The Ronstan RF48400 is a high-performance Series 40 Orbit ball bearing quad block with swivel shackle head, engineered for demanding sailing applications on dinghies, sport boats, and yachts. This four-sheave block delivers class-leading load ratings and efficiency in a compact, lightweight package.
Advanced Ball Bearing System:
The RF48400 features Ronstan's innovative 2-stage bearing system that combines ball bearings to minimize friction during trimming with a secondary full-contact bearing to maintain low friction across the entire working load range. This design ensures smooth, effortless line handling even under high loads.
Lightweight, High-Strength Construction:
Built with toughened glass fiber reinforced nylon cheeks instead of traditional stainless steel straps, this block achieves an optimal strength-to-weight ratio. At just 6.8 oz, it provides exceptional durability without adding unnecessary weight to your rigging system.
Integrated C-Cleat System:
Equipped with Ronstan's carbon-reinforced C-Cleat with stainless steel arms, this block offers secure rope holding with low entry and exit effort. The adjustable cleat arms allow you to set your preferred cleating angle, while integrated fairleads ensure fast action from any approach angle.
Key Features:
- Maximum Working Load: 1,320 lbs
- Breaking Load: 2,650 lbs
- Sheave diameter: 1-9/16 inches
- Maximum rope diameter: 3/8 inch
- Pin diameter: 5/32 inch
- Swivel shackle head for versatile attachment
- Low profile and compact design
- Four sheaves for high-ratio purchase systems
Ideal Applications:
- Mainsheet and spinnaker sheet systems on dinghies, catamarans, and sport boats up to 26 feet
- Halyard, vang, and backstay applications on boats up to 30 feet
- Control line systems on larger cruising and racing yachts
- High-ratio purchase systems up to 12:1
The quad sheave configuration combined with the swivel shackle head makes the RF48400 ideal for building complex purchase systems while maintaining easy installation and low system friction.
