What is this "static snatchblock" setup really called?

Maple Fox Farm · July 03, 2019, 07:48:07 PM

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I came across this rigging in a video for small scale teak tree extraction, with a mini skyline system made by maxwald. Anyone know what the red hardware is actually called? It's kind of like a triple block but i don't think there are sheaves/pulley wheels in the "block", i think it's just one solid piece of metal. i tired web-searching every possible name i could think of but didn't come up with anything.
Also, i get how snatchblocks create mechanical advantage but what is the purpose of this setup if this cable is the same size as the single mainline it supports/anchors?
Thanks for your thoughts.

Old Greenhorn · July 03, 2019, 08:05:49 PM

I can't tell from your photos (I'd need to see the whole rig) but this looks strikingly similar to the rig we use in Swiftwater rescue. If it is, the way we do it is anchor the high line to a tree on the farside, and around a tree on the near side. We use a Z rig (2x3 snatch blocks, pre-rigged) to pull the high line tight then secure it to the tree on the nearside. If you tell me where you found the video, I will take a look and see if I can learn more. Sorry, I do not know who makes those blocks but I really think they must have sheaves in them, because the friction would be way too high without them. Maybe you saw something I don't know yet.

John Mc · July 04, 2019, 10:28:07 AM

Quote from: Old Greenhorn on July 03, 2019, 08:05:49 PMSorry, I do not know who makes those blocks but I really think they must have sheaves in them, because the friction would be way too high without them. Maybe you saw something I don't know yet.

Not to mention it would be really hard on the cable.

Dave Shepard · July 04, 2019, 10:39:38 AM

If there were no sheaves, the cable would saw those blocks in half in minutes.

Maple Fox Farm · July 08, 2019, 02:18:39 PM

Well, I thought there was a chance that I was just wrong about the sheaves. Looks like that may be the case :

I am excited to see people actually took time to respond. Wasn't sure if the question would attract any attention; thanks!

Here is the link to the video that the image came from: https://www.youtube.com/watch?v=0-G46lkIU9Y

And another one about small scale cable logging in Vermont just for fun: https://www.youtube.com/watch?v=tNR98QQUABI&t=321s

Maple Fox Farm · July 08, 2019, 02:20:57 PM

for the first video, that setup is at 7 minutes and 56 seconds. They don't say much about it and it's only on the screen for about 5 seconds

Old Greenhorn · July 08, 2019, 06:33:40 PM

The website with the information you want is Found Here. I had searched for maxwEld instead of maxwAld. Pretty neat system, made in Austria.

Old Greenhorn · July 08, 2019, 06:37:29 PM

From what I saw in the video, it is indeed a Z rig for tensioning the high line instead of using a hand come-a-long.

firefighter ontheside · July 10, 2019, 07:13:02 PM

I concur with old greenhorn. It's a Z rig. Very similar to what we use in rope rescue. Pulleys and a rope grabbing device. We mainly use something called a Gibbs ascender or prusik loops. With a z rig, it's all done with one rope, but you can also use a system such as a block and tackle( either 4:1 or 5:1 depending on which end you put where) and piggy back it onto another rope. I don't understand what you're asking about cable diameter.