SRT_Questions about setting anchor

[apcoble]

When setting an anchor up for a single rope technique, is there a downside with respect to safety for tying a figure eight on a single hitch and feeding line through the hitch so that we maximize rope length? In other words, the anchor point is one end of a rope tied off on a large branch. We're ascending up the rope using Petzl ascenders, foot-grabs and gri-gri for self belaying.

[Paul Smith]

Do you mean using the hitch and the end of the line so there is no tail?

 

If that is your intention I would not as if you did this you could have 60-80 M to haul about the crown!

 

If you tie of at the base and climb on the tail you could be lowered in an emergency.

[apcoble]

Yes, I mean the tail is near the branch or anchor point. It makes more sense to use a ground anchor. What does it mean to have a 60-80M to haul about the crown?

[ben-jammin]

if i understand you correctly you then only have a single line of rope coming down? I am not by any means an expert or even proficient at SRT but saw the demo at the AA show this weekend and gleaned a bit of gen from the guys at tree partner who were putting on the demos.

 

I had a similair idea for setting up a footlock like where you get your rope over the desired branch and then tie an alpine butterfly, feed the other end of the line through this to create a doubled retrievable line (pull the end without a knot to ascend it to the top to choker around the stem, pull the end with the knot to retrieve) just dont try and climb the retrieving end on its own.

 

The biggest problem other than the possibility of climbing the wrong side of your line for SRT (which you know doubt would discover before you got far off the ground) is that chokering around a stem is not a belayable system from the ground. eg. a piece of deadwood falls and takes you out unconscious etc... a belayable system you are easily rescued rather than someone else running the same risk in a rescue or having to climb the same single line making for a more complicated rescue.

 

I think the system they were running was a very large version of a bowline. The access line is run through an installed cambium saver and then the bowline is tied off (Taylor or someone more proficient will have to supply the exact knot config though i think there was a yosemite tie off in there) the bowline is then lifted into the tree so that the finished setup has the knot at or above your destination (but below the cambium saver) and the bottom of the loop well onto the ground giving you two lines to set SRT up on. the other end of the rope is simply secured at the base of the tree (they used a descender but i guess you could use a munter hitch and prussic)

 

reading that back that all seems a bit long winded so i'm off to look up the meaning of brevity but i hope that makes sense and i am more than willing to stand corrected by someone far more experienced and knowledgable.

[Paul Smith]

Yes, I mean the tail is near the branch or anchor point. It makes more sense to use a ground anchor. What does it mean to have a 60-80M to haul about the crown?

 

If you have the tail near the tip then you have the remainder of the line to climb on and as you re direct though the crown you will have to pull the line through! How would you retrieve the line if you were to climb like this?

[Paul Smith]

I use 2 methods of tie off, either an alpine butterfly and the line chocked through it or chocked of at the stem. Don't over complicate things.

[ben-jammin]

I use 2 methods of tie off, either an alpine butterfly and the line chocked through it or chocked of at the stem. Don't over complicate things.

 

as per your earlier post, how would you retrieve a line choked off at the stem or would this simply be access only and then removed once in the tree?

 

I guess in a perfect world the method I saw demonstrated by the tree partner guys would be best/safest (belayable etc...) but in working life, how many people actually use a belayable system like this?

[apcoble]

You explained that well in the 2nd paragraph of your response. That is essentially what we're doing, where we have a separate rope (retrieving rope) to pull down ascending rope at the end of the day. I think you make a good point about not being able to be belayed from the ground.

 

The only problem is that I was considering having two anchor points. We currently have a horizontal cable that were operating off of. The cables were installed to trees about 15 m in the air. Below the cable, we're ascending from an anchor point that is the double-tandem pully attached to the cable. This may sound strange, but I'm conducting tree physiology research. That is why we had cables installed, they are essentially our research plots in the tree canopies.

[apcoble]

The line is choked through a double-hitch figure 8 knot and a separate rope is tied to the hitch using a fisherman's knot. Pulling on the retrieval rope allows us to get the knot down.

[Paul Smith]

A line that is chocked of at the base of the stem is easy retrievable. Un- Choke and lower the termination end to retrieve the climber, alternatively un choke and pull the tail back. An alpine butterfly chocked of in the canopy is simply retrieved buy pulling on the non tail end. The tail will be pulled through the butterfly and result in a single line.