2025 Ronstan Marine Catalogue - Catalog - Page 52
FEATURES & INFORMATION
Keelboat Blocks
50
Acetal
Stage 2
Stage 1
2-stage bearing system
Rope
Alloy
Rope
Wire
Sheave options
Aluminium alloy cheek plates
Universal head
Removable becket pins
Fully articulated stand-up
CORE BLOCKS
™
USE THEM ANYWHERE
A balanced design approach incorporating functionality, performance and style
makes our Core Blocks™ the right choice for performance cruising or racing
applications. 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 & aluminium sheave
options, alloy cheeks and stainless 昀椀xings complete the durable package.
Dynamic and high static load performance
Core Blocks™ incorporate 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 con昀椀gured 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 foot blocks.
Fully articulated stand-up
Stand-up models have a low pro昀椀le linkage that provides full rotation and articulation. A
high strength precision cast padeye minimises the footprint and a dedicated rubber boot
ensures the block is held upright when not loaded.
Universal head
The head assembly incorporates a brass bearing washer to provide smooth 360°
rotation of the post and shackle. A grub screw arrangement allows the head to be
locked at 0° or 90°. Shackles are high quality forged grade 316 stainless steel.
Aluminium alloy cheek plates
Block cheeks are manufactured from the highest quality aluminium 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 昀氀aring at the block throat and reduced gap between the cheek and sheave,
minimising rope wear. The hollow hub can be used as a becket take-o昀昀 or tie-up point.
Aluminium sheave option
models feature an aluminium sheave which has a deep groove pro昀椀le ideal for
use with rope or wire.
Suit pre-spliced lines
Removable becket pins allow 昀椀tting of pre-spliced lines. The 昀氀ush 昀椀t becket pin head is
kind on deck surfaces and won’t snag lines.
