Lewmar 72mm Synchro Block Single, Black - 7/16 Inch Max Line, 2420 lbs Safe Working Load

The Lewmar 72mm Synchro Block Single (part number 29927201BK) is a single-sheave sailboat block built to transfer power smoothly from deck to sail while minimizing rope wear. It uses a free-spin bearing and a self-aligning head, so the sheave rotates freely and stays true to the load angle even as line direction shifts during a maneuver, reducing friction and line abrasion over time. The block accepts line up to 7/16 inch in diameter and carries a safe working load of 2420 pounds, making it suitable for control lines, sheets, and other running rigging that see real load.

Construction pairs a stainless steel strap for strength and long service life with stiff glass-fiber-reinforced cheeks that resist wedging of the line, keeping the sheave running cleanly under load. The block also features a tool-free sliding swivel locking mechanism, letting the block be positioned and locked onto a track or fitting without additional hardware. It is finished in black and supplied as a single block (one count) rather than a pair. Lewmar backs this block with a 3 year manufacturer warranty.

Specifications

• Brand: Lewmar
• Manufacturer Part Number: 29927201BK
• Outside Diameter: 72 millimeters
• Sheave/Block Thickness: 72 millimeters
• Maximum Line Size: 7/16 inch
• Safe Working Load: 2420 pounds
• Weight: 0.6 pounds
• Color: Black
• Material: Stainless steel strap with glass-fiber-reinforced cheeks
• Unit Count: 1 (single block)
• Warranty: 3 year manufacturer

Frequently Asked Questions

What is the maximum line size for the Lewmar 72mm Synchro Block Single? The Lewmar 72mm Synchro Block Single (part 29927201BK) accepts line up to 7/16 inch in diameter.

What is the safe working load of this block? 2420 pounds is the safe working load rating for the Lewmar 72mm Synchro Block Single, 29927201BK.

How much does the block weigh? This single block weighs 0.6 pounds.

What color does this block come in? The 29927201BK is finished in black, as indicated by its part number suffix.

What material are the cheeks made of? Stiff glass-fiber-reinforced cheeks are used on the Lewmar 72mm Synchro Block Single to prevent lines from wedging during use.

Does this block include a locking mechanism? Yes, the Lewmar 72mm Synchro Block Single has a tool-free sliding swivel locking mechanism, so it can be positioned and locked without extra tools.

Why does the sheave stay aligned under load? A free-spin bearing and self-aligning head let the sheave in this Lewmar block rotate freely and follow the load angle, which helps transfer power smoothly and reduce rope wear.

Is this a single block or a double block? The 29927201BK is a single-sheave block, supplied as one unit (unit count of 1).

What is the outside diameter of the block? 72 millimeters is the outside diameter of the Lewmar Synchro Block, 29927201BK.

What warranty does Lewmar provide on this block? A 3 year manufacturer warranty covers the Lewmar 72mm Synchro Block Single.

What is the block's strap made of? A stainless steel strap is used on the 29927201BK for improved strength and longer service life.

What is this block typically used for? The Lewmar 72mm Synchro Block Single is used to transfer power from deck to sail on control lines and sheets, reducing rope wear while handling loads up to its 2420 pound rating.