Ronstan Series 55 Orbit Block™, Ratchet with Link Head, RF56101

The Ronstan Series 55 Orbit Block™ Ratchet with Link Head RF56101 is a lightweight, high-performance ratchet block designed for mainsheet and spinnaker systems on dinghies, sportboats, and small keelboats. Featuring up to 20:1 holding power, automatic and manual ratchet modes, and a Dyneema® Link Head attachment system, it delivers exceptional control, smooth easing, and reliable performance in demanding sailing conditions.

The Ronstan Series 55 Orbit Block™ Ratchet with Link Head RF56101 is engineered for sailors who demand maximum control, efficiency, and reliability from their sheet handling systems. Combining lightweight construction with advanced ratchet technology, this versatile block is ideal for mainsheet, spinnaker, and control line applications on modern performance sailboats.

At the heart of the RF56101 is Ronstan's advanced ratchet mechanism, delivering up to 20:1 holding power to significantly reduce sheet loads while maintaining precise trimming control. The block offers both automatic and manual ratchet modes, allowing sailors to optimise performance according to conditions and personal preference. Automatic mode engages the ratchet as loads increase, while manual mode provides constant holding power when required.

The Orbit Block™ design utilises high-strength fibre-reinforced polymer cheeks and a stainless steel load strap to maximise strength while minimising weight. At only 78 grams, the RF56101 provides an outstanding strength-to-weight ratio, making it particularly popular on dinghies, skiffs, sportboats, and small keelboats where performance gains matter.

The innovative Dyneema® Link Head attachment system allows the block to align naturally with changing load angles, reducing friction and improving efficiency throughout the rigging system. The flexible connection also simplifies installation and provides a lightweight alternative to traditional shackles.

Designed to deliver smooth easing under load, dependable grip, and exceptional durability, the Series 55 Orbit Block™ Ratchet is trusted by competitive sailors worldwide for both racing and high-performance recreational sailing.

Key Features

• Series 55 Orbit Block™ ratchet design
• Up to 20:1 holding power
• Automatic and manual ratchet modes
• Smooth easing under load
• High-performance sheet control
• Lightweight fibre-reinforced polymer construction
• Stainless steel load strap for maximum strength
• Dyneema® Link Head attachment system
• Flexible alignment reduces friction
• Easy installation and secure retention
• Excellent strength-to-weight ratio
• Designed for demanding racing environments

Ideal For

• Dinghy sailing
• Skiff racing
• Sportboats
• Small keelboats
• Mainsheet systems
• Spinnaker sheet systems
• Performance sailing
• One-design racing
• Club racing
• Competitive sail trimming applications

Technical Specifications

• Model: RF56101
• Series: Ronstan Series 55 Orbit Block™
• Block Type: Single Ratchet Block with Link Head
• Ratchet Modes: Automatic and Manual
• Sheave Diameter: 55mm
• Maximum Rope Diameter: 10mm
• Maximum Working Load (MWL): 250kg
• Breaking Load (BL): 750kg
• Weight: 78g
• Holding Power: Up to 20:1
• Attachment: Dyneema® Link Head

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