Ronstan Series 40 Quin Becket Swivel Orbit Block

The Ronstan Series 40 Quin Becket Swivel Orbit Block combines five low-friction sheaves with a becket and swivel shackle for compact high-ratio sail-control systems. The becket provides a dedicated anchor for the standing end, while the swivel head lets the moving block follow the direction of the loaded purchase. Ronstan lists Series 40 Orbit hardware for mainsheets, spinnaker sheets, halyards, vangs, and backstays on performance dinghies, catamarans, and sportsboats. Adding the becket to the quin layout makes it easier to build a complete purchase without another separate attachment fitting.

The sheaves ride on a two-stage bearing system, using ball bearings for low friction and a secondary support surface for higher loads. Toughened glass-fiber reinforced nylon cheeks save weight and protect the bearing package without relying on traditional stainless side straps. The swivel connection helps the five-sheave stack remain aligned as the tackle moves, while the becket stays available for the fixed end of the line. That integrated layout keeps the finished system compact despite the amount of mechanical advantage it can provide.

• Five sheaves plus an integrated becket
• Swivel shackle follows the working load
• Two-stage low-friction bearing system
• Lightweight reinforced composite cheeks

Ronstan rates the block for line up to 3/8 in, with a 1,320 lb maximum working load and a 2,650 lb breaking load. The published weight is about 8.7 oz, keeping the moving component relatively light for its capacity. Reeve the standing end and five moving parts as a complete system so the becket and sheaves remain square to the load. For more becket blocks and high-ratio Orbit hardware, browse more Sailing Hardware.