Knots and Me
Knot Strength
In the summer of 2006 I was allowed to use the materials testing lab at Purdue University's School of Materials Engineering to test the strength of a variety of knots:
- Unknotted Line (as a control)
- Zeppelin Bend
- Double Figure 8 Bend
- Johnson Hitch
- Full Nelson Loop (almost a Lehman's Locktight Loop I)
- Full Nelson Bend
- Full Nelson Bend Simple
- Fixed Noose
The data from those tests is available as a .zip file, and it is free for anyone to review and share as long as the accompanying ReadMe.txt file is included.
I didn't get the knot bug during my short and inglorious stint in the Boy Scouts, but in recent years they've become a minor passion of mine. I bought the Ashley Book of Knots when my son was born, and before long I'd decorated his stroller with a variety of braids, sinnets, knob knots, and monkey's fists. I never leave home without a bit of cord in my pocket that I can use to practice bends and loops if I find myself with time to kill.
Not long after arriving in Indiana (summer of 2002 or 2003) I started experimenting to see if I could come up with new knots that might have some merit. I started with loop knots, to see if I could improve on the bowline in some way. Before too long I'd produced an elaboration on the double bowline which seemed like it would be very secure.
As it happens, I was right. It turned out that I'd independently rediscovered the Water Bowline, which Geoffrey Budworth's Ultimate Encyclopedia of Knots and Ropework describes as "certainly one of the more secure bowlines, and it withstands rougher handling and dragging over rugged terrain."
I also came up with a simple bend which turned out to be a non-loop version of the Eskimo Bowline. I have no idea how secure or stong it is, but it has a pleasant simplicity to it, and can be tied very easily. It comes with a big caveat, though: if you apply the load to the wrong end of the bight that forms half of the knot, it will not hold at all! Because it would be quite easy to tie it the wrong way, I wouldn't recommend it for any but the most trivial uses.
The Full Nelson Loop (almost a Lehman's Locktight Loop I)
My next effort was what I came to call (at the suggestion of my friend and co-worker, the late Rod Heckaman) the Full Nelson Loop.
I've worked out a few different variations of it. The current version seems to draw up more neatly and may be a bit easier to tie and untie than the original arrangement. Both versions can have the working end finish either inside our outside the loop, but I prefer it on the outside.
For several years I was able to sustain the illusion that I might have been the first to discover this knot. On June 11, 2008, I learned that Dan Lehman had beaten me to it by several years. His Locktight Loop I has one more wrap in it than mine (and is no doubt the better for it), but it's otherwise identical to my version 2. Sic transit gloria mundi. I still like my finger-twirling method of tying it, and it works for Dan's version, too.
Why would you use it? To tell you the truth, I'm not sure. I suspect it may be a bit more secure than a normal bowline, and it unties more easily than the water bowline. By the same token, though, I think it may be less secure than the water bowline. I like it partly because it's fun to use the finger-twirling shortcut for tying it. Tests I conducted at Purdue have shown it to be at least as strong as a bowline.
The Full Nelson Exploding Bend
After I found the loop, I kept exploring and tried it as a bend. The basic bend didn't excite me much, but I found that if I modified it a bit and slipped it, it formed what appears to be a secure bend which fits Peter Suber's definition of an "exploding" bend.
I've got high hopes for this knot. I think it has some real utility (an opinion not shared by all), and if it does prove to be secure and strong, it may actually find it's way into common use. (I can dream, can't I?)
As with the loop, I've worked out a variation on my original design that I think represents a significant improvement over the first version. While the original bend would release cleanly once the ripcord was pulled free, the bend could easily tighten so much that the ripcord would jam and become impossible to release. This tendency is apparent in the video below.
When I made the video it inspired me to take another look at the jamming problem, and I quickly came up with the second, improved version demonstrated below. Tying it begins the same as the original, but after the second wrap of the working part you fold the bight back on top of the wraps, put another wrap around everything, then tuck the slipped working end through the loop formed by the two folded-over parts of the bight.
The resulting bend can be put under a great deal of tension and still release with a gentle pull and no fear of jamming. To make sure it doesn't slip, you need to take care to make your wraps as snug as possible, and the best practice would be to replace the bight with a fixed loop.
A known antecedent: the Johnson Hitch
The Full Nelson Exploding Bend turns out to be similar to (though still distinctly different from) an unpublished exploding bend that Prof. Suber developed some years ago. Before he got around to publishing his version of the bend, it was independently discovered by Roger Johnson, a forest-fire fighter out west who uses it as a quick-release lash for holding a coil of fire hose on a backpack. His account appeared in the March 1990 edition of Fire Engineering.
The drawing above is mine, and while the hitch (bend) will work that way, Johnson's published description replaces the bight on the left with a fixed loop. Based on some limited experiments with it, I'd strongly recommend using a loop – a bight can slip.
The Johnson hitch has at least one significant advantage over the Full Nelson bend: if you tie it with a fixed loop on one line, you can snug the other line down and apply tension as you tie it. The Full Nelson needs to be tied while the lines are slack, and then tension can be applied afterwards.
The Fixed Noose
I also came up with a not I call the Fixed Noose. I'd hoped that all the wraps would make it exceptionally strong, like the blood knot is reputed to be. Unfortunately, when I tested it, it was one of the weakest in the test group. You win some, you lose some...
As it happens, this isn't really a novel knot. Paging through my Ashley Book of Knots I recognized it as a variation of a Heaving Line knot (#538 on pg. 88 of Ashley). It appears to be the same as mine, except that I pull out a loop before threading the working end through one of the bends in the S to start wrapping it.
I hope you'll give these knots a try and let me know what you think of them – especially if you come up with a good application for them.
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