Stuck, really stuck

[danielk]

Warn 12k, snatch block and yanked right out (well, twenty minutes).
View attachment 4080780

That's some beautiful land!

 

[sailonner]

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  tractor winch.jpg

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The 12K winch mounted on my tractor. BTW a snatch block doesn't change the pulling force unless the end of the winch cable is anchored and the snatch block moves with the load. If it is anchored to a tree it only changes the direction of the pull.

 

[aircommuter]

Then it’s not being used correctly. The block attached to the load of course.

 

[sailonner]

Then it’s not being used correctly. The block attached to the load of course.

you're right. The difference is if the winch is mounted to the same vehicle being pulled. If the winch is mounted on a different vehicle than the one you are pulling, the fixed/anchored snatch block just changes the pull direction.

 

[orezok]

I was building a High School in Indio CA and the grading contractor set up his water tower in a bad location due to the availability of a fire hydrant. The soil around it was alluvial. Between the water splashing out of the water trucks and the constant leaking of the water tower the soil became quick sand.

A water truck got stuck and they sent a D8 to pull it out. The d8 sunk to its bottom plate and got stuck. They sent in a D9 to rescue the first one. It got stuck. A third 9 also got stuck.

It was quitting time so as I headed home, and the 8 and 2 9’s stuck to their frames.

I don’t know how they got them out, but they were gone in the morning.

On another occasion an operator who was cutting a road to a logging area got his D6? (Probably smaller) stuck in a mud hole. They brought in a larger cat to pull him out and he said they snapped a $10,000 rope/cable? Trying to get it unstuck.

The other operator told him, just wait a while and we will get you out.

Incomes a Sikorsky Sky crane. The cable him up and fly off with it.

That must have been a “cheap” rescue!

 

[aircommuter]

It’s simple to remember that the block must be in motion to double the pull minus friction of course.

 

[CoyPatton]

Then it’s not being used correctly. The block attached to the load of course.

There are times that a redirect is required. And there are those time that a redirect of the cable through a snatch block does not increase the pulling power of the winch and the snatch block is being used properly for one of its designed purposes.

Attachments

• 
  tractor winch.jpg

  6.1 MB · Views: 214

The 12K winch mounted on my tractor. BTW a snatch block doesn't change the pulling force unless the end of the winch cable is anchored and the snatch block moves with the load. If it is anchored to a tree it only changes the direction of the pull.

If the winch is mounted on the vehicle you want to move, the snatch block could be attached to a deadman location (such as a tree) the cable doubled back to the stuck vehicle or nearby anchor point. Thus would increase the winch’s pulling power, but the snatch block would not move as the vehicle moved
There are many ways to use a snatch block, some will increase the pulling power of the winch and others will not.
Redirects are a proper usage design of a snatch block as is the usage to increase pulling power.

 

[bcp]

Google AI Overview

The theoretical reduction ratio (or mechanical advantage) of a pulley system is equal to the number of rope segments directly supporting the movable load assembly.

And:

Rope Rescue Calculating MA by Counting the Lines

Calculating the mechanical advantage using the

roperescuetraining.com

Bruce

 

[MossRoad]

Attachments

• 
  tractor winch.jpg

  6.1 MB · Views: 214

The 12K winch mounted on my tractor. BTW a snatch block doesn't change the pulling force unless the end of the winch cable is anchored and the snatch block moves with the load. If it is anchored to a tree it only changes the direction of the pull.

If the winch is mounted to the tractor, and the cable goes out to a pulley mounted on an immovable object, then back to the tractor, that's a 2:1 mechanical advantage.

 

[MossRoad]

It’s simple to remember that the block must be in motion to double the pull minus friction of course.

I don't think so.

- Winch mounted on a tractor, cable out to an immovable object is 1X mechanical advantage, or full pull.

- Winch mounted on a tractor, cable out to a snatch block that is fixed to an immovable object than back to the tractor is 2X mechanical advantage... twice the pulling power but half the speed.

The block does not move.

 

[MossRoad]

There are times that a redirect is required. And there are those time that a redirect of the cable through a snatch block does not increase the pulling power of the winch and the snatch block is being used properly for one of its designed purposes.

If the winch is mounted on the vehicle you want to move, the snatch block could be attached to a deadman location (such as a tree) the cable doubled back to the stuck vehicle or nearby anchor point. Thus would increase the winch’s pulling power, but the snatch block would not move as the vehicle moved
There are many ways to use a snatch block, some will increase the pulling power of the winch and others will not.
Redirects are a proper usage design of a snatch block as is the usage to increase pulling power.

I don't think so.

If the cable is doubled back to the stuck vehicle, yes. If it's doubled back to a nearby anchor point, then NO. That would still be a straight pull with no mechanical advantage.

 

[aircommuter]

Then in the case of the stuck vehicle is pulling itself? Perhaps to think of all situations twice as much cable must move than what ever object is moving.

 

[johneking]

I don't think so.

- Winch mounted on a tractor, cable out to an immovable object is 1X mechanical advantage, or full pull.

- Winch mounted on a tractor, cable out to a snatch block that is fixed to an immovable object than back to the tractor is 2X mechanical advantage... twice the pulling power but half the speed.

The block does not move.

Finally -- an explanation that is almost correct.
It's ALMOST "twice the pulling power" {there are mathematical formulas for each set-up} but it has always been considered "twice the pulling power" as the difference is minimal.
Example: 8K lb winch on a vehicle that is stuck {and the doors can't be opened} and weighs 2500 lbs. -- straight line pull will overload the battery, winch motor and possibly break the cable/rope.
Snatch Block attached to a tree/anchor of sorts {I have used three axles from a salvage yard drove into the ground on a triangle then chained together and have never pulled them out!} and you now have almost 16K lbs worth of pulling power. The "stuck vehicle" will come out slower {cable speed changed due to the Block} but it will come out with WAY less strain on the battery etc.
I've been getting "things" stuck since I was 15 {in 1967} and have only needed help a couple of times -- hell, I started out using a rope off of a Mississippi River Barge -- talk about work!!

 

[aircommuter]

I started with Jeeps in 1965 when I was 17. My Jeep featured in Four Wheeler magazine in 1966. You forgot about the amount of cable on the drum effect. Most winches are rated with a minimum wrap.
We had lots of stuck trucks with the utility company drivers. Ten wheel drive trucks with big winches (hydraulic drive no voltage and amperage concerns) were the rescue vehicles. I still have a rope block in my shop mezzanine triple pull. Don’t ever use it as my 36’ Gradall handler has a decent winch.

 

[Too many Kubotas]

I can hardly wait until somebody brings up using two snatch blocks. Or three.

The amount of confusion about using just a single one is amazing.

 

[etpm]

I can hardly wait until somebody brings up using two snatch blocks. Or three.

The amount of confusion about using just a single one is amazing.

This is true. There are all sorts of sites that show how to use snatch blocks as well as plenty of YouTube videos. Folks just need to look and learn.
Eric

 

[Too many Kubotas]

This is true. There are all sorts of sites that show how to use snatch blocks as well as plenty of YouTube videos. Folks just need to look and learn.
Eric

Or just stop and think. After all, it's only very basic physics.

 

[Topzide]

Snatch blocks are your friend! Better to have a few when winching. To change angle and also double the line or more if needed!

 

[johneking]

I started with Jeeps in 1965 when I was 17. My Jeep featured in Four Wheeler magazine in 1966. You forgot about the amount of cable on the drum effect. Most winches are rated with a minimum wrap.
We had lots of stuck trucks with the utility company drivers. Ten wheel drive trucks with big winches (hydraulic drive no voltage and amperage concerns) were the rescue vehicles. I still have a rope block in my shop mezzanine triple pull. Don’t ever use it as my 36’ Gradall handler has a decent winch.

You are correct about the amount of cable/rope on the drum as per the strength.
I took the 150' 5/16" cable off of my MileMarker 10K {hydraulic off of the Power Steering Pump} and replaced it with 200' of same.
It did make it weaker {and slower} when not much was "out" -- but that extra 50' helped me quite a bit in my asphalt business on occasion when I had to load a piece of equipment that needed to go back to the shop for repairs and was "just out of reach" to the trailer.
On one occasion when moving a 6,000 gallon bulk storage tank -- we hooked up a block at the tank, one back at my truck, another back at the tank and finally back to my truck!
The truck was chained to a large white oak and the winch did the work -- one COULD THINK we then had 80,000lbs worth of pulling but that's not how it equates.
My foreman said I'd either pull the truck in half, rip the hooks off of the front of the tank or pull it completely off the skids -- none of that happened.
OH, and -- I raised my hood, put two asphalt tarps over the cables and worked the winch control from the bed of the truck while laying down!

 

[aircommuter]

I can hardly wait until somebody brings up using two snatch blocks. Or three.

The amount of confusion about using just a single one is amazing.

You mean like this?