snatch block

plural snatch blocks

1. nauticalA kind of block with an opening in one side to receive the bight of a rope.
2. A block equipped with a hook that hooks a cable so that it can be doubled back on itself in order to double the load carrying ability of the cable.

   To effectively double the pulling power of a winch, you can use a snatch block.

   1990 December, Joe Skorupa, “Wilderness Winching”, in Popular Mechanics, volume 167, number 12, page 84

   1 more example

   On a tramway installation, drag the haul rope through each intermediate tower, placing it in the snatch block as the tower is passed to lighten the load.

   1964, United States Department of the Army, Cableways, Tramways and Suspension Bridges, page 117