Pete K
Well-known member
The Bowline-on-the-Bight is currently being discussed heavily on this forum within the Fusion Knot thread http://ukcaving.com/board/index.php?topic=14580.0 and the Y-hang thread http://ukcaving.com/board/index.php?topic=14594.0.
The reason for discussion is that a film originating from the French Caving School has surfaced thanks to Damian. The film shows a method of failure with the BotB knot. The French have even gone so far as to recommend a replacement knot (Fusion).
Over the last few days myself and colleagues have performed tests on the BotB to better understand the nature and cause of the failures. The reason I have started this new thread is because what comes to light now is something that should really be more widely seen by the caving community and I was worried that the average passer by on the forum would miss the discussion.
I have added the main information to this topic from the others.
I intend to pass all the information about our tests to the relevant groups (BCA, ACI etc..) to make their own choices.
The original film highlighted by Damian in the Fusion Knot thread is here: http://efs.ffspeleo.fr/techniques/noeuds
The FFS have advised against the use of the Bowline on the Bight. This stance has also been adopted by a number of other professional bodies in the French outdoor industry.
Their replacement is under discussion elsewhere on this forum, more from me on that there.
Our original tests from the 8th Jan 2013:
Right, I've been out and done some testing today.
I think it is important to make clear that this failure can happen in caving use and would be serious. I think it is also important to make clear that as a personal and professional caver (CIC) that I do not suggest anyone goes and uses a technique that they have doubts about or are unfamiliar with. This includes the use of new fangled French knot thingies which I have yet to test and have only seen formed when people tie a BotB incorrectly.
I will stop short of giving specific advice on this knot but will say that I will continue to use it for now.
I make no apologies for being slightly self promoting here but this is what I do for a living and it is important to me to know that what I do is spot on.
YouTube film made of today's tests:
http://youtu.be/-5-YbRxceiY
Full report to be read with YouTube film here:
http://www.peakinstruction.com/blog/testing-a-method-of-failure-with-a-bowline-on-the-bight-knot/
Today (10-1-2013) I went out with another CIC to test the knot again. In the first test we tried to get a failure by doing things wrong or poorly when we tied or clipped into the knot. Today we were testing a knot that had been tied correctly and was in use exactly as we would do underground*. The results were surprising.
* We would always clip both loops of the knot with our cowstails in real life. The tests were done with one loop clipped.
Today's test film on YouTube: http://youtu.be/Kpd7RF1ybgI
The written report that should be read with the film on my blog here:
http://www.peakinstruction.com/blog/2nd-round-of-testing-on-the-bowline-on-the-bight-knot/
To summarise for those who have only skim read or do not have time to read it all presently:
We were able to make a failure occur with the BotB tied and dressed correctly. A cowstail connected to the single loop formed by the pitch rope left the caver at a significant risk of a potentially lethal fall. This risk was present in all permutations of the knot we tested, 9 & 10mm, wet & dry, tight & lose, dressed & poorly dressed etc...
The failure was only seen to occur using the one loop, clipped to the lower side. No other failures were noted but we did concentrate on the main risk configuration. The only safe way to use the Bowline-on-the-Bight knot is to have your cowstails attached through BOTH LOOPS. This has always been the advice given to people when being taught the BotB but it is now very important to re-iterate: A cowstail must be clipped through both of the loops on the knot for it to be secure. We did not have a single failure or slip of any kind in any of the test scenarios so long as a cowstail was attached through both loops.
I leave it to cavers to make their own choice as to where to go from here, think of this as a public information broadcast.
I do have a chance to test the French's replacement, the Fusion Knot in the near future. I also plan to look at a knot that we are currently calling the Double Bowline on the Bight, or D-BoB. For anyone who is interested I'll be blogging on that in the near future too. www.peakinstruction.com and click on Pete's Blog at bottom.
I'd like to thank Pindale Farm for their hospitality throughout the testing this week.
The reason for discussion is that a film originating from the French Caving School has surfaced thanks to Damian. The film shows a method of failure with the BotB knot. The French have even gone so far as to recommend a replacement knot (Fusion).
Over the last few days myself and colleagues have performed tests on the BotB to better understand the nature and cause of the failures. The reason I have started this new thread is because what comes to light now is something that should really be more widely seen by the caving community and I was worried that the average passer by on the forum would miss the discussion.
I have added the main information to this topic from the others.
I intend to pass all the information about our tests to the relevant groups (BCA, ACI etc..) to make their own choices.
The original film highlighted by Damian in the Fusion Knot thread is here: http://efs.ffspeleo.fr/techniques/noeuds
The FFS have advised against the use of the Bowline on the Bight. This stance has also been adopted by a number of other professional bodies in the French outdoor industry.
Their replacement is under discussion elsewhere on this forum, more from me on that there.
Our original tests from the 8th Jan 2013:
Right, I've been out and done some testing today.
I think it is important to make clear that this failure can happen in caving use and would be serious. I think it is also important to make clear that as a personal and professional caver (CIC) that I do not suggest anyone goes and uses a technique that they have doubts about or are unfamiliar with. This includes the use of new fangled French knot thingies which I have yet to test and have only seen formed when people tie a BotB incorrectly.
I will stop short of giving specific advice on this knot but will say that I will continue to use it for now.
I make no apologies for being slightly self promoting here but this is what I do for a living and it is important to me to know that what I do is spot on.
YouTube film made of today's tests:
http://youtu.be/-5-YbRxceiY
Full report to be read with YouTube film here:
http://www.peakinstruction.com/blog/testing-a-method-of-failure-with-a-bowline-on-the-bight-knot/
Today (10-1-2013) I went out with another CIC to test the knot again. In the first test we tried to get a failure by doing things wrong or poorly when we tied or clipped into the knot. Today we were testing a knot that had been tied correctly and was in use exactly as we would do underground*. The results were surprising.
* We would always clip both loops of the knot with our cowstails in real life. The tests were done with one loop clipped.
Today's test film on YouTube: http://youtu.be/Kpd7RF1ybgI
The written report that should be read with the film on my blog here:
http://www.peakinstruction.com/blog/2nd-round-of-testing-on-the-bowline-on-the-bight-knot/
To summarise for those who have only skim read or do not have time to read it all presently:
We were able to make a failure occur with the BotB tied and dressed correctly. A cowstail connected to the single loop formed by the pitch rope left the caver at a significant risk of a potentially lethal fall. This risk was present in all permutations of the knot we tested, 9 & 10mm, wet & dry, tight & lose, dressed & poorly dressed etc...
The failure was only seen to occur using the one loop, clipped to the lower side. No other failures were noted but we did concentrate on the main risk configuration. The only safe way to use the Bowline-on-the-Bight knot is to have your cowstails attached through BOTH LOOPS. This has always been the advice given to people when being taught the BotB but it is now very important to re-iterate: A cowstail must be clipped through both of the loops on the knot for it to be secure. We did not have a single failure or slip of any kind in any of the test scenarios so long as a cowstail was attached through both loops.
I leave it to cavers to make their own choice as to where to go from here, think of this as a public information broadcast.
I do have a chance to test the French's replacement, the Fusion Knot in the near future. I also plan to look at a knot that we are currently calling the Double Bowline on the Bight, or D-BoB. For anyone who is interested I'll be blogging on that in the near future too. www.peakinstruction.com and click on Pete's Blog at bottom.
I'd like to thank Pindale Farm for their hospitality throughout the testing this week.