Skate Blocks

Added: 2026-05-27

[00:00:04]This is a skate block and this is how you can lower somebody off of a tower.

[00:00:07]And this is Jessica and she loves skate blocks.

[00:00:10]>> So do you actually like skate blocks?

[00:00:13]I'm a rope access technician and I do confined space rescue. Is there a fear about skate blocks that we're trying to break today? There's concern in the rescue community that if you were doing a hybrid skate block and the track line were to fail, the patient might pendulum into whatever hazard you were trying to And we have a really cool technology here called Marks quick release system.

[00:00:35]So we're going to use that to test whether or not this dummy is going to actually swing into this tower. This is an example of a traditional skate block system and so how it works is you have a descent control device at the bottom anchor, which is the vehicle here. That could be a Maestro, Petzl ID, clutch. The rope travels from that lower anchor all the way up to a high point, which is going to be a pulley.

[00:01:01]And then redirected back, you have the patient right here. He's clipped back to the same rope on a pulley. And we use redundant system, so everything I just explained is doubled up. We have our descent control device, rope runs up all the way to the top there to a pulley and then back down to our patient who's clipped into the same line with another pulley. So if I give slack to this rope, it lowers them, which adds tension to this, which I guess is what pulls them away? It's going to pull them away at most 1/3 of the height of the upper anchor. So if you have a 90-ft tower, the patient is going to land about 30 ft away from the base of the tower.

[00:01:37]>> What the hell's a hybrid then?

[00:01:38]A hybrid is what you use when you need more deflection. Ah, cuz you want to get them as far away from the building as possible sometimes. How far can you get with hybrid? Uh you usually see about 2/3 the distance of your upper anchor is where the patient would land. And everybody agrees it's totally safe?

[00:01:55]There's concern within the rescue community that if you were to cut the track line or tension line in a hybrid skate, the patient might pendulum into whatever hazard you're trying to avoid.

[00:02:05]>> In that hybrid situation, that tension line is the only thing keeping them from swinging back in?

[00:02:11]Let's find out. Do they just go back to the regular arc of the track of the skating line or do they pendulum much further and hit the tower or whatever hazard it is?

[00:02:20]>> Hopefully at the tower because that makes the video cooler a lot. So you do both mastros at the same time?

[00:02:32]Is that why you want to pull them away from the structure? Stop right there.

[00:02:39]Why are you Why are you just running?

[00:02:40]You're not getting away from this camera. Where Where's your Where's that cool toy?

[00:02:45]That's scary, man.

[00:02:48]It was so safe until you showed up. So if you cut this, nothing exciting should happen.

[00:02:52]>> Going to move a little bit. It shouldn't be catastrophic. Only cut one rope or otherwise it will be catastrophic.

[00:03:01]Oh god.

[00:03:03]Get a Get a real knife. What's this knife you got there?

[00:03:07]Oh god. That's some good rope. Path line available at hownot2.com. Oh yeah. You got it. Don't bend the blade. You got it.

[00:03:18]Not catastrophic, but that sure was interesting. Okay, so this went slack.

[00:03:22]This is holding it. Our dummy did not hit their head on the the spike of death. Are you happy with that result?

[00:03:29]I'm happy with it. Okay, so let's change it so where we're not happy with it.

[00:03:33]>> We're adding this tension line to deflect the patient further away from the structure. And so we have one of two guys typically pulling on a three to one. And how much force does a a mark to one get? Got 1.67 kilonewtons right now.

[00:03:47]Terry is hanging on this tension line right now pulling him a little bit further away. We kept our ground anchor at the same position, so it's at a distance that is 1/3 the height of our upper anchor.

[00:04:00]>> Rapid descent system 3500 engaged.

[00:04:04]OH, THAT WORKED so much better.

[00:04:07]Did it move at all? 6 in a foot.

[00:04:10]What's that in meters? Nobody understands feet on the internet.

[00:04:15]1/3 the height We figured out thirds.

[00:04:18]Yeah, this is a meter the distance you can be out of is a foot, okay? So, this did not swing into your tower, so you're happy. Operated as expected. You can move the ground anchor back as far as you want. It's just that it's not deflecting it further. You hit a a limit. Terry's still going to end up here. And there's an alligator pit here we're trying to avoid. Sharks, alligator, yeah. Yeah, sharks. Yeah, alligator sharks. They're the worst kind. We're just wondering if he'll stay somewhere in this zone if we cut the orange line.

[00:04:47]Ooh, he swung a little bit. So, what's above all this? Heights, lots of heights.

[00:04:52]>> Yeah. Heights above.

[00:04:53]>> What is heights above? We're up in Arlington, Washington and we do quite a bit of training for fall hazards, work at heights, SPRAT rope access, industrial rope access. Is this bad boy part of that training? This is. This is our facility and a lot of the maneuvers that we do for the SPRAT rope access classes and we're connected today to the piece of Microflect uh telecom tower.

[00:05:15]And where'd you find that? That was a Facebook find. We now positioned our ground anchor with a 1:1 ratio. So, the ground anchor is just as far back as our structure is high. This guy might swing.

[00:05:29]That was like 4 ft-ish change in position and when you translate that to real-world large scale, what does that look like when that happens on a big structure? How much is that swing large scale?

[00:05:43]I think we need a big structure. If somebody's got a big structure around here, Oh, look, we found a bigger building. Uh having some fun with some firefighters. And they just happen to have a big building. We're in the middle of a Skate Block episode. Shall we cut a rope?

[00:06:03]How many feet is this? 10 ft.

[00:06:05]>> What do you think? If we had an obstacle there, we would have hit it, but that's not very violent. What is keeping our victim away from everything? If that fails while we're lowering, where that victim's going to go.

[00:06:23]How far away are we from the drill, Bobby?

[00:06:26]35 ft.

[00:06:27]It didn't hit the ground, but it If you were trying to avoid something, that would suck. It doesn't swing past the point that the Skate Block naturally wants to be at, but it does swing to that point. Would be fun if I was the dummy. How how how likely am I going to get to be the dummy? Uh you're going to ask.

[00:07:05]Now, I didn't think that the ground would actually be an obstacle, but back in Washington, we did want to see what a two-person load would do.

[00:07:17]We got half a kilonewton more with twice the weight.

[00:07:21]Wow. How's that math work? There's a lot of YouTube mathematicians out there. And I'm not one of them.

[00:07:29]What happens if you lower this? Fall where they fall every time.

[00:07:35]So, with a traditional Skate Block, you're going to end up here. How many track lines do you need? Uh you can keep going with that for all the strength you want, right? All the redundancy you want. Why do people only use one track line? Because the whole idea of a skate block is to keep it efficient and minimalist in gear. We need more weight and more obstacles.

[00:07:52]>> Man, if only there was a way to lift all these dummies up.

[00:08:02]Oh my god, it's so my so close. You cleared the obstacle, but stop there.

[00:08:09]What would happen, Mark, if there was a knife taken to it?

[00:08:14]I'm sure the rope would be cut. If it hits the obstacle, does that mean it's not safe? Depends on the obstacle, right?

[00:08:21]Oh, that's a good answer. If we find ourselves in this situation with three dudes doing that, Yeah. are we already got a problem? Especially yeah, if one of them gets out a knife.

[00:08:32]Oh, no, they hit the obstacle. That was so much less dramatic than I thought.