A snatch block works like a pulley that, when used in conjunction with a winch, allows you to lift or pull objects of great weight. The winch engine winds a wire rope onto a spool. The wire rope passes through the snatch block and then connects to the object you need to lift or pull. The snatch block "breaks" the pull span between the winch and the object, cutting the direct pull load on the cable by half and doubling the amount of weight the winch can pull. Rigging a snatch block to a winch allows you not only to lift or pull heavier weights, but also to pull objects at an angle. This is ideal if you need to pull a car or truck out of mud but cannot directly line up your winch to the vehicle.
Things You'll Need
U-bolt wire clamps
Press the cable lock release lever on your winch and pull enough of the winch cable off the spool to just reach your snatch block anchor. Consult the manual for your winch to locate the lever and for the appropriate length and diameter of rope to use for the weight you will pull or lift.
Wrap a wire rope around your anchor point (e.g., a tree) or through an eyelet attached to the anchor. If you are using an eyelet, simply pass the wire rope through the eyelet and do not wrap it.
Pass one end of the wire rope from your anchor through the eyelet at the top of your snatch block. Overlap the two ends of the wire rope and connect them with a U-bolt wire clamp. Press the "U" of the clamp against the "dead" end of the wire rope and the nuts of the clamp against the "live" end (the part of the rope that continues on to the anchor). Space three clamps evenly along the length of the dead end. Pull on the snatch block to make sure it pulls toward the winch and remains centered on the anchor without the wire clamps interfering with this position. If they do, take them off and readjust the cable. The snatch block should not be pushed to one side by the clamps hitting the eyelet at the top of the block.
Pull the wire rope from the winch and thread it over the pulley in the snatch block toward the object you are pulling or lifting. Pull enough wire rope through the snatch block to reach the object and allow for the rigging you will use there. Lock the cable release lever. Pull the rope firmly into the pulley channel on the snatch block.
Use the winch to put the snatch block and anchor cable under enough pressure to tighten the anchor cable before you actually begin pulling or lifting the item. This will "lock" the anchor in position and it will not slip under the load weight causing you to have to stop what you are doing and reposition it.
Never use a chain to attach a snatch block to an anchor point. Chains can be greatly effected by changes in temperature and you cannot visually tell when the structural integrity of a chain has been diminished by exposure to extreme cold or hot temperature. Such a chain will snap under the force of the pull of the snatch block causing the snatch block, the chain and the item being pulled to come free causing great injury to anyone in the area.