Thank you for making this information available. We have never even questioned the positioning of the belay when we deploy our Vortexes. There will certainly be a discussion on the topic first thing in the morning. Thanks again.
Some criticism from my armchair: No control tests. They added a lot of variables to the mix but they never isolated the systems on their own. They should have done a drop 6 and shock loaded the AHD to its rating without any slow down whatsoever. That data would be more relevant in my mind. If my understanding is correct, the Aztec elite pro is a pulley system used to gain mechanical advantage. Its not designed to catch a load, especially with how small the bend ratio is through the pulley. I would feel a lot safer if they were using a more traditional load carrying block and tackle system with a bigger pulley, but it seems like they were doing this almost out of convenience that the aztec could lift the load back up to start the test again. The diameter of the rope is everything. The prusik needs to be significantly smaller dia. than the rope going through the aztec The elasticity of the rope is not even mentioned once. Is it made from nylon, or some other synthetic? Thats going to hugely affect the peak load rating. Wheres the experimentation on different knots other than a prusik? We need more data on different friction hitches, or even a double wrapped prusik. If the prusik is glazing the rope and the blue sheath is being damaged I personally would not be happy until I tried more things for a better solution.
The designer of both the frame and the AZTEK was there, so I think he’s a bit more qualified to say what it is designed to handle than you….. This test was primarily observational in nature, as using an AZTEK in this regard has been common practice at Ropes That Rescue to limit fall exposure at the high directional since about 2005. And while extensive testing without the AZTEK in place has been performed, little testing has been performed to demonstrate that the system components can handle the forces in this scenario. This was about proof of concept. As stated several times in the video, further testing is needed. Furthermore, the Vortex and AZTEK have undergone extensive testing in the past. It is neither needed nor desired to repeat those test here, as a very specific use case was what was being tested here. That said, it appears you did not watch drop 5, as that drop was performed without an AZTEK in the system, resulting in over 300lbf higher peak loads than the worst case of the AZTEK. The AZTEK was not used for raising the load back up, nor would that be possible in any case. If you do not understand why the AZTEK is being used, simply say that, so that someone can explain it to you. Otherwise, it’s a strange point of conjecture from someone who wasn’t there. What are you basing the comment that you would feel saver with a larger block and tackle on? This was a 36kN rated AZTEK, which meets the rating of the frame itself, and in this video, it demonstrates that it can handle the forces involved, and actually reduce the peak loads. The glazing of the rope in combination with the nylon construction is what absorbs the shock forces, though a simple measurement of the stretch vs slippage tells you quite clearly that the later is by far the more significant source of absorption, and is furthermore not reliant on the amount of rope in service, meaning it’s also going to be a much more reliable source. Yes the diameter of the prussic needs to be about 75% that of the host rope. The people in the video know that at least as well as you do. This is why the AZTEK uses 6mm hitch on 8mm rope. The prussic hitch is the standard hitch used in the AZTEK. It’s odd to criticize an overabundance of variables while also saying that multiple different hitches should be tested at the same time. If you want to test friction hitches, I suggest you do so in your own testing. This series was specifically about testing the ability of the Vortex and AZTEK to sustain expected dynamic loads in common use cases as taught by Ropes That Rescue in the event of a main line failure at the edge.
Phenomenal training guys!!! Well done. This changes a lot!!
Thank you for making this information available. We have never even questioned the positioning of the belay when we deploy our Vortexes. There will certainly be a discussion on the topic first thing in the morning. Thanks again.
Some criticism from my armchair:
No control tests. They added a lot of variables to the mix but they never isolated the systems on their own.
They should have done a drop 6 and shock loaded the AHD to its rating without any slow down whatsoever. That data would be more relevant in my mind.
If my understanding is correct, the Aztec elite pro is a pulley system used to gain mechanical advantage. Its not designed to catch a load, especially with how small the bend ratio is through the pulley. I would feel a lot safer if they were using a more traditional load carrying block and tackle system with a bigger pulley, but it seems like they were doing this almost out of convenience that the aztec could lift the load back up to start the test again.
The diameter of the rope is everything. The prusik needs to be significantly smaller dia. than the rope going through the aztec
The elasticity of the rope is not even mentioned once. Is it made from nylon, or some other synthetic? Thats going to hugely affect the peak load rating.
Wheres the experimentation on different knots other than a prusik? We need more data on different friction hitches, or even a double wrapped prusik.
If the prusik is glazing the rope and the blue sheath is being damaged I personally would not be happy until I tried more things for a better solution.
The designer of both the frame and the AZTEK was there, so I think he’s a bit more qualified to say what it is designed to handle than you…..
This test was primarily observational in nature, as using an AZTEK in this regard has been common practice at Ropes That Rescue to limit fall exposure at the high directional since about 2005. And while extensive testing without the AZTEK in place has been performed, little testing has been performed to demonstrate that the system components can handle the forces in this scenario. This was about proof of concept. As stated several times in the video, further testing is needed. Furthermore, the Vortex and AZTEK have undergone extensive testing in the past. It is neither needed nor desired to repeat those test here, as a very specific use case was what was being tested here. That said, it appears you did not watch drop 5, as that drop was performed without an AZTEK in the system, resulting in over 300lbf higher peak loads than the worst case of the AZTEK.
The AZTEK was not used for raising the load back up, nor would that be possible in any case. If you do not understand why the AZTEK is being used, simply say that, so that someone can explain it to you. Otherwise, it’s a strange point of conjecture from someone who wasn’t there.
What are you basing the comment that you would feel saver with a larger block and tackle on? This was a 36kN rated AZTEK, which meets the rating of the frame itself, and in this video, it demonstrates that it can handle the forces involved, and actually reduce the peak loads.
The glazing of the rope in combination with the nylon construction is what absorbs the shock forces, though a simple measurement of the stretch vs slippage tells you quite clearly that the later is by far the more significant source of absorption, and is furthermore not reliant on the amount of rope in service, meaning it’s also going to be a much more reliable source.
Yes the diameter of the prussic needs to be about 75% that of the host rope. The people in the video know that at least as well as you do. This is why the AZTEK uses 6mm hitch on 8mm rope.
The prussic hitch is the standard hitch used in the AZTEK. It’s odd to criticize an overabundance of variables while also saying that multiple different hitches should be tested at the same time. If you want to test friction hitches, I suggest you do so in your own testing. This series was specifically about testing the ability of the Vortex and AZTEK to sustain expected dynamic loads in common use cases as taught by Ropes That Rescue in the event of a main line failure at the edge.