How Does a Snatch Block Work?by Derek Odom
The Snatch Block
A snatch block is essentially a pulley inside a metal casing that is meant to help with winching duties. It is made of very heavy-duty materials in order to handle many thousands of pounds. They can be found at most off-road supply centers and are a great tool to have if your vehicle is equipped with a winch. Most snatch blocks weigh around ten pounds and are compact enough to be stowed away in the vehicle. The idea behind them is to allow the winch to work more easily and with more power, as will be explained below.
Using a snatch block greatly increases the pulling power of a winch. When a winch drum is fully spooled with cable, it has less power than if it is spooled all the way out due to less line being on the drum, which changes the effective pull ratio. Therefore, the snatch block is attached to whatever the vehicle is winching to, and the winch line goes through the block on the pulley and back to the vehicle. In this manner, more of the pulling power is available for the extraction because of more line being out off of the winch drum.
Snatch blocks are very dangerous, and can be deadly if hooked up improperly. Because the winch and the vehicle are exerting so much force on them, they can fail violently if over exerted. The actual load on the line can be as much as twice the load being pulled! Always be sure that the item you hook the snatch block to is solid and can take the force. Try and purchase the most expensive block you can, because it is so vital that they work all the time, every time. Always use a heavy jacket or other weight on steel winch lines, because if they snap they release a large amount of energy and can go flying. Electric winches have a tendency to slow down or stop altogether when too much load is placed on them, which could save your life. Hydraulic winches, on the other hand, just keep pulling until something snaps--usually the line or the snatch block.