Ronstan Series 25 Ball Bearing Orbit Block - Becket & Swivel Shackle - RF28100

Ronstan Series 25 Ball Bearing Orbit Block – Becket & Swivel Shackle – RF28100

Upgrade your sailboat's running rigging with the Ronstan Series 25 Ball Bearing Orbit Block with Becket and Swivel Shackle (RF28100). Designed for performance dinghies and small sailboats, this compact single-sheave block combines Ronstan's efficient 2-stage ball bearing system, a versatile through-sheave becket, and a swivel shackle head for flexible attachment.

The Series 25 Orbit Block is engineered to deliver an excellent balance of strength, low friction, and minimal weight. Its high-compression-strength Acetal sheave and ball bearings promote smooth line movement, making the RF28100 well suited for frequently adjusted control systems where efficient operation is essential.

A 25mm (1") sheave accommodates line up to 8mm (5/16") in diameter. The stainless steel hollow hub provides a convenient becket take-off, allowing the block to be incorporated into compact purchase systems without adding unnecessary hardware.

The swivel shackle head provides convenient attachment while allowing the block to rotate and align with changing line loads. This makes the RF28100 particularly useful in rigging arrangements where line lead and block orientation may vary during operation.

Despite weighing just 0.6 oz., the RF28100 has a maximum working load of 500 lbs. and a breaking load of 990 lbs., providing impressive performance from an exceptionally compact package.

Ronstan recommends Series 25 Ball Bearing Orbit Blocks for applications including mainsheet and spinnaker sheet turning blocks on dinghies up to 4m (13'), along with control lines, cascading vangs, leech lines, and cunninghams.

Key Features

• 2-Stage Ball Bearing System: Provides smooth, low-friction operation across the working load range

• Single-Sheave Design: Compact configuration suited to performance sailboat rigging

• 25mm / 1" Sheave: Optimized for compact control-line applications

• Swivel Shackle Head: Allows the block to rotate and align with the direction of load

• Integrated Becket: Hollow stainless steel hub provides a convenient becket take-off

• Up to 8mm Line Capacity: Accommodates rope up to 5/16" in diameter

• 500 lb. Maximum Working Load: Provides substantial capacity for its compact size

• 990 lb. Breaking Load: Engineered for dependable performance in demanding sailing applications

• Ultra-Lightweight: Weighs approximately 0.6 oz.

• Acetal Sheave & Bearings: High-compression-strength Acetal construction provides efficient operation

• Reinforced Composite Frame: Toughened glass-fiber-reinforced nylon cheeks combine durability with low weight

• Performance-Oriented Design: Ideal for racing dinghies and small performance sailboats

Specifications

Manufacturer: Ronstan
Series: Series 25 Ball Bearing Orbit Block
Manufacturer Part Number: RF28100
Block Type: Single Sheave
Attachment: Swivel Shackle
Becket: Yes – Hollow Hub Becket Take-Off
Bearing System: 2-Stage Ball Bearing
Sheave Diameter: 25mm / 1"
Maximum Rope Diameter: 8mm / 5/16"
Maximum Working Load: 500 lbs.
Breaking Load: 990 lbs.
Weight: 0.6 oz.
Sheave & Ball Bearings: High-Compression-Strength Acetal
Frame/Cheeks: Toughened Glass-Fiber-Reinforced Nylon

Recommended Applications

• Mainsheet systems

• Spinnaker sheet turning systems

• Sailboat control lines

• Cascading vang systems

• Cunninghams

• Leech lines

• Performance dinghy rigging

• Small sailboat running rigging

Ronstan recommends the Series 25 Orbit Block range for mainsheet and spinnaker sheet turning applications on dinghies up to approximately 4m (13').