Exploring the Secrets
of Knotted Cordage to Understand How Knots Work
KM, Knotting Matters is the quarterly newsletter of the International Guild of Knot Tyers.
Ashley, Clifford W. The Ashley Book of Knots. Garden City, N.Y.: Doubleday & Company, Inc., 1944.
Barnes, Stanley. Angling Knots in Gut and Nylon. Birmingham: Cornish Brothers Limited, 1947.
Budworth, Geoffrey. Knots and Crime. London: Police Review Publishing Co. Ltd., 1985.
Chisholm, Richard M. ÒPreferred Knots for Joining Hollow Braid Poly Rope,Ó ISSW Õ98 Proceedings. Washington State Department of Transportation for the International Snow Science Workshop, 1998.
Chisnall, Robert (editor). Rock Climbing Safety Manual. Ontario Rock Climbing Association, 1985.
Chisnall, Robert (editor). Rock Climbing Safety Manual. Ontario Rock Climbing Association, 1985.
Chisnall, Robert. The Forensic Analysis of Knots and Ligatures. First Edition. Salem, Oregon: Lightning Powder Company, Inc., 2000.
Day, Cyrus L., 1947, 1955, 1970, 1986: The Art of Knotting and Splicing. Fourth Edition. Edited by Ray O. Beard, Jr. and M. Lee Hoffman, Jr. Annapolis, Maryland: Naval Institute Press.
Frank, James A., and Jerrold B. Smith. Rope Rescue Manual. Second Edition Santa Barbara, California: CMC Rescue, Inc., 1992 (1987).
Kennedy, E .S. (Chairman), F. C. Grove (Secretary), J. J. Cowell, H. B. George, W. E. Hall, and R. C. Nichols. ÒReport of the Special Committee on Ropes, Axes, and Alpenstocks. Read before the Alpine Club on July 5, 1864.Ó The Alpine Journal, Volume I, No. 7, September 1864. A note at the top of this report comments ÒThe report presented by this committee was adopted by the Club and ordered to be circulated among all its members.Ó
Long, Adam, Malcolm Lyon, and Graham Lyon. Industrial Rope Access: Investigation into Items of Personal Protective Equipment. Prepared for Lyon Health and Safety Executive. Contract Research Report 364/2001. Dent Sedbergh Cumbria UK: Lyon Equipment Limited, 2001. To link to this article in html format, use the following url: http://www.google.com/search?q=cache:0awUQ_Ubue8J:www.hse.gov.uk/research/crr_pdf/2001/crr01364.pdf+%22Personal+protective+equipment%22+%2B%22Adam+Long%22&hl=en&ie=UTF-8. This article can also be found on Google by entering ÒPersonal Protective EquipmentÓ +ÒAdam Long.Ó This report by Long et al. comes to the same conclusion about variation in knot strength, but it offers no explanation. This paper can also be found on Google by entering ÒPersonal Protective EquipmentÓ +ÒAdam Long.Ó
Luebben, Craig. Knots for Climbers. Second Edition. How to Climb Series. A Falcon Guide. Guilford, Connecticut: Falcon; An imprint of The Globe Pequot Press, 2002 (1995).
Montgomery, Neil R. Single Rope Techniques, a Guide for Vertical Cavers. Sydney: The Sydney Speleological Society, 1977.
Pieranski, Piotr, Sandor Kasas, Giovanni Dietler, Jacques Dubochet, and Stasiak Andrezej. ÒLocalization of Breakage Points in Knotted Strings.Ó New Journal of Physics 3 (2001) 10.1–10.13 Published 14 June, 2001. http://www.njp.org http://www.math.utah.edu/~lars/spaghetti.pdf (16 Nov., 2002). PII: S1367-2630(01)20698-3 1367-2630/01/000010+13$30.00 © IOP Publishing Ltd and Deutsche Physikalische Gesellschaft
Raleigh, Duane. Knots & Ropes for Climbers. Mechanicsburg, Pennsylvania: Stackpole Books, 1998.
Setnicka, Tim J. Wilderness Search and Rescue . Edited by Kenneth Andrasko. Boston: Appalachian Mountain Club, 1980.
The authors provide references to other pertinent studies and acknowledge other sources.
To link to this article in html format, use the following url: http://www.google.com/search?q=cache:0awUQ_Ubue8J:www.hse.gov.uk/research/crr_pdf/2001/crr01364.pdf+%22Personal+protective+equipment%22+%2B%22Adam+Long%22&hl=en&ie=UTF-8
Turner, John C., and Pieter van de Griend. History and Science of Knots. Series on Knots and Everything – Vol. 11. Singapore and River Edge, New Jersey: World Scientific Publishing Company Pte. Ltd., 1996.
Vines, Tom, and Steve Hudson. High Angle Rescue Techniques. The National Association for Search and Rescue. Dubuque, Iowa: Kendall/Hunt Publishing Company, 1982, 1992. Second Edition. New York: Mosby, 1999.
Warner, Charles. ÒStudies on the Behaviour of Knots.Ó Chapter 10 (pages 181–203) in Turner, John C., and Pieter van de Griend. History and Science of Knots. Series on Knots and Everything – Vol. 11. Singapore and River Edge, New Jersey: World Scientific Publishing Company Pte. Ltd., 1996.
Warner, Charles. A Fresh Approach to Knotting and Ropework:
Knots Arranged According to their Structure.
Picton, New South Wales 2571, Australia: Privately printed, 1992, 1993, 1995.
ISBN 0 9592036 3 X.
Wright, C. E. I, and J. E. Magowan. ÒKnots for Climbers,Ó Alpine Journal, 1928. Part I, 120–140; Part II, 340–351.
A handful of devoted writers have made significant contributions to our store of knowledge about how knots work.
From the earliest treatises on knots, written mainly by sailors, through the encyclopedic works by Ashley and Day in mid-20th century, to the standard modern presentations and reports of recent scientific studies, various writers have supplied us with a storehouse of information about knots. We are fortunate to have a reports of investigations of knot history and knot lore such as those collected by Turner & van de Griend, conclaves of knot enthusiasts such as the International Guild of Knot Tyers, and reports of the practical experience of climbing, rescue, sailing, and angling groups. Their work is essential to anyone interested in knots and knot tying. Taken together, these sources are rich in discussing knot performance.
All of the major knot books mention the three aspects of knot performance, security, stability, and strength. A few of them describe tests of knot security. Many of them directly mention knot structure, the parts of a knot such as a bight or crossing, knot strength and where knots break, friction, nip, load, and instability. Some show that previous explanations of how knots work are mistaken. The best of the writers, like Clifford Ashley and Cyrus Day, admit the limits of their ability to understand knot performance.
But these knot studies have been limited mainly to tying and using knots and neglect many aspects of knot performance. I have not found many studies of knot mechanics or discussions of how knots work and how they fail to work. None of the knot books that I have seen explain the devices that knots are made up of or show how they create friction, and only recently have physicists published diagrams of the forces on a loaded knot.
The curious thing about the neglect of knot performance is that so many writers come so close to the matter, but do not directly ask the fundamental questions, follow an analytical procedure, examine the function of a knotÕs structural parts, or present a description of knot performance. They do not discuss why ropes configured in their various ways behave the way they do.
The neglect of knot study is not limited to knot specialists or the writers of knot books. Knot performance has been largely ignored by both the popular and technical press. Few scientists and engineers have taken note of knots as physical devices, and the general public seems indifferent to them. Mathematicians, who have contributed so much to our understanding of knot structure, have understandably not directed their attention to studying the environment, materials, and mechanics that affect the performance of practical knots.
Many other devices and gadgets have engaged the interest of both serious and popular investigators as well as of the reading public. Numerous books explain to a lay person how things work. In any number of encyclopedias and ÒHow Things WorkÓ books, a lay person will find explanations of how other devices work, everything from electric toasters to atomic bombs, and usually in a page or two. A recent volume tells the history of the screw in delightful prose, and others trace the development of everyday things. But there is precious little on the way knots work. Even the major encyclopedias fail to take up the subject.
When I ask questions about the physical properties of knots—whether of ski patrollers, anglers, or sailors or of engineers and physicists—the most frequent reply is, ÒI had never thought of that.Ó In view of the fact that security, stability, and strength are the chief aspects of knot performance and are the fundamental properties in knots, it is unfortunate that so many knot books fail to treat them at length, that so many ignore the distinction, and that so many neglect the subject altogether.
Charles Warner makes numerous brief comments on the security and strength of knots. Following is a topical index to references on knot performance in his book A Fresh Approach to Knotting and Ropework.
viii. Preface. General comment on structure and performance.
31 Twin knots, slipping, sliding
34 Strength and security
34 Deformation
59 ¼spaces¼
46.2 A Òlong line of frictionÓ
33 Binding, crossing, etc.
39 Arrangement
143 Quick Release, 127, 146, 153, 153 (bis)
163 Unequal thickness, 166, 178
163 Backup, 52 (terms), 178 ; tightened Òon to itselfÓ (or not); 207 (Òextra securityÓ)
168 Wear on rope; kindliest knot
210 Testing
xii load¼tension, 36 slip; 44 nip definition., 94 Òfriction over long lengths,Ó 97 1/3, 127, 131, 139, 141, 142, 142 bis, backup 144, 152, 163, 164, 174, 165, 168, 171, 204, 241, 207; Ch. 11; 133 Ch 15 ff.
xiii 1/3 Binding, 30 upset (dressing + snugging), 42 Twins, conversion; 145!, 165? (Twins)
23, 27, 34 (nothing on breaking point); 73, 69, 128 1/3, 130 3/4 ! f., 146, 166; Tests and comparison: 47 (Bimini Twist), 200, 210
In his discussion of knot failure, Clifford Ashley is careful
to distinguish knot security from knot strength. As aspects of security, he
mentions two kinds of failure, slipping and deformation, which he calls
capsizing. When he describes his tests of security, however, he does not
mention capsizing. In his presentation of individual knots, he often comments
Òthis knot is secureÓ or Òit slips,Ó or Òit capsizes,Ó or words to that effect,
but he never treats these topics directly nor discusses them again at length.
Ashley made numerous other comments on knot security, slippage, and coming
apart.
Ashley mentions security frequently:
273, 274 Tests of security
In Chapter 18 on Bends, Ashley writes more often of security, as would seem natural.
50 #295 Òdoes not untie or slipÓ [=secure]
54 #331 ÒThe LinemanÕs Loop is secureÓ
55 #337 Drapper (sp?) Fly Hitch Òis particularly secureÓ
56 #343 ÒWater Knot ... is both secure and strong.Ó {This is contrary to current views}
56 #345 Òthe most secure of the threeÓ
59 #356 ÒNeither is particularly secure.Ó
60 #373 Ò...provided the surface is not too slick,Ó (a particular knot will suffice)
65 #407 a knot that will not Òwork looseÓ
74 #459 Òperhaps not so secureÓ
78 #488 Òwhich is equally secureÓ
189 #1045 Òmay appear to be insecureÓ (See this reference)
218 #1198 Sacrifice symmetry to security
257¦4 Òa wet rope is both stronger and more slippery than a dry one.Ó
#1409 Instability
258 #1410 Contrast of Strength and security in a Sheet Bend and Overhand Knot
268 #1480–1 Clear distinction and contrast between strength and security.
222 ¦3 Quote. (See this reference)
257 ¦2 Ònot to be trustedÓ
258 #1406–1409 This is a particularly important reference.
259 #1406 This is unclear to me: ÒWith the ends arranged as shown, it is more secure bend than many far more trustworthy knots.Ó This sounds self contradictory. Is Ashley being wry here, or is this a slip? Perhaps he meant Òfar more trusted knots.Ó
16 #631 Tests. My initial tests were not weighted
273 Results of security tests
267 #1474
Comparative security of various knots for joining ropes of unequal circumference:
Sheet Bend, #1464–71, various bends, Square Knot, Double Carrick Bend, #1405–1407.
The Bowline has been under suspicion for some time:
186 #1015 A Lieutenant Alston
258 #1405 This condemnation of a Granny Knot is not entirely unequivocal. This is about as close as anyone ever gets to praise for a Granny Knot
216 #1183 Tendency for a Half Knot, used as a crossing knot: Òwhen not in use they would be liable to loosen and get out of adjustment.Ó