Ronstan Series 75 Core Block - Single - Durable Aluminum Alloy Cheek and Acetal Sheave for Sailing Applications

Series 75 Core Block - Single

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.

Universal head
The head assembly incorporates a brass bearing washer to provide smooth 360 rotation of the post and shackle. A set screw arrangement allows the head to be locked at 0 or 90.

Shackles are high quality forged grade 316 stainless steel.

Features:

• Class leading performance and sleek, contemporary styling
  
• Excellent dynamic and high static load performance
  
• Less than half the friction of the nearest competitor
  
• Universal head with full 3-axis articulation
  
• Head posts can be locked at 0 or 90 degrees, by using a 2.5mm Hex/Allen Key
  
• Central hub hole can be used as a becket take-off or tie-up point

Applications:

• Ideal for mainsheet, halyard and spinnaker sheet applications on boats to 14M (46')
  
• Various control line applications on larger yachts

Materials:

• Sheave: U.V. stabilized Acetal
  
• Cheek body: Aluminium Alloy
  
• Ball Bearings: High compression strength carbon black Acetal
  
• Shackle, head post : 75mm(3")
  Max. Rope : 14mm(9/16")
  Pin : 8mm(5/16")
  M.W.L.: 1,500kg(3,300lbs)
  B. L.: 3,000kg(6,600lbs)
  Weight: 354g(12.5oz)
  
  

The Ronstan Series 75 Core Block - Single is a versatile and high-performance sailing hardware designed for both cruising and racing yachts up to 46 feet. Featuring a robust 2-stage bearing system, this block offers exceptional performance across a wide range of loads, ensuring smooth operation and long-lasting reliability. The integrated thrust bearing and high-quality materials make it ideal for sheets, halyards, and control lines, providing sailors with confidence in demanding conditions. Constructed with a durable alloy cheek plate and a UV-stabilized Acetal sheave, the core block is engineered to withstand harsh marine environments while maintaining minimal weight and ease of maintenance.

Features:

• Universal Bearing System: Combines Acetal ball bearings and sliding Acetal on stainless steel race for optimal low-friction performance under varying load conditions.

• Alloy Cheek Plates: Manufactured from high-strength aluminum alloy, designed for maximum durability, weight reduction, and easy rinsing of salt and debris.

• Universal Head with 3-Axis Articulation: Allows for flexible movement and smooth rotation, with lockable positions at 0 and 90 degrees using a hex/Allen key.

• High-Quality Components: Includes forged grade 316 stainless steel shackles and a brass bearing washer for reliable operation and corrosion resistance.

• Maximum Rope Size: Suitable for ropes up to 9/16 inch (14mm) diameter, with a maximum working load of 3,300 lbs and breaking load of 6,600 lbs.