Amelanchier
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Everything posted by Amelanchier
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Top handle 200T stolen at the end of Feb from roadside work site in North Norfolk. Almost brand new (bought in 2011 but only just brought into service). Clearly we'd like it back but we'd also like to offer a £100 reward for information leading to its recovery. Any information contact [email protected]
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Just a heads up... BS 8545:2014 - Trees: from nursery to independence in the landscape. Recommendations
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On second thoughts Laz - get your head down. Nothing to see here
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Wouldn't descending involve an acceleration as well? Rise Lazarus...
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Complicated enough that no-one explained that the mechanical advantage of a system depended on your frame of reference within it...
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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?
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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...
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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...
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Hmmm The distance thing is clearly right. The amount pulled must be divided between the number of legs. Anyone able to confirm the forces?
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I think we need another Dolly experiment With rulers instead of scissors!
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Now now - no need for rhyming slang... You'll upset my inner middle aged man
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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. 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.
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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?
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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 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.
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We can provided the same old soapboxes don't come out
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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'.
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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.
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I met the guy who designed it all at my local londis the the other day - he said it would be fine. No need for what? Scepticism at an an unsubstantiated yet timely and sensational claim of impending national disaster written on a tree forum...? Sent from my GT-I9195 using Arbtalk mobile app
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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.
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Some of the things people come up with...
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Does everyone feel better now? Great - thread closed.
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That car had to be removed to enable the development Paul. Facilitation scrappage...
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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).
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Easily fixed...
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I guess he could try that...
