Ronstan Series 25 Ball Bearing Orbit Block with Becket & Swivel Shackle, Part RF28100

Series 25 Ball Bearing Orbit Block - Becket Swivel Shackle

Single sheave ball bearing block with becket hub and swivel shackle head.

Series 25 Ball Bearing Orbit Blocks, delivering superior strength, reduced weight, and exceptional performance for high-demand dinghy and small boat applications.

Designed with competitive sailors and performance boats in mind, these compact 25mm blocks are engineered to achieve the highest possible strength-to-weight ratio. Featuring Ronstans renowned high compression strength acetal bearing system, the Series 25 BB Orbit Blocks are a lightweight yet durable solution, ideal for control line systems such as mainsheet and spinnaker sheet turning blocks, cunninghams, and cascading vangs on dinghies up to 4 meters.

Each block has a stainless steel hub for versatile lashing attachments and through-sheave becket functionality, making them adaptable to a wide range of rigging setups. The hub accommodates up to 4mm (5/32) lashing and ensures maximum efficiency without compromising reliability.

Features:

• 2-stage ball bearing system.


• Suits up to 8mm (5/16) lines.


• Hollow hub for becket take-off.


• Lashing blocks suit up to 4mm (5/32) lashing.

Specifications:

• Max. Rope diameter (in): 5/16


• M.W.L. (lb): 500


• Sheave diameter (in): 1


• B.L. (lb): 990


• Weight (oz): 0.6

Applications:

• Mainsheet and spinnaker sheet turning blocks on dinghies to 4m (13ft).


• Control lines.


• Cascading vangs.


• Leech lines cunninghams.

Materials:

• Frame/cheeks: Toughened, glass fibre reinforced nylon.


• BB Sheave and balls: high compression strength acetal.

The Ronstan Series 25 Ball Bearing Orbit Block with Becket & Swivel Shackle is a high-performance, lightweight solution designed for demanding sailing applications. This single sheave block features a 2-stage ball bearing system that ensures smooth operation and reduces friction, making it ideal for control lines such as mainsheets, spinnaker sheets, cunninghams, and cascading vangs on dinghies up to 13 feet. Its compact 25mm size delivers an excellent strength-to-weight ratio, allowing sailors to optimize performance without adding unnecessary weight to their rigging.
Constructed with durable materials, the frame and cheeks are made from toughened, glass fiber reinforced nylon, providing strength and resistance to harsh marine conditions. The sheave and internal balls are manufactured from high compression strength acetal, ensuring reliable operation and longevity under heavy loads. The stainless steel hub allows for versatile lashing attachments and through-sheave becket functionality, accommodating up to 4mm (5/32 inch) lashing, which enhances flexibility in various rigging setups. This design allows for efficient load transfer and reduces wear on lines, ensuring consistent performance across multiple sailing conditions.
Suitable for use as mainsheet and spinnaker sheet turning blocks, control line guides, and cascading vangs, this orbit block is engineered to meet the needs of competitive sailors and performance boats. With a maximum working load of 500 pounds and a breaking load of 990 pounds, it offers both strength and reliability. Weighing only 0.6 ounces, it minimizes added weight on your boat, helping to maintain optimal handling and speed. Overall, the Ronstan Series 25 Orbit Block with Becket & Swivel Shackle provides a durable, lightweight, and versatile solution for high-performance sailing rigging systems.

Features:
* 2-stage ball bearing system for smooth operation
* Suitable for up to 8mm (5/16 inch) lines
* Hollow hub design for becket take-off
* Lashing blocks support up to 4mm (5/32 inch) lashing