Basic types of clean and natural protection and the underlying principles.

Natural Protection Trees, horns, chockstones, and other naturally occurring features which can be slung or otherwise incorporated into a system to protect climbers on rock, snow, or ice are considered natural protection. Using natural protection in rock In some situations, natural protection may be better than artificial gear and may require some effort to attain. In other circumstances a sling made of cord or webbing may be slung over or tied to a natural feature. In the simplest sense, the rope is used extensively to provide running belays, protection, and anchors as guides and clients move through the terrain. If possible, it is best to simply loop the sling around or over natural protection. This is the easiest, fastest, and strongest arrangement. It requires longer slings, however. In many cases, it is desirable to attach the sling to natural protection with a hitch, either because the sling is too short to loop, or so the sling grips the protection and does not move or slip off. The girth hitch and clove hitch are commonly used. The girth hitch is simpler and faster but can create a pulley effect, especially on larger items. Care should be exercised to ensure the pulley effect of girth hitches is minimized. Clean Protection Stoppers, cams, and other devices carried by the guide which can be placed and removed without significant damage to the environment are referred to as clean protection. These devices are generally removed after use. Using clean protection in rock Clean protection falls into three broad categories: wedging devices, camming devices, and spring loaded camming devices. Types Wedging Devices Stoppers are the primary example of wedging devices. As more force is applied wedging action increases and, if the rock is strong enough to withstand the multiplication of forces, the tighter the stopper wedges. Most modern stoppers are curved so they become more versatile in placement and impart some camming action (see below) which add to their holding power. Stoppers are generally slung with wire to ease placement and maximize strength. They are most useful in small to moderate sizes (< 40 mm). Because they are simple, relatively fast, and somewhat easier to assess than other types of protection, stoppers tend to be the one universal piece of equipment that all guides everywhere use on a regular basis. Camming Devices Camming devices are designed with an offset axis. When placed correctly, they rotate from a smaller surface area to a larger one. This causes the device to jam tighter as increasing force is applied. Cams can also often be used as wedges in some orientations. Hexagonal tubular types are more stable and simpler to place than other types, especially those incorporating small points of contact. Cams are best slung with cord or webbing to maximize the camming action and reduce the chance of a piece becoming unseated by rope movement. They are most useful in moderate to large sizes (40 mm +) where camming action is more pronounced than in smaller sizes. Simplicity and relative ease of assessment make cams a useful part of a guide’s rack although spring-loaded cams have rapidly eclipsed their use. Cams are often more effective than spring-loaded units in horizontal placements where the sling runs over an edge. Spring-loaded Camming Devices (SLCDs) When loaded, friction between an SLCD’s cams and the rock cause the cams to rotate to a larger axis thus keeping the device in place as force is applied. Because the device is initially held in place by pressure from the springs a false sense of security can be attained, since even marginal placements are created quickly and easily and may stay in position regardless of the quality of placement. Used correctly, SLCDs have the potential to provide good protection in parallel cracks, overhanging cracks, and other situations where other types of clean protection are difficult or impossible. In addition, their variable size range makes them versatile: fewer pieces will fit more places. SLCDs are manufactured with three or four cams and with flexible or rigid stems. Three cam units are generally most useful in smaller sizes which fit thin or shallow cracks. While all mechanical cams are relatively unstable, i.e. they are easily moved or dislodged from their position, three cam units are even more so, requiring careful placement and a high degree of judgement in determining their quality. All else being equal, four cam units are more stable and structurally stronger than three cams. All else being equal, SLCDs with a rigid stem are more stable when load is applied than a flexible one. All SLCDs are strongest when placed with the cams near the middle of their expansion range and when all cams are equally expanded. The holding power of all SLCDs is compromised in cracks that are dirty, snowy, or icy because the ability of the cams to hold is lessened due to decreased friction. Compared to simpler devices, SLCDs are relatively difficult to assess and can be very difficult to remove if they creep or become dislodged, even without loads being applied. In spite of their complexity, SLCDs have become overwhelmingly popular. Guides are advised, however, to study their capabilities and limitations carefully and fully understand their use and application before depending on them as the main item on their rack.