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LEWMAR 72mm Synchro Single Block

Model # 13061973Mfg # 29927201BK


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: 2420lbs.
  • Weight: 6.69oz.
  • Max. Line Size: 7/16"


72mm Synchro Single Block

Becket No Becket
Diameter 1/2 Inch or 13 mm
Sheave Diameter 72 mm
Direction Any
Intergral Cleat No Integral Cleat
Mount Type Swivel Shackle
Ratchet Non Ratcheting
Safe Working Load 2420 Pounds
Type Single
Weight 6.61 Ounces

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by PowerReviews
Lewmar 72mm Synchro Single Block

(based on 1 review)

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Reviewed by 1 customer

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Works as advertised


from Redondo Beach

Verified Buyer



      Best Uses

        Comments about Lewmar 72mm Synchro Single Block:

        This is a great block for your mainsail boom if your sheet tends to twist under tension. This has a stop that you can set so that it can not rotate 360 degrees but is limited to about 20 degrees. This solved the twisting that was constricting my mainsail sheet.

        • Was this a gift?:
        • No

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