For no particular reason, I started wondering this. I’m referring to the type of bridge consisting of a rope strung between two mountains seperated by an enormous chasm. You often see them in “Indian Jones” type movies. Here is an example.
The consensus at work seems to be that some mechanism such as shooting a “pilot” rope across with an arrow is used. Is that feasible? What if the distance is too great for an arrow weighed down with rope?
It was just such a project that brought about the invention of sky hooks. 
“SepArated” and “IndianA Jones” - sheesh…bed time.
welllll, ya take some rope and a bit of wood…
The precise method of constructing a rope bridge is detailed in the Boy Scout Fieldbook, as I well recall from helping build a rope bridge once when I was a kid. We just sent a guy down through the ravine and made him climb up the other side with the rope. But I can see where this might not be practical, in cases of bridging an extremely deep chasm.
A few years ago, some guy strung a tightrope across the gap between the World Trade Center towers and walked across it. He shot an arrow with some thread attached to it. The thread was used to pull some string. The string was used to pull some twine. It took several steps to get to the point where he could pull the tightrope across.
When they built the first bridge across the Niagara River near the falls, they held a contest with a prize for whomever could fly a kite across. The prize was won by a kid, and they got a line across the gorge:
http://www.iaw.com/~falls/bridges.html#b1
I hope you appreciate the link, rather than my just quoting “Paul Harvey and the REST of the Story”, which is where I heard it.
The kite idea is ingenious - hadn’t thought of that.
I still wonder how they make those bridges in the Himalayas though, where climbing into the ravine or shooting an arrow doesn’t seem practical.
I think what they would shoot across the chasm would be string. The string is then used to pull the heavier rope across.
There’s a Nova or one of those PBS “how did they do it?” shows where they built a bridge using grass rope. There’s lots of twisting involved.
More than a few, that was in 1974, before one of the towers was even complete (the picture in the link shows exterior construction still going on).
The only footage I’ve seen of people actually constructing a rope bridge involved using a human pendulum.
A child was anchored via a rope harness to a scaffold tower built some height above the level of the cliff. He was then launched out over the gorge by half a dozen men using more ropes as a kind of improvised catapault. When the kid reached the other side (some distance below the top of the cliff) he simply clambered up and tied off the rope, allowing the men to climb across carrying more ropes.
These things are a lot faster to construct than you’d think and they had a moderately functional bridge in about fifteen minutes form the time the kid was launched.
If the base of the canyon has easy access, an easy way would be one person on each cliff, with a person at the base. Drop sufficient lengths of rope from both sides of the cliff and have the person at the base tie them together. Pull the rope up one side and you’ve got it.
Thanks for the clarification, I coulda sworn that happened in the eighties. I guess time flies when you’re having fun.
But the real reason I’m posting is that I thought of another approach. Suppose you wanted a rope bridge across a particularly forbidding gap. Maybe you could first string a rope across the canyon at a more easy point. Then with one person on each side on the canyon, they could walk to the designated spot. They would play out more rope as needed while they walked.
