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Stone shifting 4

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Suppose that you have a large block of stone 1 metre thick, just balanced over the edge of the tower so that its centre of gravity is 1mm beond the edge. It would very slowly begin to topple, but as soon as it starts to move, the centre of gravity moves too because it is half a metre above the pivot point. By the time the stone has rotated by 30 degrees, the centre of gravity has now moved from 1mm to 251mm, so now you've got a considerable turning moment. This makes it very difficult to arrange any kind of controlled descent if you want to end up with the stone at 70 degrees or more.

The angled timbers are a nice idea, but would have to be very strong if you intended them to stop the angular momentum of the stone. Presumably the top end would be supported by the tower. So the tower would have to be able to withstand the side load (7 tons static, but considerably more when stopping the rotation) without the benefit of a vertical load to hold it all together. This is the problem I was discussing with Gordon in relation to his idea of levering off the tower. I prefer the idea of letting the ground stop the stone, and that's why I wanted an angled entry slope to the hole so that the stone could enter deep into the hole while still rotating. Fortunately the Earth has enough mass to stop a 40 ton stone without too much ado. ;-)

I have to go out now, but I'll try to do post some drawings of the proposed methods later on.

Keep up the brainstorming. It's good to have different ideas in the melting pot. Even if an idea is not immediately applicable, it may give rise to one that is.

"Presumably the top end would be supported by the tower".
I wonder if you're thinking that I'm thinking the timber would be on the near (left on Gordon's model) side of the hole. I was thinking of it being in the hole and slightly leaning towards the right, i.e. propped against the right hand lip of the hole. So the earth would take much of the impact. Plus, additional buttressing for it at it's top end, if needed.
I guess in my layman's terms I was thinking if we were allowed to have a really deep tapering hole then it would be really easy to get the stone upright in it, but since we are only allowed a shallow hole why not effectively lengthen the hole's far side, upwards and at a slightly widening angle, using a tall piece of timber (or several). So far as the stone knows, it's now being tipped into a tapering deep hole and if the timbers don't break it has zero choice but to end up pretty upright.
I may have misunderstood you though in which case sorry about banging on about it.