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Gear and Carabiners

The Accessories You Need to Climb Effectively: 

Harnesses 

Harnesses make hanging from the rope comfortable by distributing your weight over a larger surface area, reducing the pressure where it contacts you.

pressure=forcearea

Minimum Comfort: 

This minimalist harness is designed for alpine climbers who are willing to sacrifice comfort for lightweight. Its thin waist belt and leg loops make it less comfortable to hang in than bulkier harnesses.
Minimum comfort harness     

Maximum Comfort: 

This harness is made for big-wall climbers who often spend days or weeks hanging in their harness.The thick waist belt and leg loops make it very comfortable to hang in.

Maximum comfort harness
          

Chalk   chemical structure of Magnesium Carbonate     

Chalk is the chemical magnesium carbonate (MgCO3). Climbers often apply it to their hands to keep them dry so that they can grip the rock. Chalk can absorb the sweat your hands create, keeping them dry and maintaining good friction with the rock.    

Magnesium, Carbon, and oxygen information from periodic table

Shoes

Climbing shoes are designed to give climbers an advantage. The rubber on the soles and around the toes is specially formulated to increase the coefficient of friction (μs) between the rock and shoes.

F = μ s × N
climbing shoe free body diagram  

Note: Increasing μ s increases the frictional force that helps the climber stand on his feet and remove weight from his hands.

Carabiners

Carabiners are a simple and convenient means of attaching ropes, slings and other pieces of equipment to each other. 

Parts of a Carabiner

Carabiner diagram   


Strength Ratings

Most carabiners are stamped with strength ratings that designate Major Axis, Minor Axis and Open Gate strengths. 

Major Axis = 22 kN

major axis Carabiner strength rating labels

Minor Axis = 7 kN

      Minor axis Carabiner strength rating labels  

Open Gate = 5 kN

Open gate Carabiner strength rating labels

Why the Notch?

Carabiners have a notch or similar feature at the nose to distribute some of the load across the gate. This makes carabiners inherently stronger and allows manufacturers to use less material. 

Factory of Safety.

The ratio that describes how much stronger a part or a system is than what it actually needs to be for its intended application. 


 factor of safety example  
FoS = breaking loadapplied loadFoS = 20 kN5 kN=4

Most climbing carabiners have a strength above 20 kN. Theoretically, this means they are strong enough to support a full-size pickup truck, even though forces of that magnitude are almost unattainable while climbing. 

truck being supported by a single carabiner             
= 22 kN 
~ 4,945 lb 
Curb Weight = 4,930 lb
FoS = 4,945 lb4,039=1.2

With a safety factor barely larger than 1, if a small amount of weight were added to the truck the carabiner would break.