Kernmantle rope
Encyclopedia
Kernmantle rope is rope
constructed with its interior core (the kern) protected with a woven exterior sheath (mantle) that is designed to optimize strength, durability, and flexibility. The core fibers provide the tensile strength
of the rope, while the sheath protects the core from abrasion during use. The name is derived from German Kernmantel... which means coat protected core.
ropes that were used in yachts for hauling were tested and found useful in climbing
and caving
, and are now the modern standard. Although there are occasional innovations, the type of rope used today is similar in construction, strength, and durability across manufacturers. There are several major manufacturers, including Pigeon Mountain Industries
(PMI) which is popular with cavers
, Mammut, Sterling, Beal, Edelweiss, Blue Water, Roca, and Maxim. Kernmantle ropes are still used in sailing and other sports, however the technical requirements are usually not as rigorous as in climbing since those applications are not as safety critical. Smaller kernmantle ropes are commonly called accessory cord; they are often used to make prusik knots and loops or attaching accessories such as chalk bags.
One or more of the rope characteristics (strength, durability, and flexibility) are often altered somewhat, depending upon the ultimate use of the rope, at the expense of the other properties. For example, rope used in caving
is generally exposed to more abrasion than other forms of recreation, so the mantle is woven more tightly than rope used in climbing
or rappelling. However, the resulting rope is cumbersome and difficult to tie knot
s in.
Kernmantle construction may be used with both static and dynamic rope
s. Static ropes are designed to allow relatively little stretch, which is most useful for hauling, rappelling, and other applications. Dynamic rope is used to belay climbers, and is designed to stretch under heavy load to absorb the shock of a fallen climber. Dynamic ropes manufactured for climbing are tested by the UIAA. This test involves tying an 80 kg (176 pound) weight to the end of a length of rope. This weight is then dropped 5 meters (16½ feet) on 2.7 meters (9 feet) of rope, with the rope running over a rounded surface simulating that of a standard carabiner. This process is repeated until the rope breaks. It is a common misunderstanding to think that the number of drop test falls (as conducted by the UIAA) is the number of real-life climbing falls a rope can sustain before it becomes unsafe. Actually, the drop test falls are of extreme severity and it is not often that a real-life climbing fall generates a comparable force. This adds a margin of safety for the climbers who use such ropes.
Rope may be cleaned by forming it into a chain sinnet
, to prevent excessive tangling, and washing it in a front-loading clothes washing machine
with soap flakes. Strong cleansers, including bleach
and detergent
should not be used with life-critical Nylon components. Commercial rope cleaning devices are available from the climbing and rescue companies CMI and PMI.
*Dynamic ropes are rated for a certain number of falls (usually 5-10) at a given impact force.
Rope
A rope is a length of fibres, twisted or braided together to improve strength for pulling and connecting. It has tensile strength but is too flexible to provide compressive strength...
constructed with its interior core (the kern) protected with a woven exterior sheath (mantle) that is designed to optimize strength, durability, and flexibility. The core fibers provide the tensile strength
Tensile strength
Ultimate tensile strength , often shortened to tensile strength or ultimate strength, is the maximum stress that a material can withstand while being stretched or pulled before necking, which is when the specimen's cross-section starts to significantly contract...
of the rope, while the sheath protects the core from abrasion during use. The name is derived from German Kernmantel... which means coat protected core.
Use as climbing rope
The nylonNylon
Nylon is a generic designation for a family of synthetic polymers known generically as polyamides, first produced on February 28, 1935, by Wallace Carothers at DuPont's research facility at the DuPont Experimental Station...
ropes that were used in yachts for hauling were tested and found useful in climbing
Climbing
Climbing is the activity of using one's hands and feet to ascend a steep object. It is done both for recreation and professionally, as part of activities such as maintenance of a structure, or military operations.Climbing activities include:* Bouldering: Ascending boulders or small...
and caving
Caving
Caving—also occasionally known as spelunking in the United States and potholing in the United Kingdom—is the recreational pastime of exploring wild cave systems...
, and are now the modern standard. Although there are occasional innovations, the type of rope used today is similar in construction, strength, and durability across manufacturers. There are several major manufacturers, including Pigeon Mountain Industries
Pigeon Mountain Industries
Pigeon Mountain Industries is an American caving, climbing, and safety rope company founded in 1976 by Steve Hudson.They produce a rope designed for the severe conditions of caving. PMI Sport rope is a stiff, white static rope which is abrasion resistant....
(PMI) which is popular with cavers
Caving
Caving—also occasionally known as spelunking in the United States and potholing in the United Kingdom—is the recreational pastime of exploring wild cave systems...
, Mammut, Sterling, Beal, Edelweiss, Blue Water, Roca, and Maxim. Kernmantle ropes are still used in sailing and other sports, however the technical requirements are usually not as rigorous as in climbing since those applications are not as safety critical. Smaller kernmantle ropes are commonly called accessory cord; they are often used to make prusik knots and loops or attaching accessories such as chalk bags.
One or more of the rope characteristics (strength, durability, and flexibility) are often altered somewhat, depending upon the ultimate use of the rope, at the expense of the other properties. For example, rope used in caving
Caving
Caving—also occasionally known as spelunking in the United States and potholing in the United Kingdom—is the recreational pastime of exploring wild cave systems...
is generally exposed to more abrasion than other forms of recreation, so the mantle is woven more tightly than rope used in climbing
Climbing
Climbing is the activity of using one's hands and feet to ascend a steep object. It is done both for recreation and professionally, as part of activities such as maintenance of a structure, or military operations.Climbing activities include:* Bouldering: Ascending boulders or small...
or rappelling. However, the resulting rope is cumbersome and difficult to tie knot
Knot
A knot is a method of fastening or securing linear material such as rope by tying or interweaving. It may consist of a length of one or several segments of rope, string, webbing, twine, strap, or even chain interwoven such that the line can bind to itself or to some other object—the "load"...
s in.
Kernmantle construction may be used with both static and dynamic rope
Dynamic rope
A dynamic rope is a specially constructed, stretchable rope. This 'stretch' is what makes it 'dynamic', in contrast to a static rope that doesn't have any give when under load. By stretching under load, a dynamic rope will soften the impact of extreme stresses on it, such as falls, and lessens the...
s. Static ropes are designed to allow relatively little stretch, which is most useful for hauling, rappelling, and other applications. Dynamic rope is used to belay climbers, and is designed to stretch under heavy load to absorb the shock of a fallen climber. Dynamic ropes manufactured for climbing are tested by the UIAA. This test involves tying an 80 kg (176 pound) weight to the end of a length of rope. This weight is then dropped 5 meters (16½ feet) on 2.7 meters (9 feet) of rope, with the rope running over a rounded surface simulating that of a standard carabiner. This process is repeated until the rope breaks. It is a common misunderstanding to think that the number of drop test falls (as conducted by the UIAA) is the number of real-life climbing falls a rope can sustain before it becomes unsafe. Actually, the drop test falls are of extreme severity and it is not often that a real-life climbing fall generates a comparable force. This adds a margin of safety for the climbers who use such ropes.
Rope care
Kernmantle rope should be inspected before and after every use for any form of damage. "Boogers," which indicate internal damage to the kern, will appear as tufts of white threads poking out from the mantle. Ropes that have been severely stressed will have tapered sections to the rope, where it is visibly or palpably thinner. Rope that has been abraded or cut on sharp edges should be examined closely by an experienced user who may choose to cut the rope at that point, rather than risk it parting at that area.Rope may be cleaned by forming it into a chain sinnet
Chain sinnet
A chain sinnet is a method of shortening a rope or other cable while in use or for storage. It is formed by making a series of simple crochet-like stitches in the line.-Tying:To tie:#Create a loop in the rope...
, to prevent excessive tangling, and washing it in a front-loading clothes washing machine
Washing machine
A washing machine is a machine designed to wash laundry, such as clothing, towels and sheets...
with soap flakes. Strong cleansers, including bleach
Bleach
Bleach refers to a number of chemicals that remove color, whiten, or disinfect, often via oxidation. Common chemical bleaches include household chlorine bleach , lye, oxygen bleach , and bleaching powder...
and detergent
Detergent
A detergent is a surfactant or a mixture of surfactants with "cleaning properties in dilute solutions." In common usage, "detergent" refers to alkylbenzenesulfonates, a family of compounds that are similar to soap but are less affected by hard water...
should not be used with life-critical Nylon components. Commercial rope cleaning devices are available from the climbing and rescue companies CMI and PMI.
Typical specifications
| Dynamic Ropes | ||
|---|---|---|
| Diameter | Typical Impact Force* | Typical Weight |
| 8.1mm (~5/16") | 6 kN (1350 lb) | 42g/m (0.45oz/ft) |
| 9.8mm (~3/8") | 8 kN (1800 lb) | 63g/m (0.67oz/ft) |
| 11mm (~7/16") | 9 kN (2000 lb) | 78g/m (0.84oz/ft) |
*Dynamic ropes are rated for a certain number of falls (usually 5-10) at a given impact force.
| Static Ropes | ||
|---|---|---|
| Diameter | Typical Breaking Strength | Typical Weight |
| 9mm (~11/32") | 21 kN (4700 lb) | 51g/m (0.55oz/ft) |
| 10mm (~3/8") | 27 kN (6000 lb) | 66g/m (0.71oz/ft) |
| 10.5mm (~13/32") | 30 kN (6750 lb) | 69g/m (0.74oz/ft) |
| 11mm (~7/16") | 34 kN (7650 lb) | 75g/m (0.81oz/ft) |
See also
- Dynamic ropeDynamic ropeA dynamic rope is a specially constructed, stretchable rope. This 'stretch' is what makes it 'dynamic', in contrast to a static rope that doesn't have any give when under load. By stretching under load, a dynamic rope will soften the impact of extreme stresses on it, such as falls, and lessens the...
- Fall factorFall factorIn climbing, using a dynamic rope, the fall factor f is the ratio of the height h a climber falls before the climber's rope begins to stretch and the rope length L available to absorb the energy of the fall....
- Static rope
- Climbing equipmentClimbing equipmentA wide range of equipment is used during rock climbing. The most popular types of climbing equipment are briefly described in this article. The article on protecting a climb describes equipment commonly used to protect a climber against the consequences of a fall....
- SailingSailingSailing is the propulsion of a vehicle and the control of its movement with large foils called sails. By changing the rigging, rudder, and sometimes the keel or centre board, a sailor manages the force of the wind on the sails in order to move the boat relative to its surrounding medium and...