Min Nylon Webbing

a. The type of nylon webbing available is tubular. Tubular nylon webbing is very strong and flexible. All rules that apply to nylon rope apply to tubular nylon webbing. The size of nylon webbing used is:

(1) 1 inch tubular nylon. Tensile strength approximately 4,000 - 4,500 lbs., depending on the manufacturer.

b. Pre-sewn Spectra Runners. Tensile strength approximately 5,500 lbs.

tr -


"~nr -


NOTE: These are minimum strengths. Some manufactures make even stronger webbing.

TRANSITION: We have just discussed general information in nylon webbing, are there any questions? Not only do we use ropes, but we also use carabiners in our installations, we will discuss the types of carabiners used:

5. (5 Min) CARABINERS. Also commonly known as snaplinks. Both locking and non-locking are used.

a. Purpose. Carabiners are used for the following purposes:

(1) To attach ropes or runners to pieces of protection.

(2) To attach the rappel rope to the rappel seat for seat-hip rappels or for crossing rope bridges.

(3) To attach the individuals safety rope to a safety line on a rope installation.

(4) To form field expedient pulley systems.

b. Nomenclature of a non-l ocking carabiner

Carabiner Nomenclature

Nomenclature of a locking carabiner

(3) Locking notch.

Characteristics The Carabiners

d. There are two types of carabiners used. The two types and their characteristics are: (1) Steel locking carabiners

(a) Large steel locking "D" (various manufacturers): Minimum tensile strength of 5,500 lbs.

(b) Steel-locking oval Stubai 82 is not in the MAC Kit and obsolete. However, it is being used at MWTC to save money, even though they are beyond the service life. Tensile strength of only 3,300 lbs.

(2) Aluminum non-l ocking carabiners

(a) Aluminum non-locking oval (various manufacturers): minimum tensile strength of 4,200 lbs.

e. Serviceability Check for a Carabiner. The following steps are used for you to check a carabiner for serviceability:

(1) The gate snaps shut with no friction and with no gap between the locking pin and locking notch.

(2) There is no excessive side to side movement of the gate.

(3) The pivot pin is tight.

(4) The locking pin is tight.

(5) The locking nut travels freely and locks securely.

(6) There are no cracks or flaws in the metal.

NOTE: The weakest part of a carabiner is the gate. If an engraver is used to mark a carabiner, it should be applied to the gate and not the load bearing side.

f. Preventive Maintenance for a Carabiner.

(1) Remove all dirt, moisture and grime.

(2) Lubricate with tri-flow graphite and clean off thoroughly.

NOTE: Whenever you use a locking carabiner ensure that the locking nut is always locked down (tightened).

6. (2 Min) CARE OF THE CARABINER. Do not drop the carabiner as this may result in either actual damage to the carabiner or in dirt getting into the workings of the carabiner and damaging it.

TRANSITION: We have covered the parts, the strength, and care of carabiners; are there any questions? Now lets move on to chocks.

7. (10 Min) PROTECTION a. Purpose

(1) Protection or pro is used to protect climbers as they ascend a cliff face. This is accomplished by wedging them into cracks and openings in the rock and securing the rope to them. Since they can be slid into the rock without banging, they are not noisy to install and are very suitable for a tactical situation that may require silence.

(2) A disadvantage of pro is that it is directional. That is, when it is installed it is wedged into a crack and is meant to take a strain in a specific direction. If you climb above your pro and inadvertently pull the rope, you may pull your pro all or part way out of the crack that you installed it in. b. Types

(1) Stoppers. These have a wedge-shaped structure and are designed to be used in small cracks. They come in twelve sizes, ranging from widths of 0.16 inches (# 1) to 0.90 inches (# 12). The sides of the wedged portion are slightly beveled, enabling the climber to insert the same stopper into a crack two different ways.

Face Shaped Like Hexagon

(2) Hexcentrics. These chocks have a six-sided structure shaped like a hexagon; the sides being of unequal width, which allows the same chock to be inserted in different size cracks depending on which way it is inserted. These chocks come in various sizes and are used in larger cracks that stoppers are too small for.

Hexcentric Stopper

(3) Spring Loaded Camming Devices (SLCD). Spring loaded camming devices are a unique solution for shallow, horizontal or vertical cracks, thin "tips" cracks and narrow pockets where other types of protection can't be placed. This is an advantage over rigid caroming devices, which can only be placed in a vertical crack.


c. Serviceability Check

(1) Stoppers and Hexcentrics

(a) Check holes used for stringing chocks for burrs that could damage the cord the chocks are strung with.

(b) Check accessory cord for wear, fraying, rupture of the outer sheath, and knot.

(c) If wired, check wires for frays that could damage climbing rope.

(d) If wired, check soldered (or otherwise joined) area for cracks or looseness.

(e) Check nut for splits or cracks.

(a) Ensure wires leading from trigger to cam are not bent or frayed.

(b) Check to ensure that cam movement is free and easy and for contraction and expansion by pulling and releasing trigger.

(c) Check that runner is not frayed and no stitches have popped.

(d) If it is stiff or corroded by sea water, spray with Tri-Flow Graphite and clean off thoroughly.

d. Strengths

(1) The strength of a chock depends on the manufacturers specifications and on the type and size of material used for the sling (rope, webbing, or wire). Below are the strengths of some of the types of chocks used at MWTC.



#1 / #2 Stopper - wired

350 kg (approx. 770 lbs.)

#3 - #5 Stopper - wired

650 kg (approx. 1430 lbs.)

#6 - #12 Stopper - wired

1,100 kg (approx. 2420 lbs.)

#1 - #3 Hexcentrics -wired

1,100 kg (approx. 2420 lbs.)

(2) Hexcentrics #4 thru #10 are only strung with Type I cord. Type II cord is used for Prusik cordage. The following are the cord specifics:








Spectra Kevlar


150 ft ± 10 ft





300 ft ± 10 ft

(3) SLCD's vary in strength depending on the manufacturer, as well as the size.



Camming Device Large

2,400 lbs.

Camming Device Small

2,600 lbs.

e. Care of Pro

(1) When placing pro, insure that the cord or wire does not rub against the rock.

(2) Do not drop pro, which may deform it, or the accessory cord that the pro is strung with, which may lead to deterioration of the cord.

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  • john winningham
    How to sew tubular nylon webbing?
    9 years ago

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