r/searchandrescue • u/Whatthedillyo85 • 25d ago

CMC RESCUE Carabiner strength question

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I’m having a hard time figuring out how strong this is.

What would it be rated to in poundage?

Thank you ahead of time for the assistance.

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u/F1r3-M3d1ck-H4zN3rd 25d ago

kN and pounds measure different things, so you'll never have a perfect conversion. Newtons measure force, while pounds measure weight - but you can say that with a static load a 255lbs weight create 1kN of force - though things get more complex when there is dynamic loads. Drewts86 already gave a good explanation, I thought I would just throw in the reason that you are having trouble finding an exact conversion.

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u/LazerBear924 Fire/Mountain Rescue, CO 25d ago

Thats not accurate. Weight is a force, just a very specific type of force caused by gravity acting perpendicular to the Earth.

Pounds are the US customary system unit for force. Engineers use pounds to measure forces in any dimension as needed in structural design, as forces are forces. Source: am a licensed civil engineer and rope rescue tech.

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u/F1r3-M3d1ck-H4zN3rd 25d ago edited 25d ago

Thanks for the correction, I did my physics education at a European university but my RRT in the USA and the fact you use pounds for force here passed me by (didn't help that I was trying to eli5 for someone that wasn't quite sure what a newton was). Do you also use pounds for mass or do you use grams (or something else) for that?

Imperial always seems like such a mess to me, but I imagine if you learned it from first principles throughout your education it makes complete sense.

Without my comment on terminology the rest of the post does hold, though. Dynamics will increase the forces involved whatever you measure them in, hence the 27kn strength rating (although cross loading in most carabiners drops this to around 10).