I hope I've chosen the right forum. I write fantasy novels and I need technical help. I'm not a mountaineer.
I have a scene where a group of fleeing soldiers use a tyrolean traverse to bridge a gorge and then cut the rope behind them, flinging the pursuers to death on the rocks below. The traverse was set up in advance, they didn't have to do that in a hurry. Wiki suggests a 500m+ traverse is possible. That would do me. Unless anyone can point out snags like extra anchor points needed. I'm assuming just one anchor at each end.
Q1 - How fast might the crossing be? I need to get 20 to 30 men across as fast as possible.
Q2 - Would it have to be one man at a time? I need an unconscious prisoner to be carried across. Or would he have to put in a sling?
Q2 - I'd like the pursuers (those that arrived after the rope was cut) to find the anchor point on their side, the remains of the rope and perhaps a pulley. In my research I've seen a warning to use two pulleys. Would that be one pulley at each end? But if the rope is cut, would the pulley just fall, like my unfortunate soldiers?
Any hints gratefully received - in non-technical terms please. Feel free to ask questions if I haven't made this clear enough.
1. Not fast. 500m, if you went one at a time it would probably be several hours.
2. If your anchors were absolutely bombproof then a few at a time would be possible, but your injured man would have to be in some sort of harness suspended underneath (as would your other men as most people hang underneath and pull themselves along)
3. It depends on the system used and which side it was tensioned from, but yes, that would be possible to find one pulley at the anchor.
It is an individual anchor at each end, BUT those anchors would be made up of multiple anchors if that makes sense.
The other issue is 500m is a LONG way. Whilst theoretically possible its highly unlikely.
At the end of the day, you're a writer, don't let the truth get in the way of a good story!
The rope will stretch/sag quite a bit despite the tension. This makes it easy going out to the middle but much slower hauling "uphill" for the second half.
So what you really want is a zipline type set-up where the far end is much lower and your soldiers can slide all the way at high speed, in which case... maybe 40-50 seconds on the line? If they're efficient (and the rope and anchors are strong enough!) you could then have three or four of them on at once, clipping on/off in a continuous rotation at each end. Add a bit of faffing time and you've got them all across in ten minutes or so.
Make them paratropers and this sort of thing would be second nature. Could be a bit of a comedy pile-up at the far end if one of them doesn't unclip in time though ;-)
500m is a long way, but by no means impossible at all, the big length might be a feature of your story, but as mentioned it would take a good few hours to get 20-30 over that distance:
"The longest Tyrolean traverse agreed by Guinness is 1550 meters. It was created on 19.09.2008 in Rila mountain Bulgaria Another famous Tyrolian traverse, set up in 2000, connected Castleton Tower and Rectory desert towers, which are about 500 meters apart."
youve got the right forum - especially if you want a multitude of opinions.
1) it would take several hours. 500m is long and the dynamics mean it will be fast for the first 250m then very slow for the next.
i regularly do a 25m tyrolean for work and its about 2mins across including clipping on and off.
over 500m it could be a 1:5 ration of time to:from the mid point.
2) not 1 man at a time. over 500m 3 at a time would actually make it faster by taking out some of the rise from the mid point.
much will depend on the rope used as it would need to be stronger (forces in traverses are dodgy).
getting an unconscious person across would be possible but very hard. would have only 1 other able soldier with them and probabaly a second rope to haul them from the far side.
unconscious person would be in a sling, sling seat or litter.
3) your pursuers could find whatever you need them to.
often pulleys are not used at all, but unless they have another rope to send the pulley back to the start for each man (more time) they will each have one.
by two pulleys, thats either to have 2 in rotation, or to use 2 at once so the load on the tensioned rope is less acute.
it would be very poor soldiering to leave a pulley behind, indeed proper tyroleans are rigged so all but the anchor is retrievable.
anything hanging on the rope would drop if the rope was cut from the far side, but if a retrieval rope was used for a single pulley to go back and forth the pulley could still be attached at the far end (in that case tho the good guys would have taken it with them).
it would help to know if these are contemporary soldiers or ww2-type stuff, as methods and equipment would be different - and theres a good chance you will find an expert on here on whatever era you have chosen.
Tyrolean Traverses take a wee bit of time to set up and involve getting the rope to both the exit and landing ends of the rope. The traverse below too about 3 hours for two of us to set up and took another hour and a half to get all 14 of our troopers across it. If you notice the sag in the rope as the person reaches the halfway point, this was on a tensioned semi static and we still got plenty of stretch.
> it would help to know if these are contemporary soldiers or ww2-type stuff, as methods and equipment would be different - and theres a good chance you will find an expert on here on whatever era you have chosen.
No high-tech, I'm afraid, just ropes,pulleys - the simple stuff. But the "soldiers" are bandits who have been holed up in a mountain stronghold for years, so they know all about the uses of ropes - unlike me. My other half always claims I don't understand levers - true!
have crossed a bunch of these myself. they use cables, not ropes, and many are more zip lines (at an angle rather than a tyrolean which is horizontal), but hillbilly rigs that may be a bit like your bandits set ups.
y'know, if you ask the right way, im sure someone may take you out for a go.
id offer but am outside the uk. if you like a can send you some crappy iphone pics of the 25m tyrolean i mentioned earlier to get an idea of the look of it.
Possibly not. It's a trap being set up using the prisoner to lure the pursuers. The rope crossing is from a fortress tower to a ruined tower on an outlying rock pillar. If I make the intervening ravine deeper and put the "angry river" at the bottom, a shorter distance would be possible. The critical part is that no one notices any activity at the ruined tower in advance. Given that sentries at the fortress should have their eyes peeled for suspicious activity, it can't be too close.
Faffing around with 500+ metres of cable/rope and tensioning is not going to go unnoticed. 50m - 100m is a far more viable thing to set up quickly and discreetly. Two towers over a narrow ravine/gorge would make a formidable obstacle for anyone to pass beneath, which would justify their original construction there.