Re: Stone shifting 4 | Forum — The Modern Antiquarian

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Stone shifting 4

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Steve Gray Sep 7, 2003 11:29:45

Replying to nigelswift

"is it practicable/useful to row the stone to make it "walk the plank"?"

Ooooo, no. If you're saying what I think you're saying it would topple while it's being lifted because the lever nearesst to the centre cannot be as close to the centre of gravity as the edge of the tower was. Very, very dangerous.

Gordon, I think you idea may work. I hadn't appreciated that you meant to have 5 men per rope (silly me - see how the practical man, even with a skinful, has the advantage over the sober intellectual).

We need to exert about 7 tons on the stone initially. A man can exert about half his own weight when pulling horizontally on a rope and all his weight when pulling vertically. So we can assume an average of at least 40kg per man of pulling power. Multiply that by your 11:1 lever advantage gives 440kg. Multiply that by 6 levers we get 2.5 tons with only one man per rope. Therefore 3 men per rope should be enough.

Your horizontal timbers attached to the tower can extend either side of the stone and be supported beyond it with uprights, braces and a transverse log at the point where the stone will be vertical. Thus they will act as guides and the transverse log will act as a stop to prevent the stone from going too far.

The main problem is the 7 ton side load exerted on the fulcrum log and on the tower, which will have to be built up to as high as the stone (24 feet). That's one hell of a torque - 168 foot-tons. Although diagonal braces are effective at resisting such a load when the weight of the stone was pressing down on the tower, they will be almost useless in the absence of vertical loading. Any ideas?

I was trying to think of a way to keep chocking the stone so that we could use intermittent pulling. Packing chalk rubble behind it is nice and simple. We could use this with a weighted rope. The procedure would be:

1. Fasten a long rope to the top of the stone and fasten the other end to a suitably large anchor stone.
2. Lever a 3 ton block up on a wooden crib close to the middle of the rope.
3. Fasten the 3 ton block to the rope and then lever it back down, thus raising the monolith.
4. Pack chalk rubble behind the monolith.
5. Jack the 3 ton block back up and retension the rope.

Repeat as necessary.

Advanteges:
1. It's easy.
2. It uses your "levering and crib" method on the 3 ton stone.
3. It's safe (as long as the rope is strong enough).
4. It's nice simple technology that is likely to have been known.

GordonP Sep 7, 2003 11:51:06

Replying to Steve Gray

Right Steve we have two methods to move the stone upright. as yet some details to work out with both. Both retain the principal of basically useing levers and logs.

Just a quick thought on how to stablise the tower once the stone has been launched. Perhaps we can tie the diagonal strutts to the bottom of the stone, as the top moves say 6 inches or so the bottom will only move a fraction, by bottom I mean ground level. This will just have the result of tightening the anchor rope. we can then slacken it a bit before the next movement. I'll keep thinking.

nigelswift Sep 8, 2003 09:05:18

Replying to Steve Gray

So you think getting the stone to walk the plank would be highly dangerous? Fair enough. Although I have to say the concept didn’t frighten me at all as I thought “100 yards away, behind a wall, I’m bound to be OK”.

But is there some part of stone rowing worth looking into, i.e. is there any mileage in some sort of controlled descent? If there was a post or posts placed in the hole, leaning at a pretty steep angle, and you rowed the stone forward until it was almost ready to topple, then by placing a very small weight on it you could cause it to tip slowly until it was lodged against the pole, halfway through it’s descent. At that point, by putting more weight on it, and/or pulling the pole a little more upright, you could eventually cause it to complete it’s descent, and it would have no choice but to be guided into a near vertical position because of the presence of the pole on it's right and the lip of the hole on it's left, certainly enough to make the hauling-up process easy. It seems to me if you got the pole angle right, and it was strong enough, you could get a high degree of control and predictability. In particular, you could eradicate most of the slippage that normally kicks in in the second part of the stone's descent, and forces the tower to be fairly high..
If this is garbage, put it down as a valid contribution to brainstorming, as it’s an aspect we haven’t discussed.