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Knot testing with Fiddlestick

Discussion in 'Tech Tips and Gear' started by Mountaineer, Aug 9, 2013.

  1. Mountaineer

    Mountaineer Is that an X slot?

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    I finally moved away from my old PVC stick, and built a similar design to the Smooth Operator (aka Fiddlestick). Now to test it out and try some knots. For each test, I climbed up and down the rope and put 2 people on it. Then pulled the stick out. I did this 3 times for each knot. No gauge used.

    How hard was it to pull out? What kind of twists left in the rope on release? And, how easy could it fall out prematurely?

    First knot: a stone knot derivative. I tied a stone, then added a twist before setting it. This was the easiest to release. It also set the stick at a ~45 degree angle due to the nature of the knot. This setup seemed the most risky for a premature release.

    Second knot: stone knot. This took some effort to start the pull, but then released very quickly and popped out. There is also a trick when tying this knot so you are left with no twists after release for a clean pull.

    Third knot: constrictor knot. This was really hard to pull. This knot really cranks down! But I was eventually able to get it out (but pulling with no corners, or other obstacles).

    And that "Smooth operator" song by Sade seemed to hum in my head during all these tests.



    IMAG0381.
    hank moon likes this.
  2. Bootboy

    Bootboy Atwood Gear

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    Pics of all your setups?

    That also looks like a dynamic nylon rope.

    With all of the knots, my experience is that if the pull side of your stick is the side that is pointed up (you mentioned the stone rotating the stick) the pull is actually easier. The lever action of pulling the "up" end of the stick down actually opens the knot up and loosens it as it comes inline with the pull force. This is especially true with the constrictor.
  3. hank moon

    hank moon lovely ligatures

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    what'r U? some kinda Yuro canyons guy? Here in American, we can make our statics any color we want. That's why my buddy died face down in the MUCK - to protect your right to rap on rainbow-y static ropes.

    Hey Mountaineer - did you measure any of those pull loads? Thanks for doing and sharing backyard test results!
  4. Mountaineer

    Mountaineer Is that an X slot?

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    I used a Sterling Static Rope (white) for my tests. The rope pictured here is a practice rope, short length but looks better for pics through the clear poly. :)

    I like the lever arm idea, may make a difference with the constrictor! I tied a modified stone to get the angle result. I'll give it a try.

    I have a rudimentary force gauge, used for weighing luggage. Ha. Might give some approximate results, but a more accurate device would be best. Hmmm.

    I'll take some pics and post.
    hank moon likes this.
  5. Bootboy

    Bootboy Atwood Gear

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    Well, I think it's a reasonable inference about the rope being nylon. When I weigh the evidence; two end carrier construction, color, and pattern, are all more typical in the construction of climbing ropes than in canyoneering ropes, at least the ones that are commonly used by CP canyoneers. In fact, if I had to venture a guess Id say it looks like a petzl nomad 9.8.
    hank moon likes this.
  6. hank moon

    hank moon lovely ligatures

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    Me n' Charly Oliver played around today with a clove for the fiddle hitch (just backyard). Noted that it's very easy to pull when unloaded, very pull-resistant when loaded. Has anyone else played the clove fiddle?
    Mountaineer likes this.
  7. hank moon

    hank moon lovely ligatures

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    how accurate is your device? have you tested it? might do that with a gallon of water or other relatively known quantity...
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  8. Mountaineer

    Mountaineer Is that an X slot?

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    I got a little less than 9 lbs with my gauge device and a new gallon of milk. Not bad.

    I tested each knot 6 times with a Sterling Rit 500 rope. This rope has a 6.1% elognation under 10% of MBS, which is 5486 lbs. I may test again with a Canyon Fire or similar. Smoothing the edges of the "stick", roughening it up, changing dimensions, etc. should also make a difference in the results.

    I tested 3 times with a cinched down knot, 3 times loosely tied. Each test I weighted the rope in a similar fashion, then put the gauge on and pulled. Maximum pull strength was recorded before it popped out. Averaged the results, although each test was reasonably consistent with the Stone being the most consistent every time.

    Stone Knot
    • Loose tie: 25 lbs
    • Tight tie: 50 lbs
    Stone Knot with a twist
    • Loose tie: 11 lbs
    • Tight tie: 70 lbs
    Constrictor
    • Loose tie: 18 lbs
    • Tight tie: 70 lbs
    Clove Hitch
    • Loose/Tight (no difference): 85 lbs +, sometimes couldn't pull this out!!
    How tightly you tie the knot makes a huge difference.
    Constrictor. Stone. twist stone.
  9. hank moon

    hank moon lovely ligatures

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    Hi Mountaineer

    Does this mean that the rope was weighted when the stick was pulled out?
  10. Mountaineer

    Mountaineer Is that an X slot?

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    Rope was tied for each test either

    a) completed knot

    or

    b) completed but then really tightened/cinched down prior to the rap.


    Then, rope was weighted on rappel.


    Finally, fiddlestick was pulled (with gauge) with no weight on the rap strand.
  11. hank moon

    hank moon lovely ligatures

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    ok, thanks for the clarification...interesting...in my (brief, unmeasured) clove fiddling, I found that the stick pulled very easily after rap-loading the rope, but was difficult with the load on the rap rope. Will need to do some measuring...eventually. :)
  12. Mountaineer

    Mountaineer Is that an X slot?

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    Interesting. Good to know.

    Many times I couldn't pull a clove free when not weighted! May be useful to test and compare with different rope and fiddlestick types.
  13. Bootboy

    Bootboy Atwood Gear

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    A clove hitch will behave differently depending on which side of the stick you pull. Pulled in one direction, the component half hitches will twist and tighten on themselves. Pulled the other, it actually open them up and loosens them. I'm not sure how big a difference it makes, but the same principle applies to varying degrees with other fiddle stick knots.
    Mountaineer likes this.
  14. Deagol

    Deagol too many hobbies

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    We tested a Smooth Operator and a Fiddlestick without gauges in the garage yesterday. The Smooth Operator built by Luke's dimensions is a lot beefier than the Fiddlestick.
    At first I thought the Fiddlestick was harder to pull (based on perception only), but after additional testing, I'm not sure.
    With both devices we used the stone knot with a twist (per Luke's video) to ensure the rope would not cross over itself when the device was pulled. Both tests involved weighting the rap rope with body weight and trying to pull it, then removing body weight and pulling it.
    I have 2 of the "new" Smooth Operator design that has longer holes in each end that allows the safety biner and the pull cord to be attached at the same time. I like the idea of having the pull cord deployed prior to LAPAR while the safety biners are still in place and allowing the knot to tighten down on the device without being adjusted to remove a biner from the knot itself (ala a regular stone knot used to fix strands of rope).

    Has anyone compared the pull forces between these two devices (Fiddlestick & Smooth Operator) and noticed a difference?
  15. Mountaineer

    Mountaineer Is that an X slot?

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    Sweet. Would be fantastic if you could find/borrow a gauge and compare your results to mine and others.
  16. Deagol

    Deagol too many hobbies

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    Yeah, that would be nice.
    What I really want to do is get in the field and start testing these devices.

    Slightly off-topic: I think I am really going to like the smooth operator better than other anchor devices due to ease of use and safety. The Buckle has been my "go to" retrievable anchor in the past, but I think the Smooth Operator will take over that roll. I still may use the Buckle in certain specific situations, but only where rope abrasion and "rolling" are an issue.
    Mountaineer likes this.
  17. Mountaineer

    Mountaineer Is that an X slot?

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    Bump. Post any tests/results you may have. How close are they to my tests/loads?
  18. Deagol

    Deagol too many hobbies

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    I tied the overhand Stone Knot with a twist on a Smooth Operator,
    I then added my body weight (160 pounds approx) to the system just to cinch it, then removed all weight from the rap strand and started adding weights to the pull cord hole.

    First added 5 pounds: absolutely no slip
    then 10 pounds: absolutely no slip
    then 12.5 pounds: absolutely no slip
    then 15 pounds: it held for a few seconds, then pulled..


    (a 10 pound weight and a 2.5 pound weight in the pic below)
    [​IMG]
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  19. Mountaineer

    Mountaineer Is that an X slot?

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    Did you cinch the knot before weighting it?
  20. Deagol

    Deagol too many hobbies

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    Yup, I always do that....
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