By Michael “House” Tain
Ropes or cordage are an ancient tool of the human race. In fact, there is archeological evidence — cordage impressions in pottery — of manufactured cordage use from 28,000 years ago, and actual existing samples of manufactured cordage that is 15,000 years old. But, in all likelihood, humans’ use of rope even predates these ancient examples. A skill that developed hand in hand with the use of rope or cordage is the art of splicing, which has been expanded and refined as rope use, manufacture, materials and construction changed and evolved through the centuries. Splicing, properly understood and correctly carried out, allows rope and cordage users to repair, manipulate, and change the fibers of individual ropes; and, when done well, results in stronger, more secure and easier-employed rope tools and products. Splicing techniques and methods are almost as wide and varied as the vast number of materials, types and constructions of ropes available to modern arborists, thus an in-depth discussion is beyond the scope of the space available in this article. However, an introduction to the basic advantages of splicing, a discussion of some of its principles and rules, and an examination of some introductory techniques will assist in giving climbing arborists the information necessary to better understand, evaluate and perhaps one day construct their own rope tools and spliced goods.
Spliced terminations in a rope or length of cordage are, by definition, significantly stronger than any knot a tree care professional could form or tie in the same rope or cordage. The simplest explanation of strength loss in rope is that the greater the bends in the rope, the greater the amount of strength lost, or the weaker the rope becomes. Knots and hitches have to create bends in the rope or cordage in order to function, thus they weaken the rope. Knots or hitches with a lesser number of or less severe bends will weaken the rope less, thus retaining more rope strength. But spliced eyes, properly done, will create the least amount of bends of all — thus retaining the vast majority of the rope strength. This advantage in strength can be easily seen in Table 1 (drawn from rope breaking tests on 1/2-inch climbing lines attached to carabiners).
PERCENTAGE STRENGTH LOSS
Clove hitch w/2 half-hitches
Bowline w/Yosemite tie-off
Triple fisherman’s/scaffold knot
Regardless of whether a climbing arborist is using a knot, hitch or spliced eye to attach his/her climbing line to him/herself, one of their key considerations must be how the chosen attachment method interacts with the connecting link. Carabiners are particularly susceptible to failure under cross or side-loading, and this type of loading can easily occur with a poorly chosen attachment method. Although there are certainly attachment knots and hitches that will grasp the connecting link securely and stay in place, a properly spliced eye, used correctly, will perform just as, if not more, securely. Large spliced eyes are intended to be girth hitched around the connecting link to provide a secure attachment with a minimum of strength loss, while smaller eyes should be spliced in such a fashion that they fit the given connecting link quite snugly.
Spliced attachment eyes on either climbing lines or split bridges/tails for climbing hitches will also increase the efficiency of the tree care professional that chooses to employ them. Climbing arborists using attachment knots and hitches who has to reposition their rope or detach from their system, while still secured by a secondary system, during movement throughout the canopy, will find themselves tying and untying their chosen attachment knots several times. Although this process may seem to only consume a small amount of time, it does add up, along with exposing the climber to the possibility of making an error when reforming their attachment knot. Spliced eye attachments, created by reputable qualified splicers, not only will lessen the amount of time required to attach and detach from the climbing line, as can be seen in Table 2, but will also eliminate the possibility of “operator error” when tying the attachment knot.
AVERAGE TIME REQUIRED
Triple fisherman’s knot
Clove hitch w/2 half-hitches
Bowline w/Yosemite tie-off
Spliced large eye
Spliced small eye
[First-level subhead, bold] Physics
The physics of splicing are relatively simple, although there are slight variations within different rope constructions and materials. In general, splices work very much like the child’s toy called the “finger trap,” where the fingers go in easily, but the harder the finger is pulled on, the more fiercely the toy grasps it. All splices — much like knots and hitches — work on friction, and require a given and specific amount of friction to provide the required strength. In a three-strand rope, this friction is created by passing the strands of the rope back through one another a specific number of times — typically five — to create the required amount of “grab.” Hollow-braid ropes are typically buried back within themselves a specific distance to create the necessary friction or “grab.” Regardless of rope construction, the basic principle and goal remains the same — creating enough surface friction or “grab” between the rope and itself that the splice will not slip. A properly created splice will actually grasp itself even more fiercely the harder it is pulled upon, in a sense growing even more secure with greater pressure.
Lock stitches do not affect the strength of a splice at all, all the splice’s strength is created by the appropriate bury distance, but the lock stitches do provide security to the splice when it is not under load, particularly if the splice is of the type known as a “straight bury.” As mentioned previously, the splice is going to grip itself even more strongly under greater loads if the proper amount has been buried. However, when not under load, in the absence of lock stitches, it is possible to “tease” or gently pull the splice apart. It is unlikely that a sane climbing arborist would do this intentionally, but should the splice not be lock stitched and a branch or other object pull part of the bury out, the danger is that there will now not be enough of the rope buried to provide the surface friction to grasp more strongly under load — causing a catastrophic splice failure.
The Locking Brummel is a method of providing additional security to an eye spliced in the end of a line or piece of cordage, and is typically used with ropes of a hollow-braid construction. In short, the line is passed through itself in such a manner to “lock” the eye so it cannot slip, prior to the final bury being carried out to provide the strength of and finish the splice. There are several ways to create a Locking Brummel, but one of the simplest — illustrated in the accompanying photos, and often used in creating eye slings for rigging — is to pass the short end of the line through the long end of the line, then the long end through the short end, then carry out the final bury. Lock stitches should still be used on a splice with a Locking Brummel to provide additional security to the final bury.
There is a great deal more to splicing than the rough introduction here, but as with many activities in the modern world, there are a number of easily accessed resources that can provide more information and illumination about this complex and fascinating art. Rope manufacturers — all of whom have their own in-house splicing staffs — have excellent information on splicing on their Web sites; and in some cases sell/provide splicing kits and splice testing/evaluation services. There are several organizations and individuals who offer arborist-specific hands-on splicing training (including North American Training Solutions, Brion Toss Yacht Riggers and Arboriculture Canada Training and Education).
Objectively, splicing is an art that allows tree care professionals to use rope and rope tools in a safer, stronger and more efficient manner. Whether they produce them on their own, or rely on reputable qualified splicers to do so, splicing should not be undertaken lightly, as lives — our own and others — may hang in the balance. Conceptually, and no less importantly, splicing connects us to our ancestors of thousands of years ago — completing a chain of skills and knowledge passed from one human to another from the dim recesses of time to the present. This chain — from splicers no longer with us such as Stanley Longstaff and Pete Donzelli to a fresh-faced branch manager learning how to make an eye sling — connects us to one another, to the ropes we use to succeed and survive, and to the trees we work in. It strengthens us, it informs us, and it makes us what we are — arborists.
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