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About Tumblemark

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  1. No more MioxPens, Dueling Life Straws!

    Giardiasis IS life threatening--to children or anyone with a compromised immune system--even though 20% of us have it in our guts. Household bleach will not effectively kill giardia cysts, nor will "chlorine;" that's why you can get it in a public pool or water park (eeuuww). Use Aquamira instead. But more on topic, wouldn't a SODIS disinfecting system be better than this straw thingie? It requires only used 2-liter PET bottles and sunlight; cheaper and more effective, seems to me.
  2. Use of one twin rope for sport climbing?

    Get one of the new Mammut Serenity ropes. It's about 52 g/m (8.9 mm) and rated as both a single and double. Even the Mammut Revelation is only 56 g/m (9.2 mm). (a typical half rope weight around 50 g/m) Falls will be a bit harder, but not enough that you'd actually notice. I've never heard anyone complain about the handling of a Mummut rope, just the price. Your friends might want to wait to buy until they're in Europe, but check availability in advance. If you're going to use a rope this thin, be sure your belay/rappel device is suitable for skinny ropes--like a Reversino or Mammut Matrix (soon to be discontinued).
  3. No more MioxPens, Dueling Life Straws!

    Not of interest to us, because its filters are too large and it uses iodine to kill bugs. From the review's website: "For those of you considering using LifeStraw™ for outdoor adventures in the continental United States, beware that the common "beaver fever" (Giardia lamblia infection) is caused by an organism with 5 micron spores, which are resistant to iodine." That sorta makes the whole thing questionable, since giardiasis is a common health problem in developing countries, too. And what's up with the Miox pens? There's been some skepticism expressed about its "mixed oxides." Is it only that its production of HClO makes for a chlorine taste, or is there something more sinister?
  4. how to learn to lead low grade class 5/4 rock?

    OK, here's a self-serving recommendation: check out The Mountaineering Handbook. Only $13 on Amazon or list price at your REI. Read the reviews at link . The book is focused on 4/5th class climbing, plus it has a lot of up-to-date info you won't find elsewhere. It talks about "Learning to Lead," which is different from "Leading." It also has sections on things like controlling fear and decision making--plus material on climbing forces and building anchors that most climbers will find very different from old school advice.
  5. nail polish to mark center of rope

    Nail polish was favored by Jerzy Kukuczka, for the obvious reason. But what about using ordinary fabric dye (á la Ritz)? The sheath fibers are already dyed, after all.
  6. Cliff Notes for Climbers

    Steve Roper "Fifty Crowded Climbs": These climbs are classic because I said so and because the pix are soooo cool. Find 'em if you can (this book won't help much). Some people have been lined up since 1981, but there's a dust-free spot on their coffee tables. I already climbed 'em so I don't care. Eat my chalk.
  7. A good bathroom read?

    OK, I'll bite. Your best starting point is The Mountaineering Handbook, McGraw-Hill 2005. $13 at Amazon, one of the places where it has been well-reviewed and compared favorably to Freedom of the Hills, Alpine Climbing, Extreme Alpinism, and even Climbing Anchors. John Long wrote that TMH is "384 pages of gold," so he must have liked the index too. Try http://www.amazon.com/exec/obidos/tg/det...ks&n=507846 In brief, FOH is much more old school and contains much unsafe or suboptimal advice. TMH is more modern in its thinking and technology, more practical, and has great illustrations. Most people find it's also more fun to read. TMH covers general mountaineering, so the sections on rock climbing are only a fraction of the content, but there's still a lot of in-depth info on modern tools (autoblock belay devices, thin ropes, etc) and 5th class techniques. There's good advice on learning to lead, climbing fast, dealing with fear, and other important topics not covered elsewhere. The sections on climbing forces and anchor building contain unique insights that will be new even to experienced climbers. Climbers like you are one of its 3 target audiences; well worth the price of admission.
  8. Belay Loop Issues

  9. Belay Loop Issues

    Dru, there ARE NO cases of belay biners being broken by belaying! If you can come up with a few examples with enough data to determine the actual cause of failure, please do so. (If you do, please start a new thread in the climbing forum. Hint: your cartoon biner isn't a belay biner.) The only reason to flog this deceased equine is that it's on a newbie forum and someone might come across it and actually believe what Dru has said. BTW: your skull is spinning in the wrong direction.
  10. Belay Loop Issues

    For an easy start on belay rope slip forces, see the Petzl web site. Or the "manual" that comes with some of their hardware. When you work through the physics it turns out that 2 kN is pretty smart, because it limits the max force on your last biner (that's the one you want not to fail) to a reasonable level--as catbirdseat is getting at. To repeat, Dru, belay biners NEVER break due to cross- or triaxial loading when using a conventional belay brake.
  11. Belay Loop Issues

    Err, here's a little detail that might have been overlooked in the paranoia about triaxial carabiner loading. The "load" will be limited by the peak force at which the belay rope slips through the belay device. That maximum force is about 2 kN, maybe as high as 3.5 kN for a Münter hitch belay. That's still half the cross-loaded spec for locking carabiners. In other words, Jason and Dru and anyone else who worries about this mode of carabiner failure, it is impossible to break a belay carabiner by applying a load through a belay device--even by a fall directly on the belay when the belayer is solidly tied off (well, you might come up with some convoluted scenario using a locked Gri-Gri or a biner over a hard edge, but that's OT) Any story to the contrary will have to explain how a sufficiently high force could be applied through a conventional belay device; finger trouble is a far, far more probable cause of failures. The belay loop on a harness may help avoid triaxial loading, but that only makes for smoother and less clumsy belaying, not prevention of hypothetical biner failure. So to Blake's question: what to do about a harness that has no belay loop? The optimum answers depend on whether you mean belaying a leader or belaying a second. If belaying the second, you should belay directly off the anchor (not through a redirect, not off your harness, any harness). There are many reasons to belay seconds directly off the anchor using a GiGi, B-52, Reverso, Matrix, Münter hitch, etc. The maximum force a second could deliberately put on a belay rope, without slack, is at most twice their weight; call it 2 kN. If belaying the leader, belay off your harness. I'd recommend creating a "belay loop" on your Alpine Bod by cinching a very short runner around the normal tie-in point (waist belt and legs loop). This will accomplish the main purpose of a belay loop: keeping the HMS biner and any fall load more or less lined up and centered on the harness where it's supposed to be. It also keeps the belay device away from clothing, hair, tie-in loop etc; this setup also works well for rappelling (especially with a self-belay). Slightly extending the HMS biner with a runner may make the belay device a little more floppy, but addressing that is a matter of rope handling technique (you wouldn't want a sloppy belay anyhow). Plenty of data (much more than just Leubben) show that side-loading a figure eight follow through (or whatever you want to call the loading that occurs to a tie-in loop made with a figure eight follow through if you clip a biner to it) can cause failure of the knot at body weight or even less. There is a lot of scatter in such data, but the message is clear: don't do it. (This is the main reason for not using a figure eight to join to rappel ropes.) I haven't seen convincing data saying that tucking the rope tail into the knot makes this worse, but that seems reasonable. I wouldn't bet that a backup knot fixes the problem either. Even if you use a Yosemite bowline tie-in knot, which is a better choice and doesn't have the side loading failure problem, it's probably still not a good idea to belay off your tie-in loop if other options are available. Sorry for the long answer. The best more thorough exposition I've found of the sense and science behind all this is a new book called The Mountaineering Handbook (see Amazon; cheap at $13).
  12. Sewn vs Tied Runners

    Yowie kazowie! I post once a year and what do I get? Outed as a dropout from wrecked.climbing! That's cold. Besides, if Dru remembers me from r.c, he's admitting to spending way too much time there hisself. But seriously, most of my favorite topics are thoroughly discussed in a new book "The Mountaineering Handbook" (McGraw-Hill; see Amazon). One issue to which this forum could contribute, and which is left unresolved by that book, is self-arrest with ski poles. Ski poles, or trekking poles, are becoming a favored tool of mountaineers, and rightly so. So the matter of self arrest with them is important and needs solid solutions. This was brought home to me last year when a friend was killed in a fall on not-so-steep terrain; he was using ski poles while his ax was on his pack. Apparently he didn't or couldn't self arrest. The moderator may want to move this post to a separate thread, but I'd be personally interested in the practical experience of this forum's members as to their recommendations on what to do when climbing with ski poles when self arrest becomes a crucial issue. How do you do it? What techniques do you recommend?
  13. Sewn vs Tied Runners

    Yo, Alpinfox! Wussup wid dis "show me your list" bidniss? Can't you see from my profile that I'm a lurker? Besides, it's totally OT. But in the spirit of good clean fun... I'm especially interested in (mainly in the contexts of mountaineering and ski mountaineering): >complex anchors and why SRENE is mostly bogus >performance nutrition >training for alpinism >pulley, rescue, and autoblock systems in the real world >fast and light climbing tools and techniques Elucidatin' enough fer ya? And how do y'all know it isn't Ms Tumblemark ;-)
  14. Sewn vs Tied Runners

    Sorry to add to the flogging of a thoroughly dead horse, but this is one of my favorite subjects (I have a list, just ask). Runners tied with beer knots (one strand inside the other in a simple overhand knot) are superior to water knots for a couple of reasons: they don't self-untie and they preserve about 80% of the runner strength compared to about 50% for water knots. Beer knots can be untied without too much trouble, easier than a double fisherman (which is what you'd use to re-tie an opened nylon runner). Water knots untie themselves when subject to repeated low loads (like body weight; think: rappelling). To tie a beer knot you need at least 10 inches of overlap with 1-inch webbing and at least 8 inches with 11/16th inch webbing. I can't imagine using beer knots with 9/16 webbing, due the pain of getting one strand inside the other; even 11/16 is questionably worth it--use double fisherman knots instead. I use a chop stick to finagle one strand inside the other. Even better, sew your own runners in nylon webbing. You can't do this with Spectra/Dyneema webbing or thread, but according to The Mountaineering Handbook, "if you can find the right thread (DB92 bonded polyester) and know how to pick the needle and set bobbin tension" you can sew you own runners on a beefy home machine. Home-sewn runners can be as strong as commercially sewn versions, as strong as the webbing itself. That won't be 22 kN for 9/16th inch webbing, but I'd challenge anyone to come up with a realistic climbing scenario where 22 kN would be approached. I admit to sewing my own, have for years, and I've tested the results. The only requirement is getting enough stitches, and that's a matter of dividing the strength of the webbing by the half the strength of the thread and adding a modest safety margin. You can make the sewn section stronger than the webbing itself just by sewing enough stitches. (Don't disagree unless you've actually done the testing.) Sewn runners (commercial or DIY) work because the webbing and threads distort enough so that the load is shared among all (except for Screamers, which are sewn differently). Why would you want to sew your own runners? To make cheap, light 48-inch runners (in 9/16 or 11/16 webbing, which are hard to find commercially) that are multipurpose (can be used to make Klemheist knots that hold on wet or snowy ropes where Spectra/Dyneema runners might not). Also, to make extra long runners on pro, potentially saving the addition of an extra runner and biner. (If the pro will hold 10 kN, the stitching only needs to hold half that, so pro runners don't have to be as strong as separate runners--in principal). To make runners that you can cut and re-tie around a natural feature; Spectra/Dyneema runners won't work because it does not reliably hold knots. Also, nylon webbing, unlike Spectra/Dyneema, does have some energy absorption, comparable to static climbing rope, so "equalized" anchors made with them might actually be closer to real equalization.
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