Ronstan’s Core Blocks include a proprietary two-stage bearing system and durable alloy cheeks. Stage one provides “ultra-low friction” when handling moderate loads. The second stage engages when the wind pipes up and loads increase. According to Ronstan, this two-stage approach cuts overall friction almost in half.
Core Block cheeks are precision-shaped with an eye toward providing maximum strength and minimum weight, while also facilitating easy maintenance. By incorporating a “flare” design at the block throat, Ronstan helps reduce rope wear.
Other features include removable becket pins for use with pre-spliced sheets; a fully articulating support base for the stand-up models; and a universal head system that can be locked in either of two planes, or left free to swivel.
Core Blocks can be used as sheet blocks on both cruisers and racer-cruisers. They also work well in high static load applications, like halyards and backstays. The blocks are available in two sizes—Series 60 and Series 75—and are suitable for use in boats up to 46 feet LOA, depending on the application. Alloy sheave models are available for use with wire cables.
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