Wire blocks provide the strength and abrasion resistance required by wire rope.

West Marine offers a number of blocks that are specifically designed for wire rope applications. Wire blocks are distinguished by their aluminum sheaves which not only provide great strength, but are necessary when wire rope is run around the block. Wire quickly cuts through nylon sheaves, so tougher material is necessary to support the load.

Types of Wire Blocks

Some blocks designed for use with wire rope can also be used with fabric running rigging. Combination wire/rope sheaves come in two styles. The first (or old style) has both a small and a large flat cross section that can support either small diameter wire or larger diameter rope. The second (or new style) has basically a V-shaped sheave. Each supports the wire and the rope correctly through successive sheave widths.

Other wire blocks have wire-only sheaves which tend to be very narrow, since wire is smaller for a given strength, yet needs a large sheave diameter because it doesn’t like to bend around tight radii.

Harken and Ronstan are the two brands of wire blocks that you will find at West Marine.