Anchoring on rocks with chocks/nuts. Stoppers: main features and usage.
- Features and design
- Installation and use
- Things to remember
Stoppers are one (of the few) types of fixation elements used to belay on rocks. Unlike friends or camalots (whose cams actively expand in cracks), stoppers are passive protection and work by jamming in rock cracks due to their wedge-shaped shape. Their installation and removal requires a little more time and skill than, for example, installing friends.
Cams/friends are, of course, generally more versatile and easier to use; one size can cover a variety of cracks. In addition, friends can cover wide cracks with parallel walls, where even the largest stoppers will not fit. However, a set of stoppers is lighter and much cheaper than a set of camalots. The stoppers are very reliable when used correctly and are easy to use. For this reason, you definitely shouldn’t exclude them from your climbing kit.
Typically, a set consists of 10-12 elements, which differ in size and number. Depending on the brand/manufacturer, the dimensions of the corresponding numbers may vary slightly. The width of the cracks in which the standard set can be used varies from 3-5 mm to 40-45 mm.
Features and design
Stopper nut is a truncated wedge with four edges, made of aluminum alloy (sometimes small sizes are made of other metals) and a cable loop. Opposite edges are located at an angle of 7 to 12 degrees to each other for reliable wedging. Each wedge is a different size and can be used in two positions (narrow side and wide side). The planes of modern stoppers are curved, which allows for more friction to be created.
Metal cable diameter is different for different sizes. For example, elements from sizes 1 to 5 are equipped with thin cables and have a strength (load limit) of 200 to 300 kg. These micro-stoppers are not used for stations, but only as intermediate support points. Each cable loop is usually marked by the manufacturer: the maximum load is indicated on it. Medium and large stoppers, according to UIAA standards, must bear 12 kN (1200 kg).
Installation and use
So, the standard set ща stoppers consists of 10-12 types, but their number and sizes are selected depending on the complexity of the route and the nature of the rocks. Stoppers work well in vertical cracks and can be used in horizontal ones. However, they are less safe and ineffective in diagonal cracks, where the direction of the load does not correspond to the direction of jamming, thus in diagonal cracks it is better to use friends. Remember that stoppers only work in one direction, avoid organizing stations only on stopers (the direction of the load may change).
Basic principles for installing stoppers:
1. Select a suitable crack that narrows in the direction of loading
2. Check the strength of the rock on both sides of the crack
3. Remove the carabiner with the whole kit and select the appropriate stopper's size. It should be small enough to fit into the wider part of the crack, but large enough to wedge in the narrow area. Remember that the stoppers are asymmetrical, so they can be positioned in different ways (on the narrow or wide side). It is important that the stopper, after installation, comes into contact with the rock as much as possible.
4. Check the position of the cable, it should correspond to the direction of the load
5. After installation, it is necessary to push the stopper deeper into the crack. Take the entire set, hanging on the carabiner under the already installed stopper, in your hand and pull in the direction of the load - your position must remain stable, even if the element pops out. Afterwards, you can snap off the carabiner with the remaining set and return it to the leash. Now this point can be used in the belay chain
6. In some cases, next to the fixed element below, another element is installed, directed in the opposite direction. Connected apposition stoppers prevent the main element from jumping out when the load direction changes
7. Pairing two stoppers in one place increases the range of use of cracks - this method is possible if suitable sizes are not available. But it is not very reliable and requires good skills
8. Removing stoppers from rock cracks is not always an easy task. A special tool (extractor) or a regular rock hook can help. In this technique, it is important to push the chock into the wide part of the crack, and then carefully pull it out along the installation path in the opposite direction
Things to remember
Correct and quick installation of stoppers is a skill. It is better to acquire this experience on natural terrain, standing with both feet on the ground - so that nothing distracts from the process. It is important to learn not only how to install correctly, but also how to see and use suitable cracks, quickly select the right size, use different options, etc.
For more convenient use, it is better to hang the set on 2 or 3 carabiners according to the types of sizes.