North_by_Northwest Posted January 28, 2003 Author Posted January 28, 2003 That's an interesting test, it's cool that you actually tried it. I'm still in favor of sitting though. This discussion has been pretty good. Quote
Bill_Simpkins Posted January 28, 2003 Posted January 28, 2003 I like it too. I think everyone learned a bit about sitting and standing. Knowledge is power. Quote
Bronco Posted January 28, 2003 Posted January 28, 2003 kinda like the theory of climbing low angle slabs, you keep as much weight over your feet as possible, as opposed to leaning on your hands. Quote
ScottP Posted January 28, 2003 Posted January 28, 2003 Weight of Climber, ie tension in rope: 170 lbs, or 756 Newtons Height of Belayers waiste while standing 3 feet, or 0.9144 meters Height of belayers waiste while sitting: 10 inches, or 0.254 meters Distance of belayer from edge: 5 feet, or 1.524 meters Here we go : SITTING theta=arctan(0.254/1.524)=9.46 degrees Force towards cliff 756cos(9.46)=745.72 Newtons, or 167.64 lbs Force to feet 756sin(9.46)=124.25 Newtons, or 27.93 lbs STANDING theta=arctan(0.9144 /1.524)=30.96 degrees Force towards cliff 756cos(30.96)=648.29 Newtons, or 145.74 lbs Force to feet 756sin(30.96)=388.91 Newtons, or 87.43 lbs So when standing there is 3.13 times more force applied straight down to your feet, which is good because you can't travel through rock and you get 3.13 times better traction. There is also 1.15 times less force pulling you straight towards the edge. Interesting data Bill, but it seems a variable that is missing is the coefficient of static friction. Butt (and perhaps legs) and feet versus just feet? Quote
Bill_Simpkins Posted January 28, 2003 Posted January 28, 2003 Interesting data Bill, but it seems a variable that is missing is the coefficient of static friction. Butt (and perhaps legs) and feet versus just feet? The coeficients of static friction doesn't matter. When you compare the two in a ratio, that variable cancels out anyways, because the coeficient of friction is the same for both cases. Sitting down, most of the weight goes to your feet anyways. If you legs are on the ground, your feet arn't. Your butt is on the ground , but most of the force is still on your feet, but yeah, the butt does add a little friction, depends on surface area , weight and material. For some of you maybe, the surface area may help out quite a bit. Quote
catbirdseat Posted January 29, 2003 Posted January 29, 2003 The most important term in the equation, BALANCE, is missing. The reason the sitting belay is more stable is balance. Three points are in contact: your two feet and your butt. When the there is no load most of your weight is on your butt. When the rope goes tight the load transfers to the feet, which hopefully you have positioned on against a couple of solid rocks, so you'll never have to explore the coefficient of static friction between your soles and the the rock. We are WAY over analyzing this, aren't we? Quote
dave Posted January 30, 2003 Posted January 30, 2003 If you are standing and belaying from the hip, and the pull is a bit outward as opposed to downward, (as is likely on easier terain) you are going to topple over, especially if you didn't anticipate the direction of pull well. This situation will be the same if the terrain is generally steep but you are on a ledge a short ways back from the edge, again some outward pull. If you prefer to stand on the edge of the cliff with no anchor, so that you can have a nice clean downward pull, ..I don't know why a person would. If the terrain is quite easy and you have difficulty keeping up with their rate of travel with your belay, and they ever fell, you'd get pulled right off your standing stance. Take care with losing the rope, sliding off the hips, with the standing hip action. If you are sitting with your feet braced widely against even small edges, you are in business, even if you didn't anticipate the direction of pull well. One can also use a hand to brace with. The rope won't slide off your hips. One can also belay dynamically when seated quite well to prevent getting pulled off a stance. I don't really believe in a good dynamic belay with an unanchored standing hip belay. Maybe the shoulder belay if the terrain is steep. Just some thoughts from my experiences, having done a fair bit impromptu belays, hip, shoulder, rock, snow. Quote
North_by_Northwest Posted January 30, 2003 Author Posted January 30, 2003 I don't think their is any question as to which is a more stable platformNew poll: which would you rather belay from: Quote
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