There are many different varieties of carabiners on the market. This article will explain the ones used for tree climbing. Whether you choose SL (screw-lock), TL (twist-lock), or BL (ball-lock) is based on intended use and/or personal preference. Carabiners are made from aluminum or steel.
For life support (climbing), your carabiner must have a minimum breaking strength of 5,000 lbs. and be positive locking-meaning, it has 3 actions (triact) to open the gate: 1. Push the sleeve up or down, 2. Twist the sleeve, and 3. Pull gate inward.
Here are some hints on choosing the shape of your carabiner, using Petzl carabiners as an example:
WILLIAM – a large size locking carabiner can combine with a FIXE pulley and a split tail to create a self-tending climbing hitch.
AM’D – an asymmetrical locking carabiner for use at the end of a lanyard, D-shaped for an excellent strength-to-weight ratio.
OK – a symmetrical automatic locking carabiner which has versatile oval shape for optimal positioning of equipment (pulleys, rope grabs, etc).
Steel rigging carabiners can be non-locking or double-locking or triple action for extra security. Though steel carabiners are heavier, they generally have a higher strength rating related to size.
One type of specialty carabiner is the DMM Revolver which has a built-in pulley which allows for:
- Provide a redirect for the climbing line
- Making quick mechanical advantage systems, and
- Hauling gear up the tree.
A Corner Trap is a wire or rubber bracket that fits snug over the end of the carabiner to help prevent the attached rope from slipping into a position where it may side-load the carabiner.
A quality carabiner will have a smoother action, longer life, and usually, a higher strength and better testing methods. Carabiners should be marked with the manufacturer’s name, strength rating and related information. Carabiners made by Petzl are guaranteed for 3 years against any faults in materials or manufacture.
Remember to purchase carabiners based on their intended use, strength rating and material used. Inspect carabiners frequently for wear, debris or defects – retire, recycle and replace as necessary.
Shop for carabiners online at www.pinnaclearboristsupplies.com or call us, 501.663.8733 and we will be delighted to help you choose just the right carabiner for your climb.