Ronstan releases next size range of Core Blocks for boats up to 53ft

Melbourne, Australia – Ronstan Series 100 core blocks can be found on most cruisers and racers, owing to their durability, light weight and high performance. Previously available in 1 ¾” (45mm), 2 3/8” (60mm) and 3” (75mm) sizes, the new 4” (100mm) size offers an impressive 7,700lb (3500kg) Maximum Working Load which Ronstan says is ideal for sheet and halyard applications on boats to 53ft (16m).

Ronstan designer Albert Mahoney says the key to the high performance of these blocks is the design and the materials used in manufacture.

“Ronstan Core Blocks use a full-contact acetyl bearing on a polished stainless steel race, which ensures low friction even under heavy loads,” says Mr Mahoney. “The ball bearings are configured to act as a thrust bearing, preventing the sheave and the cheeks rubbing against each other if the lead line isn't perfect.”

The head assembly incorporates a brass bearing washer which allows smooth 360 degree rotation of the post and the shackle, while a set screw arrangement allows the head to be locked at 0 degree or 90 degrees.

Stand-up models have a linkage that provides full rotation and articulation. A high-strength, precision cast padeye minimises the deck footprint and a dedicated rubber boot ensures the block is held upright when not loaded.

Other key materials include the use of highest quality aluminium alloy for the block cheeks, which provides maximum strength and is hard anodised for durability and corrosion resistance, along with glass fibre reinforced nylon sheaves and stainless fixings.

Mr Mahoney says the cut-away design minimises weight and allows easy fresh water rinsing of salt and debris from the bearings while the removable becket pins allow fitting of pre-spliced lines. “The flush fit becket pin head is kind on deck surfaces and won’t snag lines,” he concludes.

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