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RONSTAN Series 75 Core Blocks

Use them anywhere: Core Blocks™ are a true all-around solution. 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: 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 gap between the cheek and sheave minimizes 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
Customer Reviews
Product Models
Description WM Model # MFG Part # Availability Price Quantity  
Series 75 Core Block, Single, 9/16" Max. Rope Dia., 5/16" Pin Dia., 3300lb. MWL, 6600lb. Breaking Load, 12.5oz. 11840014 RF74100
In stock online.

$109.99

Series 75 Core Block, Halyard, 9/16" Max. Rope Dia., 5/16" Pin Dia., 3300lb. MWL, 6600lb. Breaking Load, 8.6oz. 11840022 RF74108
In stock online.

$99.99

Series 75 Core Block, Single/Becket, 9/16" Max. Rope Dia., 5/16" Pin Dia., 3300lb. MWL, 6600lb. Breaking Load, 15.1oz. 11840030 RF74110
In stock online.

$129.99

Series 75 Core Block, Single/Stand Up, 9/16" Max. Rope Dia., 5/16" Pin Dia., 3300lb. MWL, 6600lb. Breaking Load, 16.5oz. 11840048 RF74140
Limited availability.

Orig. $199.95

Now  $137.88

Series 75 Core Block, Single Footblock, 9/16" Max. Rope Dia., 5/16" Pin Dia., 3300lb. MWL, 6600lb. Breaking Load, 9.2oz. 11840055 RF74151
In stock online.

$119.99

Series 75 Core Block, Double-Fixed, 9/16" Max. Rope Dia., 5/16" Pin Dia., 3300lb. MWL, 6600lb. Breaking Load, 17.9oz. 11840063 RF74202
In stock online.

$199.99

Product Description

Use them anywhere: Core Blocks™ are a true all-around solution. 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: 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 gap between the cheek and sheave minimizes 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

Specs

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