Safe Anchor Choice article

[Wooden Hand]

Hi all - My new article has been uploaded to ODSK's homepage. You can separate the Japanese and English version, hopefully makes it a little easier to read.

 

Safe Anchor Choice

 

Thanks .

[tree-fancier123]

saved the web page - thanks for posting. Most of the stuff I paid 60 quid for in Best Practices for SRT is now around on the web for free

 

only comment - the conclusion 'seep into the wider society' prefer the diagrams and hard physics and biology myself, no need for anything too subjective

[BenR]

Good article Paul!

[Wooden Hand]

Thanks Ben.

tree-fancier, perhaps filling you in with the context I am writing in would help. Japan has a very young industry and there is a huge movement for technical rigging works right now as there is so much of this work, basically all the trees that cranes can't reach are being cut and there are thousands of them long over due. Now this technical side of what we do is not the whole picture of arboriculture, my work at the moment is creating safety procedure and guidelines for the work on Japan Rail sites, safety follows the boom of technique and hopefully after this Japanese tree workers will become more interested in the science and benefit of amenity arboriculture.

[onetruth]

Very useful article, thank you for sharing. It sounds like you have an interesting and worthwhile job.

 

I have a couple of minor criticisms, though I accept I may be a pedantic prick for posting them!

 

On the Knot Block Static Strength table, the kernmaster fails at 1.7kN. Is this a typo? Looks like there might be a digit missing. Also, when I see experiment data like this I want to know the sample size. Fair enough if it's a single test per combination, but I'd like to know.

 

On the Remote Anchoring flow chart step 4 asks "Is the throwline set against the strongest part of the anchor?". This would hugely and unnecessarily limit line placement options: surely you mean "...sufficiently strong part of the anchor"? I can see that this might be nit-picking, but if this is to function like a best-practice standard I think it is important that the user can follow the process literally.

 

One more criticism, and I really do hate myself for mentioning something so petty, is where you use pseudo-equations like "Force = Branch Angle + Lever Angle + Mass" etc. Since you are dealing with physics and actual numbers elsewhere in the article, I personally would much prefer such concepts (valid and useful as they are) more like "Force -> Branch Angle , Lever Angle , Mass" or some other way that is clearly not an equation.

 

Hope I haven't offended, trying to be constructive. I certainly learnt some useful stuff skimming through this and will no doubt refer to it again.

[stihlmadasever]

Thanks for sharing that.

[Wooden Hand]

Very useful article, thank you for sharing. It sounds like you have an interesting and worthwhile job.

 

I have a couple of minor criticisms, though I accept I may be a pedantic prick for posting them!

 

On the Knot Block Static Strength table, the kernmaster fails at 1.7kN. Is this a typo? Looks like there might be a digit missing. Also, when I see experiment data like this I want to know the sample size. Fair enough if it's a single test per combination, but I'd like to know.

 

On the Remote Anchoring flow chart step 4 asks "Is the throwline set against the strongest part of the anchor?". This would hugely and unnecessarily limit line placement options: surely you mean "...sufficiently strong part of the anchor"? I can see that this might be nit-picking, but if this is to function like a best-practice standard I think it is important that the user can follow the process literally.

 

One more criticism, and I really do hate myself for mentioning something so petty, is where you use pseudo-equations like "Force = Branch Angle + Lever Angle + Mass" etc. Since you are dealing with physics and actual numbers elsewhere in the article, I personally would much prefer such concepts (valid and useful as they are) more like "Force -> Branch Angle , Lever Angle , Mass" or some other way that is clearly not an equation.

 

Hope I haven't offended, trying to be constructive. I certainly learnt some useful stuff skimming through this and will no doubt refer to it again.

 

yes, it must be a typo. this knot block testing data comes from the second run of breaks we did, not sure how many were broken of the top of my head but for sure it was not 'batch' testing, rather testing the waters of what may seem an unorthodox way of anchoring an arborist system. There are plans to review what we got and delve a little deeper into 1 knot, if memory serves me correct the butterfly and double loop sinnet seemed to have most potential. The former for its shock absorbing potential and the latter for higher overall breaking strength. As little or no data exists for this I wanted to publish what we have so far, ongoing thoughts for sure.

 

It's an interesting comment, about the 'strongest' or 'sufficiently strong' placement. My motivation is to inspire climbers to not take gambles, I have no quibbles with what you say. If a stronger part of an anchor exists why not put the rope into it? Cutting corners quickly get out of hand, in my experience.

 

I'm not sure what a pseudo-equation is, I'm interested to hear more about this comment. The first responder, tree-fancier, said something along the same lines, perhaps, he likes science over conjecture, is this what you mean? I like tactility, for me being in a tree is an experience of many things, intellect and spirit.

 

Thanks for the comments, I hope to look more into the anchor categories based on lever length and angle, I just got this great little tool called a Goniometer, used by physiotherapists to measure how far patients can bend limbs, it's perfect for trees too.

[Wooden Hand]

Thanks for sharing that.

 

Thanks man, my pleasure !

[onetruth]

It's an interesting comment, about the 'strongest' or 'sufficiently strong' placement. My motivation is to inspire climbers to not take gambles, I have no quibbles with what you say. If a stronger part of an anchor exists why not put the rope into it? Cutting corners quickly get out of hand, in my experience.

 

If a weaker part of the anchor is in a better position, then if it is strong enough, it is a better (and safer) choice. Your article is about recognising whether an anchor point is strong enough, but by following the flow chart the user is instructed to use an inferior anchor point simply because it stronger still.

 

I'm not sure what a pseudo-equation is, I'm interested to hear more about this comment. The first responder, tree-fancier, said something along the same lines, perhaps, he likes science over conjecture, is this what you mean? I like tactility, for me being in a tree is an experience of many things, intellect and spirit.

 

No, that wasn't my complaint. I think the way you address it is correct - for practical purposes there's no way of quantifying the many variables involved every time a new anchor is chosen. By stating the 'factors to be considered' you are doing the sound thing.

 

When I first saw "Force = Branch Angle + Lever Angle + Mass ...", I thought:"ooo, an equation!", which it clearly isn't. You can't plug numbers into it, it's really just a list of concepts. My problem is that you probably could come up with an algorithm to determine whether a fork is safe. You could assign scores for species, condition, shape, size, angles, load, etc. which when multiplied give a safety score: the higher the better, under 1 is unsafe.

 

Obviously such a method is totally unfit for your purposes (might make a great HND thesis for someone), but as there is genuine science/maths within your article, I'd prefer = and + signs reserved for their precise purposes.