Snatch block

Also called pulley block, winch pulley, recovery pulley, soft shackle pulley

A snatch block is a pulley you run a winch line through to double the pulling power, halve the speed, or change the direction of a pull, and despite the shared word it has nothing to do with a snatch strap.

What is a snatch block?

A pulley in a housing that opens on one side, so you can drop a winch line into it without threading the end through. That is where the name comes from: you snatch the line into it. Anchor the block to something fixed, run the line out through it and back to the vehicle, and you have a two-part line.

That configuration roughly doubles the pull at the vehicle for the same winch load, at the cost of halving the speed and doubling the amount of line you need out. A winch rated at 9,000 pounds becomes about 17,000 at the vehicle, the losses in the pulley taking the rest.

Three jobs, not one

Doubling the pull is the one people know. The second is changing direction: anchoring a block off to one side lets you pull a vehicle around an obstacle or straight out of a rut it went into sideways, and a winch pulling at an angle spools badly and loads the fairlead.

The third is keeping the winch in its comfortable range. A pull that is close to a winch's rating heats the motor, drains the battery and takes the winch out of its duty cycle quickly. Halving the load through a block turns a marginal pull into an easy one.

Blocks and soft pulleys

Traditional blocks are steel and heavy. The modern alternative is an aluminium sheave with a synthetic loop instead of a hook, which weighs a fraction as much, attaches with a soft shackle and cannot become a projectile in the same way. If you are buying now and running synthetic line, that is the version worth looking at.