Winch Snatch Blocks – A 2021 Guide

Isaac
| Last Updated: April 8, 2021

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A snatch block is a pulley inside a casing mounted on a ring, and it may or may not have a shackle or a hook attached.

It's designed for redirection of the winch line, to increase lifting or pulling capacity, or help you pull your truck out of a muddy situation.

Snatch blocks let you change the direction of the winch cable, and allow you to perform a double-line pull/recovery.

Snatch Block Terminology and Common Concepts

Different snatch blocks are used for different situations, and before you purchase a snatch block, you must familiarize yourself with the common concepts and terms. It will help you make the correct purchasing decision and assist you in operating the snatch block without an issue.

Pulley

A pulley is a wheel on which the cable sits. The pulley supports movement and change of direction.

Sheave Block

A sheave block consists of two or more pulleys used together for extra strength.

Swing Block

A block used to perform a double line winch recovery. It consists of a pulley mounted onto a ring. A swing block is a tool most often utilized in off-roading applications; to pull a truck out of the mud.

Snatch Block With a Shackle

As the name suggests, this is a pulley mounted onto a shackle. Most often, it's used in permanent applications where you need to pull more weight than the winch can handle. However, it can also be used in temporary applications.

Snatch Block With a Hook

A snatch block with a hook has a pulley and a hook attached at the end. These types of snatch blocks are used in temporary situations, to help with the pulling capacity.

Bolt Snatch Block

A snatch block that lets you use a threaded nut to secure it.

Photo credit: treadmagazine.com

Deck Snatch Block

A snatch block with which you can mount objects vertically or horizontally.

Sideplates

The outer part of the block that covers the pulley.

Rigging Equipment

Referred to the ropes, wires, and other equipment that support a structure.

Stress Formula

This formula determines how much stress is put onto the block in pounds. The formula is loads in pounds (L) multiplied by the angle of the pull (A), which results in stress on the block (S). - (L x A = S)

Safe Working Load Limit (WLL)

The maximum capacity that the winch and the block can handle safely, measured in pounds.

Snatch Block D/d Ratio

The D/d ratio is a formula used to determine the diameter of the winch line that will be supported by the pulley. The "D" stands for the diameter of a snatch block pulley, and the "d" stands for the diameter of the winch line. For an efficient system, the D/d ratio should be no less than 20.

Photo credit: ordealist.com

How Does a Winch Snatch Block Work?

A winch snatch block works by wrapping the cable or a wire around the snatch block and then attaching it to the mounting point of a vehicle, or an object you're trying to pull. The pulling power doubles as the line moves only half the distance. The object isn't being pulled against an anchor point, the winch is instead pulling against itself. The snatch block, of course, has to be mounted onto the anchor point.

Snatch blocks with a single pulley do double the strength of pulling, but they're most usually used to change the direction of the pulling rope. Multiple sheave blocks are utilized in heavy-duty situations as they increase the pulling power greatly.

Multiple sheave blocks only differ from a single sheave block in that the rope goes through each pulley, resulting in much more power, but a shorter distance.

How to Use a Snatch Block

Using a snatch block is a relatively simple process, but you must understand how to operate a winch beforehand. If you don't, the entire process will be way too complicated, and we invite you to learn how to use a winch.

The snatch block has two side plates that can rotate, allowing you to position the line into the snatch block. Keep in mind the D/d ratio while you position the cable or the rope. Once you've placed the cable into the pulley, rotate the side plate and close it off.

Mount the winch line onto the object, or back onto the vehicle to perform a double line pull. Make sure that you're mounting the line at the correct spot, as you don't want anything to break off and cause damages. Lastly, mount the snatch block itself to an anchor point. This setup will help with an odd angle, and it will increase the pulling capacity.

In case you're using the snatch block to pull an object, or another vehicle at an angle, you should mount the snatch block to an anchor point first. Make sure that the winch faces the anchor point of the snatch block directly.

Otherwise, you'll have a cable that bunches up, or you could potentially damage your winch. In this case, you must make sure that both the winch, as well as the snatch block, can handle the pulling capacity. 

Safety Considerations

A snatch block is an extra piece of equipment that can become a projectile if the rope breaks. That's why you need to make sure that everything is set-up correctly. 

Besides checking the winch, also inspect the snatch block. The snatch block itself has an extensive amount of force passing through it. Especially be sure that the anchor point can handle the pulling weight, as the slingshot effect can cause major damages and injuries.

Lastly, always make sure that your pulling weight doesn't exceed the maximum pulling weight of the snatch block.

Pros of Using a Snatch Block

A snatch block will be, without a doubt, a great addition to your winching equipment. It has no real downsides, only upsides!

Pulling at an Angle 

The primary use and the reason for inventing the snatch block are pulling objects at an angle. This is especially useful in off-roading applications. You'll be able to mount the snatch block to a tree, hook the line to your friend's truck, and pull at an angle. In some circumstances, you wouldn't be able to pull the other truck out of the mud without a snatch block.

With a snatch block, you can also mount the line back onto your truck, for an increase in pulling force.

Photo credit: ordealist.com

Increased Pulling Power

The snatch block is mounted in a position, and the wider the angle, the less force the mounting (the anchor) point will have to withstand. However, when the line is parallel to itself, the pulling power is at a maximum, giving you a mechanical advantage.

You should be aware of the maximum capacity that the snatch block can withstand if you're pulling something by using this method. The maximum capacity of the snatch block should be double the maximum pulling capacity of your winch. And as long as you take good care of your equipment and set everything up correctly, you won’t have any problems!

Increase The Capability of Your Winch

Snatch blocks are incredibly cheap tools that will compliment your winching equipment and assist you with many difficult applications. These little tools are borderline necessary for off-roading enthusiasts. They will pull you out of muddy and slippery situations that you otherwise wouldn’t be able to get out of.

Cons of Using a Snatch Block

Snatch blocks don't really have any real drawbacks. They're used for specific situations, and if you do need to use a snatch block, you won't have anything to complain about (except your truck being stuck in the mud).

Down below are the only 'cons' to using a snatch block that we could think of:

The Extra Steps

There are necessary steps you need to take when you need to use the snatch block. First, you will need to inspect the snatch block. You will also need to measure the pulley diameter and compare it to the diameter of the cable or the rope. Lastly, you will have to find the anchoring point for the snatch block, and mount it securely. 

Photo credit: offroaders.com

However, these steps are necessary if you want to use the snatch block, so besides a bit of time you spend, it isn't a real ‘con’.

Lower Speeds

Using a snatch block, your winch will load the rope at a slower rate than it usually would. You could use a stronger motor to compensate, but you will need to be careful not to break the pulley on the snatch block.

Conclusion

Having a snatch block as a part of your winching equipment to give you a few extra options in a challenging situation will prove useful. Considering the low price of snatch blocks, you don't have anything to lose. Just make sure to properly take care of your equipment and follow the safety precautions.

People Also Ask

Snatch blocks are very useful and very versatile tools, but there's a lack of information about them. Our staff is often contacted with similar questions, so we went ahead and answered the most common ones to save you time. However, if you're still uncertain about snatch blocks, feel free to reach out!

What Should My Snatch Block Be Rated To?

The snatch block's maximum rating capacity should be two or three times higher than the capacity of the winch. This will ensure that everything works as intended, and nothing breaks or snaps causing damages or injuries.

How Do I Pick the Snatch Block Diameter?

The snatch block (pulley) diameter should optimally be twenty times greater than the diameter of the line. The diameter of the snatch block shouldn't be less than eight times the diameter of the line, no matter the circumstances. By following that rule, you’ll be able to pick the correct snatch block.

Isaac

I used to work in construction and landscaping, so I've seen my fair share of ratchet straps, winches, and similar rigging gear. I started Winch Central because I've seen some nasty accidents due to crappy rigging or poor practice. I wanted to be able to recommend good equipment that's SAFE and also provide resources for how its used. I handle the research side of things here as well as product selection for gear reviews.