Ronstan RF25109HL High Load Single Lashing Block 20mm – Ball Bearing Pulley

Push your rigging performance further with the Ronstan RF25109HL High Load Single Lashing Block 20mm—a cutting-edge high-load pulley engineered for modern high-performance sailing systems.

Designed for applications where small diameter lines carry extreme loads, this block features a high-compression acetal ball bearing sheave combined with a stainless steel reinforced frame, delivering exceptional strength and smooth operation under load.

Unlike standard lashing blocks, the HHL (High Load) design incorporates advanced stainless bearing races and reinforced components, dramatically increasing load capacity while maintaining an ultra-lightweight profile.

With a maximum working load of around 300–350kg and breaking load up to 900–1000kg, this compact block delivers performance typically expected from much larger hardware.

The lashing attachment system with integrated hub allows flexible rigging using Dyneema or Spectra, reducing weight and eliminating metal shackles—ideal for high-performance and racing applications.

Weighing only around 14–17g, the RF25109HL offers an exceptional strength-to-weight ratio, making it a top choice for foiling boats, dinghies, and performance keelboats.

Key Features

• High Load (HHL) design – handles extreme loads in compact size
• 20mm ball bearing sheave – ultra-low friction performance
• Stainless steel reinforced frame – superior strength
• Integrated lashing hub – lightweight, flexible rigging
• Exceptional strength-to-weight ratio – high performance with minimal weight
• Corrosion-resistant materials – marine-grade durability
• Compact footprint – ideal for tight rigging layouts

Specifications

• Brand: Ronstan
• Model: RF25109HL
• Product Type: High load single lashing block
• Sheave Diameter: 20mm
• Max Rope Diameter: 6mm
• Maximum Working Load: ~300–350kg
• Breaking Load: ~900–1000kg
• Weight: Approx. 14–17g
• Construction:
  • Glass fibre reinforced nylon cheeks
  • Stainless steel reinforcement
  • Acetal sheave
• Attachment: Lashing (Dyneema/Spectra recommended)

Ideal Applications

• High-load vang systems
• Cunningham and outhaul setups
• Foiling boat control systems
• High-performance dinghies and skiffs
• Compact high-load purchase systems

This block is specifically designed for modern sailing where loads are high but weight must stay low.

Why Buy from Barton Marine NZ?

• Trusted NZ Ronstan supplier
• Fast nationwide delivery
• Genuine high-performance sailing hardware
• Ideal for NZ racing and performance sailing

Pro Tip 

• Use high-quality Dyneema lashings to achieve full load rating
• Ensure multiple passes through the hub for maximum strength
• Ideal upgrade when standard blocks are failing under load