These blocks are also used in mainsheet kits. See the Usage tab to see if used on your boat. Owners have reported having to replace these when used side by side forward on the boom due to wear on earlier designed blocks that used pop rivets to hold them together. These unibody blocks eliminate that issue and provide years of great service.

We have these blocks fabricated with special Torlon bearings to provide a working load of 2800 pounds. Includes a set screw in the head to prevent the block from pivoting if desired.

With Torlon bearings they are somewhat overkill for the 27, 28, and 30 but for just a few more dollars than the same block with lower rated Delron bearings, it doesn't make sense to stock two different versions. A block can't be too strong after all.

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 Allen wrench, tighten the set screw to lock the shackle in position. When used as a swiveling block, ensure the set screw is not tightened and the swiveling shackle can self-align to find the fairest lead.

Masthead Spinnaker Halyard Block
• Catalina 27
• Catalina 28
• Catalina 30
• Catalina 309
• Catalina 310
• Catalina 320
• Catalina 34
• Catalina 36

Mainsheet Block
• Catalina 320 early: Mainsheet kit, (1) forward on boom
• Catalina 320 later: Mainsheet kit, (2) mounted on traveler bale
• Catalina 34 MkI non furling rig: Mainsheet kit, (3) total, (1) aft on boom, (1) forward on boom, and (1) at mast base
• Catalina 34 MkII non furling rig: Mainsheet kit, (5) total, (1) aft on boom, (2) on traveler (some earlier models used a double block on a single traveler bale), (2) side by side on boom bail forward
• Catalina 36 MkI & MkII non furling rig: Mainsheet kit, (4) total, (2) on traveler (earlier models used a double block on a single traveler bale), (2) side by side on boom bale forward

Approximate Dimensions:
• Shackle pin diameter: 5/16"
• Sheave diameter: 2-1/2"
• Maximum line size: 1/2"
• Bearings: Torlon
• Safe working load: 2800 pounds