RONSTAN 75mm Core Block - Swivel, RF74100

Core Blocks™ is a true all-around solution. For reliability and long service life, these blocks are the right choice for sheets, halyards, and control line applications for cruising and racing.

Universal Bearing: A tuned two-stage bearing system provides excellent performance across the full working load range with an integrated thrust bearing feature and the resilience to handle high-dynamic or static loads.

• Stage 1: Under moderate loads, Acetal ball bearings ensure minimum friction.
• Stage 2: Under heavy loads, where deformation of ball bearings alone would result in increased friction, a sliding Acetal bearing on a polished stainless race takes over. The ball bearings act as a thrust bearing between the sheave and cheeks, preventing the sheave from rubbing on the cheeks and causing friction when the line lead in and out of the block isn’t perfect.

Alloy cheek plates for maximum strength. Cut-away design minimizes weight and allows freshwater rinsing of salt and debris from the bearings. Flared cheek design at the block throat and reduced the gap between the cheek and sheave to minimize rope wear.

Universal Head: brass bearing washer in head assembly provides smooth 360° rotation of post and shackle. A setscrew arrangement locks head position at 0° or 90°. Shackles are forged grade 316 stainless steel. Removable becket pins allow connection of pre-spliced lines. The flush-fit becket pin head is kind on deck surfaces and won’t snag lines.

Fully Articulated Stand-Up: Stand-up models have low-profile linkage providing full rotation and articulation. A high-strength precision cast pad eye minimizes the footprint.

• Sheave: UV-stabilized
• Acetal Bearings: 2-stage bearing system
• Cheek Material/Finish: Aluminum alloy
• Shackle/Strap Type: Grade 316 stainless steel