International Guild of Knot Tyers Forum
General => Practical Knots => Knot Test Reports and Reviews => Topic started by: agent_smith on August 22, 2018, 03:56:35 PM
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KNOT TEST REPORT - summarized from video
Tester details: Richard Mumford
Company: Climbing Innovations
Application context: Tree climbing / arborist
Publication date: 29 Jan 2018
Testing lab type: Presumed 'Pseudo lab' (not a certified lab and not accredited by a third party agency)
Link to video: https://www.youtube.com/watch?v=UJ5DjjgDV6Q
This is another example of a tester aiming at the default #1010 Bowline - and presumably assuming that this is the only type of Bowline in existence. The author makes it clear that he is not a supporter of 'the' Bowline (preferring instead the #1053 Butterfly eye knot). It appears that Richard Mumford is oblivious to the fact that #1010 is not the only type of 'Bowline' in existence - and indeed, there is a class of eye knots known to be 'secure Bowlines'.
Note: The author's context is tree climbing.
Some criticisms (list is not exhaustive):
Testing commences at 12:47 elapsed time...
1. The default mindset is to probe the MBS yield point of knots (ie pull-to-failure mindset).
2. The author presumably places a lot of weight on knot 'A' versus knot 'B' pull-to-failure (presumably the winner of the contest is a superior knot? - This is an implied assumption).
3. Dressing of the #1053 Butterfly assumes parallel eye legs (he does not investigate crossed 'X' eye legs)
4. The author does not make a clear distinction between 'eye loading' and 'through loading' of the #1053 Butterfly eye knot (it is just assumed that viewers will know and understanding the differences).
5. There does not appear to be any scientific rigor in terms of gathering a statistically valid sample (only appears to be a sample of 1).
6. Vague on age of test cordage/rope.
7. At 19:55 elapsed time he 'ring loads' the eye of #1053 Butterfly. Now in the form of a round sling, the load to reach the MBS yield point is naturally much higher than in linear loading profile (no supporting comments offered...just assumed that viewers will know this).
8. At 21:05 elapsed time he tests #1010 in a ring loading profile (the author appears to be ignorant that this is a loading profile that is a known vulnerability of #1010...in comparison to #1034 1/2 which is resistant to ring loading. He missed an opportunity to use #1010 as a control against #1034 1/2.
9. No firm conclusion drawn or stated from his tests. What was he ultimately trying to prove? Did he prove what he set out to do? What were his conclusion drawn as a result of his test efforts? It appears unclear or implied...
The above points are just quick observations...again, the list is not exhaustive.
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I rather gathered the impression that Mr Mumford did not like the #1010 and much preferred the Alpine butterfly. It seemed his intention was to demonstrate the superiority of the AB by showing the MBS as the criterion for superiority. His tests failed to demonstrate this.
Furthermore, he missed opportunities to compare other attributes of the two knots such as deformation, creep, jamming potential etc.
He did however demonstrate an interesting method of tying the AB in the end of the rope with a contained object. Again, the value of this was lost as superior end of line loop knots exist whilst ignoring the key aspect of the AB as being a valid midline loop knot.
His point however that the use of the AB to isolate as weakened section of rope by isolating it in the loop, explained that the user would be better served by cutting the rope or using a stronger bend, as the AB significantly weakened the rope.