Cordage Breaking Strengths

Corin

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That is way cool!!! when the loop broke did it break at the fishermans?


I have supplied one piece of cord with eye splices on each end, but it has a dodgy section in the middle so probably not a good representation, The other three bits I have left to you, based on your experience, however they are not reel long bits of cord so your options may be limited, you may need to connect with some small diameter shackles or Ds to ensure you have enough length for a knot.
 

Aussie Forager CQ

Rüdiger Nehberg
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That is way cool!!! when the loop broke did it break at the fishermans?


I have supplied one piece of cord with eye splices on each end, but it has a dodgy section in the middle so probably not a good representation, The other three bits I have left to you, based on your experience, however they are not reel long bits of cord so your options may be limited, you may need to connect with some small diameter shackles or Ds to ensure you have enough length for a knot.
Cool that will be sweet, I think the loop is a good way to test the small stuff, easy way to test the short lengths too, also if you halve the result you get a roughy for a single strand with a knot.....like above 1.75 with single strand and 3.77 as the loop but we can have a look at it when it gets here
 

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Rüdiger Nehberg
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* it won't matter if the eye splices are small as long as it will fit a carabiner through the loop, it will work out well.

Yep the loop broke at the double overhand knot, right at the base where the rope comes out! Its like a python just squeezes it to death!
 

Greatbloke

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Good stuff Aussie, I like they way that you went about it. I'm thinking that you might be able to clamp rather than tie Corin's cordage if length is a problem, I'm not sure if it would just pull free from clamps though.
 

gelandangan

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AFCQ,
Thank you for your offer to test cordage breaking strength.
I have some 7/64 inch Amsteel that I bought on last year group buy, the primary use I had in mind for this is to be used on my hammock.
While I have been using it for a few trips, and it was proven safe to hold my body weight,
I still often feels uncomfortable trusting such a small rope to carry me, I am a big (um..fat..) boy.

Would it be ok for me to send you
- a meter or so plain rope
- a meter of spliced rope (spiced approximately in the middle)
- a couple of soft carabiner I made (rough circumference is about 30cm each)
- a short single line "whoopie sling" with eye splices on both ends
to be tested on your machine?

Basically these are what I used to hold my hammock together and I really wish to find out how they perform and what safety margins I get.
 

Aussie Forager CQ

Rüdiger Nehberg
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Good stuff Aussie, I like they way that you went about it. I'm thinking that you might be able to clamp rather than tie Corin's cordage if length is a problem, I'm not sure if it would just pull free from clamps though.
Yeh I have been thinking of something similar for the small stuff, we have a special bollard for rope with it's own clamp, might have to just slightly change it for the cord, an extra clamp might work well....
 

Aussie Forager CQ

Rüdiger Nehberg
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Gelandangan,

Hi mate yeh that would be no worries, I have a great boss that is happy for BushcraftOZers to send in their pieces. Each of those tests will be no worries. I can appreciate why! Bit of peace of mind while your snoozing!
Just send it on in....
 

Corin

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AFCQ,
Thank you for your offer to test cordage breaking strength.
I have some 7/64 inch Amsteel that I bought on last year group buy, the primary use I had in mind for this is to be used on my hammock.
While I have been using it for a few trips, and it was proven safe to hold my body weight,
I still often feels uncomfortable trusting such a small rope to carry me, I am a big (um..fat..) boy.
I use the same stuff on mine as you know... I weigh 93 kg and have had no issues, but every time I look at that 2.78mm string holding me up above the rocks logs and sharp hurty things I wonder just how good is this stuff!
 

Aussie Forager CQ

Rüdiger Nehberg
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Hi All,

I have received some cordage sent from Corin, here are some results.

Test #1

Maker - Corin
Material - Blackfellows Hemp
Construction - 3ply
Average Minimum Diameter - Approx. 3mm
Test Configuration - Eye splice on each end





RESULT

Breaking Strength - 0.34 kN approx. 35 kg
Failure Point - In the middle of the cord, not in a splice




Test #2

Maker - Corin
Material - Blackfellows Hemp
Construction - 3ply
Average Minimum Diameter - Approx. 3mm
Test Configuration - Eye splice on each end




RESULT

Breaking Strength - 0.36 kN approx. 35 kg
Failure Point - the cord broke at the eye splice


Test #3
Because test #2 broke at the splice there was enough cord to do another test.

Maker - Corin
Material - Blackfellows Hemp
Construction - 3ply
Average Minimum Diameter - Approx. 3mm
Test Configuration - Eye splice on one end with the other end joined with a sheet bend to make a loop.




RESULT
Breaking Strength - 0.66 kN approx. 65 kg (keep in mind this piece had already been tested once and had a knot in it as well)
Failure point - at the sheet bend



Thanks to Corin for the cordage, very nicely done. Still yet to test his Illawarra Flame Tree.
 

GStone

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This is really interesting information. Thank you for sharing.
 

Aussie123

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Well done Corin. That looks like some top notch cord.

Aussie Forager QC - thanks for doing the tests, its great to get some empirical data
 

auscraft

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good on ya Corin good test results and thanks AF for do them
 

Corin

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Hey thats not bad for 3mm thick piece of bark, better than I expected and far better than required for a fishing line.

Breaking in the middle was predictable there was a really bad join in the fibers at that location....

I am looking forward to the flame tree but I don't think it will be as strong as the blackfellows hemp, that stuff is incredible.
 

Aussie Forager CQ

Rüdiger Nehberg
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Hi All, *here are two more tests of Illawarra Flame Tree that Corin sent up.

Test #4

Maker - Corin
Material -*Illawarra Flame Tree*
Construction - 3ply
Average Minimum Diameter - Approx. 1.5mm
Test Configuration - Eye splice on each end. This stuff is obviously small gear so to save a bit of fiddling I used this method to make the eye's. Turned out quite well I think.

http://survivial-training.wonderhowto.com/how-to/make-cord-eye-splice-for-wilderness-survival-uses-273022/



RESULT

Breaking Strength - 0.15 kN approx. 15 kg
Failure Point - In the middle of the cord between the splices.

Note - Quite a good test, good quality material, without averaging other samples this result should be a reasonable indication. The splicing method held up well.



Test #5

Maker - Corin
Material - Illawarra Flame Tree*
Construction - 3ply
Average Minimum Diameter - Approx. 3mm
Test Configuration - Conventional three strand eye splice on one end and the other end joined to it with a sheet bend to make a loop. Same as Test #3.

RESULT

Breaking Strength - 0.38 kN approx. Nearly 40 kg
Failure Point - It broke where the cordage and splice meet. The photo below shows the cordage after the test. The arrow shows where the loop was joined before it broke (ignore the question mark).





There was a fair few variables with this particular test, I expected it to be a bit stronger than what it went at (it was 3mm) and also where it failed was interesting. However all materials react differently with different variables. It would be good to do another of these to see what happens a second time.

Nevertheless Black Fellows Hemp still reigns supreme!
 
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Aussie Forager CQ

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Hi All,
I did a couple of more tests today.....

I tested some Hibiscus tiliaceus that I harvested from Cairns back in March.


Test #6

Maker - AFCQ
Material - Hibiscus tiliaceus *inner bark
Construction - 2 ply
Average Minimum Diameter -Approx. 3mm
Test Configuration - Eye splice in each end. Same as Test 4.



RESULT
Breaking Strength - 0.39 kN Approx. Nearly 40 kg
Point of Failure - Where the splice meets the rope.
Notes - At first glance this is just stronger than the Blackfellows Hemp, not by much though. Keeping in mind this test was done in two ply and the BFH was three, so the tests were not technically the same and it is only one sample of each. Interesting stuff but more tests are needed for real *conclusive results.




Test #7

Maker - AFCQ
Material - Hibiscus tiliaceus inner bark
Construction - 2 ply
Average Minimum Diameter -Approx. 3mm
Test Configuration - Overhand Knot on the bight on one end and Bowstring Knot on the other.

Bowstring Knot (#1024 Ashley's Book Of Knots)







RESULT
Breaking Strength - 0.27 kN*
Failure Point - Failed at the Bowstring Knot.
Notes - A loss of Approx. 10 kg of strength with the knot compared to the splices. The tail did not slip through the Bowstring Knot at all however the Bowstring Knot must be dressed properly for it to grab, also it will slip with certain synthetic and slippery materials. Must be experimented with, cool knot though! It is very easy to undo after being heavily loaded.

 

Aussie Forager CQ

Rüdiger Nehberg
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Hi All,

Here are a couple of tests of some Venetian Blind cord just to compare things and for interest.

Test #8

Maker - Grunt
Material - Unknown......Venetians???
Construction - Double Braid
Average Minimum Diameter -Approx. 2 mm
Reported breaking strength - 64 kg - seemingly without a knot.
Test Configuration - Overhand on the bight on one end and Bowstring Knot on the other end.



RESULT
Breaking Strength - 0.38 kN*
Point of Failure - Broke at the Bowstring Knot.



Test #9

Maker - Grunt
Material - Unknown......Venetians???
Construction - Double Braid
Average Minimum Diameter -Approx. 2 mm
Reported breaking strength - 64 kg - seemingly without a knot.
Test Configuration - Overhand on the bight on one end and Overhand*on the bight on the other end. Single overhand in middle. Worst case scenario for rope strength.



RESULT
Breaking Strength - 0.32 kN
Point of Failure - Failed at the overhand in the middle.*



Test #10

Maker - Grunt
Material - Unknown......Venetians???
Construction - Double Braid
Average Minimum Diameter -Approx. 2 mm
Reported breaking strength - 64 kg - seemingly without a knot.
Test Configuration - Overhand on the bight fixed to an anchor, 10 wraps then finished with a frapping two half hitches.*



RESULT
Breaking Strength - 5.69 kN approx. 570 kg!!
Point of Failure - Broke at the Overhand on the bight.
Notes - This test simulates a lashing of sorts. Goes to show that just because a material is marginal on it's own, when wrapped, impressive strength can be achieved! Like the old story of lifting an engine block with dental floss if enough wraps are taken!!


 

Corin

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Have you thought about testing dental floss, I was told 7 strands would hold an adults weight. Great to see the results from your tests! Thanks heaps for your contribution!
 

Aussie Forager CQ

Rüdiger Nehberg
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Hi All,

Here is a test with my first ever attempt at sinew cordage. All in all a success I think!



Test #11

Maker - AFCQ
Material - Deer Sinew
Construction - 2 Ply reverse twisted Z lay.
Average Minimum Diameter -Approx. 3 mm (maybe a smidge smaller)
Test Configuration - Bowstring Knot VS Bowline Knot





RESULT
Breaking Strength - 0.53 kN just over 50 kg!!
Point of Failure - Broke at the Bowstring Knot.
Notes - This is pretty impressive strength, especially considering this is with a knot......and a relatively weak knot at that. Also this test was only 2 ply, and maybe a bit less than 3mm. I have read that sinew is the strongest natural fibre in the world, I can see why so far!!

 

Aussie Forager CQ

Rüdiger Nehberg
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Have you thought about testing dental floss, I was told 7 strands would hold an adults weight. Great to see the results from your tests! Thanks heaps for your contribution!
Better late than never! Here are some dental floss results. I won't be hanging on it any time soon :) *Like they say 'believe none of what you hear and half of what you see'.*



Test #12

Maker - Oral B
Material - Waxed floss
Construction - Strips
Average Minimum Diameter -Approx. Bugger all!
Test Configuration - 7 strands with overhand on the bight on each end



RESULT

Breaking strength - 0.14 kN (not even 15kg!)



Test #13

Maker - Oral B
Material - Waxed floss
Construction - Strips
Average Minimum Diameter -Approx. Bugger all!
Test Configuration - 30 strands with overhand on the bight on each end



RESULT

Breaking Strength - 0.69 kN (nearly 70kg)



It's weird....I'm surprised that the results were not stronger, I spose because of always hearing those type of stories, but it actually makes sense.

Mind you I wouldn't call them scientific results, I'm sure the strong floss is out there!
 
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