Why Snatch Blocks are AWESOME (How Pulleys Work) – Smarter Every Day 228

Why Snatch Blocks are AWESOME (How Pulleys Work) – Smarter Every Day 228


– Hey, it’s me, Destin. Welcome back to Smarter Every Day. It’s time for the pulley episode. These are like my favorite
things in the whole world. I bought this one, it looks
like it goes to a boat or something like that. Pulleys are one of these things that everybody knows about. They know that somehow, a pulley will give you mechanical advantage, but people don’t really understand it. We all pretend like we do, but the person that really shows up,
and is really clever, and they arrange it in the perfect way and they just make things work, that’s like the smart person
that everybody wants to be. So today, on Smarter Every Day, we’re gonna make a video about pulleys, and we’re gonna slowly
walk through how they work. And specifically, I wanna introduce you to my favorite type of pulley,
it’s called the snatch block. They’re really fancy, they can do tricks. Okay, let’s start by picking
up these cinder blocks. My kids are gonna show you
how to pick up blocks, right? If you have to pick something up, you have to pick up all of
the weight of the thing, and, whether you know it or not, all of the weight of you. How you doing, good?
– Good. – You can put it back down. How hard was that? Not that bad? The magic of a pulley is
really the magic of a rope, because a rope is always in
tension, you can’t push a rope. If you pull on this side of the rope, that force transfers all
the way through the pulley, so you basically can redirect the force. That is the primary function
of a pulley, redirecting force. (child grunts)
That’s pretty good, how was it? – Hard. – The pulley changes the
direction of your body weight, so you can use your own body weight to help you pick something up. Very good, was that hard? Not as hard.
– Not as hard. – Not as hard as what?
– Just picking it up. – Okay, so it’s easier to
pick it up with the pulley because you can kind
of lean into it, right? – Yes sir.
– Right. – So this is the part that
starts to confuse people. If you can change the way
the pulley are arranged, you can make it even
easier to pick this up. Do you want the normal
pulley, or the snatch block? – The snatch block.
– Snatch block! There you go.
(pulley clacking) Go for it. So you split it apart, don’t
cut your finger off there, there you go. So this is the magic of a snatch block. We can put a pulley in
any place at any time as long as there’s a
rope, and the snatch block is big enough for the rope. This is the part where
when you see it happen, you’re like, “Oh yeah,
of course it’s easier, “because of pulleys.” But if you don’t stop and think, you won’t really understand
what’s happening. So slowly pull, is it
really easy this time? – It’s a lot more easy.
– A lot easier, okay. So, this is what’s happening: the tension in the rope right here is being redirected by this pulley because that’s what pulleys
do, they redirect force. But down here with the snatch block, we’re doing the same thing,
we’re redirecting the force. But you have tension in the
rope, and tension in the rope. So all you do is you put
tension in a rope somewhere, and then you add up as many
ropes as possible on the thing, and that’s how you get
mechanical advantage. So in this case, how much
force is on the cinder blocks, do you know? – Two. – Two times the tension. I don’t know about you, but I
understand things a lot better if you can work with it with my hands. So I 3D printed a bunch of
pulleys and snatch blocks, and we’re gonna rig these
things up and generate a model of how we were picking
up those cinder blocks. When I pull on this rope,
that tension transmits itself all the way through the
rope to the very end. Wherever the rope is,
there’s also tension. If I pull here, think
about the word pulley, it pulls on the rope on the other side of the pulley right there. That pulls on the rope
there at the bottom, which then pulls on the
rope on the other side of that pulley, which
ultimately pulls against that hook at the very end. All of the ropes are in tension. Now, if you look down
there at the cinder block, you’ll notice that there are two arrows pulling up on that pulley. That’s why we get twice the
force on the cinder blocks. But what if we wanna pull harder? Can we just add more ropes and tension? Yes, we can using this. It’s basically a double pulley. Some people call this a block and tackle. Instead of two ropes pulling
down here, we get four. Just a little bit of force
here, even with my pinky finger, that’s like 10 pounds of force by just barely pulling at all. This is the same number of ropes, and pulleys and everything,
it’s just flattened out so we can see what’s going on. So, I’ve got a scale. I’m gonna attach a scale
to the input of the rope, and remember, if we put input tension, that tension goes all the way through. So as I pull here, I have
one, two, three, four ropes connected to the thing we’re pulling. So if I put two pounds here, look at that, I get eight pounds on the output. That’s awesome! I’m getting four times the force, but I’m only moving it 1/4th as far. How far do you think we an go with this? You think we can double it again? So now we have two blocks
with four pulleys each, which if you count all those up, one, two, three, four,
five, six, seven, eight, we have eight ropes in
tension on that block. So as I pull here, look
at this, that’s nuts. That is a little bit of
force, and a lot of output. That is some serious mechanical advantage. Look at this though, the
ropes over close to me are moving a lot, but
the ones over near you aren’t moving as much. Let’s break this thing apart again, and see if we can
understand what’s happening. This is so awesome!
(board clunks) Oh man, that’s a great shot! Okay, so here’s what we got:
we’ve got one input pulley, let’s count up the tension again, one, two, three, four,
five, six, seven, eight. I put two pounds here on the input. Oh, that is a lot of force on the output. Do you remember on the block and tackle, the ropes we’re moving at different rates? Well, think about this. On this side over here,
that rope is tied up there. It’s not going to move. On this side, I’m pulling the rope. It has to move as much as I pull it, and the same is true for this one, because it’s just redirecting that string. But after that, everything is affected by how much this moves. So, just playing around with it here, you can see that these
ropes move a whole lot more than that one over there
that doesn’t move at all. There’s a lot going on here. Not this is the sort of thing that, yes, you can probably explain it with words, but if you have a
fundamental understanding of how this stuff works, and
you just know how to use it to your advantage, you can get yourself out of some really interesting situations. For example, the other
day, the driveshaft broke on my buddy, Jeremy’s truck,
and we had to figure out how to get his truck up
onto a flat bed trailer without a winch. Snatch block! We rigged up a pulley
system so that we could pull his entire truck up onto the trailer using only ratchet straps. We figured it out, but because we were trading force for distance,
it was taking forever. That’s when a nice guy
named Jeff showed up. He drove up, offered to help,
and instantly understood our pulley system, and knew
what to do with this truck. We disconnected one of the ratchets, put Jeff’s truck in it’s place, and pulled this truck up until
the rope hit the trailer. One thing I love about Alabama
is nice people like Jeff just stop and help you,
and the instantly know what’s going on. For example, watch how
quickly Jeff figures out all the mechanics once I tell him we have an extra snatch block. (engine idling)
Oh, I’m so excited, we’re gonna do a double snatch block! Oh, this is great! Is I’m gonna put that one–
– It’s locking on the block? – Yeah, yeah.
– Okay. – If you’ll point that direction. – Yeah, I’ll do it. – [Destin] I’m gonna level with you, Jeff is the kind of guy I
wanna be when I grow up. Watch how he just picks up a snatch block and starts working. He just knows what to do. Also, his hands are just amazing. Watch this man work. (engine idling) Snatch block engaged.
(Jeff chuckles) How many snatch blocks you got? – [Jeff] About five. – [Destin] Dude, I’m a
amateur, I only got two. (Jeff laughs) – [Jeff] I got a triple. – [Destin] You got a triple? Like a–
– A wooden triple block. – [Destin] A block and tackle? – Yeah, that’ll work.
(chains clang) – Oh, dude, that’s a thing
of beauty, my friend! Any day you can use a
snatch block is a good day. So yeah, snatch blocks can get
you out of a hairy situation, knowing how to use them
can help you make friends, thank you so much dude, and they can also be a ton of fun. Zip lines are basically
just snatch blocks. You have the ability to
break apart the pulley and you can insert a cable into it without having to disconnect
the cable from either end. That’s essentially the
definition of a snatch block, a pulley where you can insert a line without having to take apart your line from whatever it’s hooked to. Snatch blocks are amazing, and where else can you get amazing views
of the rainforest canopy like this without having a snatch block? (fast forward zip lining) (pulley clanging) Muy bien.
– Amigo. (metal clanging) Can you hold this, then?
– Si. That’s awesome!
(girl chuckles) (Jeep engine roars)
(grasses rustling) Okay, so you can do a
video about snatch blocks without getting a Jeep
stuck, so let’s go do that. Let’s say you got the Jeep stuck. You might be tempted to
find the nearest tree, pull the winch out, and pull the cable directly to that tree. What do you think, Jeremy,
winch is the way to go? – Winch is the way, well, a
snatch block is the way to go. (men laugh heartily)
– Good answer, good answer! If we pull that winch out
directly to that tree, we would only be able to pull the Jeep with the force that that
winch is able to apply. Snatch block! We’re gonna snatch block
this bad boy out of here! What you actually wanna
do is put the snatch block on the tree side, then take that hook, and you hook it back to the Jeep, and so you have twice the pulling force with your snatch block. Alright, you got the winch, right? (engine idling)
– I got the winch. – [Destin] Okay, here we go. Cut the engine off and put it in gear, and just see if it’ll pull the Jeep. – [Jeremy] And like drag it, okay? – Yeah, see if it’ll just pull it. – Ready?
– Yeah. (cable motor running) Oh, that’s scary. That’s a lot of force, dude. – [Jeremy] Yeah, man. (cable motor running) – That’s good. Dude, that’s a lot of force, man. – [Jeremy] Yeah, man! – Thoughts?
– Alright, man. Snatch blocks are awesome, man. (men laugh) – There’s a type of pulley system we haven’t talked about yet,
it’s a compound pulley system. You remember the block and tackle, we had an eight-to-one
mechanical advantage? Well, this has the some
mechanical advantage, but it does it a different way. You remember we add up the
tension on these ropes, and we have one plus one is equal to two? But if we have two plus
two, it’s equal to four, and four plus four is equal to eight, we can come up with an
eight-to-one mechanical advantage just like that with less pulleys. This is fascinating, and
one of the first people to come up with this concept
is a guy named Archimedes. To learn more about Archimedes, I went to make local
library, and got a book by a man named Plutarch,
who mentions an interaction between Archimedes and
King Hiero of Syracuse. It’s a really interesting story, but it’s gonna be even
better if I tell it to you with this flannel board. So it goes like this:
Archimedes writes a letter to King Hiero of Syracuse, and he’s like, “Yo, King Hiero, I’m really
good with pulleys and stuff.” And Hiero’s like, “Why
don’t you prove it?” And Archimedes is like, “Well, I will “if you give me a war ship.” And King Hiero’s like, “Yo,
dog, here’s your war ship.” And the Archimedes is like, “Yo, dog, “I hear that you like pulleys. “I got pulleys on pulleys on pulleys.” And the Archimedes does something amazing. Under his own physical strength,
he pulls an entire war ship out of the dock, which
totally impresses the king because that’s what happens when you know how to use pulleys, you impress people. So people have been using
pulleys and snatch blocks for thousands of years,
and they’ve been impressed, all the way back in the
day with Archimedes. But they’re gonna be
used for thousands more. That’s why you need to know
how to use a snatch block. Don’t take my word for it though, I’ll let Veteran Astronaut
Commander Chris Hadfield explain it from his point of view. – The biggest difference
between being on Earth and being in space is
that you’re weightless, and when you’re floating
around weightless, like on the Space Shuttle, it’s
really hard to get leverage. You can’t dig your feet in, you can’t use the weight of
things to hold ’em in place. So having a way to hook on one
end and hook on the other end and apply a steadily increasing
force is really important. And that’s why on board the Space Shuttle, we have snatch blocks. They’re part of normal equipment. In fact, there’s a special
stowage block for them that contains a couple, and
they get used pretty regularly, both inside the ship, an
even outside on a space walk. You’re in a problem, you have a load, you have to pick it up, what do you do? Snatch block! (metal clanging) (Destin laughs)
(girl laughs) It’s kind of funnier when
it doesn’t work, isn’t it? Snatch block!
(metal clanging) Snatch block! That is exactly what you want. You wanna be the person that knows how to use the snatch block, understands mechanical advantage, and gets your team out of the situation. Snatch block! Snatch blocks are amazing. I wanna tell you something
else that’s amazing, and that is the sponsor for
this video, which is Kiwi Co. Kiwi Co is like having pure
curiosity mailed to your house to ignite the mind of a child every month. And recently, I got to take
my boys to headquarters, and we got to meet the
people that design the kits. The boys gave them feedback
on what it was like to build and play with
each one of these kits. In one case, my oldest son
collaborated directly with Rebeka whose a kit designer to
troubleshoot something she was working on. – But you pull this up, and so like, the plane that hits that
instead of your hand. – [Destin] In a matter of seconds, she prototyped his proposed solutions out of toothpicks and string,
and they tested it out, and it worked. – Yeah! – This was a really big moment in his life.
(Rebeka chuckles) It was super fun meeting these designers, and seeing how they come up with all the different ideas for the kits, and how they make these
really clear guides that go in the box so the
kids can make these things. These kits are incredible. They teach kids all kinds of subjects, like mechanics, optics, geography, art. There’s a specific kit
that is an ideal match for any kid in your life who you love, and you wanna inspire to be
more curious and creative. I love this company, I’m very proud that they’re a sponsor
of Smarter Every Day, and they just have a lot of heart, and I think that’s very evident if you meet Sandra, the Founder and CEO. Can I ambush you in your office? – Absolutely.
– And ask you some questions? – Yes.
– Let’s go. Where’s your office? – My office?
– Yeah. – I don’t have an office, I have a desk. – Can we go to your desk.
– Sure (laughs). – Okay, you don’t have an office? You’re the boss. – We have an open office environment. – [Destin] So why did you start Kiwi Co? Now, you’re an engineer yourself, right? – I am an engineer. I grew up making a lot of stuff, and once my oldest two kids got to a point where I wanted them to start making stuff, I started to compile materials and ideas. And one of my friends was
like, “This is so much fun. “You should start a business around this.” Yes (chuckles)!
– So you created this company as a fusion between parenting and the desire to have your kids tinker? – Exactly, I wanted them to be hands-on, I wanted them to see themselves as people who could create things. I hope these kids grow up not only to be scientists and engineers, but people who do make a
positive difference in the world. So I think that has been really great, and hearing about the quality time that people spend with their kids. We want kids, and families, and parents to come away from the
experience with Kiwi Co, and just be like, “Whoa, awesome!” That discovery, excitement, fun, wonder, hopefully all that packaged in a box, (laughs) and that gets delivered to your door.
– Literally in a box. – Exactly. – [Destin] Thank you so much for making this company.
– Yeah! Of course, my pleasure! Thank you for your support. – [Destin] Oh yeah, do you
remember how we started? – No.
– You don’t know how we started.
(Sandra laughs) I called the company before you
did anything on the internet and I asked if I could
sell your products online, before you had ever worked with
any influencers or anything. – We so appreciate that. – [Destin] It was really good, it was really good.
– No, we really, really appreciate that. – Do you know what the promo is? – Yeah, you get a free crate! – You get a free crate?
– Yeah! – [Destin] That’s awesome! – That’s what you get. – [Destin] KiwiCo.com/smarter, right? – [Sandra] That’s right, and
we’ll send you a free crate. Any line you want, you pick. – [Destin] And people get to pick, and you’re gonna send it to them yourself. – Abs, what?
(both laugh) What are you signing me up for (laughs)? – You’re gonna have the team do it. – We will send it out to you. – There you go, KiwiCo.com/smarter,
get a free crate, pick out the line that’s
best for your child, or in the case of a Eureka
Crate, what’s best for you. So, that’s awesome. Thanks for your time. – Yeah, absolutely. – Thanks.
– Thank you. – I’m Destin, you’re
getting Smarter Every Day. Have a good one, bye. (speeding traffic) There’s a road crew on
the side of the road repairing the guard rail
with a snatch block. (speeding traffic) Thanks, man. – Yeah, man.
– Have a good one. – [Crew Man] You, too. – (chuckles) It was kind of
weird, I pulled over and said, “Hey, can I check out your snatch block?” (laughs) And they we’re like,
“What are you talking about?” (laughs) Pretty cool, though. (speeding traffic) I should get back in my truck.

100 Replies to “Why Snatch Blocks are AWESOME (How Pulleys Work) – Smarter Every Day 228”

  1. Snatch Block!
    I want to take a moment to thank those of you who support Smarter Every Day on Patreon. I'd also like to point out 2 things about this video.
    #1. You'll notice Jeremy Fielding is in this video. He's the "Contraption Fabricator" that's started working with me now because of your support on Patreon. He's a great designer, father, and friend. You'll be seeing more of Jeremy around thanks to those who support at https://www.patreon.com/smartereveryday/
    #2. If you'd like to 3D print the Snatch Blocks and pulleys we use in this video they are here: https://www.thingiverse.com/thing:4022579
    #3. I really enjoy KiwiCo and I think you will too. I got them as a Christmas gift for my children years ago, and it was a huge hit. It was after that experience that I reached out to their team and asked if I could advertise for them because of how good it was for our family. I think you'll enjoy it too. https://www.kiwico.com/smarter
    It was 3 things… I ended up pointing out 3 things.

  2. Great video Destin! I really liked the way you integrated your ad into the video, actually had me watch until the end. Keep up the good work!

  3. I thought I'd drop you a note and let you know you helped me today. I had to put up some shade cloth today over my back patio, and generally I would struggle to get the shade tight enough. Today however after watching this video I thought I could adapt the pulley/snatch block scenario to this. The rope is connected to the shade cloth, via an metal eyelet, the rope is then connected to the fence via a closed hook thing, (I'm so up the tech speak) Normally I would have just fed the rope thru the closed hook and tried to tie it off, whilst maintaining the tension, this time however I fed the rope the closed hook, back up through the shade cloths eyelet and then back through the fences closed hook. The amount of strength required to get the correction tension on the shade cloth was almost nil and I could then maintain that tension easy and tie it off. This is probably just general maintenance 101 but I missed that class so yeah happy days for me and thanks 😀

  4. I love how polite your kiddos are, but it's a little weird to have them call you sir. You should still be daddy. Not Sir. Save that for people in public!

  5. i love your video, and this one is great, both the information and the energy you give off in your videos.
    as an extension could you do one that explains how pulleys in a multi gym work as both ends are free to move.

  6. Never used a snatchblock before.
    Used a ton of pulleys. I pulled a truck with my bike using a compound pulley before. Starter motor died. He had 6 pulleys , they were from tow trucks but the trucks had just been scrapped, he decided to keep the pulleys since they were still working.
    We linked 3 of them to some lampost in compound . It didn't work at first because I couldn't get it fast enough. But we tried a different approach where we slacked the cable a little so I could hit 50 kph before the cable snagged.

  7. Hey Destin, I recognized the book of Plutarch, found in your local library, as one from the Britannica Great Books of the Western World. I have the 60 vol. Second Edition (seventh printing) sitting prominently on my bookshelf. Good used sets are online for around $300. Not that there's anything wrong with supporting your local library, but you strike me as someone who would take great pride in having this significant collection of resource on display in your office or "think-space".

  8. Destin, sir, I've been learning from you for years. This has been my favorite episode ever and i absolutely love Kiwi co!!!! Thank you all. Now how do you estimate the distance the rope travels in relation to which snatch block it runs through or distance pulled in relation of distance work moved?

  9. I swear, you were channeling your inner Billy Mays this whole video. Truly thought you were contractually required to say SNATCHBLOCK an average of 20 times per minute.

  10. thx so much to explain the pulley system in such an easy understanding way, and also the KiwiCo, I just placed order once I completed this video, thx so much.

  11. I have always had a difficulty understanding why a pulley system works. Cause at the end of the day, no matter how many pullers you have, you’ve still got maybe 100 pounds on the end of a rope you’re pulling. Who cares where it’s situated.
    , that’s 100 lbs at one end, and you’re at the other! But then I remind myself it’s like a lever but with rope. And then it’s a coin flip whether or not I temporarily understand Lillie’s better, or levers worse. It’s like my brain refuses to connect these dots, no matter how much you talk about tension and ropes and whatever, it just never clicks!

  12. WHen I was working as a professional mariner, we used the pulley concept every single day, multiple times a day. I used to tell new hires to think of blocks and tackles like using a lever; adding more pulleys was like adding length to the lever. Most seemed to get the concept pretty quickly.

    As long as you're willing to trade effort for distance, there isn't much you can't move.

    One thing that needs to be stressed is that the anchor point needs to be able to take the entire load: Not just the weight of the object, but the weight carried by each part of the tackle. Four ropes and a hundred-pound weight means a five-hundred pound strain.

  13. For people who still doesn't understand:
    When you raise a 10kg ball by 1m or lower a 5kg ball by 2m you did the same amount of work!
    In the video destin raises a weight of 8 pounds by say 1cm by lowering his hand by 2cm using 4 pounds.
    Both are same.

  14. I love the quick cut "Snatch Block!" Action scene! Bloopers included! Lol greatstuff! I have always been so fascinated by pulleys, wver since i was a kid! I still am just as fascinated and try to use every chance i can get to use them!

  15. One thing i think you should explain is "Line Load" and "Angle Factor". These two combined is what gets people injured or killed when using a winch and wire rope. Great Video!

  16. ok why am i looking for snatchblocks in amazon when i have never needed to pulley something…. ehh, i might some day, i dont feel like a man without one

  17. Snatch blocks solve every problem in the world. Imagine a volcano spewing lava! Just apply one million snatch blocks and then: problem solved.

  18. By far the best episode. I'm buying a Snatch Block and Signing up for Kiwi Co. I don't even have kids or a need to lift heavy stuff up.

  19. A good follow up to this would be a video on sling tension. I've had to teach people about rigging nuclear things and the concept of tension with respect to lifting angle is one of the more difficult ones to get across. Which is kinda important as it the basis for angle downgrades. It would be cool to see a demonstration on how the forces go to a practical infinity when you clothesline something through a snatch block (and how it can't because line stretch doesn't allow 0deg angle). It can even be applied to your zipline video's as why ziplines have to be WAY beefier than the lines that hold you to it. Just something to keep it in your pocket for a rainy day video.

  20. Dustin, very smart guy but why have people stand by the winch? If that cable snapped someone could get very hurt. I enjoy your content but dont put yourself or others at risk.

  21. This isn't quite clear for the force mulitplier concept. The real thing that's making it easier is the length of the rope pulled, translates into smaller length of the object moving in the opposite vector of the tension of rope. F=ma, and you can't change an object's mass. So, to apply a smaller amount of force on an object, which is what actually makes something 'easier', you change how much you need to accelerate. IE 100N applied over 10ft of rope is easier than 1000N in 1ft of rope. It's the tension of the rope that enables the object to stay in one vector for acceleration.

  22. Destin, great vid, and love you like family. So I just want to remind you that catastrophic failure is always an option. You really don't want to be in the path of that wire rope when it breaks. That said, perhaps you can talk about the tension on the ropes and load calculation. And yes, snatch blocks are elegant tools! 👍

  23. This is actually amazing. But if the force that is needed to make something heavy higher can be so little, isn't it like cheating physics ?

    Was a person really lifting a war ship on his own?

    I mean, you could make infinite electricity this way:

    Lift something heavy with almost no energy needed. Let it drop and create electricity on the way. Repeat.

    Or at the very least, we could lift people in elevators by very little energy needed, maybe the energy that the people just entered the elevator …

  24. The way you nerd out on technology, engineering, and mechanical devices has to be the most genuine anyone could be about anything. Also, SNATCH BLOCK!

  25. I was waiting but he didn't say it…
    YOU ARE TAKING THE FORCE NEEDED TO LIFT THE WEIGHT AND SPREADING OVER A LONGER DISTANCE!!
    DUH! just say it!

  26. Basic rigging skill achieved congratulations..

    Probably a good idea to add USE RATED EQUIPMENT!! Those little stainless shackles are good for nothing p.o.s. Shouldnt be used for vehicle recovery.

  27. Ah yes, pulleys. My favorite part from my dynamics course. Next project, potential energy powered street light using pulleys?

  28. The best way for calculating mechanical advantage is 2x movable pulleys, so a moving block has three pulleys attached? Well thats ma of 6 and so on however if theres no movable pulleys Ma is 1.

  29. I'm only 4 minutes in, but I don't like your explanation.
    The snatch block is just halving your travel distance compared to length of rope pulled. Youre just gearing down. A normal pully, you pull a foot of rope, the object lifts a foot. The snatch block, you pull a foot of rope, the object lifts 6", because you took 6" from both side of the snatch block. It's why you can nearly double your winch strength by running it through a snatch block then back to the vehicle. You just doubled the length to pull in, halving the speed to cover the same distance.

  30. You know how they say schools don't teach anything useful? Others argue that's simply not the point of school, but videos like these are a perfect example that skills and concepts can be taught simultaneously. We need people like Destin running our public education!

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