Albere,s Bonkers Spiderjack SRT thread

[Dan Curtis]

First off, great idea Albere:thumbup1:

 

I tried this when I got back today (at low level). The first one stopped the Lockjack sitting properly and didn't really work, not enough friction added by the pinto.

 

The second sits well, and does give correct function, but is a bit jerky. IMO due to there still not being enough friction added.

[Dan Curtis]

As was pondered earlier, how much friction/load does the pinto take? I tried a few basic tests to check it out.

 

The idea I tried was to set various things up, and see if with the friction they added to a single rope with my bodyweight on it, could the grip of one hand hold me in place? I.e. if my hand can hold it, the setup is taking a lot of my weight. I used brand new tachyon, though i find friction can be improved srt (and Ddrt) once the rope has a bit of wear, so allow for that with the following. Plus, as said earlier, the pinto/sj combo only worked on 13mm, which I don't currently own.

 

First off, a munter - no problem at all holding myself free hanging on the line. Same goes for a figure 8. Obviously.

 

Second the ropewrench on its own, no hitch etc. Yes it's possible to hold my weight with one hand and the rw. We all know it works, and theres plenty of evidence to prove it, so no bother there.

 

Third, the pinto as shown in the first post of this thread. You can just about hold on with a slow, hand burning descent, lots of effort and minor hand cramp though:biggrin:

 

So, judging by that, the pinto takes very little of your load, and adds very little friction to your system.

 

Carrying on, I tried to work out how the pinto could be used as a friction aid. Set up differently, I think it could.

 

Fourth test - Running the rope through the whole pinto, creating three points of contact; one on the becket, one on the sheave and one (small) on the top of the attachment krab. Again, slow, slithery descent and a warm hand, though a definite improvement on the previous method.

 

Five - Inverting the pinto, so the attachment point is at the top. Using the becket and side plates, it is possible to use the pinto to hold your weight, still using only the one hand, and perform a controlled descent, keeping my palm intact.

 

So the pinto can add enough friction to be used this way, but in picture 6, this is what happens when you try to ascend with the pinto inverted. Way too much friction, so much infact, I couldn't move at all, even using both feet with the pantin. Though you could cobble some RADS system and use it, IMO missing the point of SRT altogether.

 

I may be missing the point, and these tests are basically belay device tests, which the rope wrench is not, so could in fact be completely irrelevant:lol:

 

BTW, don't try this at home, I accept no responsibility for any accidents occuring from use of these tests:sneaky2:

Edited August 14, 2012 by Dan Curtis
Forgot a bit

[Joe Loggs]

Dan in the second pic did you try running the rope over the attachment krab so it puts a full u bend in?

[Ian Flatters]

Interesting, Dan. Would like to see albere idea done with a simple drop test like the RW i think it was 99kgs at a 4m fall and was still perfectly fine and dropped something like 6-10 inches max.

[Ian Flatters]

Found it easy [ame=http://www.youtube.com/watch?v=EQwESiTfjo0]rope wrench drop testing - YouTube[/ame] I guess this is the test its competing against.

[Dan Curtis]

Dan in the second pic did you try running the rope over the attachment krab so it puts a full u bend in?

 

As in how it is in the fourth pic?

[Joe Loggs]

Sorry dan I put that post up just before you added your tests so ignore it, well done mate, I did notice a big difference in friction from 11mm to 13mm

[Dan Curtis]

Found it easy

I guess this is the test its competing against.

 

I tried it with a hitch in various set ups too. From what I've done,I can't see it coming anywhere near the wrench. Just need to lay my hands on a spiderjack to try it now.

[Ian Flatters]

I tried it with a hitch in various set ups too. From what I've done,I can't see it coming anywhere near the wrench. Just need to lay my hands on a spiderjack to try it now.

 

I'll bring my SJ on Saturday.

[Dan Curtis]

Sorry dan I put that post up just before you added your tests so ignore it, well done mate, I did notice a big difference in friction from 11mm to 13mm

 

I do think that if the gap between the becket and sheave was smaller, or perhaps the becket was offset to the far side that the rope travels, you might get a better bend in the rope, and more friction.

 

That said, I have my wrench fully open on tachyon, and use the pip pin, which is a bit smaller than the standard rw sheave, meaning its about the biggest aperture it can get and still all good on friction.