Quick question - SRT sans RW/HH in the interim

Well I figured I had the most to learn for this discussion so today I did a little set up.
Put a climbing line SRT using both ends attached to canopy anchors. This way I'm using the same rope. Little rain today, temp about 40 but not enough to get the rope wet.
On one line I set up my Uniscender to keep me safe, on the other I weighted it with a couple hundred pounds from my lawn mower. Tried to estimate about 200 to 300 pounds on the line.
Tried both the SK-1 and SK-2. With the weight of the mower applied to the line I could completely release the friction hitch and would not descend. It would either freely drop or as soon as a little of my weight was put on it, it would not move. I could completely hang from the hitch and release the RW or completely hang from the RW and release the hitch, nothing in between and no controlled descent either way.
Same with both versions of the RW. Once I released the weight of the mower, both functioned normally.
I have some video with my new helmet cam but I am not very good at using it yet and bumped the camera getting mostly vid of my feet. I will see what I can put together from it and post it later.
I do not own a HH but I can't imagine it not working. Seems that it would be totally unaffected by weight below as there is no change of the line weighted or unweighted.
Did not try descending WITH the mower...
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Has everyone forgotten about the Unicender?
It solves SRT ascent/descent simply and self-contained.


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And yes, it was the Unicender keeping me from getting broken today. Love it.
 
Very interesting and surprising that the wrench should bind enough to hold your entire weight. Perhaps a rope wrench with a freewheeling sheave at both friction points would work in this situation
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Very interesting and surprising that the wrench should bind enough to hold your entire weight. Perhaps a rope wrench with a freewheeling sheave at both friction points would work in this situation

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Nice looking sheaves on that RW. I suspect they lessen the wear considerably. After doing this little test, my feeling is that it still would not allow a person to descend. The friction seems to come from not only sliding across the rope but from compressing the strands as the wrench passes over them. Now put those sheaves on a steel cable and you would probably have quite a roller coaster ride. I could tell no deference between ZR- and ZR-2.
I can see how the HH would not be affected by weight on the line. Same thing for that Tenex Finger trap I made the other day.

Here is my video of the fun. RW on a taut line.

edit: lesson to lessen........I hate spelling, if I would have learned that lesson, it would lessen the errors I make.!
 
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http://www.youtube.com/watch?v=NBEfd00VqsI

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Great information.

Would I be correct in saying it this way as well.

That total weight column also represents the weight of the climber.

The combined downward force of friction, measured in pounds, shared between the RW and the hitch must be equal to the weight of the climber to keep from descending.

then from you data it can also be said........
a 204 pound climber will exert 136 pounds of friction on the wrench and must reduce the friction provided by the hitch to under 68 pounds to descend.
a 175 pound climber will exert 125 pounds of friction on the wrench and must reduce the friction provided by the hitch to under 50 pounds to descend.
a 104 pound climber will exert 79 pounds of friction on the wrench and must reduce the friction provided by the hitch to under 25 pounds to descend.
ETC..........
So, a 400 pound climber or two climbers, one on the wrench and one on the same rope below, will exert 268 pounds of friction on the wrench and must reduce the friction provided by the hitch to under 132 pounds to descend. In other words they would have to be able to break loose 132 pounds of force that is being applied to the hitch to hold them up.

No wonder I could not get the wrench to move and even if I did, I would then have to get the hitch to let up on the 132 pounds it is holding.

Sorry to continue to de-rail this topic as it was long ago established you can ascend a hitch, I just find this stuff very exciting.
 
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