Girth hitch discussion

[treesmith]

Why on earth would you girth hitch a FS? So you can climb back up and get it?

Seems pointless and counter-intuitive.

I don't have an adjustable one, and it's the simplest way to set it on a 3" stem. I don't do it regularly, just if there's no good limb/stub in the area I need it.

 

[sotc]

Sure, the bowline would be weaker than a splice and the configuration would be weaker too

 

[sotc]

Round turn is retrievable from the ground if set up right

 

[treesmith]

I've tried it, but the ones I made from 3-strand tend to "roll" down the stem too much for my liking. I usually don't venture too far down from this type of setup. I just set it to work out the stuff where I need a high TIP. Then I can drop it down to a better location before working my way on down.

 

[tophopper]

I don't have an adjustable one, and it's the simplest way to set it on a 3" stem. I don't do it regularly, just if there's no good limb/stub in the area I need it.

Easy fix. Either round turn it like Willie said. Or, add a 3rd ring on a short piece of hitch cord. Then it's adjustable to virtually any size.

 

[treesmith]

I have used an I2I to make one before, using a large screw link for the ring. I just like the bite of the girth. I've only girthed it a few times, nothing regular.

 

[Burnham]

I don't really think it's even close to a "risky" life support, Scott. Especially if you are aware of the reduced strength of the setting and take every precaution to eliminate the possibility of loading it dynamically. Which was the whole point of my observation at the outset...to make sure the awareness exists amongst my friends and fellow climbers.

I have seen climbers who wished to venture above their tie in, or way off to the side and even with it, decide to use a girthed (1" tubular webbing) sling as an anchor since it keeps the point from creeping about. In those scenarios, the risk is increased significantly. Perhaps I should have described that sort of situation earlier in the discussion.

 

[NickfromWI]

i think this whole conversation is moot without some break testing!

Also, the thing is irrelevant because every configuration we've seen so far is WAY stronger than it needs to be.

 

[Burnham]

Disagree on both counts, Nick. But that's just my opinion, worth every bit you paid for it.

But I look at it from a cone picker/scion harvestor point of view. You guys know next to nothing about tie in risk.

 

[treesmith]

I don't really think it's even close to a "risky" life support, Scott. Especially if you are aware of the reduced strength of the setting and take every precaution to eliminate the possibility of loading it dynamically. Which was the whole point of my observation at the outset...to make sure the awareness exists amongst my friends and fellow climbers.

I have seen climbers who wished to venture above their tie in, or way off to the side and even with it, decide to use a girthed (1" tubular webbing) sling as an anchor since it keeps the point from creeping about. In those scenarios, the risk is increased significantly. Perhaps I should have described that sort of situation earlier in the discussion.

And I appreciate the caution, B. Which is part of the reason I started this thread....to try to understand the risk(s) of which you speak, as I saw none with that set up. I do see the added danger of dynamic loads, but still feel that it is well within the range of safe climbing practices, especially considering that some work SRT off a bowline, which is part of what caused my surprise at your warning. I thought, if this is dangerous, what about....and so on.

 

[Burnham]

Agreed. I do not use the running bowline as life support anchor, myself...nor advocate it. Several reasons, but this strength reduction is not the least of them.

 

[MasterBlaster]

You guys know next to nothing about tie in risk.

Ha!

 

[Burnham]

Want to trade pics, perhaps?

 

[NickfromWI]

But I look at it from a cone picker/scion harvestor point of view. You guys know next to nothing about tie in risk.

Regardless of what type of climbing you're doing, there is nothing dangerous a climber can do in any climbing situation that would make any of the configurations we've talked about be a point of concern. (this assumes they are using stuff rated to 5,000 pounds, 5,400 pounds, 22kN or whatever safety guideline that makes sense)

I think in most cases a proper tie in point would bust out before any gear would break. (assuming you're tying high like most of us do)

love
nick

 

[sotc]

I think Burnham is bringing up fall factors when climbing above your tie in point as cone collectors must do/risk doing. Then it becomes real.

 

[NickfromWI]

How high above a TIP does a climber on a DRT blakes hitch with girth hitched friction saver on a solid TIP have to go before they will cause damage to the equipment (and themselves) in a fall?

 

[sotc]

Cool calculator

http://www.myoan.net/climbart/climbforcecal.html

 

[sotc]

Cool calculator

http://www.myoan.net/climbart/climbforcecal.html

 

[sotc]

Interesting how SRT falls generate higher factors quicker than DdRT

 

[treesmith]

How high above a TIP does a climber on a DRT blakes hitch with girth hitched friction saver on a solid TIP have to go before they will cause damage to the equipment (and themselves) in a fall?

I'd think a 3' fall would hurt me, but I'm a wimp. That would be a drop of up to 6' depending on circumstances.....

 

[Marc-Antoine]

Interesting how SRT falls generate higher factors quicker than DdRT

That's counterintuitive. For me, it's just the opposite.

We have to look closely to the apparent rope's length, the both anchor points are very important to consider. The calculator is based only in the mountain climbing configuration, so nearly SRT like.

I'd say that their maths don't take in count the Ddrt system and they should go deeper in the formula, with more numbers to ask.
Look this :
A - SRT with a high fixed anchor : 1 rope, 1 length of rope to take the load (length = high tie-in point to climber)
B - SRT with a bottom fixed anchor: 1 rope, 2 (at least) or many more lengths
c - DdRT : both rope's ends on the climber, so it's like 2 ropes, 1 length (and not 1 rope 2 lengths, as many guys seem to think at it).

Fall factor in C is actually the same as in A (yes it is), but 2 ropes side by side stretch 50% less than 1 rope for the same load, so the load stops in 2 time less distance, akka increases greatly the shock.
The max fall factor in A and C is 2. But you get more damage to your body in C.
Fall factor in B is the most favorable, max 1 or well less.

I hope that makes sense, it isn't easy to explain clearly.

 

[treesmith]

I hadn't thought about the 2 lines sharing the load stretching approximately the same as a single line bearing all the load, but it makes sense. I still hope to never "test" the theory.

 

[bonner1040]

I gotta disagree Marc.. In rock climbing one end is tied to you, one end to your belayer... un hook your belayer, attach the rope to you and take the same fall, its still the same factor yes?

A fall factor is determined by the distance fallen / the amount of rope in the system. Tree climbing only differs from rock climbing in that you are belaying yourself. In Ddrt a factor 2 fall is impossible.

In Scotts example, falling from 3' above the TIP you take a 6' fall on 6' of rope. Factor 1. Which would still hurt like the dickens for sure. (actually a bit less than factor 1 as some rope is going around the branch, but you factor that friction in and its anyones game at this point.)

 

[stig]

Disagree on both counts, Nick. But that's just my opinion, worth every bit you paid for it.

But I look at it from a cone picker/scion harvestor point of view. You guys know next to nothing about tie in risk.

You're not the only cone/seed picker in the house, Burnham.
I know exactly what you mean.
The weight of yourself plus the broken out top falling from above your last tie-in point.

 

[Marc-Antoine]

I gotta disagree Marc.. In rock climbing one end is tied to you, one end to your belayer... un hook your belayer, attach the rope to you and take the same fall, its still the same factor yes?

Not in my view. First, you have a fall factor 1 (max), second, you get a fall factor 2.
In this example, it's like you pass from my case B (srt with ground anchor) to my case C (ddrt). In case B, the high tie-in point acts as a redirect, all the rope work in the same way, move around the tie-in point and stretches with one full load on its full length. It's the principle in its book.
It's different in ddrt, the high tie-in point acts as a fixed anchor, both half rope pulls on each side in an opposite way (rope's axis wise) with no move in the middle, like two ropes share the same load. So half a load for each half rope. But because there is no move in the middle, it's the same as if you have half the length of an other rope with twice the strength.
The rule to define the fall factor is too simple to be always right (kindly said for "incorrectly stated") and doesn't apply as is for the ddrt.
For the math with ddrt, you have to take a virtual rope, which has half length of the real one ( this gives the right fall factor) and twice the strength (this gives the stretch capability).

In Scotts example, falling from 3' above the TIP you take a 6' fall on 6' of rope. Factor 1.

Factor 1 only in srt with ground anchor if you are 3 ' above ground.
If you are 30' above the ground, srt with ground anchor , the rope length is 33', for a 6' fall, so ff=0.18, the kindest
If you are srt with anchor at the tie-in point, the rope length is 3', fall is 6 ', so ff = 2
If you are ddrt 3' above the TIP, the virtual (stronger) rope is 3' too, fall is 6 ', so ff = 2 (and a stronger chock loading).

A drawing should be easier to follow than my text.