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johnhenry
Apr 14, 2004, 12:11 AM
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I have sung the praises of the Ushba Basic in a number of threads and have used it in many different applications. Thus, I was somewhat sickend when I came across these technical reports which showed that it severed the rope in tests as a fall arrester.
First, it is discussed in this excellent article on top rope soloing:
http://www.thebikezone.org.uk/therockzone/selfbelay.html
Second, you can read the technical report on the actual tests:
http://www.ropesafety.com/site/technique/lyon_report.htm
If you read the above report I think that you will forgo using the device for top-rope soloing. Ascending? Well I also shudder to think what might happen if a piece of pro should pull while cleaning and statically drop you on the device.
Anyhow, thought I should pass along the word.
Climb Safe,
john
P.S. If you like this style device then it seems that the Yates Rocker is the way to go.
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squish
Apr 14, 2004, 1:03 AM
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It's been discussed before.
From the article:
In reply to: Dynamic performance (section 4.2.5 prEN 12841 May 2000) Peak impact force and slippage with a fall factor 2 drop with a 100 kg mass. The tests were carried out using the 'catch plate' rig at Petzl. See section 14.4.5, in the Appendix, for details. Perhaps the most relevant test, this test investigates the energy absorbing abilities of the devices in a worst-case scenario: a fall factor 2 with an inelastic lanyard. 100 kg represents the likely upper mass limit of an operative plus equipment. A large operative might also be tall and therefore require long cow’s tails. The total lanyard length was therefore simulated as being one metre including connectors: giving a factor 2 fall of 2 metres. A catch plate method was used for these tests. This eliminates an actual lanyard from having to be used and results in more consistent results. The dynamic tests were performed on four different ropes: Beal ‘Antipodes’ 10.5 mm low stretch, Edelrid 10.5 mm low-stretch, Marlow 10.5 mm low-stretch and Beal ‘Apollo’ 11 mm dynamic. Three replications were carried out on each rope type, giving twelve tests on each device.
Basically, they're talking about a 100kg factor 2 fall on a 1 metre-long static lanyard. Their use of the Ushba is as a backup device in industrial safety, and this is not how you would attach yourself to the device when rope soloing. In our case, we use it as a primary attachment close to the body and these kinds of forces are not generated in normal rope solo use.
I don't really understand the test setup, however. It sounds like they're effectively testing a 1m daisy fall, but they don't mention how much rope is in the system. If it's truly a factor 2 test (2m fall on a 1m lanyard), then there would be zero rope out, and that doesn't make any sense.
Furthermore:
In reply to: Given that this type of ascender is designed to grip the rope without slippage, the only way that the energy of the fall can be absorbed is by the stretch of the rope and sliding of the sheath down the core if, or when, it is severed. It is, therefore, as much a test of the rope
used as of the device itself. All devices of this type will cut the sheath in an impact of this severity. The fall is only arrested when the sheath bunches and grips the core, usually after about a metre of slippage. |
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johnhenry
Apr 14, 2004, 5:20 AM
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Hmmmm. I see your point.
If the device itself does't have a dynamic action, then it would be difficult to pass the test. I am still wading through the information.
I have loved my little Titanium beauty,,, 8)
I am going check into this some more. Thanks.
john
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gunkiemike
Apr 14, 2004, 5:23 PM
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I read this as Petzl - maker of the Basic Ascender, which is widely used, and designed, for TR self belay) taking a shot at the Ushba Basic, which is the 2nd most popular device for this (based on what I've heard & read). Competitors discrediting other competitors' products is nothing new.
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tedc
Apr 14, 2004, 5:29 PM
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I think if your TR solo system allows for the possibility of generating fall forces of 4KN you should forgo TR soloing.
Don't be such an alarmist.
Fascinating article though. Thanks
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robmcc
Apr 14, 2004, 5:48 PM
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In reply to: I think if your TR solo system allows for the possibility of generating fall forces of 4KN you should forgo TR soloing.
I dunno. Mine probably did. I guess I'd have to reply that if you can't construct a system which can withstand 4kN, you should also forgo TR soloing. :D
Rob
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d.ben
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Apr 14, 2004, 6:50 PM
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I use a Petzl basic for TR soloing. I saw this article too. At first it worried me, but after using it about ten times I'm having a hard time seeing how I could fall more than two feet with the thing attached to my harness and chest. It's always at my height. Unless somehow I carelessly let several feet of slack build up in my system. I am new to TR soloing though. Does anyone see a way I could generate such a high factor fall in this situation.
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tumbleweed
Jun 24, 2005, 6:42 PM
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I read the articles referred to here several weeks ago, and agonized over having to give up my new-found love of TR soloing... But soon realized after reading the specifics of the testing methods that I needn't worry. Here's why. When climbing ANYTHING with ANY TYPE GEAR under ANY METHOD (sport/trad leading, TR belaying, TR soloing etc) you MUST be considerate of the loads you will put on EACH PIECE of your gear at ANY POINT in your system. You want to limit your fall distance as much as possible to prevent undue stress on your protection/gear/body. This applies to the above mentioned testing, as the testers eluded to.
I've seen several people (on ice and rock) attach their USHBA to a locker, and the locker to their belay loop. As they climb, the device slides along the rope but hangs below their crotch, close to mid-thigh level, because the locker dangles from the bottom of the belay loop, and the Ushba dangles below the locker. When they fall, the USHBA does not move on the rope, but in order to catch the fall, 4 things happen. 1) as you fall past the Ushba, the locker slides from the bottom of your belay loop to the top (about 6 inches by the time you consider a 4 inch belay loop plus harness expansion, etc), 2) the locker must reverse it's direction as it catches on the top of the belay loop (goes from hanging at the bottom of the belay loop to catching at the top and pointing up) (about 6 inches), 3) the Ushba must rotate to lock (again it doesn't move on the rope, but rotates on the rope) (rotation results in a loss of about 2 inches in my experience), and 4) the rope stretches, dependent on the amount out, percent of rope stretch (varies by manufacturer), and age of the rope. If a fall occurs, the body falls a MINIMUM of 14 inches.
Will this distance damage the Ushba / rope? I haven't seen it happen yet, even with a 180#-plus guy falling well OVER 14 inches before it caught him. But it is best to limit the fall factor if possible, and here is how I do it:
I use a zip-tie to secure the locker to the top of my belay loop. I clip the locker in, pull it straight up, and then wrap a zip tie horizontally around the belay loop just below the locker to keep it at the top of the belay loop. This accomplishes 2 things: 1) the locker doesn't have to slide up the belay loop before it catches me, because it is already held at the top, and 2) if it is snug enough, the locker never inverts. At worst, it lies horizontally toward the Ushba (instead of pointing down toward the Ushba). So I fall about 5 inches (minimum) (locker rotation from horizontal to pointing up, and 2 inches with rotation of the Ushba). That's 9 less inches for my falling body mass to build energy to transfer to the system. This minimizes the fall factor, thus minimizing damaging the device or rope.
So... we can't change rope stretch (#4) or the amount the Ushba rotates on the rope (#3), but we can affect #2 and #1.
As with any statistic, in order to use the results correctly, one must understand ALL of the aspects of the research methods utilized (and those not utilized) and know what the applications were intended for. Read the Lyon's report (link above) for yourself. The Ushba was not tested as an "ascender" but as a "backup device" (something to arrest a significant fall) Our fall of 14 inches (or much less, say 5 inches) compared to over 72 inches (Lyon's testing used a one meter lanyard with 220 pounds dropped on it (!) equals a 2 meter fall, over 6 feet!!!) which is a long way to fall on any device. And 3 out of 4 ropes used in testing were considered "low stretch", and only one dynamic. So does this British study, although very well executed, apply to TR soloing? Not in my mind, if rigged properly.
If you are new to TR soloing, or want to try it, talk to people that do it, and watch them. Additionally, there are at least 4 considerations as a TR soloer you must attend to:
1) besides assuring a sound redundant anchor system with no extensions, you must protect your rope at the top. If it runs over any edge that isn't perfectly round and smooth, protect it. Sometimes I use my truck floor mat.
2) you MUST weight the rope at the bottom with something to keep the rope below you from being pulled up as you climb. Some people duct tape a rock to a sling and clip this into a knot at the bottom of the climb. I use my rope bag with the rest of the rope secured inside, tied off about 2 1/2 ft above the ground.
3) always test your self belay device by weighting it before you begin climbing to assure it is oriented correctly and locks up.
4) climbing alone, there is no one to double check your setup, harness, etc. TRIPLE check your stuff, starting from one end and going to the other.
People ask me: How can you trust just one piece of gear? Well, we do it all the time belaying with one GriGri or ATC.
How can you trust just one carabiner? We do it all the time belaying with a GriGri or ATC.
I love it because I never have to worry about my belayer being inattentive... the Ushba is always right in front of me.
And actually, I am a social climber, it's just that sometimes my climbing partners can't go. Now they're annoyed with me for getting more climbing time in than they are!
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moondog
Jun 24, 2005, 9:08 PM
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johnhenry
Jun 24, 2005, 9:43 PM
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hey dudes,
Just a slight revision of my earlier views...
Recently, I have rope soloed dozens of toprope pitches. Most were less than 30m, so I tied the rope off in the center and used both the Ushba and a Petzl Mini-traxion, one on each strand, with the rope ends weighted with a water bottle. With the extra redundency and two devices with supurb feed, I felt even more confident that with a traditional belayer.
If I am pulling through a move at my limit, I simply bat the devices with the palm of my hand to cinch up tight.
On a crag with easily accesible anchors, you can log some serious milage.
Cheers,
john
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