Dr_Flash_Amazing Posted January 20, 2003 Posted January 20, 2003 Hey! When you place a directional at the bottom of a route so your pieces don't rip from the bottom in the event of air time, do you place it for outward pull or upward pull? Or does it depend? Any conventional wisdom on this? Gumbyism rocks. Quote
obsydian Posted January 21, 2003 Posted January 21, 2003 If you place one piece, say a cam, it would be placed for the most likely direction of pull between the belayer and the leader. If you create a directional with two pieces, the bottom piece is generally placed for an upward pull, to keep the top piece from being pulled upwards. Quote
Bill_Simpkins Posted January 21, 2003 Posted January 21, 2003 What I try to do for two pieces if the situation grants it: 1. I put in two pieces, say in a vertical crack, about 1.5-3 feet apart from each other. Both have biners. 2. Then I take a shoulder length runner, sewn, and with just one strand of the loop, tie a clove hitch on the bottom biner, then a clove hitch on the top biner, and make this strand of the runner tight between the two pieces. This keeps them in place. 3. Then I take the remaining part of the loop and run it back through the bottom biner, and clip another biner(preferrably a locker) to the end of the loop. 4. I then yank on it a few times real hard to check everything. 5. I run the rope through this biner. This method works for ME. Others may have reasons for doing it differently. I'd draw a picture, but my PSP trial just ran out (GETTO). Quote
Greg_W Posted January 21, 2003 Posted January 21, 2003 Simpkins - I got what you're trying to explain and I've never done that but admire the simplicity. I'll remember that one. Quote
Dr_Flash_Amazing Posted January 21, 2003 Author Posted January 21, 2003 Rocking. ( ) Good work, Simpkins! Quote
catbirdseat Posted January 21, 2003 Posted January 21, 2003 3. Then I take the remaining part of the loop and run it back through the bottom biner, and clip another biner(preferrably a locker) to the end of the loop. Wouldn't running the remaining part of the loop back through the bottom biner result in a 2:1 purchase, thus doubling the load felt by the bottom biner in the event of a fall? I prefer to let the biner (through which the rope is clipped) float on the "triangle" of webbing between the two clove hitches. Excuse the split infinitive. Quote
Dr_Flash_Amazing Posted January 21, 2003 Author Posted January 21, 2003 But isn't that only going to load the bottom piece then? Quote
chucK Posted January 21, 2003 Posted January 21, 2003 When you place a directional at the bottom of a route so your pieces don't rip from the bottom in the event of air time, do you place it for outward pull or upward pull? Or does it depend? Any conventional wisdom on this? Just figure how the rope is going to run from the belayer to the first piece to the next piece after that. If the rope makes a bend at the first piece then if someone falls above the rope will get straightened out. Figure how the first piece would get pulled should the rope straighten out at the bend. Set up the piece to handle both the possibility of a fall directly on that piece (downward) and the possibility of the rope getting pulled straight. Usuall this pull is a little bit upward and a little bit outward. Depends on the geometry of the specific situation. By the way, this rule doesn't just apply to the first piece, it applies to every piece that is going to cause a bend in the run of the rope. Try to make sure the piece will not get pulled out by the rope getting pulled into a straight line. I'm not sure why people think of this as a rule for the first piece only. Maybe it's because so many people would rather belay from a comfy spot than a spot that makes sense in terms of holding a fall. If there's not a bolt for the first piece, it's usually easier for the belayer to move to a spot such that the rope will run straight through the piece, than to spend a bunch of time dicking around for a perfect multidirectional setup (and then waiting for the second to dick around taking down the multidirectional setup). Bill's method is sound and I have used it, but I avoid it because it's such a pain in the . I only use that set up if I have to. Quote
Greg_W Posted January 21, 2003 Posted January 21, 2003 But isn't that only going to load the bottom piece then? No, basically Bill opposed the two pieces against each other. Quote
catbirdseat Posted January 21, 2003 Posted January 21, 2003 Certain cam placements have omni-directional cababilities in that cams can rotate to a certain extent and (nowadays) have flexible stems. If the line up the route is pretty straight (ie. the rope doesn't take a bend at the first piece), then a simple cam placement is probably adequate and as Chuck said, much faster. If, on the other hand, say you are at Vantage, and you want to belay well away from the base of the cliff so as not to have rocks fall on your head. Then, an omni directional anchor makes more sense. That is an anchor set with two pieces in opposition. Omnis are much more important when all your subsequent pieces are chocks, as opposed to cams. Chocks are more directional and more likely to unzip if the load is outward, as opposed to downward. Quote
Dru Posted January 21, 2003 Posted January 21, 2003 But isn't that only going to load the bottom piece then? No, basically Bill opposed the two pieces against each other. Isnt this kind of an American Death Triangle??? I need a picture... Quote
willstrickland Posted January 21, 2003 Posted January 21, 2003 I think this is so situation dependent that there is no real answer. If the belayer is a good ways from the wall, or the first piece is placed way off the deck...there's gonna be a lot of outward force. Think about it: the rope goes taut, effectively appplying the same force on both sides of the piece. However, the force is applied at an angle on both sides - between the bottom piece and the next piece on the top side, and between the bottom piece and the belayer on the bottom end. Remember vector components of force? A force at any direction in a plane can be translated to two perpendicular equivalent forces. An example: A 200lbf force fall (rope tension) is applied at 45 degrees on the first piece (say it's a steep roof). This is like applying a vertical (upward)force of 200/square root of 2 and horizontal (outward) force of the same magnitude. If the belayer is standing in a direct vertical line below the first piece and catches the climber, he is providing a vertical counter force of 200lbf / sq rt 2. Only in this case, the force is applied vertically so all the horizontal (outward) counterforce will have to be supplied by the piece itself. The relationship between the first and second piece will have a big influence on the direction of pull on the bottom piece. I've ripped the bottom piece before, and once the bottom two pieces, but there's always a cam or something else in the string of placements. Besides, the only time you have to worry about zippering pieces out is if the top piece is not solid. If you fall and the pieces go popping out, it's not likely that the piece you fell onto will come out since - your weight just hit it to keep it in place. It seems like passive pieces are usually the ones that zipper upwards. On multi-pitch stuff, you can sometimes just clip through the belay anhor as a first piece although rope drag will be hell if the pitch is not straight up. Having the belayer stand close to the wall will help alot, probably more than anything else you do. My $0.02 Quote
Greg_W Posted January 21, 2003 Posted January 21, 2003 But isn't that only going to load the bottom piece then? No, basically Bill opposed the two pieces against each other. Isnt this kind of an American Death Triangle??? I need a picture... I didn't read it as such, but I can't draw a picture of it. Quote
arlen Posted January 21, 2003 Posted January 21, 2003 Doesn't John Long suggest running a sling from the top (downward pull) piece's biner, wrapping it around the spine of the bottom (outward pull) piece's biner a couple times and clipping? Quote
Greg_W Posted January 21, 2003 Posted January 21, 2003 I believe so, Arlen. However, Bill has added a step to insure that the two pieces stay opposed without having to constantly weight them (as Long's setup would). Quote
Necronomicon Posted January 21, 2003 Posted January 21, 2003 In a fall, the rope wants to make a staight line between the top piece of pro and the belayer, so without a directional at the bottom, the pro can pull out from the bottom up. Arrange the directional in such a way that it can compensate for the distance the belayer is from the base of the climb by increasing the angle upward, as well as the length of the sling. Quote
plexus Posted January 21, 2003 Posted January 21, 2003 You can equalize the two pieces with a sliding knot, if they are not that far apart... Quote
Greg_W Posted January 21, 2003 Posted January 21, 2003 "Equalizing" and "opposing" are different Plexus. Quote
Bill_Simpkins Posted January 21, 2003 Posted January 21, 2003 ...In response to the method weighting the bottom 2:1... Actually its 1:1.5. Because the tension is halved between the pieces from the clove hitch on the bottom piece. Very good point though, and the bottom piece should be solid. However, doing the triangle could put an incredible amount force on both the pieces in the direction toward you. You would have to have the tension between the pieces EXTREMELY taught with the clove hitches to counter this or have pro that isn't so dependent on direction. The method I outlined also puts an outward force on the BOTTOM anchor , but not as much on the top anchor . The amount of outward force on the anchors in both cases depends on where you are standing. Also in the triangle method the caribiner is sliding around on that webbing under force. There would be lot's of movement. The rope and/or biner could possibly jam up in the upper biner and/or pro, does that sound reasonable? Has this ever been a problem, or am I thinking too much? The triangle way may be better for some situations though. I will do some tests at the physics lab, and simulate this on the computers there. I will measure the forces and angles on both to figure this out. Nice thread DFA! Come up to the Bham pub club! Quote
catbirdseat Posted January 21, 2003 Posted January 21, 2003 ...In response to the method weighting the bottom 2:1... Actually its 1:1.5. Because the tension is halved between the pieces from the clove hitch on the bottom piece. Very good point though, and the bottom piece should be solid. However, doing the triangle could put an incredible amount force on both the pieces in the direction toward you. You would have to have the tension between the pieces EXTREMELY taught with the clove hitches to counter this or have pro that isn't so dependent on direction. The method I outlined also puts an outward force on the BOTTOM anchor , but not as much on the top anchor . The amount of outward force on the anchors in both cases depends on where you are standing. Also in the triangle method the caribiner is sliding around on that webbing under force. There would be lot's of movement. The rope and/or biner could possibly jam up in the upper biner and/or pro, does that sound reasonable? Has this ever been a problem, or am I thinking too much? The triangle way may be better for some situations though. I will do some tests at the physics lab, and simulate this on the computers there. I will measure the forces and angles on both to figure this out. Nice thread DFA! Come up to the Bham pub club! We've established to everyone's satisfaction that the triangle is not an American Triangle because of the two clove hitches. The force applied to the anchors will depend on 1) the tension in the rope, 2) the angle the rope makes as it passes the free biner, and 3) the angle in the triangle between the slings. Get out your trig calculator. If you don't like the biner floating around loose on the triangle, you can just tie a knot to keep it where you want it. By the time you have tied two clove hitches and and overhand or figure eight knot in this sling, it would have to be a double runner to be long enough. You want the angle between the legs of the triangle to be small (<60 degrees), otherwise you amplify the load on your two pieces of pro. Quote
plexus Posted January 22, 2003 Posted January 22, 2003 "Equalizing" and "opposing" are different Plexus. Opps!! My bad...forgot the setup we were talking about. This is where graphics come in better....that or ADHD is really bad for me. Anyways, I agree with GregW's setup...that is usually what I do...If I'm at the base of a climb and I have one bomber piece in, usually I'll just clip into that and have it for both upward and outward pull. Maybe it's risky but that is usually how I do it. Quote
obsydian Posted January 22, 2003 Posted January 22, 2003 Maybe it's risky but that is usually how I do it. What? This attitude leads to accidents. Quote
Greg_W Posted January 22, 2003 Posted January 22, 2003 Maybe it's risky but that is usually how I do it. What? This attitude leads to accidents. Many things are risky, but the risk is acceptable at the time. All risk in climbing is relative to how much you can handle and the conditions you are in. 40' runouts are risky, but I'll do it on easy ground. Quote
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