Effects of vertical-speedlines on the orientation of a large top's landing?

eyehearttrees

New member
Location
Tampa-Area
Was removing a pair of shared-trunk (but wholly independent, pole-type trunks), mid-50' pine type conifers and had to take the tops off (and one of the middles) before I could fell the remainder, and because both "forward hop" on the landing - and any side-to-side jumping of the butt once it landed, or any potential 'spearing' - were totally unacceptable, I simply set a vertical zipline (5/8"), used a 3/4" ring-sling on the butt of a >25' tall / 2' wide top, and sent it.... The setup worked - I was really only asking it to keep the log/top in the orientation I'd cut / felled it in - but the angle of the tree was such that the "vertical" line was actually going backwards IE it would pull that butt 5' back towards the trunk if necessary, and I'd *swear* that on one of the tops that once the vertical line had exerted some purchase on the top, that in pulling it 'backwards' a little, that it kinda "straightened it out"!

Keep trying to wrap my head around it...if anything, a pull from the trunk should throw the piece's direction OFF, not in-line, to the directional-cut (because it'd be 'yanking the feet out' from the log) but then again since I did a Conventional notch the piece did the usual 'hop' off the trunk so maybe it's only in the rear-ward pull of the zipline that this occurs (which would then make a great case for setting the base of the vertical zipline several feet+ rearward of its top-point, so that whether there's pronounced 'hop' or not the log will still get rearward pull from the vert-line instead of just "keeping the butt near the trunk" control!

Hope I got this across properly, couldn't think of a way to draw it out...would really love feedback/thoughts on this idea because honestly this type of vert-slidelining is becoming more & more a "safety-redundancy" thing that I do when dropping anything from too-high a height, I'm actually quite happy & confident with my control of log-fall direction & spin but I like the peace-of-mind of knowing that butt is tethered to the trunk!!
(PS- should note that I am very aware of my climbline relative to all this IE no chance of the butt hitting&splitting my climbline, I actually detach from anything basally-anchored when doing such cuts anyways but still)
 

SoftBankHawks

Branched out member
Location
Japan
Hello mate, sorry, can't quite follow your words but just wanted to say a couple of things out of my own experience of using VSL's.

They are great, in fact, they are bloody fun and go a long way to helping efficiency when working on embankments and in tight quarters. That said, there is a dangerous feedback loop that pushes you into cutting larger pieces, quite unaware that the forces involved (even with smaller pieces), is immense. If things go sideways with VSL's it can be disastrous.

The most dangerous point in the sequence of events when rigging is the moment after the cut, when the load is put into the motion of fall, swing or lift. For these seconds the pre set-up becomes vital and without
well intentioned movement accidents can (and frequently do) happen. Dynamic, swing and lift rigging hold the most danger in that order. And without having any additional control within the VSL system, apart from it hitting the ground, it sits right at the top of that list. It is very different from free fall cutting, obviously, but the forces generated are similar. Rope snapping, melting, trees being jolted sideways, climbers losing stability, hardware snapping...these are common occurrences with the VSL.
 

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