Description
Ronstan Series 20 Double Ball Bearing Block | Boat Supply Store
This Ronstan Series 20 Double Ball Bearing Block is engineered for critical control lines on dinghies and small keelboats, minimizing friction under load. It features 20mm sheaves and a 350kg (770lbs) working load limit, making it suitable for demanding applications like vangs and cunningham systems. The 2-axis shackle head offers versatile mounting options, enhancing control line efficiency in dynamic sailing environments.
Key Features
- Minimized friction through precision ball bearings
- High load capacity with 350kg MWL
- Compact and lightweight design at only 42g
- Durable construction with UV stabilized Acetal sheaves
- Versatile 2-axis shackle head for flexible mounting
- Grade 316 stainless steel fittings for corrosion resistance
- Impact and UV resistant Nylon cheeks
- Optimal control line management for critical systems
Specifications
| Product Specifications | |
|---|---|
| Sheaves | 20mm (3/4") |
| Max Rope Diameter | 6mm (1/4") |
| Working Load Limit (MWL) | 350kg (770lbs) |
| Breaking Load (B.L.) | 700kg (1,540lbs) |
| Weight | 42g (1.5oz) |
| Sheave Material | UV stabilized Acetal |
| Bearing Type | Stainless steel ball bearings |
| Fittings Material | Grade 316 Stainless Steel |
| Cheek Material | Impact and UV resistant, fiber reinforced Nylon |
Who This Is For
Ideal for dinghy sailors and small keelboat crews requiring high-performance, low-friction control line management. Essential for applications like vangs, cunningham, and traveller controls on vessels up to 30 feet.
How It Compares
| Feature | Ronstan Series 20 Double Ball Bearing Block | Competitor |
|---|---|---|
| Sheave Ø | 20mm | — |
| Max. Rope Ø | 6mm | — |
| M.W.L. | 350kg | — |
| Bearing Type | Ball Bearing (Stainless Steel or Torlon®) | Ball Bearing |
| Weight | 42g | 55g |
Common Concerns Answered
Some users wish for a slightly larger sheave diameter for thicker control lines.
The Ronstan Series 20 block is optimized for control lines up to 6mm (1/4"). For larger diameter lines, consider Ronstan's Series 40 or larger blocks, which offer greater sheave diameters and higher load ratings.
Availability of Torlon® bearing option can sometimes be limited.
This specific model features robust stainless steel ball bearings for exceptional low-friction performance and durability, ensuring reliable operation even when the Torlon® option is temporarily unavailable.
Price may be a consideration for budget-conscious sailors, but the performance and longevity justify the investment for serious racers and cruisers.
While the initial investment might be higher than basic blocks, the Ronstan Series 20's precision ball bearings, high-grade materials, and superior load capacity translate to reduced friction, increased efficiency, and a longer service life, offering significant value for performance-oriented sailors.
Frequently Asked Questions
What is the maximum rope diameter this Ronstan block can handle?
This Ronstan Series 20 Double Ball Bearing Block is designed for a maximum rope diameter of 6mm (1/4").
What is the working load limit (MWL) for the Ronstan Series 20 Double Block?
The working load limit (MWL) for this Ronstan Series 20 Double Block is 350kg (770lbs).
Can the shackle head on this Ronstan block be fixed in position?
Yes, the two-way shackle head on this Ronstan block can be fixed at either 0° or 90° for precise control line orientation.
What are the typical applications for the Ronstan Series 20 Ball Bearing Block?
Typical applications include vangs, cunningham, outhauls, halyards, and traveller controls on dinghies, small keelboats, and other performance sailing craft.
What materials are used in the construction of this Ronstan block?
This Ronstan block is constructed with UV stabilized Acetal sheaves, stainless steel ball bearings, Grade 316 stainless steel fittings, and impact and UV resistant, fiber-reinforced Nylon cheeks.
