Ascender Safety 101

       Ascending Rappel Ropes 101

       Autoblock Misuse (ATC-Guide)

       Avalanche Safety

       Belay School - Why Dynamic Matters

       Can A Hot Belay Device Melt My Slings?

       Carabiner Off-Axis and Tri/Quad-Axial Loading

       Choosing the Right Carabiner

       Common Belay Screw-ups

       Connecting Two Slings Together

       Daisy Chain Dangers

       Dangers of Rope Worn Carabiners

       Dangers of Worn Lowering Anchors

       Do Ropes Need to Rest Between Falls

       Draws in a Gym

       Extending a Cam Sling

       Fall Factors Explained

       Full Strength Haul Loops

       Gear Doesn't Last Forever—Crampons

       Gear Doesn't Last Forever—Ice Tool Picks

       Gear Doesn't Last Forever—Slings & Draws

       Girth Hitching a Stopper

       How Sketchy Is a Sharp-Edged Carabiner?

       How Strong are Himalayan Fixed Lines?

       How Strong is the Spinner Leash?

       How To Belay, Part 1

       How To Extend a Rappel Device

       Knot Passing 101

       Rappelling - Climbing's Diciest Business

       Re-Slinging Cams

       Rethinking the Double-Loop Bowline

       Retiring Old Ropes

       Sharpie for Marking the Middle of a Rope?

       Sling Strength In Three Anchor Configurations

       Spectra versus Nylon

       Spotting for Bouldering

       Surviving Bad Weather on El Cap

       The Dangers of Modifying Your Gear

       The Dangers of Short Static Falls

       The Electric Harness Acid Test

       The Skinny on Super Light Ropes

       Top Roping is Not So Safe

       To Screamer Or Not To Screamer

       Via Ferrata

       Weakness of Nose-hooked Carabiners

       What is the Safest Rappel Knot?

       Worn Belay Loops and Retiring a Harness

Video Spotlight
Margo Hayes Sends La Rambla (9a+/5.15a)
Margo Hayes Sends La Rambla (9a+/5.15a)

Climb Safe: Sharpie for Marking the Middle of a Rope?

By Kolin Powick

The following article is courtesy of Black Diamond Equipment.

Years ago the UIAA published a warning (and I even remember it being written up in one of the climbing mags) that using a Sharpie to mark your rope probably isn't a good idea. Here's the relevant excerpt:

Tests done by the UIAA Safety Commission and some rope manufacturers have shown that marking ropes with liquids such as those provided by felt-tipped pens can damage them; even with those markers, sold specifically for marking ropes. The test results have shown a decrease of up to 50% of the rope strength, more correctly: of the energy absorption capacity of the rope (expressed by the number of falls in the standard test method in accordance with the UIAA Standard101).

Therefore the UIAA Safety Commission warns against marking a rope with any substance that has not been specifically approved by the rope manufacturer of that rope.

Personally I questioned the applicability of these tests in real-world scenarios. The UIAA test is consistent and an industry standard for sure, but it's also extreme. Their test imposes a violent high-impact (fall factor 1.78 with a static belay) on the same section (in the above mentioned case, on the middle mark) of a rope, repeatedly, until it breaks. Not very realistic in everyday use. Think about that for a second: to have the middle of your 60-meter rope be the point where the rope is loaded during a fall, then you would have to be taking a HUGE 60-meter whipper—not very common.

At Black Diamond, we don't make ropes, and though we do have a drop tower, we don't have the ability to perform official UIAA drop tests. However, I'm a curious guy, so I had my crack crew of engineers grab a few cords, mark them up with a Sharpie, and pull them in the tensile tester. As expected, the ropes always broke at the knot—the Sharpie's middle mark seemingly having no effect on the strength of the cord during this test.












                  Sample                  Peak Value (lbf)              Failure Mode          
No Center Mark 2222 Rope at Bottom Knot
Factory Center Mark 2226 Rope at Bottom Knot
Sharpie Center Mark 1 2311 Rope at Bottom Knot
Sharpie Center Mark 2 2334 Rope at Bottom Knot


I don't think Sharpies or any other permanent markers have really been proven to actually damage nylon—short-term or long-term. However, I can't recommend them for use on rope either because the manufacturers will not and cannot guarantee that the marker will always be free of possibly harmful chemical ingredients. In other words, they can change the formula on a whim and none of us would be the wiser.

The simplest solution, if you're worried about the effect a marker will have on your rope, is to buy a rope with dual pattern. It makes identifying the middle point simple and permanent. If you have a rope already and it's not dual patterned and the middle marker has faded, I recommend using the rope manufacturer's recommended middle marker ink to re-mark it. And you can always used the tried and true method of finding the middle each time by starting at both ends and coiling until you find the center.

Climb safe—



Kolin Powick (KP) is a mechanical engineer hailing from Calgary, Canada. He has over 20 years of experience in the engineering field and served as Black Diamond’s Director of Quality for over 11 years. He is currently their Climbing Category Director. If you have a technical question for KP, please email him at and he will TRY to respond.

To help make more climbers safer climbers, Rock and Ice has teamed up with Black Diamond Equipment to present the information here.

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