Descender, a full history

Vertical caving terminology and methods > Personal SRT gear

Descender

The device used to abseil. These rely on friction to control speed. The user can alter the friction and weight of the down rope in their hand, in order to alter the speed as needed. Descenders are usually connected to the D-ring via a carabiner. Caving descenders are designed to cope with muddy ropes, and do not need to be removed from their carabiner in order to connect or disconnect the rope. Climbing belay devices can almost always be used as a descender, but many designs normally cause twists in the rope, and most have relatively poor heat dissipation, which can be problematic on long abseils. Many need to be removed from their carabiner in order to connect or disconnect them from the rope, which risks dropping them while performing manoeuvres, and keeper cords are needed for them. Most (such as a Petzl GriGri) are not designed to cope with muddy ropes, and can be damaged or blocked up, preventing their adjustment mechanisms from working.

History

Early devices are likely to have relied on twisting the rope a few times around a rod, spool or ring, sometimes with ridges to guide the rope into specific locations. In 1550, polymath Gerolamo Cardano published a book called De Subtilitate Rerum (On The Subtlety/Intricacy/Finesse Of Things) in the Holy Roman Empire (now Italy), which included details of two descenders. (An English translation of a later edition is available, but it gets some of the details wrong.) The first of these, he attributed to Heinrich Cornelius Agrippa von Nettesheim (whose first name might be written as Henry or Henricus), from the Holy Roman Empire (now Germany). It fed the rope through a steel tube about 10 cm long, with a slight helical twist, not as extreme as a corkscrew (the diagrams show a groove like a screw thread, which would not have actually worked the way it was described, and is likely to be a mistake by the illustrators). This was surrounded by a brass casing, with two attachment points at the bottom, with short ropes that were attached to a boatswain's chair sit harness. The down rope could be pulled downwards to increase the friction (which would not have worked with a screw thread groove), or the device could be pulled towards the body in such a way that it bends the down rope. Pulling the down rope towards the body then pulling it up the side of the device would stop the motion completely. The date of its creation is not specified, but it was probably 1520-1530, when Heinrich Cornelius Agrippa von Nettesheim was adding details of how to cast metals to his book series De Occulta Philosophia, and definitely before his death in 1535. Its use was not stated, but Heinrich Cornelius Agrippa von Nettesheim had recently finished a career in the Spanish and Holy Roman Empire militaries (1508-1515). He was an academic lecturer from 1509 to 1519 and continued with academic research afterwards in many parts of the Holy Roman Empire, and was established as a polymath, well known for having a great interest in science, mechanics, natural magic, alchemy and philosophy. He likely researched it out of curiosity, believing it to have some use for rope access. Knowledge of it, however, seemed to remain entirely within academic circles, and it was not described as being used anywhere. Gerolamo Cardano stated that he had seen and held the actual devices, so they were not just theoretical.

The second descender described by Gerolamo Cardano was in use by sailors, probably sailing on local rivers in the Holy Roman Empire (now Italy). His book, which was actually written in 1549-1550, described it as a current technique, and I have not found any earlier or later references to it. The sailors would take a stick wide enough to sit on, wrap the rope around it 3-4 times, then sit on the stick as a boatswain's chair. By holding the down rope, they could alter the friction, but this was extremely clumsy, as it was below their body, between their legs, and would only be usable when held upwards. The fact that the up rope was on one side of the stick and the down rope was on the other side, caused the stick to tilt dangerously. The stick needed to generate more friction from the buttocks or legs than from the rope, or it would rotate uncontrollably, friction burning the legs, and the rope would rapidly walk off the end of the stick (which it did every time during testing for the photograph). Testing showed that the up-rope needed to be on the body side of the stick, in order to not have it roll down the legs, where control would be lost even more easily. Both of these issues could easily cause inexperienced users to fall off, and as a result, this method never caught on. It was probably just used by one ship's crew, experimentally or for entertainment, and is unlikely to have been standard practice. It is an utterly terrible idea for a descender, and was quickly dismissed by Gerolamo Cardano as being too dangerous.

One of the earliest known descenders was described by polymath Galileo Galilei in 1638 in the Republic of Florence, Holy Roman Empire (now Italy), as something created by another (probably fictional) young Italian, to get down from a window without getting the rope burns that he got the first time. Which he needed to do more than once. For reasons. It consisted of a wooden cylinder with a spiral groove carved into it, which the rope spiralled around. To keep the rope in the groove, a sleeve made from wood or tin was wrapped around it. By gripping the sleeve, the pressure on the rope could be adjusted to control the speed. This descender was then adapted by French inventor Nicolas Grollier de Servière. The new version had a handle and rope guide at the top, and attachment ropes holding a boatswain's chair as a sit harness at the bottom. The idea of holding the lower rope to increase the friction was mentioned, and the descender's sleeve was therefore deemed pointless. The exact date of this change is not recorded, but it is likely to have been shortly after obtaining the 1647 French translation of Galileo Galilei's book, and definitely before his death in 1689. Its purpose was to descend a castle wall during an invasion. The Galileo Galilei descender was updated again in 1725 by German engineer Jacob Leupold from the Holy Roman Empire (now Germany), to correctly guide the rope as it left the bottom of the descender. Jacob Leupold suggested that it could be used as a fire escape descender. The updated version appeared in Oekonomische Encyklopädie volume 13 (page 82 and appendix) by Johann Georg Krünitz, in 1778 in Berlin, Prussia, Holy Roman Empire (now Germany), and this caused it to inspire many future fire brigade descenders.

In 1787, Genevan mountaineer Horace Bénédict de Saussure used a walking pole as a descender, while descending from Mont Blanc in the French Alps. With the rope fastened to an ice axe and held by assistants at each end, he sat on the rope facing downhill, pulled it up between his legs, and looped it over a walking pole held across his thighs. The friction could be adjusted by lifting the pole, or by his assistant pulling on the down rope. Basically, this was a descender, where the level of friction was controlled by the rope running between his buttocks. Perhaps less comfortable than some other methods, but at least it would have warmed nature's pocket. As an additional benefit, it features an automatic braking system that reacts to how tightly you clench when frightened by the speed. He tried to have the depiction of this suppressed as he felt it was unflattering, and had it replaced with one where he was walking (and much younger), not realising that he had in fact made history by being the first known mountaineer to use a descender.

In 1851, fire brigades in Ulm, German Confederation (now Germany) were using a ring attached to their belt as a descender, by wrapping the rope through it twice. This approach had spread to fire brigades in Austria, Austo-Hungarian Empire, by 1872, though they would wrap it three times. This idea is what developed into a carabiner wrap. By 1877, a variation had appeared in Ulm, where the rope went through the ring, around the body, then back through the ring.

There are countless examples of descenders from the late 1800s, which were intended to be used as fire escapes, the vast majority of which can be seen in USA patents. This is mainly because the American patent system allowed any tiny change to be patented, while patents in other countries normally require more significant changes. Many inventions from other countries simply never got patented, even though they were used, and evidence of them can only be found in occasional books, newspapers and magazine adverts. (Also, many other countries have not released full details of their patents yet, with only summaries available in some cases, giving no details of the designs.) The first known fire escape descender to be properly documented was created by American Albin Warth in 1860, which worked by twisting the rope through a tube, just like the descender described by Heinrich Cornelius Agrippa von Nettesheim 3 centuries earlier.

Also in 1860, a design by American James Hobbs worked by wrapping the rope around several friction bars, with a handle for adjusting the friction.

In 1865, German fire brigades used an Archimedian scroll descender which operated on exactly the same principle as the Simple, with the two bobbins attached directly to a waist belt side by side instead of above each other. The friction was said to be fairly low, and the rope needed to be prepared using rosin to make it grip more once the bobbins wore down, but this is probably because of the orientation of the bobbins, and because they did not expect speed to be controlled with a hand. American E. K. Graves made a design in 1878 that used the same principle as the Simple, but with two extra bends that the rope had to twist around. This idea was clearly derived from the approach used by James Hobbs.

American Oscar F. Davis then changed the orientation to remove the extra corners and match the Simple in 1882, and added a lever to adjust the friction.

American John A. Griswold made a lever cam design in 1870, that allowed the friction to be adjusted.

American George A. England made a design that twisted the rope through a series of holes in 1871.

Americans W. M. Harrison and H. T. Seeley made a design that wrapped the rope several times around a spool or rod (like the future rappel log) in 1872.

American Hammond Marshall created a design that clamped the rope through a gap, in 1872.

American Thomas P. Forsyth created a device that functioned like gripping pliers in 1874.

French inventor Frederic Holthausen created a spiral descender in 1876 (the Descenseur à Spirale or Sauveteur à Spirale), which worked in almost exactly the same way as the design discribed by Galileo Galilei, though without being able to squeeze the case to regulate the speed. His French company was selling them for the fire service in 1876 and 1899, and they continued to be made by different companies for the next 100 years; not bad for such an old design. Also in 1876, Mr. Martin from France created a similar design where the sleeve could be rotated to adjust the number of turns during use.

A Belgian inventor created a device that functioned exactly like a rack, which was presented at an international rescue conference in 1876. The number of bars could not be changed during use, and it could only be threaded on to the start of the rope. By the next year, these were being sold by German fire brigade suppliers from southern parts of the German Empire (now Germany).

Several approaches were based entirely on slowing down a pulley that the rope ran over. Some ran a wooden block against the pulley, some gripped the pulley's axle, and one used pressure between two pulleys. American Edward W. Averell created a design that trapped the rope at an angle between two pulleys, with a piston slowing one of them to control the speed, in 1877.

American J. Broughton combined a clamp and spool in 1877. By 1877, fire brigades in Austria, Austro-Hungarian Empire, were wrapping the rope through a carabiner several times, known as a carabiner wrap, to lower someone. By 1878, fire brigades in Stuttgart, German Empire (now Germany) were using carabiners as a descender to abseil, using a carabiner wrap, something still used in military abseiling today. This is a logical progression from the previous belt ring, but better carabiners made it safe to do so with a carabiner instead.

American J. Amess combined pliers and friction bars in 1878. In 1878, the French Navy published details of the descenders that were available for maritime usage, and all of them were fire escape descenders. None had been developed for sailing. No examples could be found in the British National Maritime Museum's extensive collections, suggesting that in spite of how much time sailors spent working with ropes, they had never previously used descenders, with the exception of their shoes. A carabiner with an integrated pulley and braking lever was designed in 1882 by the German Lohner brothers, made for the fire brigades. It would automatically add friction when released, and reduce friction when a lever was pulled. This was described as being used either as a descender, or for lowering people, the way a modern Petzl GriGri is. The inventors complained about the pulleys falling off existing designs (which were not integrated within a carabiner), which seemed to also have a similar lever. No existing devices were described in a comprehensive manual from that region 5 years earlier. American Ray Howland created a design that used a second rope to create friction against the main rope in 1883 (a very bad idea, since it could easily burn through from the friction, though hemp would cope with this a little better than nylon). American Daniel Luscher created a design that relied on bending the rope between two bobbins in 1883. This idea would never have worked the way it was described, because it can only function if there is a very heavy weight on the down rope. However, it should be noted that this is exactly the approach that can be used to descend a loaded rope with a Simple or Stop to reach a casualty, as part of an improvised rescue. Americans Charles M. Travis and Casper H. Stibolt created a design in 1883 that was little more than a rubber grip which could be squeezed around the rope, instead of holding it directly in the hands, reducing the likelihood of injury. This is really no better than a pair of gloves, and still risked losing strength and falling. Americans Joel Conover and Frank Conrick created a design that trapped the rope between two bars in 1887. American Ernst Bovensiep created a spool design where the diameter of the spool could be adjusted, creating friction where the rope rubbed against the sprung sides of the casing, in 1888. The rapid proliferation of fire escape descenders calmed down after 1891, perhaps because the patent office finally realised that the designs were largely copying each other, but also largely because of steadily improving American fire escape regulations which allowed cities to mandate better fire escapes. By 1901, New York required external stairways on housing blocks, rather than ropes, and other cities soon followed.

In 1893, Swedish inventor Anders Wilhelm Lewin created a rope grabbing device that also featured a descent lever, so it could be used as both an ascender and descender. In 1897, Austrian inventor Zdzislaw Szpor created a dedicated belay device for self belaying, for use with rope access, in the Austro-Hungarian Empire, now Poland. The device was incredibly complex, and almost certainly had been through many years of development beforehand (it was definitely created in 1896 or earlier), though no previous versions were found. It could safely catch a fall, could be adjusted for different sized ropes, and could be used as a descender after catching a fall, using the same basic approach as James Hobbs had used. Although it was clearly designed as a belay device, it was registered in the USA as a fire escape descender, and probably also Canada, so is likely to have been widely available.

C. Wissemann stated that carabiners were being used as a descender by mountaineers in Germany/Austria by 1898, using the carabiner wrap method from the fire brigades. New Zealand inventor Robert Cockerell (who specifically wrote as a British subject!), patented a lever cam device in 1902, which worked as a friction descender when pulled in one direction, and an ascender when pulled in the other direction. It was almost certainly created in 1901 or earlier. In 1902, French inventor Alfred Wyss-Baumgartner patented a descender that used a rather unusual method of tightening springs around the rope. In 1903, British inventors P. and W. MacLellan and James Dougall patented a painting platform, which featured a lever that could be used to turn it into a descender. By 1904, designs appeared that made it easier to put the descender onto the rope using a bight of the rope. One of these was extremely similar to a figure of 8 descender, with an additional hole to get a little more friction, which was in use in Leipzig and Stuttgart, German Empire (now Germany). Ring descenders were used by mountaineers/climbers in 1910 in Germany and Austria, copying the fire brigade approach from 60 years earlier, though they needed a sling to be threaded through them as a sit harness, because they were not attached to a belt. They were not intended to be used as a descender, and were simply forged iron rings sold for general purpose at ironmongers. They were criticised in 1913 for causing the rope to twist and become worn, if they were used too often, though this was due to the way the rope was being wrapped around them, rather than a problem with the rings themselves. In 1922, German climbing newsletters stated that they were sold in hardware shops for the purpose of connecting ropes to waggons ("string rings" for waggons or carts), and were 6 cm in outer diameter. They could only be threaded on to the start of a rope, and were functionally much less useful than many other existing descenders. By the early 1900s, there were over 150 registered designs of descenders in use in the countries where vertical caving and mountaineering were already taking place, but for a long time, cavers and mountaineers had failed to recognise how all of the existing innovations could be applied to caving and mountaineering, and those existing designs had been ignored. Mountaineers/climbers had, however, used at least three different objects as descenders, even if they were not designed for that purpose.

In about 1930, in the Grenoble region of France, French mountaineer and caver Henri "Kiki" Brenot created the Frein de Descente, a precursor to the Simple bobbin descender, which functioned more like a rack by weaving the rope between a variable number of bars. It was the first descender used for caving, and had a safety brake like a Stop. It is not known when it was first used for caving, but it was not used for the 1934 SRT trips. It was in common use by 1944. Carabiners were used with brake bars by mountaineers in North America since some time before 1933, which would be used in Europe around 1940-1942. These were always used with modern oval carabiners, and were quite dangerous, as the brake bar pushed sideways on the gate of the carabiner, and could potentially push it open if pushed slightly in the wrong direction. In 1933, German mountaineers rediscovered the carabiner wrap, despite it having been used in Germany for many decades already. Italian mountaineer/climber Emilio Comici developed the idea of using carabiners as a descender, running the rope through them and then over the shoulder and around the body like a body abseil, having been developed from the classic abseil, as a way to reduce discomfort, and improve safety. This damaged ropes fairly quickly, and required thicker hawser laid ropes. The date of the development is not known, but he was filmed using it in 1939. It later became known in English as an over the shoulder abseil (confusing it with one of the body abseil techniques), seat rappel, Swiss seat rappel, seat shoulder abseil or carabiner rappel (confusing it with all the other ways to abseil with a carabiner).

In 1942, the mountaineering booklet Anwendung des Seiles published by the Bavarian section of the German Alpine Club showed a carabiner with a brake bar, which was said to have been based on the approach used by mountaineer Ludwig Gramminger, and popular for a few years already. It is not known if he developed it before the American climbers, or whether he got the idea from them, but it is very unlikely that they were independent inventions. A single carabiner was not normally considered sufficient, so in use, it was attached to a tether from the chest harness so that it was positioned a little above the head, the rope was passed through it, down to a carabiner on the sit harness, back up to a carabiner hanging from the brake bar carabiner. The down rope and section of rope below the brake bar carabiner were held in the hands to control the speed, or the down rope could be wrapped around a leg to prevent motion, and free up the hands. This effectively created the same arrangement as the Petzl Simple (but on a larger scale), in addition to the brake bar carabiner. If the rope was wet, giving more friction, the extra two carabiners were not needed, and the sit harness could be connected to the break bar carabiner with a tether. If no brake bars were available, carabiners could be interlinked to effectively make a brake bar, but these could be even more dangerous than real brake bars, and were more prone to pushing or breaking them open. The suggestion was to tape them closed to avoid that (rather than using screw gate carabiners, which already existed!). A relatively modern example of a rod that the rope wrapped around, with ridges to guide it, is the descender made by French mountaineer Pierre Allain, which looks more like a torture device, with the prototype (which looked like a simple cross) dating from 1943, and the release versions dating from 1947, sold in 1949. American caver William Franklin "Vertical Bill" Cuddington adopted Emilio Comici's seat shoulder abseil in 1953 (his biography implied that he had developed it himself). This method was in use in British caving by 1963. In 1955, Dean Abbott invented the Rappel Log in Virginia, which Bob Geil made for the first time in 1956, shared with a caving club in 1957, and announced to other clubs in 1959. This was the first caving descender from the USA, which was simply a basic spool, and would have burned nylon ropes due to the heat that spools generated. It actually once set fire to a rope during use.

The figure of 8 was used as a descender by its inventor Austrian doctor and mountaineer Max Pfrimmer since the late 1950s. Carabiners were still being used as descenders where the old method of wrapping the rope several times around the spine got upgraded by American caver Bill Plummer in 1959, to using a chain of carabiners with the rope wrapped around all of them. Using interlinked carabiners as brake bars was common in North America by the 1960s, described by American caver Tom Perera in 1962. Two carabiners could be used as bars at the same time, to add more friction, with the rope passing over both of them as if they were a single, thicker bar. Some chained carabiners with brake bars together, to provide more friction. French caver Bruno Dressler made a Simple bobbin in the Grenoble region of France in 1963, which was based on the earlier Frein de Descente, but using just 2 bars in the wrong order. The figure of 8 started to be more widely used in the early 1960s. Racks were made independently by American cavers John W. Cole and Warren Lewis, both in 1966. In 1968, Simples began to proliferate in Europe, and were advertised in the first British Descent magazine in 1969. In 1969, the first belay devices that could be used as descenders started to appear. In the same year, other descenders were being discussed in Descent magazine by British cavers. In the 1970s carabiners were again used for the Italian hitch. In 1972, Nick Reckert wrote about methods and equipment for potholing, in the Cambridge University Caving Club journal. The Pierre Allain descender was said to be dangerous because it could break or disconnect. Linked carabiners and brake bars were said not give enough control. The Simple (known as a "Roulette" at that point) was said to be good. The figure of 8 twists the rope a little, but was still said to be good. The idea behind the Stop was first experimented with in 1972, reinvented and presented in 1974, and the first commercial devices based on that principle appeared in 1977. The Stop itself appeared in 1979. The popular Petzl I'D rope access descender was patented by Petzl's sister company Zedel SAS in 1992, and operates on the same principle, but it was not sold until 2000.

This history section only covers descenders. This article also has a detailed history of many of the other devices and techniques that are used for vertical caving.

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