Flipline systems -- The Wirecore Flipline
One must realize that Tom Dunlap is one of our resident techno-geniuses. His system is highly evolved and he can probem-solve his way out of ANYTHING. I, too, look forward to the pics, or drawing, and in the meantime I will offer up my flipline evolution.
I've always been kind of a fan on steel-core fliplines. The first couple I had (starting a few years ago, OK?) were the bright orange HI VEE style ones from New England. These were 8-footers with a diameter of 1/2". For my cammed rope-grabbing device, I used a Petzl microcender and an autolock caribiner for my 'microjuster'.
The reason I like 8 foot is several-fold. First, on my 32" waist line, that 8 feet goes around me EXACTLY two times with maybe an inch or two to spare and clips back on to my left-side saddle ring. Most of us, I imagine, aren't a LOT bigger, unless you're John Paul Sanborn, in which case you would need a flipline somewhere between 12 and 19 feet (But remember, he can crush a Sasquatch!).
This flipping 2X around the waist is conveniently convenient because when not in use, the flipline is around your belly area and not hanging down in your lower saddle gear. I permanently affix the thimble/eye end of the line to my right side with a modified delta (triangular) quick link. The line originates on my right side D-ring, goes around (counterclockwise) once, twice, across my belly, clip to the left side. Yesterday I wore a Winter coat and rather than hike my coat up, I went around, once, twice and not being long enough to go across the front side to the left side, I simply clipped to my right side. I think a guy with up to a 40" waist could stow his flipline using this latter description.
Another reason I like 8 foot (aside from it's lighter than 10 foot) is that I don't very often have to flipline around circumferences bigger than 9 1/2 feet (remember, there's a spread of about a foot and a half between your right side permanent attachment, and your left side clip-in attachment) Doing our math, Circumference = pi r and we know our MAXIMUM target circumference to be 9 1/2 feet
9.5 = pi r and dividing both sides by pi, we get r = 9.5 divided by 3.14, or a radius of 3.02 (lets call it three ) feet. Radius is 1/2 the diameter, showing mathematically that you can get an 8 foot flipline around a 6 foot diameter trunk, and clipped back to yourself. You're pasted there. You can't move, but it is possible. For the RARE time that I encounter this, I pull a 30" sling off my harness and use it to elongate my flipline. Here I would clip the sling to my left side, clip the flipline to the middle of the sling and clip the other end of the sling next to the first end, giving me 15 " of extension. If I need a full 30" of extension, well, don't fold the sling in half. By the way, why aren't you just rappelling down this fat trunk anyway? If you're going UP, use your Bigshot and ascend the rope up to smaller diameters.
In searching for 'the better steel-cored flipline', I found one from Wall Safety, which is the yellow one sold through Sherrill. The diameter of this line is 1/2", but if measured with a caliper is just slightly under a half inch. This serves an advantage. Your microcender adjuster moves along it with great ease, without having to depress the cam lever with your thumb. However, when you adjust and clip back on to yoursef, the cam locks in rock solid and bombproof. Still, I back this up. Rather than letting the terminal swivel end hang free, I either continue it around my backside and clip to my right side D-ring, or just clip it on the left side, adjacent to the microjuster. That way, if the microjuster WERE to ever fail, I'mstill clipped in.
A NOTE on the microjuster. I use a Petzl microcender harboring a Kong captive-eye style aluminum biner as the attachment point (and still looking for the ideal biner for this place). The microjuster comes standard, but Petzl includes a small bolt and nylon lock nut to replace the spring pin for use in life support situations. REPLACE THE SPRINGPIN with the permanent bolt. That is all.
Lastly, about dielectric properties (electrical conductivity), wirecore fliplines are NOT APPROVED for trimming around power lines. They WILL conduct electricity, maybe even as easy as your knees, hands, or any other part that is touching a tree that becomes energized. The rope sheath around the wire core is non-conductive, as is a conventional rope or nylon web buckstrap, but that only goes for if it's not wet, or impregnated with grit.
Second lastly, in an earlier thread, there was a statement of a chainsaw having been shown to go through a steelcore flipline in less than a second. Under test conditions, I've no doubt you can make this happen. However, in 'in-tree' conditions I speak from experience, if you are momentarily careless enough to hit your flipline, colorful nylon fuzz will fly everywhere, and there will be a ratcheting vibration through the flipline and INTO your saddle. If these two rather obvious clues aren't enough to make you shut off your saw immediately, then have a nice landing. A regular rope, or nylon buckstrap, I'm sorry, the chainsaw will go right through it, and unless you're roped into a TIP up higher, you're in-flight. That's precisely WHY they make wire core fliplines.
Use that often do ya Mike?
