Tom Moyer’s test data is the best available, but…
I have also pulled a few EDKs and EDK8s on a test machine, and reached somewhat different conclusions than some have reached from Mr. Moyers.
Critique of TM’s report. A. Loading was done across the knot, single strand. Actual field loading is half as much, therefore, TM’s numbers should all be doubled. B. ANY analysis of knots in ropes is inherently limited by the inability to test all the combinations.
What I noticed is that both the EDK and the EDK8 do tend to capsize. On a 10.5mm used climbing rope, dry, the load to capsize on either was quite large ~ 1000 lbs, difficult to achieve in a rappel.
Capsizing on a test machine relieves the stress, unlike in the real world, where it would just drop the rappeller a bit, and the force would stay much the same. On a test machine, each capsize requires slightly larger force. Each capsize crawls 3″ to 6″ along the rope.
Even a very loosely tied backup knot prevented the capsize from getting past the backup knot.
Mostly, what I am concerned about is not equal ropes, dry; IS ropes that are quite different in size and stiffness, possibly wet.
My conclusions are: A. Almost always back up the EDK or EDK8 or EDK9 with an overhand knot. Even more important if the ropes are “different”. B. Either version of the EDK works fine. C. Dress the knots well and tighten firmly.
If really worried about the knot getting stuck – re-rig rappel or do other tricks (pre-pulling knot, etc). At worst, use single EDK for the LAST person (me), rappelling carefully to minimize force.
I got to see the ropes from the accident in Zion. They were super- stiff, big fat climber cords, the kind you would retire and perhaps only use for fixing ropes on big walls. The knotability of those ropes was very, very bad. If people are using ropes like that for canyoning, I would suggest that they not do so. If people are using ropes like that for climbing, rigging or fixing ropes, you would obviously want to take great care in tying them, because they obviously tie very poorly.
You might reach other conclusions. Its your (and your friends’s) life (lives), so be smart.
Tom
— In Yahoo Canyons Group, hmoon@p… wrote:
The knot you refer to (EDK8) was shown by Tom Moyers’ 1999 testing to be a potentially dangerous knot and TO BE AVOIDED. What is the title of the book you saw this knot in?
It’s clear we’ll never know what *exactly* what happened in the Zion > accident. Most likely given what we know is that Ross (the deceased) tied an EDK8 too loose or with insufficient tail. The report prompted a lot of people (myself included) take another look at Moyers’ EDK8 test data to confirm that the EDK8 is pure junk. That be good. Partner checking is also good when possible.
I use an EDK for fat, thin, and any combination thereof. Testing supports it. If I were feelin’ paranoid for some reason, I would use the Double EDK. See below for some references on this subject.
http://www.xmission.com/~tmoyer/testing/EDK.html
http://www.needlesports.com/gearreviews/abseilknots.htm
http://jost.gudelius.bei.t-online.de/spst.htm
> hank
rbrapper
Why not just tie the double sheet bend knot? It is such an easy knot to tie and untie using same and different sizes of rope. We used it all the time in the commercial diving and marine industry. Am I missing something regarding the knot strength? John
— In Yahoo Canyons Group, ian bailey wrote: > Thanks very much for the PDF. Remember it was devised especially for nylon rope, because, unlike sisal or manilla, nylon can be slippery. I have never seen it used except by our group. > I use it for tying slings and ropes together.With the finished knot, you will notice that it has a leg or loop crossing over the main legs. By pulling down or out from these loops, you tend to be able to break the knot easily. Another reason I use it is, it identifies my slings or rope knots left in situ, such as around a tree etc. Cheers > Ian Bailey > —– Original Message —– > From: Tom Jones > To: Yahoo Canyons Group
Sent: Monday, July 28, 2003 1:31 PM > Subject: [from Canyons Group] Re: TECH – tying two ropes together
> — In Yahoo Canyons Group, “ian bailey” wrote: > > If I may suggest and if I am back in the good books, have a look > at the Hunters Bend. I use it all the time for joining ropes. Very > easy to tie and undo, never slips.
> Ian Bailey >
> Interesting – here’s a pdf on how to tie it:
http://www.scoutingresources.org.uk/downloads/knots_huntersbend.pdf
> Tom
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Bombastic Bolt Debates are allowed to only a limited extent. Folks should go to the Canyoneer Group for a truly un-moderated forum. http://groups.yahoo.com/group/canyoneer
> To change your delivery options, go to the Canyons Egroup page on yahoo: > http://groups.yahoo.com/group/canyons/
> This will require logging into Yahoo. Click on the "Edit My > Membership" link, and change your delivery option. Press "Save > Changes".
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>
ian bailey
Thanks very much for the PDF. Remember it was devised especially for nylon rope, because, unlike sisal or manilla, nylon can be slippery. I have never seen it used except by our group. I use it for tying slings and ropes together.With the finished knot, you will notice that it has a leg or loop crossing over the main legs. By pulling down or out from these loops, you tend to be able to break the knot easily. Another reason I use it is, it identifies my slings or rope knots left in situ, such as around a tree etc. Cheers Ian Bailey —– Original Message —– From: Tom Jones To: Yahoo Canyons Group Sent: Monday, July 28, 2003 1:31 PM Subject: [from Canyons Group] Re: TECH – tying two ropes together
— In Yahoo Canyons Group, “ian bailey” wrote: > If I may suggest and if I am back in the good books, have a look at the Hunters Bend. I use it all the time for joining ropes. Very easy to tie and undo, never slips.
> Ian Bailey >
Interesting – here’s a pdf on how to tie it:
http://www.scoutingresources.org.uk/downloads/knots_huntersbend.pdf
Tom
Groups Sponsor ADVERTISEMENT
When you post, please change the Subject appropriately, to make reading and searching easier. You can use the following abbreviations: TRIP = Trip Report; BETA = Canyon Beta; PARTNER = Partner and/or Rides; ETHICS = Ethics; TECH = Technical Questions and Tips; BIZ = E Group Business; SALE = Stuff for Sale. Please use a Tilde ~ after the abbreviation, so we know you are coding for us, such as:
Subject: BIZ~ New Abbreviation List – working?
Bombastic Bolt Debates are allowed to only a limited extent. Folks should go to the Canyoneer Group for a truly un-moderated forum. http://groups.yahoo.com/group/canyoneer
To change your delivery options, go to the Canyons Egroup page on yahoo: http://groups.yahoo.com/group/canyons/
This will require logging into Yahoo. Click on the "Edit My Membership" link, and change your delivery option. Press "Save Changes".
DAILY DIGEST OPTION will deliver one email to you each day summarizing that day’s messages.
WEB ONLY OPTION will not deliver email; you must visit the web site to view messages.
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Tom Jones
— In Yahoo Canyons Group, “ian bailey” wrote: > If I may suggest and if I am back in the good books, have a look at the Hunters Bend. I use it all the time for joining ropes. Very easy to tie and undo, never slips.
> Ian Bailey >
Interesting – here’s a pdf on how to tie it:
http://www.scoutingresources.org.uk/downloads/knots_huntersbend.pdf
Tom
ian bailey
If I may suggest and if I am back in the good books, have a look at the Hunters Bend. I use it all the time for joining ropes. Very easy to tie and undo, never slips. Ian Bailey
—– Original Message —– From: Tom Jones To: Yahoo Canyons Group Sent: Monday, July 28, 2003 10:36 AM Subject: [from Canyons Group] Re: TECH – tying two ropes together
Tom Moyer’s test data is the best available, but…
I have also pulled a few EDKs and EDK8s on a test machine, and reached somewhat different conclusions than some have reached from Mr. Moyers.
Critique of TM’s report. A. Loading was done across the knot, single strand. Actual field loading is half as much, therefore, TM’s numbers should all be doubled. B. ANY analysis of knots in ropes is inherently limited by the inability to test all the combinations.
What I noticed is that both the EDK and the EDK8 do tend to capsize. On a 10.5mm used climbing rope, dry, the load to capsize on either was quite large ~ 1000 lbs, difficult to achieve in a rappel.
Capsizing on a test machine relieves the stress, unlike in the real world, where it would just drop the rappeller a bit, and the force would stay much the same. On a test machine, each capsize requires slightly larger force. Each capsize crawls 3″ to 6″ along the rope.
Even a very loosely tied backup knot prevented the capsize from getting past the backup knot.
Mostly, what I am concerned about is not equal ropes, dry; IS ropes that are quite different in size and stiffness, possibly wet.
My conclusions are: A. Almost always back up the EDK or EDK8 or EDK9 with an overhand knot. Even more important if the ropes are “different”. B. Either version of the EDK works fine. C. Dress the knots well and tighten firmly.
If really worried about the knot getting stuck – re-rig rappel or do other tricks (pre-pulling knot, etc). At worst, use single EDK for the LAST person (me), rappelling carefully to minimize force.
I got to see the ropes from the accident in Zion. They were super- stiff, big fat climber cords, the kind you would retire and perhaps only use for fixing ropes on big walls. The knotability of those ropes was very, very bad. If people are using ropes like that for canyoning, I would suggest that they not do so. If people are using ropes like that for climbing, rigging or fixing ropes, you would obviously want to take great care in tying them, because they obviously tie very poorly.
You might reach other conclusions. Its your (and your friends’s) life (lives), so be smart.
Tom
— In Yahoo Canyons Group, hmoon@p… wrote: > > The knot you refer to (EDK8) was shown by Tom Moyers’ 1999 testing to be a potentially dangerous knot and TO BE AVOIDED. What is the title of the book you saw this knot in? > > It’s clear we’ll never know what *exactly* what happened in the Zion > accident. Most likely given what we know is that Ross (the deceased) tied an EDK8 too loose or with insufficient tail. The report prompted a lot of people (myself included) take another look at Moyers’ EDK8 test data to confirm that the EDK8 is pure junk. That be good. Partner checking is also good when possible. > > I use an EDK for fat, thin, and any combination thereof. Testing supports it. If I were feelin’ paranoid for some reason, I would use the Double EDK. See below for some references on this subject. > > http://www.xmission.com/~tmoyer/testing/EDK.html > http://www.needlesports.com/gearreviews/abseilknots.htm > http://jost.gudelius.bei.t-online.de/spst.htm > > hank
Groups Sponsor ADVERTISEMENT
When you post, please change the Subject appropriately, to make reading and searching easier. You can use the following abbreviations: TRIP = Trip Report; BETA = Canyon Beta; PARTNER = Partner and/or Rides; ETHICS = Ethics; TECH = Technical Questions and Tips; BIZ = E Group Business; SALE = Stuff for Sale. Please use a Tilde ~ after the abbreviation, so we know you are coding for us, such as:
Subject: BIZ~ New Abbreviation List – working?
Bombastic Bolt Debates are allowed to only a limited extent. Folks should go to the Canyoneer Group for a truly un-moderated forum. http://groups.yahoo.com/group/canyoneer
To change your delivery options, go to the Canyons Egroup page on yahoo: http://groups.yahoo.com/group/canyons/
This will require logging into Yahoo. Click on the "Edit My Membership" link, and change your delivery option. Press "Save Changes".
DAILY DIGEST OPTION will deliver one email to you each day summarizing that day’s messages.
WEB ONLY OPTION will not deliver email; you must visit the web site to view messages.
Your use of Groups is subject to the Terms of Service.