Monday, May 14, 2007
Rope Swing History in Modern Application
[Lola Lemieux Kindly requests information] Since searching seems to be your bliss, I venture to ask your help. I need either a) a zip line like at outdoor adventure places; or b) a rotating swing hook from which to hang a swing-and-drop board. Our pool - it's a long and gripping saga - is now complete again, except that I need something with which to swing out over the pool and drop in. It's true there are glass windows on all sides of the pool, so one will need to zip or swing with some caution - well, either caution or finesse. But I do think it is an essential piece of equipment, and I don't know where to look.
[Noting the finese requirement, Chuck Cooper offers historical perspective and questions] The swing and drop idea is tough to conceptualize for a small private pool, both from the necessary orbit and from safety issues. First, a story. I was in grade school, maybe 4th or 5th grade, at Sunnydale, and Glen Ellington and some neighbor guys (Larry Parker?) who lived across the street from Sunnydale had rigged a rope swing tarzan style over Millers Creek. The banks were fairly high on both sides, so the idea was to reach out with a stick to catch the rope, which was slung from a tree limb that extended over the creek, then grab the rope and swing to the opposite bank. At the bottom of the arc your feet were about 2 or 3 feet above the water. Well, at least the other guys were. When my turn came I made it half way, my hands slipping from the rope, and landed at high velocity in the creek. To this day I have an image of that gravel bed coming up to meet me. The creek was running only 8 or so inches deep in that wide spot.
Now this illustrates several problems. First, assuming you have no tree next to your pool with a branch extending over it, to what will you attach the swing rope? The bottom of the arc has to be over the pool, and so does the point of attachment. Second, how will you make sure that people let go of the rope at the right point? Too soon and you break your back or your head on the edge of the pool. Too late, and it is the other side of the pool. Further, the arc dictates that you have a high place from which to swing, and that is not safe unless it is right at the pool edge, so that those falling immediately miss the pool edge. Assuming you have such a platform, just how long is your pool? You don’t want anyone making it to the far edge. Or maybe the shallow end could pose a problem. And what about someone that forgets to let go and swings all the way back. What about the edge of the pool then, should their let go timing be just right?
[Ken Linville brings a more powerful historical prospective] Bringing into the equation, of all things, a rope swing, to an old fool that’s lost in nostalgia, (moi?), is like throwing gasoline on the fire. I had many terrifying experiences on rope swings. Down behind my house in McMicken Heights on 33rd Ave South, in the verdant forest that stretched all the way down to the Pacific Hiway was the mother of all rope swings. It actually was a rusty old cable tied to a branch of an ancient Doug fir at least 150 ft. high. Whoever tied it up there, we never knew. It had been redundantly fixed to two branches for safety but one branch had broken off so, still having the cable tied around it, swung freely and the end of the cable was now tied to just one branch and the broken branch swung around wildly as the huge pendulum swung out and back. The broken branch cut the safety factor of the contraption in half. Maybe more. Of course, on the other end of the cable, sitting on an old stick that was inserted through a loop in the cable, flying through the air with the greatest of ease, grasping the cable for dear life with both hands, was none other than one small boy at a time on the wildest ride of his life. This was on the thrill scale of the roller coaster at Playland. To start the ride, it was necessary to wrap a long rope tied to the end of the cable around your waste and climb about 25 feet up another tree about 30 yards north of the tree supporting the cable to a small platform which was attached to the trunk. Then, as you gingerly got up on the platform, you put the cable with the stick lodged between you legs so you could sit on it, screamed “BONZAI!!!” and stepped off into space. By the time you reached the bottom of the swing arc, you had accelerated to approximately warp 5 and had no doubt that you were going to die as you began the upward swing which took you 20 feet or so above the ground again. Only those of us with the utmost courage even dared to look down. The guys who took us down there were older than us and double-dared us to try it. I bravely muttered, “You go first, Rudy!.” “Sheeee-ittt!” he says. “This swing is for sissies” and heads up the tree without hesitation, jams the stick between his legs, and doesn’t just step off the platform; He leaps off it! Hanging on with only one hand, he swings his other around like he’s riding a rodeo bull. The big kids are impressed. As he hands the stick to me and says, “Your turn”, I say, “Shit, I think I heard my mother calling me for dinner.” A big kid named Billy McGlassen says, “Take a ride, punk, or we’ll stomp the shit out of you.” Now I don’t really give a damn if Billy thinks I lack the nuts to get on the swing but I can’t let Rudy think I’m a yellow belly so, up I go, close my eyes, and step off the platform. Wild! I’m thinking this is great! After that, we rode that swing every day, hoping that big, loose branch wouldn’t come loose and wipe us out. Remember the rope swings on the log booms at Angle Lake Plunge? Our swing made ‘em look like kiddie rides.
I doubt if this is what Lola has in mind for her pool but I’ll think on that problem and address it another time, as I will the Greek system. You forgot to mention, Coop, that aeronautical engineering has absolutely nothing to do with flying aeroplanes. (Nor a hell of a lot else for that matter) Seems I do remember, however, in a kinetics course, something about the motion of pendulums and how the frequency of the swing remains constant even though the amplitude of the arc may change. Does that help, Lola? If you do get that rig up and running, Coop and I will come down and test it. I can’t see how he could possibly be as klutzy as he says he is. He’s hiding behind a smoke screen and blowing the smoke you-know-where. It takes a lot of coordination to take a swan dive into 8-inch deep water.
[Lola clarifies her request] It appears I haven't made myself clear here. The image I have in my mind is Nicole Kidman enchanting the clients at the Moulin Rouge or the Girl in the Golden Cage, gracefully draped charmingly in the swing, legs crossed at the ankles and toes pointed. At the point in the arc of her choice, she may langorously - notice NOT langoriously - she may langorously slip into the water. Probably not screaming, "BONZAI!"