ru Wed, 29 Apr 2026 18:52:59 +0300 Rappelling on Ultra-Thin Lines https://bikulov.net/tpost/thin-rappel https://bikulov.net/tpost/thin-rappel?amp=true Sat, 25 Apr 2026 09:17:00 +0300 How rappelling on thin ropes and cords works, which devices may be adapted for small diameters, and how to add friction for safer, slower emergency descents.

Rappelling on Ultra-Thin Lines

PART I: WHO NEEDS IT, AND WHY

This post was prompted by an interesting case that was recently discussed in the Russian telegram-channel “Earthwide Mountaineering” . To set the context, I’ll quote the subject initiator at some length:

I do bivouac paragliding flights (vol-biv). That’s when you fly fully self-supported (tent, sleeping bag, cooking kit, etc. — except water) for 3–7 days. I haven’t gone longer yet. You land on sites suitable for launching the next day, usually on summits. Every year I try to do such bivouacs, gradually increasing the difficulty. The last one ended two weeks ago: I flew 365 km across the Himalayas. I was almost brushing 6,000-meter peaks with my wing, but for overnight stops I descended to around 4,000 m, because pitching a tent and sleeping on snow is far less comfortable than on grass. With suitable weather the next day, I can regain that altitude in 20–40 minutes. And once the camp is set, you can take light day trips around the area — which I really enjoy. I have great respect for people who hike into the mountains on foot, but I’m too lazy for that myself and prefer to use natural forces to get up high.

The possibility of ending up in a difficult situation — hanging in a tree — is very real. And trees in the Himalayas are tall. That’s why an ultra-light descent device is needed. I have a strict weight limit for flying and can’t exceed it, and in autonomous mountain flights you have to carry a lot of essential gear. That’s why a 3 mm cord is required.

You can imagine what kind of uproar and mockery erupted in the chat at that point... =)

We are talking about an emergency, one-time descent as the only way to save a life. The alternative, of course, is waiting up to a week for rescuers.

I can’t use the carabiners from my paraglider harness, because I have to descend while wearing it. It effectively is my climbing harness, and it also holds all the gear I need to make my way back to civilization.

Yes, branches are a hazard — you have to be careful.

Now imagine this: you’re hanging in your harness, usually twisted sideways. You can’t reach the trunk, and if you do, it’s often too thick to wrap your arms around. All nearby branches are thin. Below you there’s about 15 meters of height and a slope at roughly 45 degrees. And there’s no room for a standard diameter climbing rope.

The descender is attached to the harness I’m hanging in. We assume the worst-case scenario, where you can’t reach a single solid branch. The paraglider riser-lines are tied at the top in a way that keeps the load evenly distributed and prevents them from sliding off the canopy. For this I use a self-tightening knot normally used to tie fishing hooks to line. Then, using three meters of additional 6 mm accessory cord, I transfer the load from the wing’s risers onto a loop made from this cord. I re-clip the carabiners, then arm the descender and slowly lower myself, seated in my harness.

I use this device (the KONG "Kisa" energy absorber, 65 g — ed. note), only with the Dyneema threaded slightly differently. That gives roughly 15 bends, resulting in a manageable level of friction during the descent"

So we can see that there are situations where the weight of equipment must be reduced so radically that even battle-hardened alpinists feel scared, uncomfortable, and slightly nauseous all at once. And while there are almost certainly ways to save weight elsewhere and avoid descending on a single 3 mm cord, I think this problem should be treated as a given — and the user as a rational, competent person who fully understands and accepts all the risks involved.

The descent option I “suggested” Anatoly to consider will be discussed in the “How to rappel safely on Dyneema” post. But before we move away from this distant yet strangely compelling topic of paragliding, I’d like to draw your attention to one off-the-shelf solution, developed specifically for such a niche and frankly “suicidal” use case:

CTOMS “FireFly Paraglider Kit” — a 600-gram set that includes:

• The "FireFly" descender;
• 20 Meters of 3.8 mm aramid cord;
• 180 cm Dyneema anchor sling;
• An ultra-light triangular harness (100 g)
• 2 Locking carabiners;
• A carry bag.

Valid? Yes.
Sketchy? Absolutely.
For everyone? Definitely not.

PART II: SUITABLE DEVICES

In addition to various Munter hitch variations, special devices can also be used for descending on thin ropes. Although most of them are not designed for diameters below 7 mm — both in terms of intended use and certification standards — they can still be adapted for this purpose by applying extra caution and specific techniques (which we will discuss in Part III).

Horned Figure Eights:
• Petzl «Pirana Guide»
• KONG «Oka»
• CE4Y «Axe-8»
• Edelrid «Mago 8»
• Rock Exotica «MiniEight»
• SMC «Escape 8»
• Mammut «Nano Eight»
• AustriAlpin «Nemo»

Canyoning-Style Rappel Devices:
• KONG «Hydrobot»
• BG Gear «SQWUREL»
• Sterling «ATS»
• Imlay «Critr3»
• CTRA «Bat»
• Glacier Black «Axol Pivot» (alu)
• Glacier Black «PaliKoa v2 Pivot»
• CE4Y «Devil-8 Mini» (alu)

Tubers and Belay Plates:

Grivel «Scream»
Black Diamond «Alpine ATC-Guide»
Petzl «Reverso»
Edelrid «Nano Jul»
Zartman «RPL»
Vertical «Indalo Duo»

Assisted-Braking Devices:
• CTOMS «FireFly» (3.8 mm rope* integrated)
• CTOMS «Quickie Descender»
• Protecttion «Wind Escapettor» (5mm rope* integrated)
• Rapid Rappel Descender (4 mm rope* integrated)
• Highnovate «QRAB» (7.5 mm rope* integrated)
• ISC «D1Pro Escape» and «D1Pro Tactical»
• Sterling «F4»

*Rope material: Technora.
** For more niche descenders, see verticalmuseum.com → “rappel devices”.

PART III: INCREASING FRICTION

To slow the descent and regain control on thin ropes, friction must be deliberately increased. Here are the main approaches, depending on the type of descender used.

• Horned Figure Eights & Canyoneering Devices: start with the manufacturer’s instructions. Most manuals show multiple rope-routing options that provide different friction levels. If a single wrap around the horns isn’t enough, add another — or even two — identical wraps until the friction becomes manageable.

• Tubers & Belay Plates plates: the techniques here are more subtle and rarely spelled out by manufacturers:

a) Choose carabiners with an H-shaped cross-section instead of round-profiled ones.
b) Use two identical carabiners rather than a single one.
c) Run both rope strands through one slot of the device.
d) Cross the rope strand(s) over the device centrepiece.

e) Rig the device in semi-autoblock mode.

f) Use two, three — or, if things get really serious — four devices (just kidding! …or not?).

+ Add a Friction Hitch (French or classic prusik) below the descender. With the right diameter, suppleness, and number of wraps, such hitches work even on 3 mm cord (especially when doubled). They significantly improve speed control and allow you to lock off and go hands-free when needed.

Regardless of the Munter configuration you choose (Munter, double Munter, triple Munter) or the type of descender used (manual or assisted-braking), friction can always be increased by adding standard or purpose-built redirect-carabiners (for example, the Petzl «Freino»). Redirecting the brake strand through these carabiners creates Z-shaped rope paths and additional friction. The carabiners can be placed either above or below the device.

Before applying any of this in the field, thoroughly test your setup and its compatibility with the chosen rope or cord diameter in safe but highly realistic conditions. If your plan involves descending in thick gloves while braking with only one hand — train exactly like that.

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]]> UIAA 110 "Static Ropes" Standard https://bikulov.net/tpost/uiaa-110 https://bikulov.net/tpost/uiaa-110?amp=true Mon, 20 Apr 2026 11:59:00 +0300 #standards & certification #ropes A practical overview of UIAA 110, the new static rope standard, including its key requirements and relevance to ultralight, low-elongation rope systems.

UIAA 110 "Static Ropes" Standard

At the end of 2025, the International Climbing and Mountaineering Federation introduced UIAA-110 — a new standard regulating the quality of static ropes.

Which means we now have not 3, but 4 classes of climbing ropes:
UIAA 101 | EN 892: Dynamic ropes
UIAA 102 | EN 564: Accessory cords
UIAA 107 | EN 1891: Low-stretch ropes (aka semi-static)
UIAA 110: Static ropes⠀

*Concise summaries of each standard are available in my standards table.
__________________________

According to the explanatory note, the new standard is intended to bridge the gap between:
a) low-stretch ropes with diameters of 8.5–16 mm, elongation up to 5%, and minimum strength of 22 kN (Type A) and 18 kN (Type B; for full requirements, please refer to bikulov.net/en-1891); and
b) accessory cords with diameters of 4–8 mm and minimum strengths of 3.2 kN and 12.8 kN respectively.

This distinction currently leads to a situation where many high-performance and exceptionally strong ropes end up in the traditionally underrated accessory-cord category (think of the Petzl “Rad Line”), simply because they are thinner than the 8.5 mm required for “full-size” certification or because their low elongation makes them a poor fit for standards built around shock absorption.

In Europe, this becomes a practical problem, because certification is mandatory for both work-at-height equipment and sports gear. If a rope does not fit an existing certification category, it may be difficult or impossible to market it for those uses — even if its actual performance is entirely sufficient for specific applications.

In the United States, by contrast, thin, superstatic and non-EN-certified ropes made of polyester (PET), para-aramid (PPTA), and polyethylene (HMPE) are widely and successfully used in rescue, rigging, canyoning, and other ultralight applications.
__________________________

So what does a “true static” rope require according to UIAA-110?

• Construction: kernmantle
• Static elongation at 150 kg: ≤ 2.5%
• Minimum breaking strength (without knots): ≥ 12 kN
• Minimum breaking strength with a figure-eight knot: ≥ 8 kN
• The rope must withstand an 80 kg mass dropped at FF = 0.15 without breaking
• The sheath/core ratio and elongation at 250 kg must also be specified.

Meanwhile, diameter limits, sheath slippage, shrinkage, knotability, water resistance, dynamic elongation, and other parameters — are left outside the scope.

Interestingly, the UIAA considers 8 kN to be the “very minimum breaking strength for textile products to survive a ‘normal’ use, for example the peak force generated by an abrupt stop while abseiling.”

__________________________

In short, we now have one more reason to argue about terminology and to call people out for labeling low-stretch ropes as “static”;..;

Image from: blacksheepadventuresports.com

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]]> Climbing Harness Failure Reports https://bikulov.net/tpost/climbing-harness-failure-reports https://bikulov.net/tpost/climbing-harness-failure-reports?amp=true Sun, 12 Apr 2026 18:55:00 +0300 #harnesses Corrosion, hidden wear, chemical damage, and design flaws — real incidents and lessons for safer gear inspection.

Climbing Harness Failure Reports

• 2026 — CME “Deja Vu” caving harness, Russia

Situation: waist double-back buckle failure during an indoor training session.
Outcome: no injuries.
Cause: metal corrosion.
Comment: the harness was regularly used in caves and for gym training; washed, dried, and stored properly; not used on major expeditions; condition appeared normal at first glance; service life — 6 years; user weight ~100 kg.

• 2021 — Mammut Ophir 3 climbing harness

Situation: failure of the quick-adjust waist buckle while climbing outdoors.
Outcome: no injuries.
Cause: metal corrosion.
Comment: according to the user, the harness was less than two years old and had been used in very hot and humid conditions (rain + sweat); signs of corrosion had been noticed beforehand, but no action was taken.
Source: reddit.com

• 2018 — Singing Rock “Digger” caving harness, Cedar Knob Cave, USA

Situation: leg loop failure while ascending a rope.
Outcome: no injuries.
Cause: severe localized wear.
Comment: the harness had been used for about 6 years and roughly 3,500 times; it had been inspected regularly, but the critical wear zone was partly hidden by a protective cover.
Source: caves.org

• 2017–2018 — canyoning harnesses, France

Situation: three independent cases of harness failure under body weight.
Outcome: no serious injuries.
Cause: critical strength loss caused by intensive use in harsh canyon environments — water, abrasion, and UV exposure.
Comment: follow-up testing showed strength losses of up to 90% after 3–4 years of heavy collective use; visual condition did not always reflect residual strength.
Source: 1) theuiaa.org 2) theuiaa.org

• 2013 — Black Diamond harness, climbing gym

Situation: once the rope was weighted, the load-bearing webbing suddenly delaminated from the waist belt; the climber felt themself tipping backward, grabbed the rope, and was lowered safely to the ground.
Outcome: no injuries.
Cause: critical weakening of the textile material due to chemical exposure — most likely sulfuric or hydrochloric acid.
Comment: according to the user, the harness appeared to be in near-perfect condition, had been used for about a year exclusively indoors, and was carefully stored; the damage was not obvious: slight corrosion on the buckle and discoloration of the nylon stitching (which turned pink and, as it turned out, could be torn by hand).
Source: blackdiamondequipment.com

• 2012 — Black Diamond “Blizzard” harness, climbing gym

Situation: right leg loop failure during a standard indoor lead fall.
Outcome: the user was uninjured, left hanging in a distorted harness.
Cause: critical weakening of the material due to exposure to an unknown acid, likely sulfuric.
Comment: aside from faded areas (tie-in point and inner sides of the leg loops), the harness appeared to be in acceptable condition.
Source: thebmc.co.uk

• 2006 — Todd Skinner

Situation: belay loop failure under body weight.
Outcome: fatal fall.
Cause: severe wear of the belay loop, partially hidden by the connected gear.
Comment: the case is especially notable because Skinner was one of the most experienced climbers of his time and was aware of the harness’s poor condition.
Source: americanalpineclub.org
________________________

It is important to understand that these cases represent only a small fraction of all incidents that actually occur. Some failures are never documented; others are never made public.

A significant number of incidents are also linked to manufacturing defects or design flaws. One of the most recent high-profile examples was the 2024 failure and subsequent recall of the Black Diamond “Vision” harness line: mountainproject.com. Unfortunately, cases like these offer little room for analysis — or reassurance.

If you are aware of other cases, please feel free to contact me via Facebook, Instagram, Telegram, or at bikulov.r.a@gmail.com so they can be included in this list.

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From helmets, wetsuits, and whistles to high-tech ropes, intricate descenders, butt-protected harnesses, and other wet canyon equipment.]]> EN 1891 Standard for Static Ropes https://bikulov.net/en-1891 Mon, 15 Jan 2024 10:11:00 +0300 #ropes #standards & certification All about the characteristics of static, aka semi-static, aka low-stretch kernmantel ropes

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