top of page

Personal Anchor Drop Tests - Cow Tails

HOW bad is it to fall on personal anchors? It's obvious-ish that it's not a good idea to fall on a short rope since there isn't much there to absorb your fall, especially if it is really static. We drop tested cow's tails, which are personal anchor systems (PAS) that cavers use.

Drop testing personal anchors

We were hoping the dynamic ropes would absorb enough to not hurt but damn, since we were dropping 300lbs/136kg it still got to forces that were pretty gnar. Dropping the same cow's tail after the knot cinched up took it from 6kn which is survivable to 10+kn which isn't.

Just extending the length of it a bit got it to enough force to break... a dynamic rope! When you fall twice as far as you have rope in the system, that is a fall factor 2 (FF2) and that is when things start breaking.

After the knots cinch up and the rope stretches

Static material is even worse. Semi static got us above 10kn with fresh knots but then it was just breaking stuff after that. The super static polyester rope broke on the first drop. The Petzl Speleoglyca dyneema PAS didn't break on the first drop only because the stitching broke.

Our Data

300lbs = 136kg and 200lbs = 91kg

At our store, we sell Swift Dry Protect dynamic rope by the foot so you can make cow tails with cut-resistant rope.

What's Next

We cross loaded a carabiner in our drop tests. See this video to watch us do it on purpose!


bottom of page