By Michael “House” Tain
Martin Morales using the rope angle to his best advantage by leaning into it.
Photos courtesy of Michael ‘House” TainThe term “redirects,” within the tree care profession, typically refers to the practice of rerouting a climbing or rigging line for advantage — perhaps to improve the rope angle to a climber in climbing operations, or to assist a rigging line to enter a lowering device in a more appropriate way for maximum safety and efficiency. In addition, some thought and planning put into the rope route prior to beginning the operation — whether using redirects or not — will not only increase the speed and efficiency of the job, but can also lessen and reduce the forces experienced by the tree’s structure, thus making the climbing or rigging operation inherently safer. Unfortunately, redirects and rope route choices can just as easily — if incorrectly employed or made — make a job more challenging, less efficient, and magnify dangerous forces within the tree’s structure. However, knowledge of a few basic principles and methods, coupled with some basic practice and training, can assist climbing arborists in using redirects to route their climbing or rigging lines in the most effective safe manner.
This diagram illustrates the forces on the two parts of the line and block in a vertical orientation.
This diagram illustrates the forces on the two parts of the line and block when the rope angle is “opened.” The forces will increase gradually as the parts of the line move closer to a vertical orientation.Rope angle is a term used in both climbing and rigging; and, in its simplest form, refers to the angle the rope takes reaching the climber, lowering device, pulley, block, etc. In climbing operations, the climber is going to be, in most cases, best served and most supported the more vertical or above them the rope leads. This vertical rope angle supports the climber while helping maintain his/her balance more easily. The rope angle in rigging can have a different effect; and is more related to safety with regards to rope strength and the use/function of lowering devices. Most lowering devices will be strongest and function best when the rope leads directly into them, rather than at an angle to one side or the other, let alone in a fully perpendicular fashion. The rope angle at blocks or pulleys radically affects the forces experienced there. Simplified, the maximum force will be exerted when both parts of the line enter and exit the block vertically, as is to be expected. However, “opening” the angle or moving/redirecting the line on entrance to the block lessens the force experienced considerably.
The technique of using natural redirects, the structure of the tree itself to redirect the line, is one most tree care professionals are probably familiar with, both in a positive and negative way. Natural redirects are often discovered by chance climbing through the canopy when the climbing line drops into a branch attachment point or over a lead unintentionally. But once the possibility of these natural redirects is understood and employed with intention, they can be quite useful while requiring no additional equipment to install or retrieve. The use of natural redirects requires some forethought and understanding that they will increase the amount of friction the line is experiencing. For example, a long, exposed horizontal limb walk can be eased considerably by the use of a branch attachment point above the limb to be walked as a natural redirect. Dropping down through this keeps the climber’s line more secure and prevents or lessens the likelihood of an uncontrolled swing should they lose their balance. However, without thinking ahead a bit, once the limb walk is completed, the climber will be confronted with climbing back up and through their cleverly used natural redirect to continue their work — an obviously inefficient and often fatiguing process. By simply thinking ahead, climbers can leave the running end of their rope (the one leading to the ground) draped over the branch on the side they next wish to go; and, after securing themselves with a lanyard along with their climbing hitch to prevent slippage, pull their hitch and rope up/through the natural redirect and back down to themselves using the tail/running end of the rope — thus eliminating the need to climb back up and through.
This term refers to any number of devices, cordage, pulleys, carabiners, rings, etc., that might be installed in the tree to redirect the line. Their disadvantage is that they require more gear, installation and retrieval, but their advantages will often outweigh this. The climber or rigger is able, due to their manufactured nature, to put the redirects wherever they are needed, rather than being limited to the existing structure of the tree as with natural redirects. Additionally, when properly installed and employed, manufactured redirects will significantly reduce the amount of friction experienced by the line within the system, particularly in comparison to natural redirects — reducing not only climber effort but also damage through “burning” of the tree’s bark and cambium. Although the majority have to be retrieved by the climber returning to them, there are types/systems that are retrievable from the ground or another location within the canopy (though they often require the use of an additional small lightweight line or a clear unobstructed path for the redirect to travel back to the climber).
As mentioned, rigging redirects can be used to provide a variety of advantages, including ensuring a correct rope angle into a lowering device or reducing forces at a particular block. They can also be used to reduce or better distribute forces within the structure of the tree. For example, rigging and removing a tall leader on itself that extends out and away from the primary structure of the tree without redirects might lead to excessive forces at the attachment point of the leader while also creating a negative bending moment, as both parts of line would be pulling down at the angle that is going to create maximum force. Using another block within the tree’s primary structure to redirect the line or even trailing the line in the “fishing pole” technique along the leader itself would lessen and redistribute these forces. In addition, this use of redirects would keep the running end of the rigging line back and away from the load, preventing that great frustration of ground personnel everywhere — the “whirling dervish” effect. Natural redirects can certainly be used in rigging operations with the understanding that friction is going to be increased considerably. This additional friction may be a slight positive in allowing better control of loads, but will certainly damage both trees and ropes. Rigging lines that are double braid in construction will also lose a fair amount of strength when running through natural redirects, as the cover will be experiencing more of the load due to the friction, not to mention abrasion — thus, their use with “natural crotch” rigging or natural redirects should be avoided if at all possible.
As with rigging redirects, climbing redirects may be natural or manufactured, and are most often used to provide a better rope angle and greater stability to the climber. However, they can certainly be used, and often are, to allow a climbing arborist to get into a required position that typically would not be possible. For example, climbers using a redirect slightly elevated and off to the side of the branch or lead they are working on can then lean back or to the side, putting their weight on the redirect and reach that dead tip that was beyond their reach before. The two line technique — using two lines and climbing hitches at the same time within the canopy — can be considered a redirect; and, while not only allowing for better support and stability, often provides much easier movement from one side of the canopy to the other. A refined version of the two line technique, sometimes called the “M” method, eliminates the need for a second line and hitch by running the line through a pulley on the climber’s harness, through a redirect (natural or manufactured), and back through a climbing hitch on the climber’s harness — thus allowing for movement laterally or vertically while only having to mind one hitch. A longer climbing line is a distinct advantage when using the “M” technique, particularly in the event the climber needs to reach the ground in a speedy fashion.
A rigging line being redirected by a block in a mechanical advantage situation.As always, equipment employed to form manufactured redirects previously used, even once, for rigging should never be used for climbing, as the forces they were exposed to in that application may have compromised their strength. Although manufactured redirects are not the sole or even primary means of support for the climber using them, the equipment and cordage employed for climbing redirects should meet the ANSI standards with regard to strength and function, particularly as redirects are most often used in climbing operations to prevent uncontrolled swings or increased hazard exposure.
The use of redirects in tree care climbing or rigging is only limited by the imagination and foresight of tree crew members. And, while not always necessary or even desired, when required by the situation and employed correctly, they can certainly increase the efficiency and safety of all concerned.
Michael “House” Tain is a contract climber, splicer, educator and writer associated with North American Training Solutions www.northamericantrainingsolutions.com and Arbor Canada Training and Education www.arborcanada.com He is currently located in Lancaster, Ky., and can be reached via e-mail at firstname.lastname@example.org.