Amelanchier

Its not that complicated.

Complicated enough that no-one explained that the mechanical advantage of a system depended on your frame of reference within it...

Each leg bears the full load Tony...

Even when the load is attached to itself? If you had two legs attached to a static load through a pulley that'd be the same as a single leg surely? The anchor point couldn't be experiencing double until it moved? So the legs experience half then full load dynamically?

Each leg of rope holding a static load must bear half the load. So if you are the load, then you only need to apply a force greater than half that load to move yourself. If you are not the load then you must apply a force greater than the load to move it. Simultaneously both a 1:1 and a 2:1 depending on where you are...

Well every day is truly a school day. The mechanical advantage gained by a system depends on where you are when applying the force - so yes a climber experiences 2:1 as he pulls himself up with each leg of the rope holding half his weight (i.e., you guys are right) but a ground based person pulling the same rope beneath the climber would only experience 1:1 - pulling on all the climbers weight (so I'm not entirely wrong... )

How about that...

Hmmm The distance thing is clearly right. The amount pulled must be divided between the number of legs. Anyone able to confirm the forces?

I think we need another Dolly experiment With rulers instead of scissors!

Having met before and myself thinking he was a middle aged man turns!! out he's a young brad Pitt.

Now now - no need for rhyming slang... You'll upset my inner middle aged man

I respectfully disagree. In order to ascend one metre, 2 metres of rope passes through the hitch when climbing DdRT. Hence 2:1.

Really? Forget about the hitch for a minute - are you saying that if you pull down two metres on one leg of rope running through a cambium saver at the top of a tree you only move the load attached to the other leg one metre...?

That is the right criteria for a MA system though - distance of rope pulled through multiplies proportionally with the forces generated.

Tony, 2:1 is Ddrt you have 2 legs at the moving block! 1:1 is a straight pull bearing no moving blocks..

I should have been clearer - for a 2:1 MA system the pulley moves with the load. A static pulley just redirects force without multiplying it.

Just as an aside and without picking on Adam (I've seen it said before) - I've always thought DdRT was redirected 1:1 system. From what I vaguely recall 2:1 systems require a moving pulley component don't they?

What a load of crap mate, the evolution of arborists had been happening for decades!! For anyone such as yourself not to see this is unbelievable!!

 

What where climbers using 20/25 years ago?? What changes they made 10 years after was phenomenal!! And 10/15 years later here we are!! It really does not take a genius to work out how beneficial SRTWP is on the body let alone the safety standards of work position!!

 

This is crazy that people still refuse to agree that we as an industry have seen the light!! Probably the last industry who use ropes to work from SRT!! Tell me Tony, where do you see this industry in the next 10/15 years from a climbing point of view??

That's not what I'm saying. I'm saying that evolution doesn't go anywhere - it runs on the spot. So its a mistake to say that climbing systems are evolving if you want to say that they are getting better. SRTWP might well be the pinnacle of rope work in trees or it might not be - I'm not well placed to say. What I can say is that there isn't a substantial pressure on climbers to make that leap - an effect of the law of diminishing returns (they can climb pretty well on DdRT). So to use the evolution metaphor - unless there's a substantive pressure on climbers to use it, it will remain at a low frequency in the population (a bit like green eyes or the AB blood group).

Fifteen years from now? 2029 is the year of the hoverboot - mark my words

I understood perfectly!!

 

There's no pressure it's not being force upon anybody, but other than the facts like I stated like the benefits of using your larger muscle groups rather than your arms which is a major advancement working 1:1 rather than 2:1 and the fact it's far more superior in the work position safety factor also.. To call SRTWP a counterculture and say we are outcasts is ridiculous!!!

Again, that's not what I'm saying at all. Historically countercultures have been very effective at shaping the mainstream - it's not an insult just an observation.

We can provided the same old soapboxes don't come out

Also, given that the guidance admits consideration of future amenity (i.e., small trees getting bigger) you should be aware that the threshold for a suitable amenity value starts fairly low and normally gets a lot lower depending on the LPA's interpretative flexibility of the terms 'amenity' and 'value'.

I read something tonight that really and honestly made sense, the person who said it I respect in all manors and from my point of view maybe one of the best climbers this forum has to offer!!

 

The thing is with SRTWP is it's new, every single climber or climbing technician in our industry that called them selfs experts have suddenly found there not experts anymore, because a new style or system of climbing has hit the shelves!!

 

IMO most climbers are like ordinary people who live there's life's day in day out and dread the thought of change!! There's heaps of climbers out there that still to this day are using the Prussic body thrust method!! I have nothing against that what's so ever. But there's reasons behind them still using it! Either they're comfortable with it or they really don't want to try anything new! Because they're scared of change?? Maybe?

What ever the reason that maybe, should it really justify trying to pick holes in every new method that our industry has to offer?

 

Evolution is a funny thing!! and maybe the mammoths sat down one day and argued amongst them selfs that it was time to loose the locks and bare all in the form of an elephant!!

The notion of SRTWP as an evolution of climbing styles doesn't quite fit for me. Evolution is a lateral process, nothing evolves towards progressively superiority - it just gets as good as it needs to get to avoid getting dead (there's no such thing as progress huh Tim). besides, nothing evolves without a selection pressure. What would the selection pressure on climbers to use SRTWP be?

As an ex- competent but not that special climber safe in the warmth of my ivory tower SRTWP has all the hall marks of a counterculture rather than that of an evolution.

Guy who mentioned this to me was ex defence guy ......your actual rocket scientist

it was bothering him a little bit .......

I met the guy who designed it all at my local londis the the other day - he said it would be fine.

Arthur has commented on a very serious issue that affects us all,there's no need for that mate.

No need for what? Scepticism at an an unsubstantiated yet timely and sensational claim of impending national disaster written on a tree forum...?

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Adam, does anyone really think that? I've heard the 'high up' industry voice allegation as well from several sources. None of them have ever substantiated it to me, even in confidence.

Some of the things people come up with...

Does everyone feel better now?

Great - thread closed.

That car had to be removed to enable the development Paul. Facilitation scrappage...

Someone I work with often expresses RPAs as polygonal CEZs on the basis that things like heras fencing comes in straight lines.

It does, but only in multiples of 3.5m! (plus 75-100mm for connectors)

Given the requirement for an accurate dimensionable plan I decided that it was more efficient in the long term for both us, client and LPA to show each and every heras panel (with scaffold or proprietary foot supports), trakpanel and Cellweb unit on our drawings. Its easily done on AutoCad using blocks as shown (the straight line in the attached is a length of post & wire across a low risk area).

Glad you chaps found this I see I have put it in the firewood forum and not the woodcraft one Oooops

Easily fixed...

He could also ask angrily for it to be re-activated

I guess he could try that...

Seems a bit harsh to do that so soon, maybe he was just having a bit of a down moment?

He can always ask nicely for it to be re activated.

Yawn.

I do the same as Scott and Paul. I think most important thing to do when adjusting the shape is to justify yourself - it only takes a paragraph or an annotation. On the flip side, in the event that I use the circular model I feel obliged to justify that also.

As far as weird polygons go, I have an ongoing site with a row of Pops between a river, some buildings and bridges. It took most of a day trudging around with a probe, crowbar and an auger just to work out where the viable rooting areas are and the resulting RPAs are as far from circular as you were ever likely to see. Most were vague asymmetric 'S' and 'T' shapes and one even had to be argued down in area - it just wasn't physically possible for it to follow the model given the reality of the site.

Recently we had the opportunity to put a hand dug root investigation trench in across the limit of one of the more speculative sections of one of these RPAs to inform the feasibility of a trench footing. Given the distance and convoluted path to the trench from the nearest Pop, I was expecting a number of shallow small diameter (<10mm) roots just under the hard surface but instead we found a single 28mm root disappearing off outside the RPA... I couldn't justify reducing the other extents (they were too obvious) so I just increased the provision for that tree.

A model is just a model.

Sloth -

the carbs grains thing

its not that they are truly heinous

 

but it boils down to how man has changed the grains over the last few centuries - and that old wheat found pre-industrialization was a far better product than found today - due to the genetic changes now found (faster growing, drought resistant, mould resistant, etc)

that is the main reason.

 

2nd if strictly paleo is due to the hunter gatherer lifestyle the tribe would not have access to large amounts of wheat/rye etc so they may have enough for a small loaf per month and only when the plant was in season.

 

i shall let others do the more scientific explanation.

pre-industrial wheat was better how?

More nutrients? More availability? More honesty?

More capacity to host parasites that could drive you insane?

Natural stuff can hurt you just as bad as synthetic stuff...