Knot Block Against a Pulley

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Knot Block Against a Pulley

Postby terrwe » Mar 19, 2017 12:00 am

I have a rope in my back yard for practice.

Currently, I have a chain around a tree limb attached to a triangular screw link and small screw link and small descending ring attached to that. I have been able to use a single rope pulled through that. The rope is held in place by a washer (from On Rope book) in front of a stopper knot. After that is a figure 8 with a carabiner that I put back on the rope the first time I ascend. I have a small rope on the carabiner I use to retrieve the rope. It works, except I think it would all be easier to run the rope through a pulley and have the system stop against the pulley. I confirmed that the washer or any of the knots would stop against the pulley, so the size is good, and it seems solid to me. I cannot find evidence of others using this application, though. Any opinions regarding if that would be a safe application to have a knot block against a pulley?
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Re: Knot Block Against a Pulley

Postby NZcaver » Mar 22, 2017 12:59 am

Why use a knot block against a pulley? Just curious. If this setup is for rope practice, you could use a cord to draw the rope through the pulley and secure the rope to the tree trunk (or another tree) near ground level. When tied off with a Munter hitch or locked descender, a person on the ground can very easily lower a climber back to the ground if necessary.

Like this - http://i270.photobucket.com/albums/jj82 ... age006.jpg
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Re: Knot Block Against a Pulley

Postby terrwe » Mar 22, 2017 1:23 pm

That is a good question and something I should have clarified in the description. Basically I have a 50 ft rope that I want to use for practice and the limb is about 35 ft that works best. I probably should consider buying more rope. Part of it is likely that I cannot resist the urge to solve the problem, but also want to be safe. What I have now is safe, but I wanted to get opinions about how safe it is to use a pulley with a knot block as an improvement to the usability of the system.
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Re: Knot Block Against a Pulley

Postby GroundquestMSA » Mar 22, 2017 7:25 pm

It can't possibly be difficult to pull 35' of rope through a carabiner... can it? My practice rope is held up by a chain too, closed with a large pear-shaped carabiner which I also run my rope through. This leads to a mild version of the dreaded tri-axial loading, but I'm not worried.
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Re: Knot Block Against a Pulley

Postby NZcaver » Mar 23, 2017 3:07 am

OK, sure. With a limited amount of rope for the height you want to climb, and if you want to use a draw cord to rig and retrieve your rope, a knot block would be a reasonable solution.

I'd just do something like this with a screw link. I wouldn't worry about securing the bight at the top with a locking carabiner if it's just you practicing.
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Re: Knot Block Against a Pulley

Postby terrwe » Mar 23, 2017 3:41 pm

GroundquestMSA wrote:It can't possibly be difficult to pull 35' of rope through a carabiner... can it? My practice rope is held up by a chain too, closed with a large pear-shaped carabiner which I also run my rope through. This leads to a mild version of the dreaded tri-axial loading, but I'm not worried.


Pulling the rope through is pretty easy. I leave a cheap rope line going through the small screw link up all the time when I do not have the climbing rope on. I have a rope trap from swaygo that works like magic when I attach the climbing rope to the cheap rope and pull it through the screw link. When I go to put the cheap line back after practicing, the lip on the end of the rope trap catches and releases the climbing rope. Thankfully that only happened once to necessitate a second rope and climb to reset. I fixed that by wrapping some black tape around the end of the rope trap, but that little bit of tape makes it a bear to pull through, and think the tape could slip off and again levae me standing at the bottom with both ropes on the ground. So that is why I thought a pulley with a little more space and roll might be a good solution.

Admittedly, those details might have been good on the initial post, but it hard to know which are most important when the crux of the question was if it is safe to have knot block with a pulley.

I have appreciated the discussion and hope it has not induced too many eye rolls. I am new to vertical, have a lot to learn, but am hoping to do so and increase my skills.
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Re: Knot Block Against a Pulley

Postby terrwe » Mar 23, 2017 3:46 pm

NZcaver wrote:OK, sure. With a limited amount of rope for the height you want to climb, and if you want to use a draw cord to rig and retrieve your rope, a knot block would be a reasonable solution.

I'd just do something like this with a screw link. I wouldn't worry about securing the bight at the top with a locking carabiner if it's just you practicing.


Thanks. That is basically the setup I have now, except I have a stopper knot behind a washer in front of the figure 8. Might be unnecessary redundancy. I am hoping to replace the rapide with a pulley to ease retrieval of the climbing rope and leave a cheap rope behind. I am swapping ropes based upon research that suggests that leaving a climbing rope outside all the time is not a good idea.
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