A Brief Review of Side Bends: Application, Rationale, Accidents and Testing

Yıl 2020, Cilt: 3 Sayı: 2, 38 - 52, 30.12.2020

Robert Charles Chısnall

https://doi.org/10.36415/dagcilik.831394

Öz

When climbers descend from long routes, they sometimes need to join two ropes together. This is necessary in order to rappel a full rope length to the next anchor because the ropes are doubled up and looped through the anchor point. Troubles can arise when a climber attempts to pull one line in order to retrieve both ropes to prepare for the next rappel. The knot joining the two ropes could get snagged as it drags against the rock, over edges, into cracks and behind flakes (Baillie, ND-no date provided; Gommers, 2019; Kemple, 2006). A jammed knot might result in entrapment, preventing climbers from descending any farther unless they implement effective self-rescue strategies (Fasulo, 1996; Tyson & Loomis, 2006). Such events have been regularly observed and reported. Knots traditionally used to join two rappel lines together belong to a class of knots inconsistently called one-sided, offset, side, flat or indirect bends. These are knots that afford less resistance when dragged over rock surfaces owing to their shape and relatively smaller contact footprint. It is purported that they have a lower chance of getting jammed in cracks and behind flakes. Accidents have been linked to side bend failures, making them a topic of contention amongst climbers (AMGA & ACMG, 1999; Baillie, No date provided; Baillie, 1982; Chisnall, 1985, 2020; Evans, 2016; Gaines & Martin, 2014; Geldard, 2016; Gommers, 2019; Jackson, 2016a, 2016b; Helmuth & Burnhardt, 2003; Jones, 2012; Kirkpatrick, 2008; Lottman, 2016; Magnuson, ND; Martin, 2009; Martin, 2011; March 1976; Momsen, 2016; Powick, 2016; Prattley, 2016; Prohaska, 1998; Raleigh, 1998; Needle Sports, 2020; Siacci, 2019). Some side bends are more secure than others, although test data and theoretical modelling are not in agreement. The purpose herein is to critically review available information pertaining to these issues.

Anahtar Kelimeler

Side Bends, Rappelling Accidents, Test Reliability and Validity

Destekleyen Kurum

None

Proje Numarası

None

Düğümlerdeki İp katları ile ilgili Kısa Bir Değerlendirme: Uygulama, Gerekçe, Kazalar ve Test

Öz

Tırmanıcılar uzun rotalardan inerken bazen iki ipi birbirine bağlarlar. İpler ancak düğüm noktasından birleştiğinden ve bu kısımda ipin genişliğinin iki katına çıktığından dolayı bir daha ki bağlantıya kadar düz bir ip boyu inmek haliyle önemlidir. Bir tırmanıcı, bir sonraki ipe hazırlanmak için her iki ipi de çekmeye çalıştığında sorunlar ortaya çıkabilir. İki ipi birleştiren düğüm, sürüklenirken kayaya, kaya kenarlarına, çatlaklara veya tabakaların arasına takılabilir (Baillie, TY-Tarih yok; Gommers, 2019; Kemple, 2006). Sıkışmış bir düğüm, takılmaya yol açabilir ve etkili kendi kendini kurtarma stratejileri uygulamadıkları sürece tırmanıcıların inişe devam etmesini engelleyebilir (Fasulo, 1996; Tyson & Loomis, 2006). Bu tür olaylar düzenli olarak gözlemlenmiş ve rapor edilmiştir. Geleneksel olarak iki ipi birleştirmek için kullanılan düğümler, tutarsız olarak tek taraflı, ofset, yan, düz veya dolaylı kıvrımlar olarak adlandırılan bir düğüm sınıfına aittir. Bunlar, şekilleri ve nispeten daha küçük temaslı taban alanları nedeniyle kaya yüzeyleri üzerinde sürüklendiğinde daha az direnç sağlayan düğümlerdir. Çatlaklarda ve tabakalar arkasında sıkışma ihtimalinin daha düşük olduğu ortaya atılmıştır. Öte yandan, ip katlarındaki arızalarla ilişkilendirilen kazalar bu düğümleri tırmanıcılar arasında bir tartışma konusu haline getirdi (AMGA & ACMG, 1999; Baillie, TY; Baillie, 1982; Chisnall, 1985, 2020; Evans, 2016; Gaines & Martin, 2014; Geldard, 2016; Gommers, 2019; Jackson, 2016a, 2016b; Helmuth &Burnhardt, 2003; Jones, 2012; Kirkpatrick, 2008; Lottman, 2016; Magnuson, TY; Martin, 2009; Martin, 2011; Mart 1976; Momsen, 2016; Powick, 2016; Prattley, 2016; Prohaska, 1998; Raleigh, 1998; Needle Sports, 2020; Siacci, 2019). Her ne kadar test verileri ve teorik modelleme bu konuda uyum göstermese de bazı yan halkalar diğerlerinden daha güvenlidir. Buradaki amaç, bu konularla ilgili mevcut bilgileri eleştirel bir şekilde incelemektir.

Anahtar Kelimeler

Güvenlik Dügümleri, Rappelling Kazalari, Test Güvenilirligi ve Geçerliligi

Proje Numarası

None

Kaynakça

• Adams, C. C. (2001). The knot book: An elementary introduction to the mathematical theory of knots. Providence, RI: American Mathematical Society.
• All About Knots. (November 21, 2010). Knot Strength: Structures that Make a Natural-Fiber Knot Strong or Weak. Retrieved from, http://www.allaboutknots.blogspot.com
• Ashley, C. W. (1944). The Ashley book of knots. New York, NY: Doubleday & Company, Inc.
• Association of Canadian Mountain Guides (ACMG) and the American Mountain Guides Association (AMGA). (1999). Technical handbook for mountain guides: Alpine, rock, and ski guiding techniques. Golden: AMGA; Canmore AB: ACMG.
• Audoly, B., Clauvelin, N., & Neukirch, S. (2007). Elastic knots. Physical Review Letters 99, 164301. https://doi.org/10.1103/PhysRevLett.99.164301
• Baillie, R. (No date provided). The Side Figure Eight Knot for Rappelling. Explore Magazine Technical Series, 2.
• Baillie, R. (1982). Forces Generated in a Rappel. Explore Magazine Technical Series, 13.
• Bao, X. R., Lee, H. J., & Quake, S. R. (2003). Behavior of complex knots in single DNA molecules. Physical Review Letters, 91, 265506. https://doi.org10.1103/PhysRevLett.91.265506
• Bayman, B. F. (1977). Theory of hitches. American Journal of Physics, 45, 185-90. https://doi.org/10.1119/1.10652
• Borwick, G. R. (1973). Mountaineering ropes. Alpine Journal, 1973, 62-70.
• Budworth, G. (1983). The knot book. Kingswood, Surrey, United Kingdom: Elliot Right Way Books.
• Chamarro, A., & Fernández-Castro, J. (2009). The perception of causes of accidents in mountain sports: A study based on the experiences of victims. Accident Analysis & Prevention, 41 (1), 197-201. https://doi.org/10.1016/j.aap.2008.10.012
• Chisnall, R. (1985). The ORCA rock climbing safety manual, (2nd ed.). Toronto, ON: Ontario Rock Climbing Association, Ministry of Tourism and Recreation.
• Chisnall, R. (1995a). A few notes on testing knot strength and security, Part I. Terminology. Knotting Matters, 48, 29-34.
• Chisnall, R. (1995b). A few notes on testing knot strength and security, Part II. Testing methods. Knotting Matters, 49, 14-8.
• Chisnall, R. (1995c). A few notes on testing knot strength and security, Part III. A review of some research. Knotting Matters, 51, 40-9.
• Chisnall, R. (2000). The forensic analysis of knots and ligatures. Salem, OR: Lightning Powder Company, Inc.
• Chisnall, R. (2010). Knot-tying habits, tier handedness and experience. Journal of Forensic Sciences, 55, 1232-1244., https://doi.org/10.1111/j.1556-4029.2010.01451.x
• Chisnall, R. (2011). An analysis of more than 100 cases involving knots and ligatures: knot frequencies, consistent tying habits and noteworthy outliers. Australian Journal of Forensic Sciences, 43, 245-262., https://doi.org/10.1080/00450618.2011.561497
• Chisnall, R. C. (2016a). Analysing knot evidence: associating innate habits with sophisticated tying tasks. Scandinavian Journal of Forensic Science, 22 (2), 21-32., https://doi.org/10.1515/sjfs-2016-0005
• Chisnall, R. (2016b). Structural recognition and nomenclature standardization in forensic knot analysis. Science and Justice, 56, 282-301., https://doi.org/10.1016/j.scijus.2016.04.002
• Chisnall, R. (2016c). Categorizing innate tying behaviour and knot sophistication using fundamental principles. Journal of Forensic Identification, 67 (3), 447-472.
• Chisnall, R. (2020). Analysing knots and ligatures: tying principles, knot characteristics and structural changes. Forensic Science International., https://doi.org/10.1016/j.forsciint.2020.110272
• Construction Safety Association of Ontario (CSAO). (1975). Rigging manual. Toronto, ON: CSAO.
• Daily-Diamond, C. A., Gregg, C. E., O’Reilly, O. M. (2017). The roles of impact and inertia in the failure of a shoelace knot. Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences, 473, 20160770. https://doi.org/10.1098/rspa.2016.0770
• Denscombe, M. (1991). Personal health and the social psychology of risk taking. Health Education Research, 8 (4), 505-517., https://doi.org/10.1093/her/8.4.4505
• DMM. (December 1, 2012). ANSI standards for carabiners. Retrieved July 8, 2020 from, https://dmmprofessional.com/Knowledge/December-2012/ANSI-standards-for-carabiners
• Evans, T. (2016). A review of knot strength testing. International Technical Rescue Symposium (ITRS). Retrieved July 8, 2020 from, http://itrsonline.org/wordpress/wp-content/uploads/2016/11/Evans_Truebe.A-Rev iew-of-Knot-Strength-Testing
• Ewing, H. A. (1973). Knots and hitches in synthetic fibre ropes. The HydroElectric Power Commission of Ontario, Research Division Report.
• Fasulo, D. J. (1996). Self-rescue. Evergreen, CO: Chockstone Press.
• Filion, J.-M. (1979). Belaying theory - An update. North Bay, ON: Chevres de Montagne.
• Funderburke, R., Debruin, D. (2019). Know the ropes: Managing risk. Accidents in North American Climbing, 11 (4) Issue 72, 8-15.
• Gaines, B., & Martin, J. D. (2014). Rock climbing: The AMGA single pitch manual. A Falcon Guide. Guilford, CT; Helena, MT: Falcon Publishing, Rowman & Littlefield.
• Geldard, J. (October 2, 2016). Skills: Abseil Knots Explained. UK Climbing. Retrieved July 8, 2020 from, https://www.ukclimbing.com/articles/skills/abseil_knots_explained-8792
• Gommers, M. (December 14, 2019). Analysis of Offset Overhand Bends. An analysis of offset abseil rope joining knots. Sep 2017. VER 1.7., http://www.paci.com.au/downloads_public/knots/Analysis_Offset-Joining-Knots.pdf
• Hage, J. J. (2007). How capsizing, flipping and flyping of traditional knots can result in new endoscopic knots: a geometric review. Journal of the American College of Surgeons, 205, 717-723. https://doi.org/10.1016/j.jamcollsurg.2007.05.016
• Helms, M. (1987). Factors affecting evaluations of risks and hazards in mountaineering. In J. F. Meier, T. W. Morash, & G. E. Welton (Eds.), High-Adventure Outdoor Pursuits: Organization and Leadership (pp. 388-392). Columbus, OH: Publishing Horizons, Inc.
• Helmuth, E., & Burhardt, M. (2003). Get down on it: rappelling safely – with and without a pack. Rock and Ice, 128, 79.
• Jackson, J. (March 3, 2016a). Euro-Death Knot (Flat Figure-8) Mysteriously Fails. Rock and Ice. Retrieved July 8, 2020 from, http://www.rockandice.com/climbingaccidents/euro-death-knot-mysteriously-fails
• Jackson, J. (September 26, 2016b). Rappel Knot Fails, Climber Falls to Death on the Goat Wall. Retrieved July 8, 2020 from, https://rockandice.com/climbing-accidents/rappel-knot-fails-climber-falls-to-deathon-the-goat-wall/
• Kahneman, D. (2011). Thinking, fast and slow. Canada: Doubleday.
• Kemple Sr., T. (2006). Tech tip trad: avoiding the slab rappel epic. Climbing, 245, 74.
• Kirkpatrick, A. (December 8, 2008). The Ultimate Abseil Knot. Retrieved July 8, 2020 from, https://www.andy-kirkpatrick.com/articles/view/the_ultimate_abseil_knot
• Langseth, T. & Salvesen, Ø. (2018). Rock climbing, risk, and recognition. Frontiers in Psychology, 9, 1793. https://doi.org/10.3389/fpsyg.2018.01793
• Lazarus, E. D., & Constantine, J. A. (2013). Generic theory for channel sinuosity. Proceedings of the National Academy of Sciences of the United States of America (PNAS USA), 110 (21), 8447-8452. https://doi.org/10.1073/pnas.1214074110
• Llewellyn, D. J., Sanchez, X. (2002). Individual differences and risk taking in rock climbing. Psychology of Sport and Exercise, 9 (4), 413-426., https://doi.org/10.1016/j.psychsport.2007.07.003
• Lottman, D. (September 27, 2016). One of These Knots Can Kill You. Retrieved July 8, 2020 from, https://northeastalpinestart.com/2016/09/27/one-of-these-knots-can-kill-you/
• Maddocks, J. H., & Keller, J. B. (1987). Ropes in equilibrium. SIAM Journal of Applied Mathematics, 47, 1185-1200. https://doi.org/10.1137/0147080
• Magnuson, M. (No date provided). Use of the Overhand Knot for Rappels. Cragmont Climbing Club. Retrieved July 8, 2020 from, https://www.geocities.ws/danielzimmerlin/pages/stories/knot.html
• Marbach, G., & Rocourt, J.-L. (1986). Techniques de la Spéléologie Alpine, (2nd ed.). France: Chocanche.
• March, B. (1976). Modern rope techniques in mountaineering, (2nd ed.). Manchester, England: Cicerone Press.
• Martin, J. D. (March 9, 2009). The Euro Death Knot. American Alpine Institute [Blog post]. Retrieved July 8, 2020 from, http://blog.alpineinstitute.com/2009/03/euro-death-knot.html
• Martin, J. D. (March 7, 2011). Rappelling safely. American Alpine Institute [Blog post]. Retrieved September 22, 2020 from, http://blog.aplineinstitute.com/2011/03/rappelling-safely.html
• Martin, D. A., Boron, K., Obstalecki, M., Kurath, P., & Horn, G.P. (2015). Feasibility of knots to reduce the maximum dynamic arresting load in rope systems. Journal of Dynamic Behavior of Materials, 1, 214–224., https://doi.org/10.1007/s40870-015-0015-5
• Masson, J.-B., & Martin, J.-L. (2017). Sinuosities in vascular structures., European Physical Journal Applied Physics, 40: 351-356., https://doi.org/10.1051/epjap:2007161
• McKentley, J. (November 7, 2014). Rescue knot efficiency revisited. International Technical Rescue Symposium (ITRS). Retrieved July 8, 2020 from http:itrsonline/rescueknot-efficiency-revisited
• McKentley, J., & Parker B. (2000). One inch webbing anchor tests. International Technical Rescue Symposium (ITRS). Retrieved July 8, 2020 from, http://itrsonline.org/wordpress/wp-content/uploads/2015/11/Evans_Truebe_Webb ing-Anchor-Research-Final.pdf
• Microys, H. F. (1977). Climbing ropes. American Alpine Journal, 21, 130-147.
• Momsen, R. (2016). The Euro-Death Knot is NOT. Common Climber. Retrieved July 8, 2020 from https://www.commonclimber.com/edk.html
• Moyer, T. (March 22,1999a). Water Knot testing. International Technical Rescue Symposium (ITRS). Retrieved July 8, 2020 from, http://caves.org/section/vertical/nh/46/waterknot.html
• Moyer, T. (November 9, 1999b). Rope and gear testing, pull tests of the “Euro Death-Knot.” Retrieved July 8, 2020 from https://user.xmission.com/-tmoyer/tsting/EDK.html
• Moyer, T., Tusting, P., & Harmston, C. (2000). Comparative testing of high strength cord. International Technical Rescue Symposium (ITRS). Retrieved July 30, 2020 from https://user.xmission.com/-tmoyer/testing/High_Strength_Cord.pdf
• Needle Sports. (2020). Abseil Knots. Needle Sports. Retrieved July 8, 2020 from http://www.needlesports.com/Information/Need-Advice/Abseil-Knots
• Nute, H. D. (1986). Mirror images in knots. Journal of Forensic Sciences, 31, 272279. https://doi.org/10.1520/JFS11881J
• Oreskes, N. (2015). The fact of uncertainty, the uncertainty of facts and the cultural resonance of doubt. Philosophical Transactions of the Royal Society. A. Mathematical, Physical and Engineering Sciences, 373 (2055) 20140455., https://doi.org/10.1098/rsta.2014.0455
• Patil, V.P., Sandt, J. D., Kolle, M., & Dunkel, J. (2020). Topological mechanics of knots and tangles. Science, 367, 71-75. https://doi.org/10.1126/science.aaz0135
• Peranski, P., Kasas, S., Dietler, G., Dubocher, J., & Stasiak, A. (2010). Localization of breakage points in knotted strings, New Journal of Physics, 3, 10. Retrieved July 8, 2020 from https://doi.org/10.1088/1367-2630/3/1/310
• Pinker, S. (1997). How the mind works. New York, NY: W. W. Norton & Company. Pope, J. F. (1972). Tests of knots. Summit, April, 18 (2).
• Powick, K. (September 7, 2016). QC lab: What is the strongest rappel knot? Black Diamond®. Retrieved July 8, 2020 from, https://www.blackdiamondequipment.com/en_CA/experience-story?cid=qc-lab-wha t-is-the-best-rappel-knot
• Prattley, G. (June, 2016). Which bends for joining ropes? Testing and analysis of flat bends used for rope retrieval (Version 2.0). Over The Edge Rescue. Retrieved July 8, 2020 from https://canyonsandcrags.com/pdf/which-bend.pdf
• Prohaska, H. (1998). Gefahren bei anseilknoten [Dangers with rope knots]. Die Alpen 2/1998, 28-30.
• Raleigh, D. (1998). Knots & ropes for climbers. Mechanicsburg, PA: Stackpole
• Richards, D. (2005). Knot break strength vs rope break strength. Vertical Section of the National Speleological Society. Retrieved July 8, 2020 from, http://www.Caves.org/section/vertical/nh/knotrope=hold.html
• Ropeik, D. (2010). How risky is it, really?: Why our fears don’t always match the facts. Canada: McGraw-Hill Books.
• Rosenthal, J. S. (2005). Struck by lightning: The curious world of probabilities. Toronto, ON: Harper Collins Publishers Ltd.
• Roy, A. (December 13, 2012). Bye Bye Bowline: Time for a New Knot. Outside. Retrieved July 8, 2020 from, http://www.outsideonline.com/1911861/bye-bye-bowlinetime-new-knot
• Saitta, A.M., Soper, P.D., Wasserman, E., & Klein, M.L. (1999). Influence of a knot on the strength of a polymer strand. Nature, 399, 46-48., https://doi.org/10.1038/19935
• Schad, R. (2000). Analysis of climbing accidents. Accident Analysis & Prevention, 32 (2), 391-396. https://doi.org/10.1016/S0001-4575(99)00026-3
• Siacci, R. (October 28, 2019). In Defense of the European Death Knot. Retrieved July 8, 2020 from, https://www.climbing.com/skills/in-defense-of-the-european-deathknot
• Šimon, J., Dekyš, V., Paleèek, P. (2020). Revision of commonly used loop knots efficiencies. Acta Physica Polonica A, 138 (3)., https://doi.org/10.12693/APhycPolA.138.404
• Specter, M. (2010). Denialism. New York, NY: Penguin Books.
• Spörri, S. (2008). La valeur indiciale des noeuds [The indicative value of knots]. Unpublished dissertation. University of Lausanne, Ecole des sciences criminelles, Institut de Police Scientifique, Lausanne-Dorigny, Switzerland.
• Taleb, N.N. (2010). The black swan: The impact of the highly improbable. New York, NY: Randon House Trade Paperbacks.
• Taylor, S. J., Aral, S. & Muchnik, L. (2013). Social influence bias: A randomized experiment. Science, 341 (6146), 647-651. https://doi.org/10.1126/science.1240466
• Thompson, D. (2008). Counterknowledge. Toronto, ON: Penguin Canada.
• Turner, J. (1996). On theories of knots. In J. C. Turner & P. van de Griend (Eds.). The History of Science and Knots, Series on Knots and Everything – Vol. 11. (pp. 261-297). River Edge, NJ: World Scientific Publishing Co.
• Tyson, A., & Loomis, M. (2006). Climbing self-rescue: Improvising solutions for serious situations. The Mountaineers Outdoor Expert Series. Seattle, WA: The Mountaineers Books.
• Udall, J. R. (1987). Thinking about safety. In T. W. Meier, T. W. Morash, & G., E. Welton (Eds.) High-adventure outdoor pursuits: Organization and leadership. (pp. 380387). Columbus, OH: Publishing Horizons, Inc.
• van de Griend, P. (1996). A history of topological knot theory. In J. C. Turner & P.
• van de Griend (Eds.). The history of science and knots, Series on Knots and Everything – Vol. 11. (pp. 205-260). River Edge, NJ: World Scientific Publishing Co.
• Walker, D. J., & McCullar, R. (November 7, 2014). Slow Pull Testing of Progress Capture Devices. International Technical Rescue Symposium (ITRS). Retrieved July 8, 2020 from, http://itrsonline.org/slow-pull-testing-of-progress-capture-devices/
• Warner, C. (1996). Studies on the behaviour of knots. In J. C. Turner & P. van de Griend (Eds.). The history of science and knots, Series on Knots and Everything – Vol. 11. (pp. 181-203). River Edge, NJ: World Scientific Publishing Co.
• Weller, S., & Davies, P., Johanning, L. (2015). The influence of load history on synthetic rope response. Ocean Engineering, 96, 192-204. Retrieved July 8, 2020 from https://doi.org/10.1016/j.oceaneng.2014.12.013
• Wheelock, W. (1967). Ropes, knots & slings for climbers, (revised ed.). Glendale, CA: La Siesta Press.
• Wilde, G. J. S. (1998). Risk homeostasis theory: An overview. Injury Prevention, 4: 89-91. http://dx.doi.org/10.1136/ip.4.2.89
• Zabrok, P. (2003). Techtip aid climbing: The Alpine Butterfly–the better way to join free-hanging fixed ropes. Climbing, 222, 78.
• Zartman, B. (2005). Better beta: 5 Tips to get you outta that fix. perfect lead. Rock and Ice, 142, 110.