Laz

Thanks Dave - I hadn't spotted your reply Tony. My observations are never meant in a personal manner, unless I specifically mention a name. Take care Laz

I'm not sure about that 40cm shock absorber Rob??? Take pics of how the system is anchored next time around. Any absorber in rec or industry is normally at least 400cm once activated. Not sure about the reason for putting the black lock on the Pantin - except to stop the rope flicking out. A small krab in the hole underneath the cam will do the same job. I understand where you are coming from on efficiency. But the kind of efficiency I'm focused on is ergonomic. But I'm at an advantage regarding my education in that department, so I understand not all in industry are likely to be up to speed. The reason I promote the Frog Walker, is that its a good all rounder - low risk - Simple - ergonomically efficient - Quick - Easy to don and Doff - Easy to store. - Versatile - with spurs, through air, through dense brush, against the trunk or against branches. You can't see it clearly in the vid, but the tree was plastered with ivy. At a glance. the issue I have with SaS technique is an opportunity for quite a fall onto a second ascender requiring an energy absorber. If that activates, it could be just as bad clattering off what you just climbed past - better to negate it altogether. Dean mentioned retaining the rope in the shell with a krab as avery important point. The second is upper body efficiency - it seems the climber has to hold themselves upright? Third is, with the trees we have round here, I'd get the pulley and lanyard system fouled. There could be issues with the minitraxion in this department too - it is very important to study how items interact with the rope in a factor 1 fall. Its great SRT is being considered and discussed. For me, like Tom and DMc, the point is increased bio-mechanical efficiency and safety. If we start counting seconds in an industrial environment, over time we could be sorry.

You got it Dave! (of course!). With a conventional re-direct or secondary system, there will be a swing but not a fall if either fail, and the primary anchor should remain intact. The difference with the M technique, is if the second anchor fails, there will be likely so much slack in the system that a howler of a fall will result, plus the swing. Falling any distance on a doubled low stretch rope is likely to lead to injury, if it doesn't break out the primary TIP. This type of fall would likely result in serious internal injury/death from high fall forces. This risk compared to using a trad re-direct or secondary system, far out weighs any benefit. It does worry me about the future of the industry if these techniques are being promoted without the serious limitations explained or understood. Take care! Laz

400cm, but then the slip and stretch in the anchor Two ropes to anchor is a bit OTT for me. I have to walk up steep banks long distance sometimes. So I only have to carry a 60m rope for 30m trees (tied into an endless loop), with a second rope for working (plus chainsaw and fuel etc). I use a Frog Walker which should be easier (upper hand ascender and a supportive chest rig), just as quick, more ergonomic and a lot less fiddly it seems. http://arbtalk.co.uk/forum/showthread.php?t=2307 I've never seen a Pantin with a plastic thumb catch before ??? Cheers Laz:001_smile:

I don't disagree with either of you on the points raised...except that you don't have brown sludge instead of grey matter, Steve. I just tire of doing others risk assessment legwork for them, so thought I'd go through the thought process on the whiteboard with y'all. My point is, re-directs can fail on the extremities of branches, due to leverage, increased anchor forces and reduced safety factors of wood with poor H/D ratio. Particularly some species like Eucalyptus, poplar and willow, whose form often requires re-directs but whose strength is lacking where they are most usefully applied. Anyway... 3. What happens if the re-direct anchor fails? 4. What happens if a secondary system anchor fails?

It occurred to me when out on a bough using the technique about 8 years ago. Come on - get the grey matter working! Let me start you off: 1. What are the disadvantages of re-directs? Especially at 90 degree angles? 2. What should be the advantages of a second anchor point?

Does no-one appreciate the risks of using these M techniques??? There is no real efficiency benefit, but huge compromises in safety.

Thanks for replying. Nice place. You can keep the Eucs though So, if I understand this correctly, the energy absorber is attached to the cinch which is attached to the base of the tree? 1. If so, how does the groundie lower the climber once the energy absorber has deployed and the cinch is 6m up the tree? 2. Do you always climb through mid air? A 4m fall back down through branches would cause serious injury after the energy absorber ripped. 3. How does a knotted rope pass the cinch during lowering, or do you use 100m ropes? Could you please video this set up from take off? I'd like to compare it to other systems for efficiency.

Nice pics. What happens if the rope comes out of the Croll? Looks like quite a fall onto the second ascender, without any energy absorption.

Thanks for taking the time to reply Linda. My motivations aren't based on 'offense'. Let me explain a little; I've been in this industry 21 years, in most departments, in most positions. Except expert witness, though I have advised expert witnesses. In that time, whether the office or field, I have learned that one of the greatest causes of mistakes, injury, MSDs, RSIs, near misses and accidents in Arboriculture, is people acting under an assumption, that turned out to be incorrect, inefficient, unsafe or down right dangerous. Constant reminders that to assume makes an 'ASS' out of 'U' and 'ME' ! Some of these assumptions exist as a culture in some operations, and are very difficult to re-dress. Work positioning harnesses are a case in point for all work at height. Assuming information from surviving the EXTREME forces applied from drag racing or parachuting, is in some way relevant to tree work positioning, is in my opinion mis-guided, producing yet more mis-information about risks that don't exist, and if they do, aren't practicably controllable. Though I'm sure it makes interesting reading none the less. It just shows that such forces must be avoided. And fortunately for responsible arborists, they easily are. A work positioning or fall arrest system is not designed to exceed a force greater than 6kN in Europe, or 8kN Canada. For good reasons, some of which are no doubt included in the research you mention. Which is why parachute research was used to help establish a safe limit of force for work at height. Anyone who disrespects this limit and exposes themselves to high fall forces, will have a whole host of serious issues to contend with if they are lucky (some might say unlucky) enough to survive. Such that child bearing will be the least of their concerns. Climbers that expose themselves to high fall forces without energy absorbers and free fall space are guilty of bad practice; the equipment they are using will not be designed to absorb such forces, and the body certainly isn't. I know some of us have pretty tough skins, but at the end of the day, we're just soft squeezable bags of saline and calcium. TreeFlex isn't sold as gender specific, because it isn't. It is flexible, sized and adjustable to adapt as much as possible to most human morphology within the realms of cost effectiveness. The only harnesses sold specifically for women, are based on designs for above waist use (which we don't recommend). And these are based on increased flex to adapt to the top of the hips, or usually just a more feminine colour. i.e. its a marketing exercise rather than scientific. From our research, THE best place to site a work positioning harness (when shaped correctly!) is the pelvis - male, female or those that chose to switch. You pay your money and take your choice.

Hmm....well spotted Tony. I'll check some facts and give Linda a chance to do the same before responding.

Quite a few claims you make there Linda. On what basis? Are you saying the TM will cause problems, or any belt fitted to the pelvis? We disagree that a harness properly designed to the pelvis will cause women flexibility issues. After all, the TreeFlex pelvic fit concept was designed by a woman (and mother) with 28 yrs experience as a remedial fitness professional, carefully considering male and female form. The flexibility adapts to the female pelvis well, though there is quite a range of female hip morphology. What science makes you claim that a pelvic belt will cause child bearing issues? The TM and TFX are very different in how they fit the pelvis. There are child bearing issues that need to be considered by female climbers, but not in this respect. The short torso of the woman makes for more serious lower back issues and higher compressional forces to internal organs, if an above waist design is used. But hey, what do I know, right? I am but a man!

Oh, great, nice to meet you Peter! Sorry I wasn't firing on all cylinders with regard to your TFX enquiry. Yes, someone mentioned the apf - thats a good idea. You really have to try harnesses. I'll be there if you (anyone) wants to come and get sized up in a Treeflex and go through the design points - from the horses mouth (been hearing alot of mis-understanding in that dept.).

A TreeFlex size small might work. With the waist risers pulled in short, and the leg risers removed and shackled direct to the sliding leg loop rings - Snug up the leg loops, and they should keep it low. Its flexibility should mould to female form well too. Having the hip Ds closer together in front of the harness isn't really a safety or comfort issue. Someone asked me the same thing at the trade fair, but I forgot to mention about removing the leg risers on Treeflex. It has been tested both ways.

..........No! Turn the volume up!

WHAT??? Being a member of such an institute has got no relevance for the instruction of industry specific technical skills! We don't don't need more irrelevant badges and government hoops that aren't cost effective.

Come on Kevin - out with it please. ...I can't hold my breath much longer

There aren't any chin scratching finger waggers at HSE to worry about - just the arborists that advise them.

Thats excellent Drew. I've used similar simple tricks, but I think yours is the most useable. It will fit in with my 'minimalist versatility' climbing concept very well. Thanks for the great pics.

http://www.expeditioncave.com/srt/petzl/failure/BC_UDAR_reply_050204.pdf This reinforces my stance on twin cam reasonable redundancy, with cams secured to the rope through top holes.

Here is the pic. Not very close up, but you can see the red edelrid clip on my right leg loop of the TreeFlex harness. It also shows the low pelvic position of the harness for creating more distance between the stride of handled ascender to chest ascender. Another identical clip runs through the top hole of the Croll. The Karabiner that holds the Croll is a Williams ball lock with steel barrel - cannot be activated by rope action.

I'm very glad about that Drew - you're welcome of course. The rope will feel bouncy for sure at the start, especially on long ascents like your avatar. But for me, thats always reassuring. With smooth technique, its not noticeable. I'll try and post that photo of the clips later (once I get it off my good friend Jez, whom also clipped the video).

Your thinking is in keeping with our own opinions - there is more to ergonomic working than just ascent. But we have to start somewhere of course. Climbing a ladder and climbing the tree are both very ergonomic practices compared to others. Like I've said all along, ergonomics is not about avoiding effort, its about efficient effort. But you often get those awkward sections with no branches. What I like about the Frog walker is the ability to climb the tree like a ladder with safety when possible, and revert to Frog when not. The pity about the vid that started this thread, is it ended just as I reached the branches - I climbed another 30ft on the frog walker by climbing the tree. BUT This thread wasn't started to discuss ergonomics, as its too complex to do it justice on-line. It was just to show the frog Walker for those that are dabbling with SRT, but haven't seen a frogwalker system.

Yes Dean, In that picture, both cams should be secured to the rope through the top holes. I would also substitute the Blaze for a true 11mm kernmantle to EN1891 type A. I might also clip the rope to the harness below the Croll, as explained in this thread a page or two back. I've never seen or heard of anyone else mentioning the inertia thing. Its just an observation of mine. I first picked up on it when just opening the cam and sliding it down the line (because the top holes are secured) - once it picked up speed it would clamp to the rope every time. Maybe it only works with the new Petzl cams with stiffer springs???

Do you mean you climb on dyneema? I wouldn't recommend that. Polyester nylon does just as good a job, with a lot less risk. That goes for any high mod fibre in life support.