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 pro racing 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. To help ensure that the benefits of design translate into improved performance, optimal line sizes are marked on sheaves.
Synchro blocks improve efficiency by nearly 5% on a single block at a load of 442lb. (200kg). Calculated over a typical six-block mainsheet system, this approaches a 40% improvement over conventional blocks.
This range of blocks transforms performance, not only by improving efficiency, but also speed and handling. Optimized block geometry, a revolutionary Free Spin bearing and a self-aligning head combine to reduce friction. Each component is synchronized with the movement of the line providing an easier, smoother transfer of power from deck to sail, and all with less line wear.
- Sheave: Reinforced plastic
- Sheave Size: 4-13/16"
- Ball Bearings: Composite bearing
- Cheek Material/Finish: Stainless steel and plastic
- Shackle/Strap Type: 15° swivel
- SWL: 7700lb.
- Line Diameter: 5/8"
- Line Size: 9/16"
- Maximum Rope Size: 5/8"
The West Advisor
The West Advisor articles have answered boaters' questions and provided solutions to boating problems for more than 20 years. West Marine has compiled one of the Web's most comprehensive collections of technical boating information articles.