Description
Ronstan Series 25 Swivel Shackle Block | Boat Supply Store
Engineered for dinghy and small keelboat applications, this single block provides an efficient and durable solution for critical control lines. It incorporates a 25mm acetal sheave with a 6mm (1/4") maximum rope diameter capacity and a robust 150kg (330lbs) Working Load Limit (MWL). The construction utilizes UV-stabilized acetal sheaves and Grade 316 stainless steel cheeks for extended service life in harsh marine environments, making it ideal for applications like vang or cunningham adjustments.
Key Features
- Durable Grade 316 stainless steel cheeks resist corrosion
- Low Friction UV-stabilized acetal sheaves ensure smooth operation
- Maintenance-Free Acetal sheaves require no lubrication
- Versatile Attachment Hollow rivets accept shackles or allow becket addition
- Lightweight Weighs only 20g (0.7oz) for minimal system impact
- Reliable Performance 150kg (330lbs) Working Load Limit
- Cost-Effective Excellent value for performance and longevity
- Easy Integration Swivel shackle head for flexible mounting
Specifications
| Product Specifications | |
|---|---|
| Sheave Ø | 25mm (1") |
| Max. Rope Ø | 6mm (1/4") |
| Pin Diameter | 4mm (5/32") |
| M.W.L. | 150kg (330lbs) |
| B.L. | 300kg (660lbs) |
| Weight | 20g (0.7oz) |
| Cheek Material | Grade 316 Stainless Steel |
| Sheave Material | Acetal |
Who This Is For
Sailors of dinghies and smaller keelboats requiring a dependable, low-maintenance single block for control line adjustments. It's suitable for various applications where reliability and cost-effectiveness are paramount.
How It Compares
| Feature | Ronstan Series 25 Swivel Shackle Block | Harken 163 Single Swivel Block |
|---|---|---|
| Sheave Ø | 25mm | — |
| Max. Rope Ø | 6mm | — |
| M.W.L. | 150kg | — |
| Cheek Material | Grade 316 Stainless Steel | Nylon |
| Sheave Material | Acetal | Nylon |
| Weight | 20g | 15g |
Common Concerns Answered
Is the working load limit sufficient for larger boats?
The 150kg (330lbs) Working Load Limit is optimized for dinghies and smaller keelboats. For heavier-duty applications on larger vessels, higher rated blocks are recommended.
Is a swivel shackle head as secure as a fixed eye?
While a swivel shackle offers superior versatility and articulation, some users may prefer a fixed eye for perceived security in specific high-load, static situations. However, for its intended use, the swivel shackle is highly secure and functional.
How does this block handle long-term exposure to UV and saltwater?
Constructed with UV-stabilized acetal sheaves and Grade 316 stainless steel cheeks, this block is engineered for excellent durability and resistance to degradation from prolonged UV exposure and corrosive saltwater environments.
Frequently Asked Questions
What is the maximum rope diameter this Ronstan 25 Series Utility Block can accommodate?
This Ronstan Series 25 Utility Block is designed to accommodate a maximum rope diameter of 6mm (1/4").
What is the working load limit (MWL) for the Ronstan Series 25 Utility Block?
The Working Load Limit (MWL) for the Ronstan Series 25 Utility Block is 150kg (330lbs).
What materials are the Ronstan Series 25 Utility Block made from?
The Ronstan Series 25 Utility Block features UV-stabilized acetal sheaves and Grade 316 stainless steel cheeks.
Can I add a becket to this Ronstan Series 25 Utility Block?
Yes, the hollow rivets on this Ronstan Series 25 Utility Block are designed to allow for the addition of a becket.
What are the typical applications for the Ronstan Series 25 Utility Block?
Typical applications include control lines such as vang, cunningham, trapeze retrievers, leech lines, and bunk adjusters on dinghies and smaller keelboats.
