Can someone tell me why this 5/8 double braid line has a much lower breaking strength than others?

Amarine Made 5/8 Inch 25 FT Reflective Double Braid Nylon Dock Line
it is saying 7700 pounds
I have seen double braid in 5/8 for like 10,000 or more pounds. Some say 13,000 pounds

Is it not an issue or what is the reason.

Example this one is 9500 pounds, why?
Amarine Made 4-Pack 5/8 Inch 25 FT Double Braid Nylon Dockline,Mooring

Then this one is 13,500 pounds, a massive difference. why?
WEST MARINE 5/8" Prespliced Double Braid Nylon Dock Line 4-Pack with Bucket | West Marine

Is a rope with a higher rating going to last longer?

 

5/8" x 300' Reel, Double Braid Nylon Rope (e-rigging.com)
Has an expandable chart.
Their DB nylon rope of 1/2" has same breaking strength as the larger 5/8 of the other company.
I did watch their instructional rope video, and was mentioned many nylon ropes now have added polyester yarns into the nylon rope, so creating a blended mix. Is that a possible reason for the large difference in breaking strengths? As in more polyester mixed into the nylon rope versus pure nylon rope?
video here
Rope (Soft Rope/Fiber Rope) (e-rigging.com)

 

Not all plastic is equal. Not all mfgs are equal. As bulk purchaser annually of more cordage than I'd like.... I bet if you held them in your hand you could answer the question just holding them.

Our domestic maker has been absolutely surpassed by the Japanese, Indian and Portuguese cordage. My most consumable cordage is a 7/8 inch line. They run through a hauler and it takes about 2x days to find its true working diameter. The Japanese has almost no shrinkage from new. The Garware will need to have 2 shims from the hauler pulled as it wears. Unsurprisingly they have rather disparate breaking strength for similar chemical composition and relative starting diameter.

 

Some of the links are for dock lines with splices, and others are for plain rope. Where do the dock lines with splices fail? Does a dock line with a splice fail at a lower load than the plain rope it uses?

Are all published breaking strengths based on the same test criteria and procedure?

 

Is there only one domestic (US) of rope?

 

Of the variety we use, technically 2 but one hasn't had product out in so long its not relevant and quality was abysmal. Domestic companies make some really good cordage but in the fishing specific lines have been radically surpassed by the aforementioned countries. All things aren't equal, Korea still makes the best pva floats. And the USA makes the best webbing, up until recently the best sinking line as well. Recently the Portuguese put out a product that may be better.

All is a moot point, aside from the Indians nobody has any product on the shelf. My last order from Japan landed took 3 days shy of 11 months...

Like kind products can vary rather substantially. Even withing seemingly identical ranges that should be identical. Its not until a lot of it goes through your hands that you realize just how big a difference.

 

My sample is much smaller. I still have some domestic 3 strand nylon from a spool bought ~35 years ago. It is dense and wears very well. Most-all newer 3 strand feels loose compared. You know firm, dense rope will be stronger than the same size loose, fluffy rope of likely inferior material.
I'm not buying rope regularly but I've seen nothing better than that old New England Ropes.

 

They are made of different materials. Also, the percentage of fibers makes a difference; a tight weave has more fibers for the same diameter.

 

Some pics of recent Amazon rope dock line buys all double braid.
Top rope is ACY 5/8" 25 feet
Middle is Seasence 5/8" 35 feet
Lower is Amarine 3/4" 25 feet

Notice the weave for the middle rope is different, the other ropes have a much tighter weave and feel denser. The middle rope is also looser and softer feeling, so I suppose the other 2 ropes are better as perhaps more fibers went into the making? I have seen some advertised as 16 strand and some as 24 strand, is this an example of that?



Noticed this in the ad, except maybe the stranding has to do with the core, not the outer cover.

• 24 STRAND CORE; ACY Marine dock lines features a super strong 24 strand core that’s designed to withstand extreme forces; The durable core of this nylon boat rope means our dock line is ideal for mooring in all conditions; This boat rope is crafted to the highest standards, trusted by professional mariners