Wotan
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Re: give 'em enough
Sep 16, 2003, 16:19
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Sounds cool! I work near the docks, and theres a rope supplier nearby, so if you need the new stuff..
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GordonP
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Do we need ropes?
Sep 16, 2003, 17:09
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I still think levering off the top of the tower will be the best option, levers give mechanical advantage, ropes give none, unless used with an "A" frame.
Using an "A" to gain advantage assumes a knowledge of gearing,
I'm just a simple bloke, like the builders of Stonehenge, I would use the tools I used on the journey.
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Steve Gray
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Re: Neolithic Rope!
Sep 16, 2003, 17:18
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I think it's good to pursue these ideas. If we could get a small piece and perform some testing on it (and film ourselves doing it), or get your Scandinavian contact to provide authoritative documentation of her testing, then we can estimate the size of rope that would be needed for the job.
We don't actually have to use replica rope (big expense and big H&S problems), we only need to have demonstrated that Neolithic Man could have made rope that was equally well suited to the task.
If, for example, it turns out that Neolithic Man would have needed multiple ropes rather than one (to keep the thickness down) , then we can do that too, and just use the equivalent diameter of modern rope (which will, of course, be much stronger than required).
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Earthstepper
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Re: Neolithic Rope!
Sep 16, 2003, 17:31
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Rope used to lift the main tree trunk at Seahenge was honeysuckle (see Pryor) Don't know how this would cope with stone though. Compare weight of your stone with estimated weight of trunk when first installed or TT's replica?
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GordonP
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Re: Neolithic Rope!
Sep 16, 2003, 17:33
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Very true, but do we need ropes to pull the stone upright? Ropes used on the ends of levers will only need to withstand a breaking strain equal to the weight of the man pulling. Which is a very differant proposition.
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pebblesfromheaven
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Re: clunk
Sep 16, 2003, 17:35
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Flipping eck.
Maybe they all wore stilts. That would solve the river-crossing problem...
.o0O0o.
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Steve Gray
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Re: Do we need ropes?
Sep 16, 2003, 17:37
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I'm not very happy about levering off the tower. It's one thing to use an unjointed tower structure to raise a deadweight, but quite another to apply massive side loads to it. These side loads are likely to be in the region of 7 tons at a height of 24 feet. I've said this before, but that's one hell of a torque. In order to counter that torque we would need some very long (70-100 foot) diagonal bracing poles against the tower, or guy ropes in the opposite direction, or both.
I'm also not sure that I agree about their lack of knowledge of gearing (I prefer the term "mechanical advantage" because gearing implies cogs and things). They already knew about using levers to attain a mechanical advantage. I could imagine that someone pulling on a rope might have thought to wrap it around a long branch, stick the end of the branch into a hole in the ground and then pull on the top to get extra leverage. An A-frame is not much more. In fact the job of an A-frame can be done with a single pole provided that tether ropes are attached on each side to stop it falling sideways.
I'm not arguing for one method over any other, but I think we shouldn't exclude any avenue of research that MAY end up being needed.
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nigelswift
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Re: Neolithic Rope!
Sep 16, 2003, 17:46
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Gordon, I'm confused, I thought we were thinking of doing it 2 ways, and both would need rope?
And not using an A frame seems an arbitrary stance for us to take. There's no evidence of pulleys, so we can't use those, but A frames and levers are accepted as likely, as they're so obviously apparent. Also, I've been playing around with Steves 100 ft tree system and it seems very efficient on my model.
Steve, if we do need any rope then yes, just a bit would be good to have, I'll talk to her. I don't think we should totally give up on the idea of buying some merely on the grounds of cost though. I think we have quite a product here and will find it easy to get some sponsorship- maybe even from Norway, as it would be such a prestigous thing for them.
When we've settled if we're using ropes, and in what context, could you let me know what strength would be needed so I can write to her?
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Steve Gray
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Re: Neolithic Rope!
Sep 16, 2003, 17:53
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I was flinching at the cost of replicating large quantities of Neolithic rope for use in the project. A small piece for testing should be OK.
If we haul the stone up from 70 degrees, the initial strain on the rope(s) would be about 7 tons, provided that the angle is not too steep (i.e. a long rope).
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GordonP
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Re: Neolithic Rope!
Sep 16, 2003, 18:03
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That's it exactly 7 tons compared to 200lb.
Sorry Nigel, as far as I know we are still talking about doing it two ways, talking being the operetive word, nothing is decided, but I still think we are over-engineering the erection bit.
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