Author Topic: Zeppelin Loop and Double Dragon Loop - security based on experience  (Read 17348 times)

erizo1

  • Full Member
  • ***
  • Posts: 52
Judging from past exchanges on the forum, I'm aware that there are some strong feelings about the zeppelin loop, so I beg for responses to the following questions that are based on practical experience with the knots in question, leaving aside for the moment issues related to its name, the nature of its structure, its relationship to the Zeppelin bend, etc. Also, please assume that the strain I'm putting on the rope stays way below its breaking strength, so for the purposes of this post, strength is not a concern. Again, I'm exclusively interested in the practical results of using these knots.

1.  Has anyone ever used a zeppelin loop and had it fail or become compromised? I'm wondering if anyone has had or knows about an experience that could be used to complete this sentence: "The zeppelin loop is very secure, except _____."

2.  Same question as above about the double dragon loop.

3.  Assuming that the knot was tied correctly (leaving aside for the moment how easy it is to tie correctly and double check), is there any reason based on experience why the zeppelin loop should not be used as a tie-in when climbing? I am trying to understand why I see so many references on the internet to the impressive security and jam resistance of the zeppelin loop, and yet it is not mentioned on any climbing page that I can find. Does ease of tying and checking account for the disparity, or is there some other reason?

4.  Is anyone aware of some kind of formal testing that has been done on the security of the zeppelin loop or double dragon loop?

Thanks very much!
« Last Edit: March 26, 2014, 08:17:09 PM by erizo1 »

xarax

  • Sr. Member
  • *****
  • Posts: 2781
Re: Zeppelin Loop and Double Dragon Loop - security based on experience
« Reply #1 on: March 26, 2014, 11:19:59 PM »
   
is very secure, except _____."

   ALL loops based on an overhand knot ( or, for that matter, on a fig.8 knot ) tied on the Standing Part ( so, loaded with 100% of the total load from the Standing End side, and with 50% of the total load from the eye leg side ) are NOT as easily untied as the bowline-like loops - which are based on nipping structures topologically equivalent to the unknot. Also, all these overhand knot- ( or fig.8 knot- ) based loops, should be untied in two steps : in order to get a clean, unknotted rope ( which will not run the danger to be caught somewhere ), one has to untie the "relic", remaining overhand knot ( or the fig.8 knot ) from the Standing Part, after he has already untied the loop itself.
   When tied on ordinary materials, there is no issue with the slippage of this non-Zeppelin eyeknot - just as it happens with ANY other of the dozens of dozens interlocked-overhand-knot bends turned into eyeknots : on the contrary, one of the many disadvantages of this fake Zeppelin knot is that oftentimes, after the first overhand knot ( the one tied on the Standing Part ) "closes", the second overhand knot ( the one tied at the returning eye-leg / Tail End ) does not - so, one can see that the degree of the complexity of this second part of the eyeknot is redundant. Even if it would had been entangled on a simpler than an overhand knot "nipping structure", tied on the Standing Part, an also simpler than an overhand knot "collar structure", tied on the returning eye leg, would had been enough ( See an example of this, at (1).

   1. http://igkt.net/sm/index.php?topic=4736
   2. http://igkt.net/sm/index.php?topic=4606

  "... as the "main" first overhand knot, which is tied on the Standing part, is loaded first and more forcefully, it also "closes" and "locks" first, well before the second overhand knot, which is tied on the Tail. Consequently, this second overhand knot can well remain slag, with half of its structure not participating / contributing in the locking mechanism of the knot at all. The most evident result of it is a very tight, compact, rock solid first overhand knot, that has immobilized the eye leg of the Tail without any involvement of the second loose overhand knot, which is locked before / without been able to lock."

   "With the start of the loading of the eye-knot, the overhand knot tied on the Standing part, which is pulled by both its limbs, "closes" faster than the overhand knot tied on the Tail, which is pulled by its one limb only. Therefore, at some point, the main overhand knot "locks" around the secondary one, before the later has given the opportunity to do the same around the former... The original genuine Zeppelin knot works so well because the two links are in such a perfect balance the one in relation to the other, that they are loaded equally, they close around each other at the same time, they lock and they themselves are locked at the same time, and they suffer the strain of the tensile forces in tandem, re-distributing them along the common "pivot" made by the pail of tails. Nothing of the above is happening with the evil imposter of the Zeppelin family of knots - and its ugliness, its tying complexity, its asymmetric dressing... are only evidences of a knotting crime committed the moment some thought it would be so easy to kiss a prince, and do not transform it into a frog..."

   P.S.
   It turns out that an overhand knot ( or a fig.8 knot) can clinch too tightly, even when tied on the returning eye leg / Tail End - i.e., as a "collar structure", which is loaded only with 50% of the total load from the eye leg and with 0% of the total load from the Tail... If such a knot can be less easy to untie when it is loaded less, it will not become more easy to untie when it is loaded more !  :)   
« Last Edit: March 26, 2014, 11:35:20 PM by xarax »
This is not a knot.

roo

  • Sr. Member
  • *****
  • Posts: 1838
    • The Notable Knot Index
Re: Zeppelin Loop and Double Dragon Loop - security based on experience
« Reply #2 on: March 27, 2014, 12:11:42 AM »

1.  Has anyone ever used a zeppelin loop and had it fail or become compromised? I'm wondering if anyone has had or knows about an experience that could be used to complete this sentence: "The zeppelin loop is very secure, except _____."
I haven't had any such problems.  On a more theoretical level, extremely slick line would likely pose issues for just about any loop knot.

Quote
2.  Same question as above about the double dragon loop.
I was doing some shake testing of the double dragon loop with some Bluewater II, and found that it popped open and untied much earlier than I'd prefer when compared with other similar size or complexity loops.

Quote
3.  Assuming that the knot was tied correctly (leaving aside for the moment how easy it is to tie correctly and double check), is there any reason based on experience why the zeppelin loop should not be used as a tie-in when climbing? I am trying to understand why I see so many references on the internet to the impressive security and jam resistance of the zeppelin loop, and yet it is not mentioned on any climbing page that I can find. Does ease of tying and checking account for the disparity, or is there some other reason?
If you're fine with tying it, I'd recommend it.  As more people use it, it may eventually get mentioned in more places, but that takes time, often decades.

Quote
4.  Is anyone aware of some kind of formal testing that has been done on the security of the zeppelin loop or double dragon loop?
This forum is probably one of your best online resources, but I haven't done a recent web search.  I have noticed that some of the search engine results have degraded quite a bit recently, as an aside.  Don't be afraid to do testing yourself with the line type you use and conditions that you expect.

« Last Edit: April 02, 2014, 07:10:18 PM by roo »
If you wish to add a troll to your ignore list, click "Profile" then "Buddies/Ignore List".


SS369

  • Global Moderator
  • Sr. Member
  • *****
  • Posts: 1878
Re: Zeppelin Loop and Double Dragon Loop - security based on experience
« Reply #3 on: March 27, 2014, 12:17:16 AM »
Hi erizo1.

" "The zeppelin loop is very secure, except _____."

To fill in the blank I will put that there is no evidence I can find to suggest or prove that the Z-loop performs adequately in a drop test for climbing rope. I am sure that it can survive a slow pull test to a degree sufficient for hanging around,etc., but should one fall while climbing and the rope snatch tight, this is when a climber wants to know as absolutely as possible that the security and strength is there.

Then there is that annoying tail that sticks out to the side, distractingly so. I just don't want or need any of that type of thing during an ascent.

Same thoughts and feelings with the Dbl. Dragon loop.

My experience having used this loop as a tie in for anchoring something I was hauling is that it is not so easy to untie and so I've relegated it to the interesting and not used section.

Both do not offer any ease of loop size adjustment as some proven knots. Not necessarily a deal breaker, but something to consider if there is a need for speed.

SS

erizo1

  • Full Member
  • ***
  • Posts: 52
Re: Zeppelin Loop and Double Dragon Loop - security based on experience
« Reply #4 on: March 27, 2014, 01:25:57 AM »
Thanks, everyone. Shock-testing the zeppelin loop seems like it would be a necessary step in that knot becoming an accepted tie-in knot.

xarax

  • Sr. Member
  • *****
  • Posts: 2781
Re: Zeppelin Loop and Double Dragon Loop - security based on experience
« Reply #5 on: March 27, 2014, 05:23:49 AM »
Shock-testing the zeppelin loop seems like it would be a necessary step in that knot becoming an accepted tie-in knot.

   There is nothing that would be relieved by such a test !  The first overhand knot ( the one tied on the Standing Part ), which will be too tightly locked around the second knot, will not open up, and the second overhand knot, which is nipped and locked by the first, although itself does not nip and does not lock it ( so, it does not contribute in the security of the knot ), will not close any more ! The imbalance of the two parts, regarding their contribution to the security of the whole knot, will be maintained, and it will probably be amplified as well.
   If the mere property that a knot just does not slip during shock-pulling would be enough to be "accepted as a tie-in knot", each and every ugly tangly composed by overhand knots tied upon overhand knots, fig.8 knots tied upon fig.8 knots, and half hitches tied upon half hitches, would be fine ! In particular, each and every interlocked-overhand-knot bend blindly turned into an eyeknot by this ingenious "paste" way, would be sufficient, because it will not slip... There are dozens of dozens such bends that will not slip - so, their corresponding eyeknots will not slip, too, because eyeknots are more "secure", in this sense, than bends. And there are dozens of dozens bowline-like loops that are much easier to tie and to untie, that will not slip either - why on Earth one would like to test one particular more difficult to tie and to untie knot, and not all the others, is beyond my understanding. Perhaps the attraction of this fake Zeppelin knot, the so-called "Zeppelin loop" to some people, is due to the mesmerizing, indeed hypnotic effect of the Zzzz ...zzz...zzz consonant, repeated over and over again.  :)
   The real Zeppelin knot, the Zeppelin bend, is a marvellous, almost unique bend, which does not work as most of the other bends we know. It is a rope-made hinge, and the security and easiness with which it can be untied even after hard loading is based on this fact. People that learn knots only by reading knot books and memorizing knot recipes were astonished, because it was not easy for them to understand how it works - and it was not included in their Bible of knots, the ABoK. So, they made the ingenious thought to use it as an eyeknot, too, so they would be able to kill both birds with the same bullet... Mis-using the Zeppelin knot this bad way reveals two things : First, that the person who does this has not understood how the true, genuine Zeppelin-like knot, the Zeppelin bend, works, so he does not understand that this imposter is NOT a Zeppelin knot ( For Zeppelin-like loops, see, among others, (1)). Second, that the person who does this has not understood how the bowline works, he does not trust it, and he does not know anything about the dozens od dozens secure bowline-like loops, which are more easy to tie and untie ( and untie in only one step ) than any eyeknot based on an interlocked-overhand-knot ( or, for that matter, an interlocked-fig.8 knot bend ).
    This fake Zeppelin knot will NEVER become "accepted as a tie-in knot", albeit for the wrong reason !  :) Its difficulty to be tied will save the true Zeppelin knot, the Zeppelin bend, from this faux bijoux. So, people who had never understood how the real Zeppelin knot and/or the bowline works, will also not understand why this knot recipe will not be mentioned in many places - even after centuries:) A necessary ingredient for a popular myth is to be naive and simplistic enough, in order to be able to be rehearsed / reproduced by the believers easily - and, unfortunately for them, this knot is not so easy to tie ...     


1. http://igkt.net/sm/index.php?topic=4095
« Last Edit: April 23, 2014, 11:30:47 PM by xarax »
This is not a knot.

erizo1

  • Full Member
  • ***
  • Posts: 52
Re: Zeppelin Loop and Double Dragon Loop - security based on experience
« Reply #6 on: March 27, 2014, 07:07:33 AM »
Judging from past exchanges on the forum, I'm aware that there are some strong feelings about the zeppelin loop, so I beg for responses to the following questions that are based on practical experience with the knots in question, leaving aside for the moment issues related to its name, the nature of its structure, its relationship to the Zeppelin bend, etc.... Again, I'm exclusively interested in the practical results of using these knots.

   There is nothing that would be relieved by such a test !  The first overhand knot ( the one tied on the Standing Part ), which will be too tightly locked around the second NOT, will not open up, and the second overhand knot, which is nipped and locked by the first....
   ...why on Earth one would like to test one particular more difficult to tie and to untie knot, and not all the others, is beyond my understanding. Perhaps the attraction of this fake Zeppelin knot, the so-called "Zeppelin loop" to some people, is due to the mesmerizing, indeed hypnotic effect of the Zzzz ...zzz...zzz consonant, repeated over and over again.  :)
   The real Zeppelin knot, the Zeppelin bend, is a marvellous, almost unique bend, which does not work as most of the other bends we know. It is a rope-made hinge....
    This fake Zeppelin knot will NEVER become "accepted as a tie-in knot", albeit for the wrong reason !  :) Its difficulty to be tied will save the true Zeppelin knot, the Zeppelin bend, from this faux bijoux....

Xarax, I'm pretty sure I've read all of what you wrote above in other posts where you've expressed your opinion of the zeppelin loop. I'm hoping that by focusing on just a couple of things about the knots I mentioned, we can avoid needing to talk about all of the things about them.

Have you used the zeppelin loop for some practical application? If so, what was the result? I'm looking for information about what people have used the knot for and what the knot actually did or didn't do when it was used (hold, deform, slip, jam, etc.).

Dan_Lehman

  • Sr. Member
  • *****
  • Posts: 3903
Re: Zeppelin Loop and Double Dragon Loop - security based on experience
« Reply #7 on: March 30, 2014, 06:00:43 AM »
Judging from past exchanges on the forum, I'm aware that there are some strong feelings about the zeppelin loop,
And there are various knots that can lay claim
to that title (or to some part of it).  We'll presume
that you mean the most commonly known (echoed)
one (but I recently discovered another TIB/PET one
which is holding my interest).

Quote
3.  ...  I am trying to understand why I see so many references on the internet
to the impressive security and jam resistance of the zeppelin loop,
and yet it is not mentioned on any climbing page that I can find.
One can find things occurring all over the Net that
turn out to be echoes of some initial item.
(E.g., ca. 2008-10 there was an article claiming that some
testing of the then-new $500 list Canon G10 compact camera
showed that medium-sized (big, really, for many (13x19"))
prints made with it couldn't be distinguished from ones
made with a $40k Hasselblad medium-format camera
(as judged by experienced persons w/photography,
examining them on photo-viewing light stands)!!
I cannot find any challenge to this, but lots of echoes
citing it and presuming its truth.  --incredible.
Not quite two years later, the very same site had an
article asserting that one could readily distinguish even
small prints (let's say 8x10") made with a MF camera
from even top-end DSLR (35mm) cameras at 30' (!!!).
Now, this one did draw fire, but only a slight retreat from
the general assertion.)

Your question might as well be put for a great number
of eye knots, though it's not the case that these have
gotten into the echo chamber.

Do you think rockclimbers & cavers & SAR folks are interested
in experimental knots vs. the old tried-&-true ones?  Why
would they be?

Quote
4.  Is anyone aware of some kind of formal testing that has been
done on the security of the zeppelin loop or double dragon loop?
... or on ANY eye knot?!
I don't know of a test method for this.


--dl*
====

SS369

  • Global Moderator
  • Sr. Member
  • *****
  • Posts: 1878
Re: Zeppelin Loop and Double Dragon Loop - security based on experience
« Reply #8 on: March 30, 2014, 04:47:20 PM »

Do you think rockclimbers & cavers & SAR folks are interested
in experimental knots vs. the old tried-&-true ones?  Why
would they be?

I can think of at least one or two climbers/spelunkers who are interested and have shown their interest either here in this forum or some other forums. Sometimes the tried and true lack in some way to the user(s).
Or they have an adventurous spirit about them and like to explore new things.
Or they are just a knot tyer.......

Quote
Quote
4.  Is anyone aware of some kind of formal testing that has been
done on the security of the zeppelin loop or double dragon loop?
... or on ANY eye knot?!
I don't know of a test method for this.


--dl*
====

There have been numerous tests done in a formal format on a few eye knots. Whether these tests are formally recognized as the final words on the topic, that remains contested or not accepted.
The Fig. 8 loop is basically tested every time a climbing rope manufacturer does a drop test, which is generally daily.

Most climbers that I know and climb with are comfortable with their knot knowledge and usage needs and don't feel it necessary to change how they do things. They want to climb, etc...

Erizo: Go to a climbing gym if you can and try out some of these ideas you have >>> close to the ground <<< and see if they inspire confidence. See how easy or difficult your chosen "test" loops are to tie, adjust or feel as they scrape between you and the wall and holds. Bounce on them hard and determine if the results are acceptable to  you. Get some experienced opinions there as well.

I personally feel better with an eye knot that has its eye's legs that are normally in line (as they exit the nub as much as can be) with the standing part when they are unloaded because the majority of the time, when the eye knot is needed to work , this is most likely the load profile.
I just don't personally care for the open-ness of the Z loop or the added complexity to tie the Dbl Dragon as tie in loops. (Both with their tails sticking out like they do.)

SS

erizo1

  • Full Member
  • ***
  • Posts: 52
Re: Zeppelin Loop and Double Dragon Loop - security based on experience
« Reply #9 on: March 31, 2014, 05:48:43 AM »
Erizo: Go to a climbing gym if you can and try out some of these ideas you have >>> close to the ground <<< and see if they inspire confidence. See how easy or difficult your chosen "test" loops are to tie, adjust or feel as they scrape between you and the wall and holds. Bounce on them hard and determine if the results are acceptable to  you. Get some experienced opinions there as well.

I personally feel better with an eye knot that has its eye's legs that are normally in line (as they exit the nub as much as can be) with the standing part when they are unloaded because the majority of the time, when the eye knot is needed to work , this is most likely the load profile.
I just don't personally care for the open-ness of the Z loop or the added complexity to tie the Dbl Dragon as tie in loops. (Both with their tails sticking out like they do.)

SS

SS, that's a great idea, somehow I had not thought to try it at a climbing gym. I don't have any kind of rig set up to test knots, especially to test something like a fall in climbing, so I've had to rely on whatever other people could tell me. Not sure where I'll find a climbing gym, but it's an option I can pursue.

I know what you mean about having the legs of the loop in line with the standing part, and in general, I do prefer loops like the angler's and double dragon when I can use them, for that reason. But looking for a loop that's secure enough to trust with critical applications, and easy to tie and untie, narrows the field way down.

None of the bowlines I have seen have the legs of the loop coming out in line with the standing part, and the ones that people generally agree are secure enough are also the ones that seem most convoluted to me (e.g., the end-bound single bowline). Maybe I'm just lazy. I have to admit, I have an inexplicable prejudice against the rethreaded figure eight. It's a simple enough knot to tie, but the whole thing seems needlessly laborious to me for some reason. The double dragon has that nice alignment of the legs and standing part, but Roo has tested it and found that it came loose too quickly.

This is why the zeppelin loop appeals to me so much. I find it a quick and easy knot to tie; I'm faster with a bowline, but the difference isn't big enough for me to care about. The alignment isn't what you and I prefer, but when it's weighted, as compared to the bend, the weight on what would be the working end doesn't pull the knot all that far out of its natural alignment. And it clamps tight, there's no creep, and I can always undo it easily. I've never seen any creep in the knot, which makes me tempted to say that you could just tie it with a really short tail and not worry about it getting in the way. Of course, I wouldn't rely on having absolutely no slippage without some good tests first.

SS369

  • Global Moderator
  • Sr. Member
  • *****
  • Posts: 1878
Re: Zeppelin Loop and Double Dragon Loop - security based on experience
« Reply #10 on: March 31, 2014, 02:20:57 PM »
SS, that's a great idea, somehow I had not thought to try it at a climbing gym. I don't have any kind of rig set up to test knots, especially to test something like a fall in climbing, so I've had to rely on whatever other people could tell me. Not sure where I'll find a climbing gym, but it's an option I can pursue.

The gym is the best idea for it will allow you to be the test subject in a fairly controlled environment that is mostly representative of what you may find in the wild.
Or if you have the wherewithal to set up on a low tree branch at a suitable height, with say an old mattress directly under it, you could do at least something. ;-) But beware, if you go to the gym, you will be addicted.  ;)

 
 
Quote
I've never seen any creep in the knot, which makes me tempted to say that you could just tie it with a really short tail and not worry about it getting in the way. Of course, I wouldn't rely on having absolutely no slippage without some good tests first.

Just plain forget this line of thinking! Short tails are a good way to get hurt. They can actually find their way to being pressed into the knot's nub and loosen it to the point where the rope's springiness takes it from there, all without you knowing it. On the rocks, you most likely will not being reviewing your tie in.

I personally tie in with a bowline now. One that incorporates a simple lock for the tail.  I offered it here> http://igkt.net/sm/index.php?topic=19.15 Reply #19. It performs excellently with consideration to the #1010's purported shortcomings, e.g., ring loading and capsizing. It is very easy and simple.
There are other offerings there that seem to be good too.

Whatever you select for your use, be sure to test it to your satisfaction using the actual rope you'll be defying gravity with! So many ropes out there that don't share the same performance characteristics.
Ultimately, you are responsible, (even though your climbing buddy(ies) should be backing you up), so make it right.

SS
« Last Edit: April 01, 2014, 03:33:25 AM by SS369 »

Dan_Lehman

  • Sr. Member
  • *****
  • Posts: 3903
Re: Zeppelin Loop and Double Dragon Loop - security based on experience
« Reply #11 on: April 18, 2014, 06:40:58 PM »

Quote
4.  Is anyone aware of some kind of formal testing that has been
done on the security of the zeppelin loop or double dragon loop?
... or on ANY eye knot?!
I don't know of a test method for this.


--dl*
====

There have been numerous tests done in a formal format on a few eye knots.
Whether these tests are formally recognized as the final words on the topic,
that remains contested or not accepted.
The Fig. 8 loop is basically tested every time a climbing rope manufacturer
does a drop test, which is generally daily.
...

Whoa, this is misreading : the "security" I'm looking
towards is that of an unloaded, jostled knot,
not that of a heavily loaded one.  (I also doubt that
folks are daily or even weekly using test devices
--an expensive proposition, I think (time & labor).)
This, at least, is the "security" of concern to most
of the cordage-using world,
although as some recent discussion about HMPE
cordage showed, there is some serious security-loaded
concern for that extreme material.

Now, one might suggest that the regular (daily,
even) usage of Fig.8 eyeknots goes some way
towards the sort of security testing I intend;
but that's not a formal method.


--dl*
====

SS369

  • Global Moderator
  • Sr. Member
  • *****
  • Posts: 1878
Re: Zeppelin Loop and Double Dragon Loop - security based on experience
« Reply #12 on: April 18, 2014, 07:51:04 PM »

Quote
4.  Is anyone aware of some kind of formal testing that has been
done on the security of the zeppelin loop or double dragon loop?
... or on ANY eye knot?!
I don't know of a test method for this.


--dl*
====

There have been numerous tests done in a formal format on a few eye knots.
Whether these tests are formally recognized as the final words on the topic,
that remains contested or not accepted.
The Fig. 8 loop is basically tested every time a climbing rope manufacturer
does a drop test, which is generally daily.
...

Whoa, this is misreading : the "security" I'm looking
towards is that of an unloaded, jostled knot,
not that of a heavily loaded one.  (I also doubt that
folks are daily or even weekly using test devices
--an expensive proposition, I think (time & labor).)
This, at least, is the "security" of concern to most
of the cordage-using world,
although as some recent discussion about HMPE
cordage showed, there is some serious security-loaded
concern for that extreme material.

Now, one might suggest that the regular (daily,
even) usage of Fig.8 eyeknots goes some way
towards the sort of security testing I intend;
but that's not a formal method.


--dl*
====

Misreading? There were no qualifiers in your statement.

To me and maybe another out there, security of a knot is its ability to stayed tied, loaded or unloaded. I personally am more inclined to think about it staying tied while used and loaded, doing some work so to speak. I do tend to view the usage from a personal point of view, how I use them. But, I do investigate other's usage as well.

I reckon one could assemble a specimen in short rope or cord, chuck it in a drill and spin it up while shaking and slamming it against something. Perhaps that would simulate worse case scenario.

Ashely described and illustrated his method of cyclic testing and it has merit.

But, in a real world, if a knot is dressed and firmly tightened the actual chances of it losing its security and coming undone when unloaded is minimal. imo And it behooves the user to check their project along the way.

Should we truly be concerned about the rogue knot tyer who drags his knot down the road unwittingly and then uses it unchecked?
Shall we grade a knot based on sensible application and attention or not?

The local rope manufacturer does scheduled testing at a frequent level based on product demand, production, machine changes, etc., and sometimes it can be daily. Their test cell and drop tower are used extensively.
Given there are more than one rope manufacturer out there that operate similarly, I feel safe enough to say that it would be daily. For that kind of security test.
No, they are not specifically testing a knot exactly, but then again with the drop test they are. At least one knot type.

The HMPE challenge is out there to be worked on. We have seen so far that normal knotting rules/techniques are not necessarily applicable.

SS

alanleeknots

  • Sr. Member
  • *****
  • Posts: 524
Re: Zeppelin Loop and Double Dragon Loop - security based on experience
« Reply #13 on: April 20, 2014, 06:29:55 AM »
 
      Hi All,

      We talk a lots about zeppeline loop here, when you have a over hand knot pulling 100% force by the standing part,
      in my mind the over hand knot bound to jam, it is not just a common sense? I am confuse.

      Any way I have a few simple load test here to share with everyone.

      This 7-16 inch nylon braid(very soft rope) the tensile strength may be around 3000 to 3500 lbs no so sure,
      I test it with 1/4 of it tensile strength, I found it can be untie with a lot of effort, when I top up another
      200 lbs. to 1000 lbs. now you need tool to untie it. and the rest of test just jam so bad, even with tool is very
      difficult to untie.

      謝謝  alan lee
« Last Edit: April 20, 2014, 12:32:10 PM by eric22 »

alanleeknots

  • Sr. Member
  • *****
  • Posts: 524
Re: Zeppelin Loop and Double Dragon Loop - security based on experience
« Reply #14 on: April 20, 2014, 06:42:58 AM »

   More photo here.