Part A Climbing Ropes And Types Of Knots

1. Climbing Ropes.

No one rope is ideal for all applications. The commander must determine the situation in which ropes may be used (such as: urban, rock, ice, climbing, rappelling, rope installations) and in what type of terrain and climate.

Rope selection is affected by the following factors:

• Fall factor measures the severity of a fall. This is calculated by dividing the length of a fall by the amount of rope paid out at the belay point. The higher the fall factor, the greater the amount of force generated. Rope drag, intermediate protection, and other factors of the safety chain reduce the severity of a fall.

• Impact force is the sudden stress put on the safety chain (belay anchor, attachment to belayer, belayer, rope, intermediate protection, attachment to climber, and climber) when a fall is held. The whole system is only as strong as the weakest link. If there is a weakness at any point, the shock loading from the impact force can cause a failure of the system. The impact force occurs once the fall has stopped (usually with a sudden jerk on the climber's body). It is the maximum load placed on a rope after all of the energy from a fall has been absorbed in the rope's stretch.

• Knotability is the ease in tying and untying knots in the rope, as well as the ability to hold a knot once tied.

• Elongation or stretch dissipates the energy produced during a fall, throughout the rope rather than directly to the climber's body. Other than in a fall, the rope should stretch as little as possible.

• The rope should be soft, flexible, resistant to kinking, durable, water repellant, have a high fall rating, and have no sheath slippage (kernmantle only).

There are two types of ropes available to you during a mountainous operation:

• Static ropes are designed for rappelling, rescue operations, load hauling, and rope installations. They allow for minimal elongation or stretch of the rope. They stretch about 5 to 15 percent at the point of failure and about 2 percent under a working load. The minimum tensile strength for 11 mm (7/16 inch) static ropes for military use is 4,500 pounds. They range in diameter from 3 mm to 11 mm. static ropes are called "kernmantle" (kern means core and mantle means sheath). Due to the internal parallel strand construction of these ropes, there is less spinning and kinking than with a dynamic rope. These ropes can be used for slings, harnesses, etriers (stirrups), rappelling, rope installations, hauling lines, and wherever elongation of the rope is not desired. You should not conduct a lead climb with a static rope since the force exerted in a fall is transferred to the climber rather than absorbed through the rope.

• Dynamic ropes are designed for climbing, and allow stretch or elongation within the fibers of the rope. This degree of elasticity allows the energy produced in a fall to be dissipated through the rope rather than being absorbed directly by the climber's body. This elongation can be a disadvantage in rappelling, Prusik climbing, and other applications. Dynamic ropes are more susceptible to abrasion and wear. Where the fall factor may be high (such as lead climbing) it is important to use a dynamic rope. They have about 5 to 10 percent working elongation. The minimum tensile strength for 11 mm (7/16-inch) ropes for military use is 4,500 pounds.

There are two types of dynamic ropes:

Nylon-laid ropes. Synthetic fibers have proven to be superior to any other climbing material. Nylon has become the standard material for climbing ropes and has replaced manila, flax, hemp, and sisal. Military mountaineering critical application rope is constructed in a "laid" fashion with continuous multifilament nylon fiber yard twisted into strands. Three strands are twisted into a climbing rope of a specific diameter (Figure 2-1). The following specifications pertain to the standard military nylon-laid climbing rope:

36 1/2 meters (120 feet) long.

At least a 4,500-pound tensile strength.

Right-hand lay.

One-third stretch factor.

May lose as much as 15 percent of its strength when wet. Weighs 6 pounds when dry.

FIGURE 2-1 Nylon-laid Rope

FIGURE 2-1 Nylon-laid Rope

Hopkins Rope Course

You should inspect these ropes for serviceability by twisting the fibers. Laid ropes tend to untwist slightly when under a load, causing kinking and spinning. They are also susceptible to abrasion.

Kernmantle ropes. These ropes are similar to their static counterparts in that they consist of an inner core and an outer sheath. The core is constructed of continuous twisted nylon filaments, which are laid or braided together and enclosed in a tightly braided outer sheath. It is well suited for climbing on rock, snow, or ice where a brief elastic elongation of the rope occurs during a fall. Dynamic kernmantle ropes have an elongation of about 40 percent at the point of failure. The breaking strength is high, and there are no exposed strands for rock crystals to work between, which damages the rope (Figure 2-2). There is less sliding friction through the snaplink and over other surfaces, since the outer sheath is smooth. Kernmantle ropes come in a variety of sizes, lengths, stretch factors, tensile strengths, and fall ratings.

FIGURE 2-2, Kemmamtle (pore and stieatfo) Rope

FIGURE 2-2, Kemmamtle (pore and stieatfo) Rope

Types Sliding Knots

Kernmantle ropes are not readily identifiable as dynamic or static and must be marked accordingly.

The selection of rope for military operations usually requires ropes for various types, lengths, and diameters. It is unsafe to use a rope for other than its intended use. Ropes that do not have military specifications should meet UIAA-approved standards.

During a mountainous operation, the use of a rope may not be necessary; however, on steep, unbroken cliffs where exposure is great, climbing with a rope is necessary.

The most common terms used in military mountaineering are:

• A bight of rope is a simple bend of rope in which the rope does not cross itself (1, Figure 2-3).

• A loop is a bend of rope in which the rope does cross itself (2, Figure 2-3).

• A half hitch is a loop that runs around an object and locks itself (3, Figure 2-3).

• The running end (working end) of the rope is the free end of the rope that can be used.

FIGURE 2-3 of 5r~5

FIGURE 2-3 of 5r~5

Rope Knots Guide
1. bight 7, loop half hitch i. ¡iotjn:: turn

• The standing part of the rope is the part that is static (anchored, coiled); the remaining part of the rope not being used (also called static end).

• The lay of the rope is the same as the twist of the rope.

• The round turn is a single complete wrap of the rope around an object providing 360-degree contact. The running end leaves the completed circle in the same direction as the standing part. In a round turn, the rope is wrapped around an object 1 1/2 times (4, Figure 2-3).

• The pigtail is the short length of rope remaining at the end after tying a knot or coiling a rope.

• Back feeding (or stacking) is taking off one wrap at a time from a coil, and letting it fall naturally to the ground.

After you have selected a rope, you should make preparations. Before starting an operation, ropes must be cut to the desired lengths and frayed ends should be bound or seared. Whipping is the most secure means of fastening ends. A less satisfactory means is tightly binding rope ends with electrical tape. The ends (nylon-laid and kernmantle) may be fused by heating over a flame until the fiber melts and flows. To protect the rope end, you should dip the ends in fiberglass or lacquer and allow 24 hours to dry. Make sure you dip only the ends since lacquer weakens ropes.

The ends of a new rope or ends caused by a cut should be whipped with thread or cord and fused by heat. Nylon thread used in parachute repair is ideal for this purpose (Figure 2-4).

FIGURE 2-4. Techniques Used to Whip End of Rope

FIGURE 2-4. Techniques Used to Whip End of Rope

Mountaineering Ropes

When in areas of loose rocks, you should inspect the ropes as often as possible to detect cuts and abrasions before they render the rope unsafe.

When using a rope, there are two methods of coiling that you should follow:

• Mountaineer's Coil. One of the techniques is to grasp the rope about 3 feet from the end with the left hand. The right hand is then placed next to the left hand and runs along the rope until both arms are outstretched. Grasping the rope firmly, the hands are brought together forming a loop, which is laid in the left hand. This is repeated, forming uniform loops that run in a clockwise direction until the rope is completely coiled. If the rope tends to twist or form figure eights, it may be given a slight twist with the right hand when each loop is formed. The rope is coiled in a clockwise direction to conform with the lay.

In completing the hasty coil, a bight about 30 centimeters (12 inches) long is formed with the starting end of the rope and laid along the top of the coil. The last loop is uncoiled. Using the length of the rope thus obtained, wraps are made around the coil and the bight. Wrapping is made toward the closed end of the bight, making the first wrap bind across itself to lock it in place. Six to eight wraps should be made to adequately secure the coil. The end of the rope is pushed down through the closed end of the bight. The running end of the bight is then pulled tight to secure the coil. This coil may be carried either in the pack (by forming a figure eight, then by doubling it and placing it under the flap); or by placing it over the shoulder and under the opposite arm. If the rope to be coiled is anchored as in coiling a belay or rappel line, the coil should start near the end closest to the anchor so that the kinks can work themselves out of the free end (Figure 2-5).

• Farmer's Coil. This method is best for carrying a rope when you want maximum use of your upper body. This coil is also easier and faster than the mountaineer's coil. The center of the rope is established either by locating its center mark or by grasping both ends of the rope and feeding them out until a bight comes up that is the center of the rope. Coiling begins with the doubled rope the same as the mountaineer's coil method. About 4.6 meters (15 feet) of rope are left uncoiled, then the coils are squeezed together and four to six wraps are made around the middle of the coil, ensuring that the first wrap is held in place by the other wraps.

A bight is formed with the two running ends and is placed through the bight formed by the top of the coil. The two running ends are then run over the top of the coil and through the bight that they formed and dressed down. The running ends are separated, placing the coil in the center of the back of the carrier. The two ends are run over the shoulders to form shoulder straps. The running ends are then brought under the arms, crossed in the back over the coil, brought around the body of the carrier, and tied off with a square knot at his stomach (Figure 2-5).

FIGURE 2-5. Coil Tying.

FIGURE 2-5. Coil Tying.

Climbing Ropes And Types Knots

Inspection of a rope is necessary and involves the following procedure:

• Each dynamic climbing rope should have a corresponding rope log (Figure 2-6), which is a record of the usage, history and life of a rope. On this form, you should annotate use, terrain, weather, application, number of falls, dates, and other pertinent data as required or necessary to assist other members of the climbing party. This form is a safety record.

• You should inspect the rope on a daily basis, before, during, and after use. They must be color coded or marked to identify its use such as leader climbing rope, rope installation, or rappelling rope.

FIGURE 2-6. DA Form 5752-R - Rope Log, (Usage and History)

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When handling ropes, you should observe the following rules:

• The rope should be kept clean since dirt can damage a rope through abrasion. The rope should not be stepped on or dragged on the ground since it could cause small particles of dirt to be ground between the strands and slowly cut them. Climbing ropes should be washed in cold water with a mild nylon-safe soap without bleach or fabric softeners, rinse thoroughly. The rope should be air-dried out of direct sunlight.

• The rope should never come in contact with sharp edges. Nylon rope is easily cut when under tension. If a rope must be used around a sharp edge, the edge should be padded.

• The rope should be kept as dry as possible. If it should become wet, it should be hung in large loops on round wooden pegs above the ground to air dry. A rope should never be dried next to an open flame or in an automatic clothes drier.

• The rope should not be knotted or tightly stretched for long periods. It should not be hung on sharp edges such as nails.

• When using ropes in installations, they should not rub against each other. This causes fraying. Allowing rope-on-rope contact with nylon rope is dangerous since the heat produced by the friction may cause the nylon to melt. The rope must be examined immediately after it has been hit by a falling object (rock, helmet, rucksack, piton hammer). If a sudden strain has been applied to the rope while passing over a sharp edge, it should be inspected.

• The rope must be protected from chemicals, paints, oils, solvents, acids, corrosives, petroleum products, or excessive heat since these weaken and damage rope fibers.

Throwing. To ensure that the rope does not snarl when thrown, it is backfed. The rope is backfed (stacked) by taking off one wrap at a time and letting it fall to the ground, ensuring that there are no kinks, knots, or twists that may hinder the rope from feeding out. When the rope is backfed, one end of the rope is anchored off.

• The opposite end of the rope is picked up and six to eight coils are made in the left hand and set on the ground next to the climber. A second set of coils is made with the remaining rope; two separate stacks of coils should be present. The stack with six to eight coils is picked up and placed in the left hand. The other stack of coils is placed in the right hand.

• There are two methods in which to throw the rope-underhand and overhand. The overhand method should be used when trees or shrubs are on or near the rappel point. Once the method of throwing has been determined, a few preliminary swings are made with the right arm (this arm holds the second set of coils). Just before the rope leaves the hand, the warning "Rope" is shouted to alert personnel at the bottom of the cliff. As the coils are going down the cliff face, the climber feels a tug. At that time, the coils in the left hand are thrown down. Throwing the rope this way is best to ensure that the rope reaches the bottom without snagging.

2. Types of Knots:

A knot is a fastening made by intertwining or tying pieces of string, cord, ropes, or webbing. All knots used by a climber are divided into four classes:

These classes of knots are intended only as a general guide since the variety of knots, bends, bights, and hitches is almost endless. The knots discussed may be appropriate in more than one class.

Class I - Joining knots includes the square knot; double sheet bend; fisherman's knot; double fisherman's knot; and the water knot. Each of these knots is discussed as follows:

Square Knot. This knot is used to tie the end of two ropes of equal diameter (Figure 2-7).

FIGURE 2-7 SqusreKn«

FIGURE 2-7 SqusreKn«

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