iain Posted October 27, 2003 Share Posted October 27, 2003 scott_harpell said:thta prolly has to do with the high loads there prolly eh cheif? not the brightest crayon in teh box now are we? no, because it's easier to untie. Relative knot strength is irrelevant, as has been stated ad nauseum here. Were you referring to him as "chef" or "chief"? Quote Link to comment Share on other sites More sharing options...
Dru Posted October 27, 2003 Share Posted October 27, 2003 the snaffle goes around the tree and thru the hole iain you fool! you didn't even snaffle! Quote Link to comment Share on other sites More sharing options...
catbirdseat Posted October 27, 2003 Share Posted October 27, 2003 RuMR said: AlpineK said: Yosemite Bowline This knot was sent to me by Bonnie Crystal. This is a variant of the basic bowline which gets around the problem of the knot loosening itself by taking the end of the rope and threading it back through the knot. This is a neat alternative to using a half-hitch to secure the end of the rope and the resulting knot has the strength of a figure of eight. source Only knot to use!!! Great pic! Nice diagram. You will notice that the last turns of the knot make a figure eight. So the bowline with Yos finish is a compound knot. Cool. Quote Link to comment Share on other sites More sharing options...
Dru Posted October 27, 2003 Share Posted October 27, 2003 nice troll cbs... tie a real figure 8 and compare it to the yobo minus the bowline loop... knot the same knot . Quote Link to comment Share on other sites More sharing options...
Thinker Posted October 27, 2003 Share Posted October 27, 2003 Here's some info on hitches and knots I was forwarded via email over a year ago. The same info may be on Paul's website, I don't have time to check: We did not really have any clove hitch data on file here so I conducted a quick test with the following results: All tests involved a bight knot (i.e. Figure 8 or Bowline) being used to attach one end of the rope to the moving crosshead of our universal testing machine and the other end of the rope being attached to the stationary base of our testing machine via a dressed down Clove Hitch on a Carabiner. The load rate was 200 mm/min (~8 in/min). Test #1: Knot: Bowline Rope: 10.5mm Std Biner: Oval Result: Rope Broke at Bowline @ 3378 lbs (Note: Figure 8 was used for the rest of the tests) Test # 2,3: Knot: Figure 8 Rope: 10.5mm Std Biner: Oval Result: Rope Broke at Clove Hitch @ 3236 & 2876 lbs Test # 4,5: Knot: Figure 8 Rope: 8.1mm Dry Half Rope Biner: Oval Result: Rope Broke at Clove Hitch @ 2034 & 1873 lbs Test # 6,7: Knot: Figure 8 Rope: 10.5mm Std Biner: Light D Result: Rope Broke at Clove Hitch @ 3142 & 3208 lbs Test # 8,9: Knot: Figure 8 Rope: 8.1mm Dry Half Rope Biner: Light D Result: Rope Broke at Clove Hitch @ 1918 & 1909 lbs Conclusions: There does not seem to be any significant difference between using a Oval and a Light D with a Clove Hitch. None of the Clove Hitches slipped at all (I don't know what would happen if the ropes were soaked). No only do Ovals and Light D's have difference geometries but they also are made from significantly different rod stocks; the Oval stock is quite a bit bigger than the Light D. You may be curious why these loads are much less than the strength of our Runners (22 kN / 4946 lbs) or a hand sized Camalot (16 kN / 3597 lbs). There are several reasons for this. First, during a lead fall the top anchor "feels" almost twice the tension in the rope. This is due to the climber generating force on one side of the lead piece and the belayer resisting this force by pulling on the other side of the piece. The second reason is that the ultimate strength of a climbing rope is not nearly as important as it ability to absorb energy. More energy it can absorb, the smaller the peak forces generated during the fall. BD ropes are well below (by at least 30%) the CEN criteria for maximum impact force during a test fall. Climbing ropes are amazing in their ability to absorb energy, I have never heard of a case where one has "broken" during a fall (it is possible to cut a rope as I am sure you know). I hope this answers your Clove Hitch question. Sorry to go on the tangent but whenever I supply real data to a customer I try to help convey the conclusions that can be drawn from it. Paul Tusting, ME Black Diamond Quality Assurance Engineer Quote Link to comment Share on other sites More sharing options...
Thinker Posted October 28, 2003 Share Posted October 28, 2003 Damn....sorry for killing this thread by posting pertinent information.... Quote Link to comment Share on other sites More sharing options...
lummox Posted October 28, 2003 Share Posted October 28, 2003 Thinker said: Damn....sorry for killing this thread by posting pertinent information.... what is pertinent about posting information of a poorly designed set of tests? whynt you tie the clove hitch around a larger diameter anchor? whynt you perform the tests in triplicate to get a handle on error with a standard deviation calculation? Quote Link to comment Share on other sites More sharing options...
mattp Posted October 28, 2003 Share Posted October 28, 2003 Why would testing a clove hitch around a large diameter anchor be of any relevance? We use clove hitches on carabiners, don't we? That was one thing about Kurt's reference to "testing" the clove hitch that I didn't quite think was directly applicable -- he "tests" it on tree limbs that are much larger in diameter than a carabiner and have a textured and comparably soft surface, and he probably uses a static rope that has handling characteristics that differ from a climbing rope and this may affect the way the hitch grabs the tree limb. Quote Link to comment Share on other sites More sharing options...
lummox Posted October 28, 2003 Share Posted October 28, 2003 mattp said: Why would testing a clove hitch around a large diameter anchor be of any relevance? We use clove hitches on carabiners, don't we? That was one thing about Kurt's reference to "testing" the clove hitch that I didn't quite think was directly applicable -- he "tests" it on tree limbs that are much larger in diameter than a carabiner and have a textured and comparably soft surface, and he probably uses a static rope that has handling characteristics that differ from a climbing rope and this may affect the way the hitch grabs the tree limb. the point of the test seemed to be to find the breaking strength of the figure eight and the bowline. instead they tested the strength of a clovehitch around a 10mm carabiner with various rope diameters (but didnt do enough to yield a standard deviation). a larger diameter anchor for the clove hitch would result in a higher tensile strength breaking point since the bight is of larger radius. Quote Link to comment Share on other sites More sharing options...
catbirdseat Posted October 28, 2003 Share Posted October 28, 2003 The test violates the Rule of One, which states that only one variable be tested at a time. Sounded to me as though there were always two knots in the test, so one would have to break before the other. Quote Link to comment Share on other sites More sharing options...
Thinker Posted October 28, 2003 Share Posted October 28, 2003 The 'point of the test' was to test possible differences in the strength of a clove hitch when used on oval biners vs D-shaped biners. Granted, there weren't enough trials performed to obtain statistically 'confident' data, but in my opinion it's more precise than a few sentences about clove hitches on logs without any quantitative data. I glean this from the results: Clove hitches probably won't 'slip' before the rope breaks in any situation I use them for. Clove hitches don't appear to slip at the 1,000 pounds cited in previous literature. CBS, how would YOU have attached the rope to the pulling mechanism without using a knot? Quote Link to comment Share on other sites More sharing options...
catbirdseat Posted October 28, 2003 Share Posted October 28, 2003 Use a "no-knot" hitch. You wrap the rope around a large diameter (>>10 the rope diameter) bollard at least four times. Quote Link to comment Share on other sites More sharing options...
lummox Posted October 28, 2003 Share Posted October 28, 2003 Thinker said: The 'point of the test' was to test possible differences in the strength of a clove hitch when used on oval biners vs D-shaped biners. Granted, there weren't enough trials performed to obtain statistically 'confident' data, but in my opinion it's more precise than a few sentences about clove hitches on logs without any quantitative data. oh. nevermind. Quote Link to comment Share on other sites More sharing options...
Thinker Posted October 28, 2003 Share Posted October 28, 2003 (edited) catbirdseat said: Use a "no-knot" hitch. You wrap the rope around a large diameter (>>10 the rope diameter) bollard at least four times. THAT doesn't sound like any fun..... In any case, it seems like a reasonable followup test might be to test the difference in strength between the fig8 on a bight and the bowline on a bight. I suspect there's already loads of data on that and BD was confident that the fig8 would stand up to the torture...which it did in every case. edit: it's also interesting to note that when the bowline was used, the rope broke at the highest tension in the complete set of trials. Certainly not related and not significant, but still an interesting side note. Edited October 28, 2003 by Thinker Quote Link to comment Share on other sites More sharing options...
AlpineK Posted October 29, 2003 Share Posted October 29, 2003 mattp said: Why would testing a clove hitch around a large diameter anchor be of any relevance? We use clove hitches on carabiners, don't we? That was one thing about Kurt's reference to "testing" the clove hitch that I didn't quite think was directly applicable -- he "tests" it on tree limbs that are much larger in diameter than a carabiner and have a textured and comparably soft surface, and he probably uses a static rope that has handling characteristics that differ from a climbing rope and this may affect the way the hitch grabs the tree limb. The diameter of what you're tying the knot around may have some relevance. The ropes I use for tree climbing are more static than a rock climbing rope, but not static, and thus will generate more force on the knot you tie due to the lack of energy dissipation. Quote Link to comment Share on other sites More sharing options...
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