Ronstan Series 40 Quin Swivel Orbit Block

The Ronstan Series 40 Quin Swivel Orbit Block is built for high-ratio purchase systems that need five low-friction sheaves at a single moving point. Its swivel shackle allows the block to follow changes in load direction, an important feature when several rope parts are sharing the same assembly. Ronstan uses the Series 40 Orbit platform on mainsheet, spinnaker, halyard, vang, and backstay systems for performance-oriented small boats. The five-sheave layout keeps a complex purchase compact and reduces the number of separate attachment points required.

The bearing system uses ball bearings for easy movement and a secondary full-contact surface to support the sheaves as load rises. Toughened glass-fiber reinforced nylon cheeks keep the structure light and eliminate much of the metal strapwork found on conventional utility blocks. A swivel head helps all five sheaves stay better aligned with the tackle instead of locking the block into one orientation. The result is a practical way to build substantial mechanical advantage without giving up the low-friction character of the Orbit range.

• Five-sheave block for compact high-ratio purchases
• Swivel shackle helps the assembly self-align
• Two-stage ball-bearing design
• Reinforced composite cheeks reduce moving weight

This version takes line up to 3/8 in and carries a 1,320 lb maximum working load with a 2,650 lb breaking load. Ronstan lists its weight at about 8.5 oz, which is modest for a five-sheave moving block. Check the complete reeving path before loading the tackle so all five rope parts run freely and remain clear of neighboring fittings. For more quin blocks and high-mechanical-advantage rigging hardware, browse more Sailing Hardware.