Each style of fixed rope has its uses, but surprisingly, the style used the most is the third style. Short sections of fixed rope are common at cragging areas throughout the country. Most of these ropes are used to facilitate classes for beginners.
Fixed lines are designed to protect an individual who is moving over exposed second, third or even fourth class terrain. In this application (with beginners) they shouldn't be used for more difficult terrain. Instead, such terrain should probably be belayed.
Fixed lines are relatively simple to install. Build a 12-point SERENE anchor at the top and then work your way down the exposed area, placing gear along the way. At each piece of gear, the fixed line should be clipped in with an overhand eight knot. It should not run through the carabiners freely as this would defeat the purpose of the pieces. Each stretch of rope should be isolated.
There are three ways that an individual might use a fixed line. First, they might simply use it as a handline. This is the simplest way as there is little for climbers to do but hold the line. Such a use indicates that the likelyhood of a fall is low and that an individual or a group simply needs a little bit of additional security.
Second, they might use the lobster claw technique. This is where an individual girth-hitches two slings to their tie-in point. A locking carabiner is then clipped to the end of each sling. A climber can then clip both slings to the fixed line as he or she moves up the line. As the climber gets to set pieces, he or she can clip past the piece without coming completely off the rope.
The third technique is to place a prussik on the fixed line. A prussik offers the most security as it won't allow a person to fall anywhere if they slip. If you have one section that requires such tactics, it's not a bad idea to pre-rig the prussiks so that the beginner doesn't have to rig it in an exposed area.
No matter which style of line you employ, a good rule of thumb is that only one person should be attached to a given part of the line. You should never have two people in the same part of the system.
Fixed lines are great, but they should not take the place of a real belay. Before exposing your beginner friends to a fixed line, be sure that it makes sense. Be sure that it is the best solution to your problem. And be sure that everybody knows what they're supposed to do when they move up or down the line...
--Jason D. Martin