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Everybody knows that Charles Gibbs and Warwick Doll invented and named the Ropewalker climbing system, and then described it in the February 1969 NSS News [1]. The article described the climbing system using the Gibbs Ascenders that Charles first invented in 1965 [2]. The article described mounting one ascender at foot level and a second at knee level, a substantial improvement over Henshaw and Morehouse’s system [3] that mounted climbing cams on each foot. The Ropewalker proved to be faster than any other system, at least on free-hanging drops, and with improvements such as bungy cords and a change in ascender, it remains much, much faster than more versatile systems.
Well, that is the official story, but it isn’t wholly accurate.
In September 2023, Eric Landgraf posted a note on FaceBook [4] showing some “Prusikers” and offered to put me in touch with one of their inventors, David Netzer. David had described them to Eric as follows:
My name is David Netzer. I am a 1960 graduate in Mechanical Engineering from Virginia Tech. In my freshman year I joined the VPI Caving Club. Was active in 1956-1959.
I am doing some decluttering in my home and have a box of old caving/climbing gear. It includes rappelling pads as well as some devices we called Prusikers. Another climber (believe his name was Tom Bunker) and I came up with an idea to make prusiking easier and faster. We made two pairs using the welding shop at Tech. One attached to one boot and the other to the calf of the opposite leg. Each was attached to the climbing rope with a prusiking slip knot. Those, plus another slip knot attached to our chest strap let us "walk/step" up the climbing rope. When raising each leg, the coil pushed the slip knot upward. Thus, we did not have to lean back and move the knots using our hands. Not sure if anyone else ever made something similar, but they worked quite well, reducing the climbing effort.
I tried contacting David without success. Shortly thereafter, Eric Stanley contacted me, saying
Hello Gary,
My name is Eric Stanley, I am the current VPI Cave Club faculty representative. I have recently come into temporary possession of some gear that was being used in the 1950's. I would love to pick your brain about it. Are you familiar with "Prusikers"? I did not see any on your website.
Cheers,
Eric Stanley
I replied, and we established that the two Erics were referring to the same “Prusikers.” Thanks to them, these are now in my Vertical Museum collection.
A set of Prusikers has one for the left foot and one for the right calf. The foot Prusiker consists of a steel foot step with a rope guide coil welded to the side and a prusik attachment loop welded to the top.
The foot Prusiker sits with the coil on the inside of the foot. A small hole in the step portion allows one to use a cord to tie the Prusiker to the foot. This cord is now missing. Tie the prusik loop to the attachment loop. This keeps the loop nicely centered above the foot, limiting torque on the ankle.
Strap the calf Prusiker to the inside of your right calf, just below the knee with the open end of the coil pointing down. Attach the prusik loop to the small loop near the base of the Prusiker.
The Prusikers work best with normal ¾-inch (19 mm) manila caving rope (we are in the 1950s). Attempts to use thinner 5/8-inch rope will simply lead to more jamming. I recommend standard 3/8” (9.5 mm.) manila prusik slings. You can use thinner 5/16 (8 mm) manila if you can find it (the 1950s again), but it is more likely to jam. Avoid ¼-inch (6.4 mm) manila. If you are lucky, it will jam before it breaks and you start accelerating downward until you reach terminal velocity or an intervening floor.
In both cases, make your prusik loops short to reduce lost motion.
Do not make the foot loop too short, though, as this will lead to torquing the ankle. Do not forget to include a chest harness and third prusik to keep yourself upright.
So, there you have it: an early ropewalking system using knots. Their metal construction would preclude using Prusikers for racing in the knots category at the NSS Convention. With all the restrictions in the current rules, knots are about as slow as climbing Frog. Under older rules, knots are much faster – for example, in 1969 Dick Mitchell climbed 100 feet (30.5 m.) in 72.2 seconds using knots [5]. Are you that fast with your Frog?
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[1] Gibbs, Charles and Warwick Doll, 1969. “Vertical Caving and the New Cam Ascender.” The National Speleological Society, NSS News, v27, #2, pp.28-31.
[2] Gibbs, Peter, 2023. “Gibbs Ascenders - A Short History.” Gibbs Products, Inc. Downbloaded 2024-02-28 from https://gibbsproducts.com/.
[3] Henshaw, Robert E. and David F. Morehouse, 1965. “The Climbing Cam: A New Ascender.” The National Speleological Society, NSS News, v23, #11, pp.158-160.
[4] https://www.facebook.com/groups/141284484638389/permalink/652942633472569
[5] I did not witness this climb, but I’ll bet that Dick used his Mitchell System for the climb. I know that he had a similar time in 1967, using the same system prior to the Chest Box.
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I acquired this Netzer - Bunker Foot Prusiker from Eric Stanley in 2024.
My Netzer - Bunker Foot Prusiker is 123 mm. long, 182 mm. wide, 50 mm. high, and weighs 326 g.
The Foot Prusiker is made from steel plate with an eye for a Prusik loop and a helical coil for lifting the Prusik. The plate is 2.8 mm. thick. The eye and coil are made from 1/4" (6.4 mm.) round stock. The inner diameter of the helix is 21 mm.
A small hole in the step portion allows one to use a cord to tie the Prusiker to the foot. The original cord is now missing.
The Prusikers work best with the ¾-inch (19 mm) manila caving rope that was standard in the 1950s. Attempts to use thinner 5/8-inch rope will simply lead to more jamming. I recommend standard 3/8” (9.5 mm.) manila prusik slings. You can use thinner 5/16 (8 mm) manila if you can find it, but it is more likely to jam. Avoid ¼-inch (6.4 mm) manila.
Make your foot prusik loops short to reduce lost motion. Do not make the foot loop too short, though, as this will lead to torquing the ankle.
[ Top | Foot | Return to Most Misc. ]
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I acquired this Netzer - Bunker Knee Prusiker from Eric Stanley in 2024.
My Netzer - Bunker Knee Prusiker is 155 mm. long, 75 mm. wide, 89 mm. high, and weighs 425 g.
The Knee prusiker is made from 2.98 mm. steel plate. This plate is curved to fit comfortable on the inside of one's calf. A 1/4" (6.4 mm.) steel rod welded to the plate has an eye at the bottom for attaching a Prusik loop and a helical coil above to raise the prusik knot. The inner diameter of the helix is 21 mm. The inside of the plate is padded with1/4" (6.4 mm.) felt. Cotton webbing straps stapled to the plate provide means for strapping the Prusiker to one's vcalf.
Strap the calf Prusiker to the inside of your right calf, just below the knee with the open end of the coil pointing down. Attach the prusik loop to the small loop near the base of the Prusiker.
The Prusikers work best with the ¾-inch (19 mm) manila caving rope that was standard in the 1950s. Attempts to use thinner 5/8-inch rope will simply lead to more jamming. I recommend standard 3/8” (9.5 mm.) manila prusik slings. You can use thinner 5/16 (8 mm) manila if you can find it, but it is more likely to jam. Avoid ¼-inch (6.4 mm) manila. Make your prusik loops short to reduce lost motion. Do not forget to use a chest harness and third prusik to keep yourself upright.
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