Load Testing Results

[Paul Elliott]

I would like to see tests on a Brummel eyesplice in modern single-braid. It seems that even with a good tail bury there would be more strain at the in/out points than there would be with a typical buried splice.

[estarzinger]

Paul, yes, I plan to do that . . .but there is a nice video test done by a chicago rigger that shows exactly what you suggest - the brummel breaks before the straight bury. They did not have a load cell (at least in the video), so we don't know how much weaker it is.

Back to dacron double braid for a minute - adding New England Ropes Stayset data.

Bowline still statistically equal to Figure 8
NER ropes breaking at lower % of rated strength, but that may be because they are using a different measure of rated strength. I have asked, and I will check with my own "full strength" breaks.
NER ropes appear to have lower stdev (perhaps higher quality consistency?)
The NER line is 2.33x times higher in (retail) price than the Samson LS

Bowline
Samson LS 1/4": 1582lbs, 83% of rated strength, 5% StDev
Samson XLS 1/4": 1582, 71% of rated strength, 3% StDev
New England Ropes StaySet 1/4": 1575lbs, 67% of rated strength, 1% stdev

Figure 8 loop
Samson LS 1/4": 1590lbs, 84% of rated strength, 3% StDev
Samson XLS 1/4": 1590lbs, 69% of rated strength, 2% StDev
New England Ropes StaySet 1/4": 1558lbs of rated strength, 66%, 1% StDev

[StuM]

> I think it will be worth looking at the other 'quick' bends like the ashley and zeppelin

I'd be very interested in the zeppelin - it's my preferred bend for most applications.

[Benz]

Hi Evans,

I use a sort of soft shackle with wooden toggles on my boat that I'd love to have you test (concerned about the strain on the toggle). If you PM me a mailing address, I'll be happy to mail you one to pull on, and the remnants need not be returned.
Happy New Year,
Ben Zartman

[estarzinger]

Benz - Pm sent to you.

Three Amsteel tests first thing this morning, and the bowline is a total FAIL on dyneema singlebraid.

Regular bowline slipped/slide at average 370lbs (15% of break strength)
Double bowline slipped/slid at average 750lbs (30% of break strength)
Double double* bowline slipped/slid at 950 lbs (38% of break strength).

* This is a bowline with two loops around 'the hole' and two loops around the standing part before the end goes in the hole.

[estarzinger]

Still amsteel . . . Figure 8 loop does hold, breaks average 44% of line strength (1100lbs in this case) 4% stdev.

[estarzinger]

Still on Amsteel - here is a bit of a surprise to me - Buntline hitch - FAIL - all slipped 385lbs, 15% of breaking strength. I first did buntlines on both ends, and the first two both slipped around the same pin end (which has a smoother pin) at around 385lbs. I then tied a firgure 8 around that end and a bunline on the other end and those slipped around 500lbs.

I guess we knew this . . . but you really need to use splices with dyneema!

[estarzinger]

So, for you "knot experts", are there any other loop knots worth testing in the dyneema? Is there a know that is easier to untie than the figure 8 but may not slip like the bowline? Or a knot that is less bulky than the figure 8 but will not slip like the buntline? Or do we just conclude "figure 8 or splice"?

[estarzinger]

Someone suggested the Alpine Butterfly as a no-slip knot for the amsteel..

It did not slip . . . 5 pulls gives an average of 1140lbs (45% of rated strength) statistically equal to the figure 8 (1102lbs, 44%)

[thinwater]

Originally Posted by estarzinger

Someone suggested the Alpine Butterfly as a no-slip knot for the amsteel..

It did not slip . . . 5 pulls gives an average of 1140lbs (45% of rated strength) statistically equal to the figure 8 (1102lbs, 44%)

Did you test that as an end knot or as a middle knot (this was commonly used back in the day as a middle man knot when climbing on easier ground)? Would a butterfly make any sense as a mid-point knot in a jackline system? Tied small, a biner would glide over it. If the line is large enough, the weakening might be acceptable. Risk of slippage doesn't matter much in this application.

Personally, I like fat jackline I can grab with my hand, but most don't. Hang-up could be irritating; probability depends on the biner and the line.

[B-Baysailer]

could you try a palomar knot tied to a shackle it works fairly good on spectra fishing line thanks

[estarzinger]

palomar knot . . . that's a new one to me . . .I will look it up and test it.

Here is a summary chart of the knots. I could not get any of the bends to hold/ not slip on the dyneema single braid, surprised that even the double fisherman slipped. . .will have to try the triple fisherman. There may be some fishing line bends I should try . . .any suggestions?

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I have a question into NER about their rated strengths. West marine shows completely different numbers than the NER spec sheets show. I have used the NER numbers, but unlike Samson they do not say exactly what they represent and I would like to understand them a bit better.

[estarzinger]

Originally Posted by B-Baysailer

could you try a palomar knot tied to a shackle it works fairly good on spectra fishing line thanks

You have a winner there. Thanks.

In endura12, breaking strength is 1510lbs (54% of rated strength) vs the figure 8 at 1144 (41%). That is a statistically significant gain.

That looks like a good 'replacement' for the buntline in tieing to shackles. It's only limitation is that you do need to be able to take the loop fully around the attachment - works for shackles but not for say installed padeyes.

[nigel1]

Was the Palomar knot easy enough to remove after the load test, or after being loaded up.
How would a halyard hitch compare, I know they are a bugger to remove after being tensioned.

[sabray]

I would love to see heat tests under cyclic loads. The kinds we talk about melting 3 strand.
Having experienced multiple lines fail from chafe or heat that would be cool to see. Guess that most of the failures are from repetitive loading and unloading of the connection points. Single point pulls are good but that is not the primary failure of most lines. Chafe and heat need to be replicated to get a good picture.