So in this installment of Litter Hauling Techniques Using Dual Capacity or Twin Tension Rope Systems Part 2, I would like to jump into anchor and anchor systems used in a few of the systems we set up here this week. Neverland has three upper platforms or stages (as we call them) and the lower Ground Floor... A, B and C... or Main, Near Side and Far Side. We'll jump to the Main stage first with our Gin Pole skate-block, raise and lower. Already you might a bit skeptical... you don't do that with gin poles do you?
Generally, a gin pole should be erred forward just until the resultant is in line with the compression member. The one we have here has the resultant pulling way forward on purpose, so as long as there is substantial back tying it should be ok right? We built the skate block as a ground based lowering system, and used a second rope for a mirrored skate block... and as such is now a low tension system technique to deflect a rescue package slightly away from a structure.
Given the fact, that as we said earlier, this type of AHD (artificial high directional) is not normally your "first out" option when rigging for a skate block, but most of what we do here at Neverland is what we call "proof of concept". That simply means that we are not concerned with "running numbers" during the evolution and are more interested in seeing if something can actually work. Because we have what we know as base line data for the gear and the general configuration... we are good to go with most set ups. That is not to say we aren't going to be out of line occasionally... as with this first configuration.
The first anchor system configuration would be the back-ties. Since the resultant is so far forward and away from the foot print of the gin pole (which is tiny to begin with), back-ties are crucial and since we are running a much more "casual" system with a reduced load, as are common with all skate blocks, I felt pretty comfortable with a Delta (3) guy system plus and additional stabilizing anchor (green sling) off the post.. which never saw any load to speak of.
The back-ties were built from a single length of Petzl 8mm Segment cord. A pretty simple non-working mechanical advantage configuration with a jumper between the two legs.
The other guy was a front guy coming off the head of the Arizona Vortex Gin Pole down to a front anchor and as before, used a non-working mechanical advantage to give the system it's minimal 3 guying legs. This cord was Sterling's 5.9 Powercord.
And last, but certainly not least would be the skate block control system on the Ground Floor. This is a Shared Anchor System where we have two separate PMI/Climb Tech Removable Bolts (each 5,000k rated) where both legs come together as one point. We felt this was more than adequate (not needing independence from each other) as a skate block by form and function simply has considerably less tension and force vectors associated with it and as I said before... is a pretty casual system to deploy.
So all in all, this is a pretty fun piece to set up. I would have liked to play a bit more with the angles of the gin pole and play around with some other configurations... but this too in due time.
If you want more information on these configurations, be it anchor systems, artificial high directionals or the physics of all this stuff... head over to Rigging Lab Academy. We have a ton of ways to get involved and on your way to greatness.
Peace on your days...