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LEWMAR 50mm Synchro Double Block

Model # 13061759Mfg # 29925002BK


Customer Reviews
In stock online.

Product Description

Synchro blocks combine geometry, sheave ratios and a unique Free Spin bearing to deliver performance that’s comparable to ball and roller bearing blocks used in racing, but at a more affordable price. With conventional blocks, one of the biggest losses in efficiency comes from the distortion of line as it wraps around the sheave. Synchro blocks provide the optimal ratio between line size, sheave diameter and the interface between rope and sheave. The result is larger sheaves with a smaller axle than exist on conventional blocks. Synchro blocks improve efficiency by nearly 5% on a single block at a load of 442lb. Calculated over a typical six-block mainsheet system, this approaches a 40% improvement over conventional blocks.

  • Safe Working Load: 990lbs.
  • Weight: 5.01oz.
  • Max. Line Size: 3/8"


50mm Synchro Double Block

SWL 990
Type Double
Max Line Diameter 3/8" or 10 mm

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by PowerReviews
Lewmar50mm Synchro Double Block

(based on 1 review)

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Reviewed by 1 customer

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Exactly what I needed

By Concerto

from Oyster Bay, NY

Verified Buyer


  • Fits My Purpose


    Best Uses

      Comments about 50mm Synchro Double Block:

      Used these double blocks to replace the single furling line block. Needed a second block for the Gennaker tack line. Installed on life line stanchions with SS u-bolts, lockwashers and cap nuts.
      Now I can adjust tack line from the cockpit for varying wind conditions

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