Photos by Michael (House) Tain.
The footlock, a common and efficient technique used for ascent into the canopy, was for many years performed unsecured, meaning the climber was attached to the climbing line only by the grip of their hands and feet. If either failed, and the climber was unable to achieve an on-rope rest position to recover, they would fall to the ground uncontrolled. Those days are gone now, and any climber employing the footlock technique in the ascent must be secured in some manner. The most common method of security to the ascent line is a length of cordage forming any of a variety of hitches, though the use of mechanical ascenders is becoming more common in this application. Although a difficult skill for some to master, with practice, the speed and efficiency of the secured footlock technique makes it an excellent “tool” to have available, as long as its limitations are understood.
|The Petzl Piranha (left) and DMM Offset Eight, two descent devices that can be installed while hanging in a static system.|
Any secure climbing hitch that grips the rope adequately when loaded is acceptable in the secured footlock technique. Though a wide variety of hitches are used, the most common is the Prusik. The Prusik, or whatever climbing hitch is being employed, is meant to act as a backup, or security, should the climber lose their grip. Once the technique has been mastered, the climber’s weight is almost never on the Prusik, except in the case of rest, repositioning or emergency. A Prusik may be formed on the ascent line through the use of a tied, spliced or stitched endless loop, or through the use of spliced/stitched rope tools made specifically for footlocking. The cordage used must meet the 5,400-pound breaking strength for personal/life support and be somewhat smaller in diameter than the ascent line to ensure that it will grip well. Climbers using strong enough, but extremely small diameter, cordage may find it grips too well when loaded, and is difficult to loosen to continue in the ascent. Forming a Prusik on the ascent line is a relatively simple process, in which the loop or rope tool is passed back through itself three times, forming a six-coil, three-wrap Prusik. Additional wraps/coils will provide more security, but may increase friction, making advancing the hitch difficult.
|The grapevine knot, or double fisherman’s knot, used to form an endless loop (tied with larger diameter rope than typical for ease of viewing).|
Tied, dressed and set (TDS)
Climbing arborists must always make sure that any knot or hitch they use is tied, dressed and set; and in ones used for personal/life support, this is obviously important. Users should ensure they have tied the knot/hitch correctly, dressed it to make sure all the various pieces and parts are in the proper place, and set it by loading it prior to use to ensure it works correctly.
Climbers using the footlock technique on a static line, regardless of the hitch securing them to the ascent line, must remember that they are in a static system. This means their hitch is bearing the load of their entire body weight, instead of the half borne by the hitch in a dynamic system. Thus, the Prusik must be used for ascent only, as an attempt to use it descending may result in an uncontrolled fall due to the change in forces. This inability to use the Prusik or hitch for descent in this static system means that users must always have some means of descent with them and should not count on their dynamic system as this means of descent, as they may need to descend while not in a location where it is possible to switch over safely to a dynamic system. Some common descent devices that can be put into place while hanging on a static line are any of the wide variety of figure eights, Petzl Piranhas, etc.
|An example of a six-coil, three-wrap Prusik tied and dressed on the two parts of the ascent line.|
The user’s hands must always remain below the Prusik or hitch, and the length of cordage used should be adjusted accordingly. This practice will prevent the climber from inadvertently grabbing the hitch causing it to release, and leading to an uncontrolled descent in the static system.
An ascent line that is spread apart by being over a branch can cause hitches that are pushed into this spread to fail in a doubled line static system. An excellent guideline to avoid advancing the Prusik into this spread is to follow a 5-to-1 ratio: for every 1 inch of branch diameter, keep the hitch 5 inches below the branch. Additional options to avoid the problem of spread are using friction management devices such as a Friction Saver, using the footlock technique on a single line, or even tying an appropriate mid-line knot such as the Alpine Butterfly, passing one end of the ascent line through it and running the Alpine Butterfly up beneath the branch.
|Rope Tools: (top to bottom) A spliced footlock leash with a large loop for forming the hitch and a small loop for attachment, a long spliced eye and eye for footlocking, and a tied and taped endless loop for footlocking.|
Twigs, sticks and even leaves getting between the two parts of the ascent line or into the coils/wraps of the Prusik may cause it to fail when loaded. Climbers should monitor their hitch during the ascent, and remove any debris as soon as possible.
The secured footlock technique, with varying amounts of practice and experience, will quickly provide a relatively simple method for safe, efficient ascent into the canopy for most users. This ability to ascend fairly quickly, while expending less energy due to efficiency, allows climbing arborists to focus on the work once they arrive in the canopy, and use the energy conserved to carry it out, providing yet another valuable tool for tree care professionals.
Michael (House) Tain is a contract climber, splicer, educator and writer associated with North American Training Solutions/Arbor Canada Training and Education, currently located in Lancaster, Ky.