Special Purpose


Series 60 Core Block™, Halyard with Aluminium Sheave

Halyard block with screw pin and roller head. Aluminium sheave is suitable for use with wire or rope.


Class leading performance and sleek, contemporary styling.

Excellent dynamic and high static load performance.

Less than half the friction of the nearest competitor

Durable alloy Rope/Wire sheave.

Suits direct attachment to mainsail headboard for 2:1 halyard.

Removable 8mm (5/16”) threaded pin at head.

Acetal roller on head pin to suit spliced line attachment.

Central hub hole can be used as a becket take-off or tie-up point


Product Specifications
B.L. (kg)2000
M.W.L. (kg)1000
Max. Rope diameter (mm)12
Weight (g)212
Pin Ø (mm)8
Notes:Full block rated load can only be achieved with uniformly distributed load across full length of screw pin. i.e. 14mm (9/16”) diameter mast collar post or 14mm (9/16”) wide mast collar plate/tang.

Product Information

Core Blocks™ are a true all round solution. A tuned 2-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. Acetal sheave, alloy cheeks and stainless fixings complete the durable package. For reliability and a long service life, these blocks are the right choice for sheets, halyards and control line applications for cruising and racing. Universal Bearing -. Dynamic and high static load performance. The Ronstan Universal Bearing incorporates our proven 2-stage bearing system. 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 steel race takes over, maintaining low friction performance. Additionally the ball bearings are configured to 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. Particularly important for cheek blocks. Alloy cheek plates Block cheeks are manufactured from the highest quality alloy for maximum strength. Material optimisation and the cut-away design minimises weight and allows easy fresh water rinsing of salt and debris from the bearings. Cheek design has been further styled with flaring at the block throat and reduced gap between the cheek and sheave, minimising rope wear.

. Acetal & aluminium sheave options. Selected models are available with an aluminium sheave which has a deep groove profile specifically made for use with wire.

Technical Information


Sheaves: U.V. stabilised Acetal. Cheek plates & cleat arms: Aluminium alloy. Ball Bearings: High compression strength carbon black Acetal. Shackle, post & hub: Grade 316 stainless steel. Padeye & snap shackle: Grade 15-5PH stainless steel. Snap shackle: Grade 15-5PH investment cast stainless steel. Cleat: Fibre reinforced compositePin: 2205 stainless steel


Resource Files


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