would out weigh its constant shedding.

Most would not hit the deck in a breeze.

 

[Mako]

For many sailors, FREE would out weigh its constant shedding.

Most would not hit the deck in a breeze.

To clarify my earlier statement, all the big boats I saw in Vietnam and Thailand were using 8-plait polypropylene. Usually this is a mooring rope. Not ideal for anchoring, but really inexpensive and readily available in those areas.