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Ronstan RF74100 Series 75 Core Block Single with Universal Bearing

Manufacturer

Ronstan

<h3>About Ronstan – A Legacy Built on the Water</h3><p>Few names in the sailing world carry as much weight as Ronstan. <strong>Founded in 1953</strong> by Ron Allat and Stan Lenepveu, the company began as a small boatbuilding operation in Highett, a suburb of Melbourne, Australia. What started as handcrafting custom yacht fittings for fellow sailors at the nearby Black Rock Yacht Club steadily grew into one of the most respected sailboat hardware manufacturers on the planet. The brand name itself is a nod to its founders — Ron and Stan — whose passion for sailing and precision craftsmanship shaped the company's DNA from day one.</p><p>Today, <strong>Ronstan International</strong> is a globally recognised manufacturer and supplier of sailboat hardware, rigging components, winches, sailing gear, and accessories, with its head office remaining in Braeside, Victoria, Australia. The company has established manufacturing facilities in Australia, Denmark, and Indonesia, along with sales offices in the United States, and distributes products to sailors in over 40 countries around the world. In November 2023, Ronstan joined <strong>Groupe Wichard</strong>, aligning with an industry leader whose portfolio spans more than ten world-renowned brands in the sailing and safety markets — a move that further strengthens Ronstan's global reach and product offering.</p><h3>Engineered for Every Sailor, Proven at the Highest Levels</h3><p>Ronstan's reputation spans the full spectrum of sailing — from first-time dinghy sailors to elite competitors at the America's Cup and Olympic Games. The brand serves as the official supplier to the Australian Sailing Team, and Ronstan hardware has appeared aboard medal-winning boats across multiple Olympic campaigns. That pedigree at the pinnacle of racing directly fuels the innovation available to everyday sailors: the demanding performance requirements of top-tier competition have driven many of the technical breakthroughs found throughout Ronstan's broader product range.</p><p>The company's catalog encompasses well over 2,000 products, including pulley blocks, traveller systems, furlers, rope cleats, stainless steel fittings, shackles, snap shackles, and winches. Whether you're outfitting a small racing dinghy, a family cruiser, or an offshore race yacht, Ronstan offers hardware designed and tested to perform in real-world conditions. Their in-house capabilities span design, engineering, precision injection moulding, CNC machining, metal pressing, and assembly — all of which contribute to the consistent quality sailors have come to expect from the brand.</p><h3>Top Ronstan Product Categories</h3><p>Among Ronstan's most popular product lines are their <a href="/11561-ronstan-tiller-extensions-accessories-202641">Tiller Extensions &amp; Accessories</a>, which encompass both their renowned carbon fibre and alloy tiller extension ranges. Whether you need a lightweight, rigid fixed-length stick or a telescopic option for adjustable reach, Ronstan's tiller extensions are engineered for decisive helm response and positive grip in all conditions. Complementing these are Ronstan's <a href="/11561-ronstan-tiller-extensions-accessories-201068">Tiller Extension Accessories</a> — including universal joints, retaining clips, and end knobs — that allow sailors to fine-tune their setup or replace worn components with ease.</p><p>Ronstan also produces a well-regarded line of <a href="/11561-ronstan-fairleads-201944">Fairleads</a>, designed to guide lines smoothly across a boat's deck. Available in UV-stabilised nylon and with optional stainless steel liners for added strength and longevity, these practical fittings are a staple of both dinghy and keelboat rigging setups worldwide.</p><h3>Why Choose Ronstan?</h3><ul><li><strong>70+ years of marine hardware expertise</strong> rooted in Australian sailing culture</li><li>Products trusted by Olympic sailors, offshore racers, and cruising sailors alike</li><li>Over 2,000 products covering everything from small dinghy fittings to superyacht systems</li><li>Advanced manufacturing across three international production facilities</li><li>Part of Groupe Wichard, adding complementary product depth and global support</li></ul>

Part Number

RF74100
06/21/2036 9:19 AM
Sale Price

$127.23

In Stock (6)

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Product Details

The Ronstan RF74100 Series 75 Core Block is a high-performance single block designed for demanding sailing applications. Featuring Ronstan's innovative 2-stage Universal Bearing system, this block delivers exceptional performance across the full working load range while handling both dynamic and high static loads with ease.

Universal Bearing System:

The advanced 2-stage bearing technology ensures minimal friction under all conditions. Stage 1 uses Acetal ball bearings for smooth operation under moderate loads, while Stage 2 employs a sliding Acetal bearing on a polished stainless steel race to maintain low friction performance under heavy loads. The ball bearings also function as an integrated thrust bearing, preventing sheave-to-cheek contact and eliminating friction even when line lead angles aren't perfect—especially important for cheek block applications.

Key Features:

  • Class-leading performance with contemporary, sleek styling
  • Less than half the friction of competing blocks
  • Universal head with full 3-axis articulation and 360° rotation on brass bearing washer
  • Head posts can be locked at 0° or 90° using a 2.5mm hex key
  • Lightweight alloy cheek plates with cut-away design for easy rinsing and debris removal
  • Flared block throat and reduced cheek-to-sheave gap minimize rope wear
  • Central hub hole serves as becket take-off or tie-up point
  • High-quality forged grade 316 stainless steel shackle included

Applications:

  • Mainsheet, halyard, and spinnaker sheet systems on boats up to 14M (46')
  • Control line applications on larger yachts
  • Racing and cruising applications requiring reliability and durability

Construction Materials:

  • Sheave: UV-stabilized Acetal
  • Cheek body: Aluminum alloy
  • Ball bearings: High-compression carbon black Acetal
  • Shackle, head post, and hub: Grade 316 stainless steel

Specifications:

  • Sheave diameter: 75mm (3")
  • Maximum rope diameter: 14mm (9/16")
  • Pin diameter: 8mm (5/16")
  • Maximum working load: 1,500kg (3,300 lbs)
  • Breaking load: 3,000kg (6,600 lbs)
  • Weight: 354g (12.5 oz)

Products specifications

Type

Single

Diameter

9/16 Inch or 14 mm

Mount Type

Swivel Shackle

Becket

No Becket

Direction

Any

Integral Cleat

No Integral Cleat

Ratchet

Non Ratcheting

Safe Working Load

3300 Pounds

Sheave Diameter

75 mm

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