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Posted: 12/8/2019 12:53:15 PM EDT
[#1]
Quote HistoryQuoted:
i carry a z rig in my snowmobile with 2 double pulleys to make it a 4 to 1 if needed. Unload, deflate, pull It's always a little too exciting. Last season we had one with a firefighter, so maybe a little over confident...anyhow he wrapped in a rapid with his kids in the boat. We shuttled his kids off and that was terrifying but the easy part. It took both of our kits to get him out of the middle of the river. We absolutely could not have done it without 8-1 pull. Crazy |
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Posted: 12/8/2019 12:56:01 PM EDT
[#2]
Quote HistoryQuoted:
Take a drink every time they say "SNATCHBLOCK"!  |
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Posted: 12/8/2019 1:57:24 PM EDT
[#3]
SNATCH BLOCK
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Posted: 12/8/2019 2:01:21 PM EDT
[#4]
Quote HistoryQuoted:
They're a good purchase. 
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Posted: 12/8/2019 2:10:03 PM EDT
[#5]
Quoted:
I never knew how pulleys worked until I saw this video. Pretty cool.  https://www.youtube.com/watch?v=M2w3NZzPwOM |
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Posted: 12/8/2019 5:46:35 PM EDT
[#6]
I'm pretty sure my 6th grade science text book explained mechanical advantage a lot more succinctly than he did.
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Posted: 12/8/2019 6:25:56 PM EDT
[#7]
Pulleys are heresy. He is a heretic. Burn both. Only God is meant to have that level of understanding.
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Posted: 12/8/2019 6:36:11 PM EDT
[#8]
Quote HistoryQuoted:
I see what you did here. Quote HistoryQuoted:
Quoted:
They're a good purchase. 
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Posted: 12/8/2019 6:39:29 PM EDT
[#9]
Quote HistoryQuoted:
A sheave is a component of a pulley, AKA pulley wheel. Pulley is an assembly. |
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Posted: 12/8/2019 7:51:50 PM EDT
[#10]
Quote HistoryQuoted: River guide here. We train with zdrag stuff. It's amazing the forces at work when a raft is wrapped on a rock. Unload, deflate, pull It's always a little too exciting. Last season we had one with a firefighter, so maybe a little over confident...anyhow he wrapped in a rapid with his kids in the boat. We shuttled his kids off and that was terrifying but the easy part. It took both of our kits to get him out of the middle of the river. We absolutely could not have done it without 8-1 pull. Crazy 
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Posted: 12/8/2019 8:23:52 PM EDT
[#11]
Can't push a rope? Whiskey and my gf say otherwise.
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Posted: 12/8/2019 10:32:49 PM EDT
[#12]
been wanting to buy one of these...https://www.portablewinch.com/us_en/ Been in a few situations where iot would have been helpful.
Is it possible to move an item that exceeds the load limit of the rope using pulleys? |
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Posted: 12/8/2019 10:39:45 PM EDT
[#13]
Quote HistoryQuoted:
I'm still over there quite a bit. Glad to know there are other sailors on here. |
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Posted: 12/8/2019 10:41:29 PM EDT
[#14]
Quote HistoryQuoted:
Isn't the other way around? A pulley is a single wheel, a sheave is two blocks, each with pulley(s) in them to allow multiplication of the pulling force. Quote HistoryQuoted:
Quoted:
A sheave is a component of a pulley, AKA pulley wheel. Pulley is an assembly. Block is an assembly consisting of the frame, axle, and sheaves. Pulley is a synonym for a block. |
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Posted: 12/8/2019 10:46:07 PM EDT
[#15]
Quote HistoryQuoted:
F=MA, and you can't push with a string. All you need to know.
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Posted: 12/8/2019 11:07:26 PM EDT
[#16]
Quote History |
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Posted: 12/8/2019 11:53:10 PM EDT
[#17]
How many pulleys to pull this out?
 Attached FileTwo, the answer is two. And a winch on a Timberjack 350A skidder. |
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Posted: 12/9/2019 12:54:52 AM EDT
[#18]
Quote HistoryQuoted:
How many pulleys to pull this out? https://www.AR15.Com/media/mediaFiles/109172/29040779994_951e7f62c8_o_jpg-1188801.JPG Two, the answer is two. And a winch on a Timberjack 350A skidder. 
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Posted: 12/9/2019 8:39:34 AM EDT
[#19]
Quote HistoryQuoted:
Snatch block I just love saying that ETA: Recovery in reverse direction with a front mounted winch. I keep three snatch blocks, three tree savers, and multiple shackles in the recovery kit for this very need. There, I said snatch block again. https://www.AR15.Com/media/mediaFiles/319389/ACC95F38-9547-471C-AC46-BE8246BDBFD7_jpeg-1187932.JPG are you saying this rigging would allow a front mounted winch to pull a truck backwards? That legit boggles my mind how it works. |
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Posted: 12/9/2019 8:44:31 AM EDT
[#20]
Quote HistoryQuoted:
@TZ250 are you saying this rigging would allow a front mounted winch to pull a truck backwards? That legit boggles my mind how it works. Quote HistoryQuoted:
Quoted:
Snatch block I just love saying that ETA: Recovery in reverse direction with a front mounted winch. I keep three snatch blocks, three tree savers, and multiple shackles in the recovery kit for this very need. There, I said snatch block again. https://www.AR15.Com/media/mediaFiles/319389/ACC95F38-9547-471C-AC46-BE8246BDBFD7_jpeg-1187932.JPG are you saying this rigging would allow a front mounted winch to pull a truck backwards? That legit boggles my mind how it works. |
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Posted: 12/9/2019 9:03:55 AM EDT
[#21]
Quote HistoryQuoted: Yes, it pulls the vehicle backwards. It’s actually exerting a pulling force on the front and the rear, but depending on the rigging/blocks it’s either twice or more as much force in the rear as in the front. The vehicle moves toward the greatest force. |
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Posted: 12/9/2019 9:08:05 AM EDT
[#22]
That video in the OP was terrible.
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Posted: 12/9/2019 10:04:50 AM EDT
[#23]
Quote HistoryQuoted:
How many pulleys to pull this out? https://www.AR15.Com/media/mediaFiles/109172/29040779994_951e7f62c8_o_jpg-1188801.JPG Two, the answer is two. And a winch on a Timberjack 350A skidder. |
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Posted: 12/9/2019 10:11:02 AM EDT
[#24]
Quote HistoryQuoted: @TZ250 are you saying this rigging would allow a front mounted winch to pull a truck backwards? That legit boggles my mind how it works. I have a front winch, but if I need to pull myself out from the rear I use a Handyman Jack. Luckily I have always been able to winch out from the front. |
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Posted: 12/9/2019 10:27:11 AM EDT
[#25]
Quote HistoryQuoted:
Spent a lot of time working with them when I designed cranes. On cranes we called them sheaves. |
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Posted: 12/9/2019 10:31:09 AM EDT
[#26]
Quote HistoryQuoted:
On hot days did you prefer short sheaves or long sheaves? Quote HistoryQuoted:
Quoted:
Spent a lot of time working with them when I designed cranes. On cranes we called them sheaves. 
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Posted: 12/9/2019 10:33:30 AM EDT
[#27]
I have a VX One I travel with and am.looking for something bigger to leave in the water at the club.
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Posted: 12/9/2019 10:36:51 AM EDT
[#28]
Quote HistoryQuoted:
been wanting to buy one of these...https://www.portablewinch.com/us_en/ Been in a few situations where iot would have been helpful. Is it possible to move an item that exceeds the load limit of the rope using pulleys? Example: the 100 ton crane I'm running right now has a single line pull of 14,000 lbs, 6 parts of line gets me roughly an 80,000 lbs lifting capacity. |
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Posted: 12/9/2019 10:52:42 AM EDT
[#29]
Quote HistoryQuoted:
@TZ250 are you saying this rigging would allow a front mounted winch to pull a truck backwards? That legit boggles my mind how it works. Quote HistoryQuoted:
Quoted:
Snatch block I just love saying that ETA: Recovery in reverse direction with a front mounted winch. I keep three snatch blocks, three tree savers, and multiple shackles in the recovery kit for this very need. There, I said snatch block again. https://www.AR15.Com/media/mediaFiles/319389/ACC95F38-9547-471C-AC46-BE8246BDBFD7_jpeg-1187932.JPG are you saying this rigging would allow a front mounted winch to pull a truck backwards? That legit boggles my mind how it works.  Reverse winch |
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Posted: 12/9/2019 10:56:02 AM EDT
[#30]
Quote HistoryQuoted:
That's crazy! it doesn't just snap the rope? Quote HistoryQuoted:
Quoted: Yes, it pulls the vehicle backwards. It’s actually exerting a pulling force on the front and the rear, but depending on the rigging/blocks it’s either twice or more as much force in the rear as in the front. The vehicle moves toward the greatest force. |
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Posted: 12/9/2019 10:57:48 AM EDT
[#31]
Quote HistoryQuoted:
Worse, Germans! Quote HistoryQuoted:
Quoted:
Rube Goldberg making farm equipment now? |
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Posted: 12/9/2019 11:02:26 AM EDT
[#32]
 Big Stump, Little Tractor |
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Posted: 12/9/2019 11:02:53 AM EDT
[#33]
Quote HistoryQuoted:
Not in a recovery situation, the pulley is an anchor point, and the anchor and working end of the line are what moves. Quote HistoryQuoted:
Quoted:
Realizing this helped me. It may help others. Obvious in hind site.
The only way the effort is halved is if the pulley is moving. The stationary pulley does nothing. |
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Posted: 12/9/2019 11:05:24 AM EDT
[#34]
Do any companies make snatch blocks in the US that don't cost over $100? Everything I can find is China made or 5x as expensive.
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Posted: 12/9/2019 11:20:05 AM EDT
[#35]
Quote HistoryQuoted:
Do any companies make snatch blocks in the US that don't cost over $100? Everything I can find is China made or 5x as expensive. |
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Posted: 12/9/2019 11:20:38 AM EDT
[#36]
Quote HistoryQuoted:
Any idea who or what culture invented the pulley system? |
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Posted: 12/9/2019 12:17:13 PM EDT
[#37]
Quote HistoryQuoted: This might help him understand it. In this picture, the snatch block would be the weight, the bumper would be the anchor point on the top left, and the winch would be the pulley on the top right. The amount of line required to move the object a fixed distance is now doubled, but as a result it only requires half the force from the winch. In the picture the goal is to move the weight, but pretend the weight is a fixed point, the bumper that the anchors are attached to will move first. https://s.hswstatic.com/gif/bt3.gif At zero degrees between the ropes. (Ropes Parallel) the tension in the rope is 50% of the load As the angle between ropes increases, so does the load, slowly at first, then it starts rising quickly. At a 60 degree angle its going to be 57, at 90 it jumps to 70.7 at 120 its up to 100 lbs and around 150 degrees its double at 200 lbs |
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Posted: 12/9/2019 12:38:22 PM EDT
[#38]
Quote HistoryQuoted:
As a guy who (I thought) had used pulleys effectively as a wrecker operator, I'm feeling pretty stupid about this, but I'm going to keep talking through it until it makes sense. You're proposing that if the winch were to reel in 12" of cable, the jeep would only move toward the pulley 6"? I still can't fathom that- there's nowhere for that distance to get lost. So is the part of this that I'm missing in the fact that the pull point and the anchor point are the same? Quote HistoryQuoted:
Quoted:
Quoted: Doubled the force at no sacrifice to distance pulled? I would understand a second pulley, or block and tackle setup where the force is redirected twice. But only being run through one pulley should only change the direction of force, not the magnitude... ? You're proposing that if the winch were to reel in 12" of cable, the jeep would only move toward the pulley 6"? I still can't fathom that- there's nowhere for that distance to get lost. So is the part of this that I'm missing in the fact that the pull point and the anchor point are the same? |
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Posted: 12/9/2019 12:59:38 PM EDT
[#39]
Quote HistoryQuoted:
How many pulleys to pull this out? https://www.AR15.Com/media/mediaFiles/109172/29040779994_951e7f62c8_o_jpg-1188801.JPG Two, the answer is two. And a winch on a Timberjack 350A skidder. My buddy calls me after 9 pm on Sunday. Come help I got a skidder stuck. 
The tree trimming crew followed the line and left track in the snow on both sides of a frozen over wet spot. He presumed wrongly they drove through the little frozen bog, nope, the reach along the line from both sides, not going through the bog. He spent hours making it worse before popping the emergency flare. We ended up building cribbing to put under the outriggers and lifted the machine on the out riggers, then tossed many rocks under the tires. Finally pulling with a backhoe boom. |
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Posted: 12/9/2019 1:27:53 PM EDT
[#40]
I did find a site with instructions to make blocks from elm. Lignum vitae was a self lubricating wood for the sheaves but is on the protected species list now so they were using nylon sheaves.
Found it on a traditional boat building site. I might make a set. I have seen old school blocks hanging in many a deer cutters shop. Never ran across a nice set that wasn’t rotted though. Sitting in the corner of a leaking barn is no bueno. Hanging in a dry barn for 60 years and they seem to last forever. I literally have a completely cheap Harbor fright set for deer processing. It’s garbage quality but it does work. A 140 pound deer goes up with just a few pounds of pull. |
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Posted: 12/9/2019 1:37:33 PM EDT
[#41]
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Posted: 12/9/2019 1:41:00 PM EDT
[#42]
Quote HistoryQuoted:
So this is actual a bad example as the photo is wrong. The effective force is doubled only when the two lines are parallel. If the two ropes are at an angles trigonometry and vector math come into play, and increase the tension in the rope. As the crate is lifted the angle between the ropes increase, as does the tension. At zero degrees between the ropes. (Ropes Parallel) the tension in the rope is 50% of the load As the angle between ropes increases, so does the load, slowly at first, then it starts rising quickly. At a 60 degree angle its going to be 57, at 90 it jumps to 70.7 at 120 its up to 100 lbs and around 150 degrees its double at 200 lbs Quote HistoryQuoted:
Quoted: This might help him understand it. In this picture, the snatch block would be the weight, the bumper would be the anchor point on the top left, and the winch would be the pulley on the top right. The amount of line required to move the object a fixed distance is now doubled, but as a result it only requires half the force from the winch. In the picture the goal is to move the weight, but pretend the weight is a fixed point, the bumper that the anchors are attached to will move first. https://s.hswstatic.com/gif/bt3.gif At zero degrees between the ropes. (Ropes Parallel) the tension in the rope is 50% of the load As the angle between ropes increases, so does the load, slowly at first, then it starts rising quickly. At a 60 degree angle its going to be 57, at 90 it jumps to 70.7 at 120 its up to 100 lbs and around 150 degrees its double at 200 lbs |
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Posted: 12/9/2019 1:43:52 PM EDT
[#43]
I knew some guys in AZ about 15 years ago who had a band called Snatch Block.
Mike PS: Texas too: https://www.facebook.com/pg/SnatchBlock/about |
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Posted: 12/9/2019 1:44:15 PM EDT
[#44]
Quote HistoryQuoted:
Isn't the other way around? A pulley is a single wheel, a sheave is two blocks, each with pulley(s) in them to allow multiplication of the pulling force. Quote HistoryQuoted:
Quoted:
A sheave is a component of a pulley, AKA pulley wheel. Pulley is an assembly. |
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Posted: 12/9/2019 1:46:51 PM EDT
[#45]
I think this a snatch block conspiracy by the snatch block companies to sell more snatch blocks
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Posted: 12/9/2019 1:48:40 PM EDT
[#46]
Quote HistoryQuoted:
Check the AW Direct catalog. We use Gunnebo Johnson blocks on the wreckers. Never ever had a problem with them. Quote HistoryQuoted:
Quoted:
Do any companies make snatch blocks in the US that don't cost over $100? Everything I can find is China made or 5x as expensive. It sucks that higher rated Chinese versions are $30. I'd rather go domestic, but damn, the 5x premium is tough to swallow. |
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Posted: 12/9/2019 2:11:11 PM EDT
[#47]
Quote HistoryQuoted: The sheave is just the "wheel" inside the block. (I hate the word pulley). |
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Posted: 12/9/2019 5:40:39 PM EDT
[#48]
Quote HistoryQuoted:
Their cheapest G-J is $105 (marked down from $130). The cheaper ones in the AW catalog don't state origin, and neither did the manufacturers' websites, that I could find. :-/ It sucks that higher rated Chinese versions are $30. I'd rather go domestic, but damn, the 5x premium is tough to swallow. Quote HistoryQuoted:
Quoted:
Quoted:
Do any companies make snatch blocks in the US that don't cost over $100? Everything I can find is China made or 5x as expensive. It sucks that higher rated Chinese versions are $30. I'd rather go domestic, but damn, the 5x premium is tough to swallow. |
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Posted: 12/9/2019 6:17:18 PM EDT
[#49]
One of my favorite channels on youtube
Quoted:
I'm pretty sure my 6th grade science text book explained mechanical advantage a lot more succinctly than he did. Quoted:
That video in the OP was terrible. |
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Posted: 12/9/2019 6:29:21 PM EDT
[#50]
Quote HistoryQuoted: Yup - inclined plane, lever, wedge, wheel and axle, pulley, screw, and C4 |
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