Ronstan Core Block Range

Designed to be robust, durable and provide trouble-free performance, the range has the following features:

• Two-Stage Universal Bearing system - For low to moderate loads, the acetal ball bearings are used. For higher loads where these bearings can deform, a sliding acetal plain bearing on a polished stainless-steel race takes over. This results in low friction through the full load range.

• Aluminum cheeks – High quality, hard anodized aluminum with a low-weight, cut-away design.

• Universal swiveling head with brass bearing washer provides smooth 360° rotation of the post and shackle

• The hallow hub has been specially designed with flared edges, to allow it to be used as a becket.

Source: Ronstan

The 45 Core Block keeps it minimal, with just three blocks in the series! A single block with swiveling shackle head, a halyard block with swiveling fork head and a 360-degree articulating standup block completes the range.

With 16 different block styles available, the Series 60 is the “core” of the range. With single and double blocks; shackle, snap shackle and screw pin attachments; cleats, fiddles, beckets, aluminium sheaves, and foot blocks, there is everything you might need for ropes up to 12mm diameter and boats up to 36ft.

The Series 75 Core Block takes the range up to a maximum 14mm rope diameter, covering higher load applications on boats up to 46ft. With nine block styles focusing on single blocks, with a variety of attachments suitable for halyard applications, plus the fully articulating standup block and a single / double foot block, the Core range is complete.

Where do the Core Blocks fit relative to Ronstan’s other ranges?

Ronstan has an extensive range of blocks available from the smallest dinghies to the largest superyachts. The Core Block range marks the transition from the dinghy / Sports boat ranges to the top level big boat, cruising / racing blocks.

With a Maximum Working Load (MWL) of 700kg, the Series 45 is the ‘baby’ of the big boat, performance ranges. The only alternatives in this load range are from the top end of the performance dinghy (Orbit) and general-purpose Utility ranges. 

Core vs. Utility and Orbit

* Approx. at time of writing

The Utility blocks are basic, functional blocks with stainless-steel cheek plates and acetal, plain bearing sheaves. The Orbit Series 70 is a high performance, super-low friction ball bearing block which needs a larger diameter to carry the load on ball-bearings alone. The two-stage bearing of the Series 45 Core block however, allows it to be significantly smaller and lighter than the other two options with smooth running at both high and low loads.

The Series 60 and 75 Core Blocks are the “go-to” for most cruising sailors with boats from 33 – 46ft. The only alternatives are the no-compromise Series 60 and 75 Orbit Range. Orbit blocks have advanced, open, two stage bearings which provide 80% greater load rating.

Core 75 vs. Orbit 60

* Approx. at time of writing

The advanced bearings of the Orbit range offer 20% higher working load but 27% lower weight and they are designed for race boats with narrower, performance, high load ropes. That, however, does come with a price premium!