This double block is typically used on the boom of a Catalina 42 for the mainsheet.

If you require a retrofit kit for use with this double block, see #T2142 Mainsheet Block Kit w/Double Block shown below.

To prevent the line from twisting or binding when used in a cascade or mainsheet system this block is supplied with a feature to lock the rotation of the shackle that is on top of the body of the block. With the use of an open ended wrench, tighten the nut on top of the block body to lock the shackle in position. When used as a swiveling block, ensure the nut is not tightened and the swiveling shackle can self-align to find the fairest lead.

• Shackle pin diameter: 5/16"
• Sheave diameter: 3-1/4"
• Maximum line size: 5/8"
• Bearings: Torlon
• Safe working load: 3500 pounds