Cross over gear

[JCSJC]

The whole 'Photos of personal gear' http://www.arboristsite.com/showthread.php?s=&threadid=17523&pagenumber=3 got me thinking. I have a few things in my box that one would not pick up from Bailey's or Sherrill's but from stores that don't cater to arborists or loggers. The rope grab, the 4 ton clevis, the winch straps, and yes, the duct tape.

The items I've ended up with, were all pretty self explanitory, I mean, anyone can use duct tape,( ) but, I recently was offered the chance to snag some rock climbing rope, very reasonable. Blue Streak, Safety Blue, even Arbor Plex is pretty idjut proof. Size, number of strands, weight per 100 ft and breaking strength, simple, but the info sent to me looked more like....

*Weight per metre: 66.4g
*Impact force: 8.5 kN
*UIAA falls held: 9
*Static elongation: 5.6%
*Dynamic elongation: 32.8%
*Sheath slippage: 1mm

and

*Type: Single
*Weight per foot: 76 grams
*Diameter: 11 millimeters
*UIAA falls: 14-16
*Dry treated: Yes
*Impact force: 9.2 kN
*Stretch: 29%

Has anyone had any experience, or have some words of wisdom on using rock climbing rope for tree climbing, or rigging rope? I suspect the number of falls listed is a test case, along UL lines, but I don't see any such info when I check out Stable Braid. If the rope gets "shockloaded" is this counted as a "fall"? ie only 14-16 lowerings on the Mammut 11mm?

Any advice would be helpful, and remember, the life you save, may be mine. But don't let that stop you from answering.

 

[Stumper]

Multiply the kN value by 225 to get breaking strength in pounds. (No that isn't EXACTLY the valuo but who cares about the fractions?)

The Falls testing is widely misunderstood-even by rock climbers. I may get some details wrong-if so Tom Dunlap can set us straight. I THINK that the standard fall test shockloads the rope to either 1/2 breaking strength or to what constitutes a fatal fall(About 2200lbs of force). WHat I do remember with certainty is HOW the test is conducted. The rope is bent over a small radius-standard 'biner stock -and the weight is dropped. and dropped and dropped until the rope breaks. Nylon(and other synthetics) has a recovery time. Repeated drops do not allow the stressed fibers (which are maintained at the same spot) time to recover from the deformation incurred.) What this means is------a rope is not going to fail from shock loading in less than its rated number of falls in actual use. Practically speaking it should last for a HUGE number of falls more than the rating. The rating just gives a standard of comparison.:angel:

 

[JCSJC]

Kool

Thanks for the heads up, Stumper. Sure cleared up my basic misconceptions.

Using a pulley with a 4in sheave, even a smaller pulley (in a pinch) should go a long way to improving the fail rate.

By multiplying the kN value, by 225 on the 11mm, yields a 2070 result. Interesting. With a 10-1 ratio, that would mean a safe workload of 207lbs? Oh, Mr. Dunlap, any pointers on how to straighten out my figuring?

I did note that the person wanting to get rid of the rope, said one had sustained 2 falls, of less than 6 ft (the perils of an indoor gym, I guess). A CYA moment? I'm assuming he wants to be covered, just in case. I expect if I use it for light rigging of limbs, it will sustain more falls, of less height in a days time.

I better quit thinking, the smoke is making it hard to see my keyboard.

Thanks again for the info, Stumper, you rock.

 

[Guy Meilleur]

Originally posted by JCSJC
Has anyone had any experience, or have some words of wisdom on using rock climbing rope for tree climbing, or rigging rope?

1. don't nick it with your saw or you may ruin it.
2. Static line is too stiff; some dynamic line is way bouncy.
3. What stumper said.

I use 10mm dynamic most of the time. I only rig very light stuff with the tail. I love the ease of handling and the lightness.

 

[TheTreeSpyder]

Ummmmmmmmm the 225 factor multiplys the Kn to Lbs.; but i think you just multiplied by the test weight, not failure tensile? i think at 11mm you'd be looking for around 25-30kn?

13mm is ~ 1/2"; so this would be a smaller, lighter line i think to work with. The high elasticity, absorbing dynamic loads. Works well for a lot of things, needs more bottom side clearance for drop than static lines(arborist 'dynamic' is less elastic than other disciplines static). Real nice light line in smaller branching and weights i think.

The smaller loads can stretch the line more for the shock absorbtion, dissipating the shock load, to even small support branches (rigging) with this quality. A DWT in static hold is less load than just a pulley redirect; DWT in dynamic load increases support loads though do to less elasticity with 2 legs of line on load. The more elastic line replaces this loss, to lower the dynamic loading on the support for DWT (or anything else that it doesn't make 'bounce').

Lighter and smaller line to drag through tree and crotches easier too. The softer dynamic line, doesn't leverage against itself like stiffer lines when bent against short axis/dimension. The softer line (in tradeoff )also easier (i think) for contanimants (sand etc.) to get past the kern and into the workings of the mantle.

Dynamic nicer to impact for sweating in to grab a bigger purchase on line for pre-tightening i think. Which is good, cuz'harder to get to self pretighten as load pivots on hinge though in next stage. Friction on support close to load, can help to reduce elastic value, by reducing the amount of line volume area shocked by loading.

Or something like that;
those are my guesses;
Tom's Turn!
:alien:

 

[Derek]

Great thread Jase,

I see these ropes pop up all the time on ebay AU, Increadibly expencive to get new, I have priced them online ....

Ive had very similar problems tring to figure out what the stats ment...WTHell is a "fall" only 9 of them...Gee I would hate to loose count on a busy night indoor rockclimbing....6 or 700 dollars is a lot to pay for one night tring to get to somthing, fall ten times and you need a new rope?

This is helping clear things up for me over here in the bush!

I would love to here from anyone eles using the same sort of rope..And I hope aswell Tom pops in some input!

A month ago I bought one from ebay AU, from a pregnant woman,
I could see why she dident need it

Absolutly still in its bag and factory tied (I thought) She dident ever use it. Placed a bid, then as i do, did the research...

I saw the prices online and knew i would get out bid...
Lucked in for a change, got it for 100 bucks BARGIN!

I have used it to swing out of, I find the braid a little tight to "work" well with French prussicks, should I try some other friction knots for that sort of rope?

It appeled to me at the time because its 50m (165 foot)..The climbing line I bought(xtc) is only 35m ( still AU$350.00)

I could use it till i replace the other pinched ropes..With two ends on me I can only desend 22meters (with knots), most of my work is at 30 m Least leave the tree at that height...

I am getting use to it, a bit thin on glovless hands and still tight grained but the weight change was noticable

What ive realy wanted to know is what happens to it if iuse it for light rigging, again the weight is unreal!...What if it got shockloaded, more importantly what if I had to use it back in a tree again..Thats two lives you might save guys...

How does it factor in to my MA=6 tables, because of the length I could be tempted one day to use it as a "system" and take down some thing larger...Should I??

Ill be back in a sec, ill post the pic and stats or the Beal rope I got..Derek.. Good work Stumper!

 

[Derek]

Dont know if the pic will come through, heres the info on the one i got.... In my absents Treespyder has put a lot into his responce..

Thats gunna take a couple of times to read!

Mammut Galaxy 50m, 10mm single rope. UIAA falls rating 8. Weight 65g/m. Only used once and no falls.
--------------------------------------------------------------------------------

 

[JCSJC]

I thought so too

Originally posted by TheTreeSpyder
Ummmmmmmmm the 225 factor multiplys the Kn to Lbs.; but i think you just multiplied by the test weight, not failure tensile? i think at 11mm you'd be looking for around 25-30kn?



Or something like that;
those are my guesses;
Tom's Turn!
:alien:

I thought it seemed like a light figure, but I'm winging it here. :angel:

The stats sent to me lacked the breaking strength, maybe there is a standard multiplier, I was lacking. Say... break strength = X"Impact Force".


Hey Derek..."A month ago I bought one from ebay AU, from a pregnant woman,
I could see why she dident need it"
.... I bet when her child hits the "terrible twos", she'll be wishing she had that rope back, or at least some duct tape.

 

[TheTreeSpyder]

The lengths are nice 50mm/60mm = ~165ft/195ft.

Length very usable for MA rigs multiple legs on load. Dynamic line good for catching absorbing force. A lil'less favorable for MA tightening/lifting , though workable. The dynamic quality that absorbs the force of shock in catching load, then (when using to lift/tension line) turns around and absorbs some of your effort in pulling the line (i think). The increased legs of line (6) on load drop this elasticity some (in your favour tensioning, less elacticity to catching a load now though). Going from tensioning to catching is a point where calculations can invert on you; a twist to watch for.

Similarily, in some situations comparing something moving/dynamic to a motionless/static state are were things can invert. A pulley on overhead support can place 2x load on the support. A DWT (Double Whipped Tackle) shares the load between 2 legs of support and still has only 1 control line to ground; so will only load the support at 1.5x/1.

Under the dynamics of motion, each leg of the DWT(lowering) can loaded almost as much as the single line of support in just pulley on branch. So can load support more as DWT(2/1) under motion than 'simple' (1/1) of just pulley on support. When statically/still loading the DWT loads less, but can load more in motion. The more elastic line would help ease the higher loading potential of the DWT support/load catch under motion.

From the venerable TB (Tom's Board?) i re-present this chart showing how more static lines deliver more loads to support under dynamic conditions. Also, that multiple legs of support (like splitting load the load between 2 legs of a DWT) increase the static properties of the system; thereby the loading under dynamic/moving conditions. Once again more elasticity in the line type helps compensate for loos of elasticity in sharing load between lines.

The higher the loading is in ratio to the tensile strength of the line, the more of the elasticity property of the line is usable, just like the longer a line. So, placing another leg of identical line on load, drops the loading to each leg, thereby the usable elasticity; increasing collective loading on support(s); in motion.

2 parts to line i think; kinda a male/female. We have the raw macho strength of the tensile, catching your eye, red and bright; raw strength. Then we have the softer 'give' componenet of the elasticity; under motion, many times the quiet giant. They both work together, dynamic moving forces can be immense. What dynamic force is not carried/dissipated on the give of the line instrument, must be carried on the non forgiving tensile property instead. Kinda like a speed/power reciprocation to equal the same force output from a system! Dynamic forces carried on the tensile, are transferred to the line connection points.

Or, somethinglike that;
:alien:

 

[Derek]

Hey Jase, Ill cut and paste all the emails between us over that rope, and send em to ya. She wouldent post it..wouldent take a direct deposit into her bank, couldent send her a check...Had to get my Dad who is in Sydney to be the middle man...very funny stuff!

Back to business, While your at the figure checking Tom, could you convert it to metric, kilos.. I might be a lot eaiser with the 10, 11 12 13 mms ect, for my rope its 50m long, will the lenght matter? more so if the load were droped 1o meters before shock as opposed to one meter before shock...

Either way im not going to use it till i get sorted out on it!

BTW I had a bit of a day like that....Tonis at collage (exams)
Could of used a roll or two of tape myself today!

Gee you know your ropes there Treespyder...(or somthing like that!)

 

[Derek]

hugh?

ya did it again, posted while i was typing...Now is that a slightly more confussing page ...I have to print that one and take it to bed...Can't "get it" here on the screen...

I take back the "or somthing like that" you really do know your ropes...Wow..thas a lot of work to share with us Mate Thanx very much!

Now could someone please tranlate it for me...Are you still scratching your head there Jase..( I thought i heard somthing )

and then after that translation could some one eles translate that into Yes Derek use the rope, Or use it to tie down the chit on your truck with! ...AWSOMEWORK...Derek..

 

[Stumper]

Derek, Don't use the rope to climb on.-Not because it isn't safe but because it will drive you nuts. Dynamic climbing ropes are designed for crazy rock climbers to climb ABOVE their anchors. When they fall (and they all fall) it has to catch them without turning them into sacks of broken mush in their harnesses. It does that by stretching-very much, very easily. Dynamic rope's bungee-like qualities make it poor for workpositioning. It will work for light lowering where you have room for things to drop a little. It will also work as a pull-line for felling- you can pre-tension it and the line will take up the initial slack as the tree starts to move-Just don't try to ask too much of it on some heavy back leaner since the stretch can allow movement the other way.

JCSAC, I agree with KC that the impact force values on your lines are probably the test impacts. Actual strength should be higher (Double if my previous post was correct.) Rock climbers use 10-12 mm ropes as single lines. (9mm are usually used doubled but I don't think they are always). The 8mm are always doubled. I do not use the full dynamic ropes but have a couple of static kernmantles. Their construction makes them heaver ,harder and stiffer than the dynamics. My 3/8th (9mm) static is 5700 lbs tensile and handles pretty nicely. My 7/16ths kernmantle is 7700 lbs tensile and is pretty stiff (as Guy was mentioning) 1/2' (13mm) statics are usually about 10,000 lb ropes but are horrible to knot compared to arborist lines.
My old standby rope for light rigging and as a tagline for felling was,for many years, Military 7/16ths medium-hard lay 3strand rapelling line. 100% Nylon, 4500lb tensile, and somewhere between static and dynamic (Almost as stretch resistant as statics with body weight/200lbs loads but showing more stretch at 800 lb loads. The stuff lasts nearly forever. I have never broken one ( I don't drop huge pieces into rigging). Frankly, arborist braids handle better in nearly all respects but I still have a mi-spec 7/16ths that I use for a tagline or lowering line occassionally-the stuff served so well for so long that I have a fondness for it.:angel:

 

[Stumper]

Derek, One more item. kN is metric. A Newton is the force of 1 gram(I think) falling at the rate of one metre per second. It works to think of one kiloNewton (kN) as 100 kilograms. Technically ,however one is a measure of force and the other a measure of Mass.


I came back to edit. I got to questioning myself about what I posted and double checked-all messed up but I'll leave it and just restate things correctly.
A Newton is the force required to ACCELERATE one kg at a rate of one metre per second. Technically, one kN is equivalent to 101.97 kg. (I knew that the 100kg=1kN was workable shorthand.) One is a measure of mass the other of weight (I tend to forget that those are technically different)._ You guys have to watch me, sometimes I muddle the details up. -Somebody will probably have me drawn and quartered by the time I finish the edit.

 

[OutOnaLimb]

Hey Justin, I remember using that Mil Spec rappell rope of yours. Not a bad rope just kinda a bear to tie a knot into. Those ropes make fair speed lines or you can order a 1/2" static kernmantle from Bluewater and you will have almost no stretch when you tighten and load the line.

Oh by the way Justin, I didnt fill my bull tag, but I got a good sized cow.

Kenn

 

[Stumper]

Kenn, Congratulations. The cow'll taste better anyway. I still have some climbing for us to do together but it'll probably be the end of next week before I can get to it-let me know about your schedule.
BTW,Thank you for the recommendation to Mrs. Megel- I zapped that Maple stump for her.

 

[OutOnaLimb]

Cool deal about the stump, I got some more for ya if you want them. Gimme a call.

Kenn

 

[NickfromWI]

The big differences I see between rock climbing rope and tree climbing rope is that in most tree climbing ropes, the core is mostly for shape and firmness. In rock climbing ropes the core is what is holding almost all of the force in a fall.

Rock climbing ropes are designed for fall protection and impact absorbtion. Arbo ropes are for work positioning.

Arbo ropes are designed to withstand the rope on rope friction caused by our friction hitches. Try that a few times with a rock rope and if you're not careful you will damage the rope.

Rock ropes are very colorful. Tree ropes.....not so much (though there are some exceptions)

Arbo ropes can and should be spliced. Rock ropes....well...I've done it, but not sure if it's strong enough to be used!

They don't give breaking strengths for rock ropes because to use them (properly) you musn't be concerned with that number. That's not what these ropes are used for. In tree ropes we DO care because what I call a climbing line another may call a rigging line and we need to know how how much wood we can drop in to this rope. In rock rope we know how much weight is going to be put into it. It will be, under normal/proper use, the force of one (maybe 2) people falling.

I started my tree climbing after first learning to and about rock climbing. I was really confused when I saw the ropes at the store and had no idea how "strong" they were because arbo ropes don't give the UIAA Fall rating. After getting this far into tree climbing and "arborism" I like how they rate tree ropes much, much better.

love
nick

 

[Derek]

More exelent info

Thanx Nick...I understood every word of it to..

Do/did you different friction hitches on the rock rope?

In light rain, one sort of loop is way to loose, then my BLUE ones grip to much.. Thats a lot of factors working there I realize, Is it the rope, the knot or the prussic cord i use.. or just dont use it wet..Another sticky point, all the info I could get on my own seemed to strongly suggest its a "dry" rope...Im assuming that means dont store it in water as you do some nylon ropes...

Surley you can wash them! and hang em out to dry..

Then I supose, if I used it only as a tag/pull line how would they go being "squashed " by the tree your pulling over..9 out of ten hit the rope in vairious places. The core more so than the sheath would cop the dammage. Arb ropes have "firmness" in rock gear it is more the "force of a fall"..Any more comments?..Derek

Great to hear you guys "networking" over there..
Can't really give Aussie_lopa a hand, hes 20 hours away 60 if I took my truck!

 

[NickfromWI]

Yeah, I tried it once, when I FIRST started climbing. I thought, "hey, this rope is MEANT for climbing. It should work." Well, I footlocked up on it no prob, though it was bouncy. Then when I came down, I foolishly caused significant glazing to some sections of the cover/sheath.

The next day I ordered my first Arbo rope. I quickly discovered the difference and learned an important lesson. Use the tools that are meant for the job. If you need a hammer and you find a heavy wrench, look a little further until you find the hammer.

I know people who DO climb trees on rock rope. I know you have to change things a tiny bit. Descend at a REASONABLE rate (which you should be doing anyways, eh). Get ready for a bit more bounce...things like that.

love
nick

 

[JCSJC]

Suhweet

I feel like I tapped into the Library of Congress. I'm not sure where to begin, except for maybe.... Ctrl P.

Note to self, look into the rigging software.

Might go ahead and snag some, just for the heck of it. Keep it low and slow till I see how it fits into my bag-o-stuff.

May just head over to Tally Rock Gym and see what's, what.

"What do you mean I have to take my gaffs off? Ok, where can I get some crampons? Baseball cleats? C'mon, gimme something...."