Harken Carbo swivel block
Harken Harken sailboat hardware
  • Harken Carbo swivel block

Harken 40mm Carbo Single Swivel Block with Becket

Harken Single Block 2637 with becket is used for jib and mainsheet systems on high-performance dighies and for loaded control lines on small keelboats.

40mm Carbo AirBlocks have 1-9/16 inch diameter sheaves. The shackle swivels to prevent line twist. Carbo AirBlocks are 60 percent stronger and 30 percent lighter than Harken Classic blocks.

This type of block is suitable for mainsheets, jibsheets, mainsheet fine tune, control lines, vangs, cunninghams and outhauls.

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Tech Spec Product Info User Generated Content


  • 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.




2637 Block

Sheave diameter  1-9/16 inch 
Length  4 inch 
Weight w/ shackle  1.7 oz 
Shackle pin diameter  5/32 inch 
Max. line diameter  3/8 inch 
Safe Working Load  485 lbs 
Breaking Strength  1620 lbs 
BRAND: Harken
Type: Blocks and Sheaves
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