Description
Ronstan Series 40 Double Swivel Block | Boat Supply Store
For critical sailing applications requiring reliable load management, this double block offers superior performance through its Acetal sheaves on stainless steel races. It supports a maximum working load of 600kg (1,320lbs) and accommodates rope diameters up to 10mm (7/16"). The robust, fiber-reinforced Nylon cheeks and Grade 316 stainless steel components ensure exceptional durability for demanding operations on dinghies, catamarans, and sportboats.
Key Features
- Exceptional working loads up to 600kg
- Low maintenance for extended service life
- Self-lubricating Acetal polymer sheaves
- Smooth operation with polished stainless steel bearing races
- Versatile rigging with two-way head post
- Impact and UV resistant construction
- Corrosion-resistant Grade 316 stainless steel fittings
- Reduced fouling with slotted pin shackle
Specifications
| Product Specifications | |
|---|---|
| Sheave Diameter | 40mm (1-9/16") |
| Max Rope Diameter | 10mm (7/16") |
| Pin Diameter | 5mm (3/16") |
| Maximum Working Load (MWL) | 600kg (1,320lbs) |
| Breaking Load (BL) | 1,200kg (2,650lbs) |
| Weight | 135g (4.8oz) |
| Sheave Material | UV-stabilized Acetal polymer |
| Cheek Material | Fiber-reinforced Nylon |
| Bearing Race Material | Polished stainless steel |
| Load Strap Material | Grade 316 stainless steel |
| Head Fitting Material | Grade 316 stainless steel |
| Head Type | Full Swivel Head |
Who This Is For
Cruising and racing sailors, dinghy sailors, catamaran sailors, and sportboat owners who require reliable and durable blocks for sheets, halyards, and control lines. This block is designed for those who demand high load capacity and minimal friction in critical sailing applications.
How It Compares
| Feature | Ronstan Series 40 Double Swivel Block | Competitor |
|---|---|---|
| Sheave Diameter | 40mm (1-9/16") | — |
| Max. Rope Diameter | 10mm (7/16") | — |
| Maximum Working Load (MWL) | 600kg (1,320lbs) | — |
| Head Type | Full Swivel Head | Swivel Head with Ratchomatic, Swivel Head |
| Sheave Material | Acetal Polymer | Carbo (Composite), Synchro |
| Bearing Race Material | Grade 316 Stainless Steel | Stainless Steel |
Common Concerns Answered
Is the swivel head difficult to operate?
While some users report an initial stiffness in the swivel head, this is common for high-load, precision blocks and typically resolves with use. The full swivel head offers exceptional articulation for optimal line lead angles.
Is this block overpriced compared to simpler options?
The Ronstan Series 40 Double Block is engineered for superior load capacity and durability, utilizing premium materials like Grade 316 stainless steel and Acetal sheaves. This investment ensures a longer service life and reliable performance for critical sailing tasks, justifying its price point over basic alternatives.
Do I really need a block with this high of a load rating?
The 600kg (1,320lbs) Maximum Working Load is ideal for actively used control lines, halyards on larger dinghies, or mainsheets on sportboats where high forces are common. For less demanding applications, a lower-rated block might suffice, but this provides significant safety margin and longevity.
Frequently Asked Questions
What is the maximum rope diameter this Ronstan block can accommodate?
The Ronstan Series 40 All Purpose Double Block is designed to accommodate a maximum rope diameter of 10mm (7/16").
What is the working load limit (MWL) for the Ronstan Series 40 Double Block?
The Maximum Working Load (MWL) for this Ronstan Series 40 Double Block is 600kg (1,320lbs).
What materials are used in the construction of the Ronstan Series 40 All Purpose Block?
This block features UV-stabilized Acetal polymer sheaves, fiber-reinforced Nylon cheeks, and Grade 316 stainless steel components for the bearing race, load strap, and head fitting.
What are the typical applications for the Ronstan Series 40 Double Block?
Typical applications include use as a mainsheet block, vang block, halyard block, or control line block on dinghies, catamarans, sportboats, and cruising sailboats where high loads and durability are required.
How does the full swivel head benefit the user?
The full swivel head allows for 360-degree rotation, providing an optimal lead angle for lines, reducing chafe, and improving the efficiency of the rigging system, especially in dynamic sailing conditions.
