DdRT off of a ground anchored pulley

[ozy365]

Finishing a 60' maple in 90 degree weather makes a guy philosophical.

Is any one tying in with DdRT to a pulley placed on a separate line and anchored at the ground? There was a thread in March that Old Monkey mentioned he'd seen this at a rescue course.

I think this would be a good system because:
1. Fast rescue: Ground dude can lower the entire TIP to the ground with wraps around tree, munter or porta wrap
2. Less time for limb isolation: The single line with pulley has got to be easier to line up than DdRT (think Big Shot into a pine, pull over SRT line and place pulley and climbing line and pull SRT line to place pulley).
3. Floating TIP: pull the TIP to fist spot for trimming and tie off at base. Climb higher with spikes, ALT etc, as groundie moves up TIP.

Limits: 1. Doubled force on limb as in SRT 2. Availability of anchor point 3. Increased equipment.

Come on guys, tear me apart...I think this may be our new approach if no one can talk me out of it. Check my math.

Todd

 

[underwor]

I use this when I am giving climbing demos to kids in particular. It beats climbing the tree to get them down if they forget how the friction hitch works or if they are just too light in the rear to let gravity work (not a problem for me).

 

[roachy]

I will apply that method quite often when just going after target limbs,its already set up on my ascender so its up then down.I dont like it when prunning the whole tree I may need to re tie groundies may untie the rope accidetally etc.but its alot of fun and productive if used in the right situation.

 

[Bermie]

I've used something similar to get up to the top of a tall tree without busting a gut. Groundie (hubbie!) uses bow & arrow to get throwline real high, then pulls up single rope with pulley (with climbing rope in it), tie off ground end, then he pulls me up as I tend my split tail with a pulley and fend of branches on the way up.
I'm not really comfortable using it as a final TIP as there is that thought at the back of my mind - has the end on the ground REALLY been tied off right? - I can go back to it for the ride down - elevator (lift for the limeys) style, ground floor please!

 

[darkstar]

we use 3 guys to pull the climber up ... once 2 of my guys weighed 285 and 320... talk about effortles climbing up ....now i got a crew of 4 climbers so we are all near 170 soaking wet ....

 

[Bermie]

Ha Ha, that's when it pays to be a titchy tree climber, 120 WITH all the kit!

 

[Treeman14]

Ha Ha, that's when it pays to be a titchy tree climber, 120 WITH all the kit!

I had to look up "titchy". Thought maybe it was a typo.

 

[Tom Dunlap]

This is called a floating false crotch, FFC. It's shown in the 1989 version of the NAA, now TCIA Aerial Rescue video and has been around before that date.

A good option.

 

[Dadatwins]

Have to REALLY trust in your groundspeople to use this option, with most grounds folk unable to tie a pole saw on properly I would be scared to death of them tying off my life line. Sounds like good plan for the well trained and experienced crew.

 

[ozy365]

Thanks for all of the input, guys. Any one use this for light rigging? MB BS a line into a top, run a running bowline around branch and block and then pull the whole thing up?

I can see the thing about trusting the ground dude, but you could be the guy tying the system to the anchor as long as you were going to do the DdRT to the tip. I also like to cheat and tie a prussic with foot loops for my DdRT. It is slower going, but I am a lot less tired at the top. When I am hauling a saw it also lightens the work. I also like the prussic (sp?) as a place to "stand" to lighten the abrasion from my saddle while cutting.

Has anyone done any of this for more than a few climbs? I think this may become our standard, so I really want to find wholes in it at the computer rather than laying on the ground. I figure the greater diameter bend on a pulley and the reduced friction vs. a friction saver would have to increase the life of your climbing lines. A 3 strand 5/8" bull rope to the TIP would probably be a cost effective line that would wear well. You could probably cut off 5' at a time as wear was noted.

Cut this apart... I really want some input...why is this method not used regularly?

 

[Bermie]

I had to look up "titchy". Thought maybe it was a typo.

See, I'm bilingual, out here in the middle of the Atlantic we speak American and Limey, oops might offend someone, 'English' !

 

[Tom Dunlap]

Ozy,

The MOST important thing to understand when using a FFC is the load multiplier. This is mechanical advantage rove to disadvantage. Using this for rigging would double the load of the piece being dropped. That can make the load on the TIP too high, blowing up the tree.

Why would you use it for rigging? With some planning you could make scaled-up version of a ring and biner false crotch just like climbers use. I've got a couple of oval rings that I got from a company that makes slings for constrution that have a breaking strenght of 20,000#. Get a heavy sling made up and add a stout pulley to the other end and you're good to go. When you're done, the whole works can be retrieved with a throwline just like a climbing FC.

If you do choose to use a FFC take time to consider what tool you're using as a friction device for the whole works. With the load multiplier you'll need a stout device.

 

[huggybear]

I think with this setup your TIP would have to be lower, which would be the major disadvantage because of rope angles and such, I like to tie in as high as i can. I have used this system to access tall white pines in the summer, because isolation would be a bear with the heavy sap flow. But after access we would climb as normal. As with most anything with tree climbing, you have to pick the right time for the technique.

 

[ozy365]

Thanks for the replies. We've had a bear with this maple. There is a line (220v) that runs from the house to the garage by way of the maple. The house is under the lean about 12 feet away. Tree is 60' plus and there are three stems left that go straight up for ~15" at less than 8" diameter and then crown out. I am kinda running out of limbs to put a friction saver around and the diameter makes me hesitant to spike with multiple angle changes on the stems. After all of this discussion, I think I'll have to set up a block a stem at a time and drop the tops that way. The 220 line is off at the box when we work, but every branch we lower wants to straddle the line. I was hoping to lower them butt first, but I don't want them to drop 15 feet and then snap to if tied to the distal end. This has been one of those trees that we tried to give a church friend a deal on that we regret doing at this time...another thread. The whole tree is boxed by the garage line, the house and house service line and pole lines. Clearances are adequate, but do limit our options. I imagine I will pole saw the thing to little pieces from my highest comfortable TIP, but there will still be issues with not ripping the 220 out as limbs are lowered (the 220 is too high for ground dude to do more than swear and try to put a second line in distal ends for landing while he manages the porta wrap). Originally, we had been assured that the 220 would be down, but "come on guys, do you have any idea how much that would cost? Can't you work around it?" :angel:

 

[Tom Dunlap]

"come on guys, do you have any idea how much that would cost? Can't you work around it?"

So "they" will pay for putting the line back up if you happen to tear it out, right?

 

[TheTreeSpyder]

Ozy,

The MOST important thing to understand when using a FFC is the load multiplier. This is mechanical advantage rove to disadvantage. Using this for rigging would double the load of the piece being dropped. That can make the load on the TIP too high, blowing up the tree.

Why would you use it for rigging?

Ummmm i think i see differently Tom; i believe a climber in DdRT w/FFC gives 2x Load - (Friction + Deflection Angle) on support; as their is only 1 termination at ground. But, if used in rigging; there are 2 'nested' pulls at ground/anchor. So becomes a nested multiplier of 4x Load - (Friction + Deflection Angle). Being that we are close to the inline position of Zer0 degrees, the loss of force from opening bend up a few degrees is marginal, but the direction of the angular pull on the support can give more reduction in leverage on support by that count (more favorable direction of pull to the long axis of support/ column for waterer the force is). Conversely, changes in bend degrees close to the other inline position of 180/flat; give more change to power than direction.

Conversely; we have much more elasticity in system; so though static pulls on support are higher; in some situations, the increased elasticity could save the day, in absorbing dynamic impacts before transferring to overhead support and Porty positions.

Ozy,
If you do choose to use a FFC take time to consider what tool you're using as a friction device for the whole works. With the load multiplier you'll need a stout device.

Ummmmm; if we are lowering through the rigging line and not the FFC line; i believe that the brakeforce required by Porty would be same as mounted pulley/ FC; only previous friction changing that value. If we lowered thru the FFC, and had rigging line locked off, then we would have 2x on Porty, and be lowering Load 2x as fast as line speed at Porty i believe.

 

[Tom Dunlap]

Spydey,

A FFC rigged for climbing wouldn't have the 4x multiplier. Well, it might depending on the bouncing. Again, back to the variable MA of a climbing system.

Thanks for posting the drawings.

 

[ozy365]

Tom

The way this gig has gone I am sure that we will be doing the electrical and the siding work for this guy. No threat of thunderstorms on Saturday so I imagine we will be done.

We are MB doing a camp down the lake in preparation for a prefab home. I imaginge the prefab trucker will just cut the line to get his load under...If we had just done them the other way around.