Ronstan RF35101 Series 30 Orbit Block Single Lashing Head

The Ronstan RF35101 is a lightweight, high-strength 30mm single block designed for modern rigging systems using high-tech lines. This versatile workhorse excels in applications including spinnaker sheets, barber haulers, 2:1 jib sheet systems, downhauls, and general control lines on dinghies and small keelboats.

Engineered for Maximum Strength-to-Weight Ratio:

Through advanced computer modeling, Ronstan replaced heavy metal components with engineered glass fiber reinforced nylon cheeks and head, achieving the highest strength-to-weight ratio in its class without compromising durability. The unique design accepts high-tech lashing (4mm), eliminating the need for heavy shackle pin posts and metal load frames. The hollow bearing at the sheave's center doubles as a becket, further reducing weight while adding versatility.

Advanced Two-Stage Bearing System:

• High-compression grade acetal orbital ball bearings migrate to loaded areas of the sheave for efficient handling of light to moderate loads
• Full-contact 316 stainless steel center bearing shoulders larger static loads
• UV-resistant acetal sheave compatible with both conventional double-braid and high-tech 12-strand lines
• Smooth, efficient operation throughout the entire load range

Key Features:

• 30mm sheave diameter for 5/16" (8mm) line
• Lashing head design accepts 4mm lashing line
• Glass fiber reinforced nylon construction
• Compact footprint and low profile for tight installations
• Highest working loads in class
• Hollow becket reduces weight and increases functionality

Ideal Applications:

• Spinnaker sheets and barber haulers
• 2:1 jib sheet systems
• Cascade system boom vangs
• Dinghy and small keelboat control lines
• Downhauls and other line control systems

The RF35101 delivers professional-grade performance in a compact, lightweight package—perfect for sailors who demand efficiency and reliability from their rigging hardware.