THE TASK WILL REVEAL ITSELF - PUSHING ON A ROPE
This particular task did not reveal itself, or at least not to me personally, so I had to ask. Actually I had no idea the task in question even existed, but once I learned what it was I became curious about how it would even be possible to do what I saw them doing. Details to follow.
At the present time there are several dozen holes on our block, roughly six feet deep and anywhere between six to eight feet square, or perhaps even bigger. One of those holes destroyed a nice perennial garden I have been cultivating for many years, but that will be another story once I get around to redesigning it. The existence of these excavations can be explained as part of the plan developed by the City of Montreal to replace the antiquated lead pipes carrying fresh water into each residence with much safer copper tubing. The water in every residence was tested for lead content last winter, and evidently many our homes have too much lead in the water, not good for anybody really, but especially harmful to infants and young children. So overall a worthwhile project, though not particularly easy to live with while the street is torn up and the noise gets started promptly every morning at 7:00 AM.
One of the first things they teach you in Engineering School is that you can’t push on a rope. This seems an odd thing that you would have to teach somebody in an Engineering School, but the person who told me this was the Dean of Engineering at McGill so I guess he knew what he was talking about. Nice guy - we worked together on committees from time to time and had quite a few enjoyable conversations over lunch at the faculty club. If you think Engineers and English Professors wouldn’t have that much in common you probably don’t know as much about Engineers and English Professors as you think you do. Two things we have in common are curiosity and creativity, two notable virtues not actually mentioned in Aristotle’s Ethics - although Aristotle wouldn’t have called them virtues. He would have called them excellences.
If you have ever threaded a needle or strung beads on a string you already know that it is quite difficult to “push a rope” through any kind of a hole, but not really impossible, as long as you don’t have to make it go any distance. The point my Engineering friend was making is that a rope - could be a tiny silk thread or a steel cable or even a chain - is primarily effective when used in tension, or in other words you use them for pulling, not for pushing. Do aircraft carriers have anchors? I have no idea, but if they do have anchors then you have to pull them up out of the water if you want to go anywhere and you’re going to need an extra-large heavy duty rope to get the job done. It turns out that an aircraft carrier has not one but two 30-ton anchors. They pull them up with a chain made out of 360-pound links. Gives a whole new meaning to the expression “weighing the anchor” doesn’t it? You won’t be spending any time pushing on that thing.
A few years ago when the boat at the family place on the lake broke loose from its mooring in a strong wind, I learned that the weight of the anchor is not what keeps the boat from wandering off on its own. The crucial element is the length of the chain, that has to be long enough so that it doesn’t actually - um - pull the anchor off the bottom of the lake in a strong wind. This not an easy thing to explain to people since it involves a catenary curve, which is the graph of the hyperbolic cosine function and I’m not getting started on it here. I’m already way over my head as it is on this one.
At around 7:30 AM one morning last week the doorbell rang. There was a young man wearing a hard hat on the front porch and he was there to advise me that the water was going to be turned off in our house for about an hour and a half. I immediately went upstairs and filled up the bathtub. It was roughly at this point that I realized the nature of the task that would eventually be revealed. There was a guy in a hard hat standing in the hole that used to be my perennial garden, holding two coils of copper tubing. There was another guy in a hard hat standing in a hole in the street where the water main is located, let’s say about twenty feet away. The task they have to perform is to somehow pass the tubing under the sidewalk from the point where it attaches to the residential plumbing to the point where it attaches to the main. I have no idea how they are going to accomplish this.
At this point you should immediately find a way to see a documentary film called Man on Wire, which is the story of how Philippe Petit pulled off “the artistic crime of the century” by walking on a tightrope strung between the now vanished Twin Towers of the World Trade Center in downtown Manhattan. This is a wonderful film, but I’ll limit my comments here to just one aspect: the “task” they had to accomplish in order for him to commit the “crime,” which was to develop some way to actually string the heavy steel “wire” between the buildings. The Twin Towers were already finished but the buildings were not occupied at the time, which meant that two crews had to sneak in, get up on the roof of each tower with their equipment and then rig the wire. To do this they used a bow and arrow to shoot the first, relatively light and slender wire from one building to the next. Does this count as pushing a rope? Not sure how to answer my own question here. The arrow was pulling the wire, but in order to do that the bow had to push the arrow I think you would say. The first wire was used to pull a heavier wire, which in turn was used to pull the actual wire he walked on, that was then braced and tightened so Petit could actually perform this terrifyingly hare-brained scheme. It took most of the night and into the next morning to complete the task, not including the actual “crime” of walking - or dancing - across. There is no law on the books about walking on a tightrope between two skyscrapers in New York City, so they arrested him for disorderly conduct and criminal trespassing.
I thought about this film when I actually saw the guys standing in the holes outside our house pulling what looked like about a half-inch thick woven steel cable to pull the copper tubing under the sidewalk. They had to use a back hoe to do the pulling, so you get an idea how challenging the operation was. So there is your question for today, class - which is how did they thread the cable underneath the sidewalk? Hint: they did not use a bow and arrow. The did, however, use a fairly light gauge wire to pull the cable through, but the question remains - how did they get it through the twenty-foot long “hole” and for that matter what were they using for a hole?
I’m not sure if anybody cares about this, but if you’re still reading I assume you want to know the answer so I won’t keep you in suspense. The guy standing in what used to be the perennial garden had shoulder-length hair and he spoke English with a pronounced Québec accent. When I asked him how they got the light gauge wire through he said “we use hair.” I realized of course that he was actually saying “we use air.” Happens all the time around here and it’s a good thing to learn how English is spoken by many of your fellow citizens. There was a large, noisy machine right next to us generating a lot of air pressure so I asked if they were using suction to pull the wire through and he said “no, we use the hair to push it through the old water pipe. You put some electricians tape on the end and then the hair pressure takes it through.” You solve the problem by finding a way to push on a rope without using a bow and arrow, and then once you get the lead wire to go all the way through the old pipe you can attach it to the half-inch thick woven steel cable which is attached to the end of the copper tubing and start pulling everything back in the other direction in one complicated move that will take you at least an hour and a half if it doesn’t take the entire day. Hook up one end of the tubing to the house and the other end to the water main and there’s another residence with safe drinking water.