Harken 57mm Double Swivel Carbo Block

Item #


Product Description

Harken 57mm Double Swivel Carbo Block

Carbo AirBlocks are 60% stronger and 30% lighter than the classic Harken block. The nylon-resin sideplates are densely packed with long-glass fibers for a compact block with a high strength-to-weight ratio. Sheaves spin on high-load ball bearings with fitted races for low-friction operation. Ball bearings, sheave and sideplates UV stabilized with black additive for maximum protection. The high-load 57mm Carbo has a broad working range.

Use for main and jib sheets on centerboard and keelboats like Lightnings, Dragons, Solings, J/24s, and for mainsheet systems on catamarans.


  • Sheave dia. - 2 1/4in (57mm)

  • Length - 4 3/4in (120mm)

  • Weight w/shackle - 6.3oz (178g)

  • Shackle pin dia. - 1/4" (6mm)

  • Max. line dia. - 7/16in (10mm)

  • SWL - 1584lb (720kg)

  • Breaking strength - 3300lb (1500kg)