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Ronstan RF74100 Series 75 Core Block Single with Universal Bearing

Manufacturer

Ronstan

<h3>Ronstan: Precision Sailing Hardware Built for Every Sailor</h3><p><strong>Ronstan</strong> is one of the most respected names in sailboat hardware — and with good reason. <a href="/11561-ronstan">Ronstan</a> traces its roots back to 1953, when two Australian sailors, Ron Allatt and Stan Lenepveu, founded Ronstan Marine Equipment Pty Ltd in Melbourne, Australia. What started as a passion project supplying handcrafted yacht fittings to their local sailing club gradually grew into a global enterprise recognized for engineering excellence and real-world performance.</p><p>Today, Ronstan is headquartered in Braeside, Victoria, Australia, with international offices in the United States and Denmark, and production facilities across three continents. The brand distributes to more than 40 countries and handles upwards of 4.9 million units out of its Melbourne facility every year. In November 2023, Ronstan joined Groupe Wichard, further cementing its place among the world&apos;s most influential marine hardware groups.</p><h3>Engineering That Performs On the Water</h3><p>What sets Ronstan apart from generic marine suppliers is its deep commitment to innovation and in-house manufacturing capability. Ronstan&apos;s engineering teams — spread across Australia, the United Kingdom, and Denmark — draw on diverse sailing traditions to develop products that meet the demands of wildly different markets: from club dinghy racers to offshore bluewater cruisers. The brand&apos;s catalog spans blocks, winches, travelers, furling systems, batten systems, stainless steel rigging hardware, and a full suite of deck gear. Ronstan is also the official hardware supplier to the Australian Sailing Team.</p><p>The brand&apos;s in-house manufacturing includes precision CNC machining of aluminum, brass, and stainless steel, as well as advanced plastic injection molding using high-performance engineering polymers — including composites reinforced with up to 60% long-strand glass and carbon fiber. This vertical integration means Ronstan controls quality from design to delivery.</p><h3>Core Product Categories</h3><p>Three categories stand out as workhorses of the Ronstan lineup. <a href="/11561-ronstan-fairleads-200387">Ronstan Fairleads</a> are purpose-designed to guide, contain, and correct the lead angle of control lines across a range of deck configurations — a deceptively simple piece of hardware that plays a critical role in clean, friction-free sail handling. For securing lines under load, <a href="/11561-ronstan-cleats-200268">Ronstan Cleats</a> offer a comprehensive range spanning jam cleats, vee cleats, and the brand&apos;s well-known C-Cleat&trade; and T-Cleat&trade; cam cleat families, each engineered for reliable cleating and easy release in all conditions. Completing the rigging equation, <a href="/11561-ronstan-shackles-200937">Ronstan Shackles</a> — including the innovative Triggersnaps&trade; snap shackle range — are individually proof-load tested and designed for intuitive one-handed operation, making them a trusted choice for racers and cruisers alike.</p><h3>From Dinghies to Maxis</h3><p>One of Ronstan&apos;s most distinctive qualities is its breadth. The same brand that equips Olympic-class dinghies also supplies hardware to some of the largest and fastest offshore racing yachts in the world. Whether you&apos;re outfitting a small club boat or a serious offshore campaigner, Ronstan&apos;s catalog has a solution engineered to the right weight, load rating, and finish for the task at hand.</p>

Part Number

RF74100
09/13/2036 6:00 AM
Sale Price

$127.23

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Usually delivered within 2 days

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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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