Description
Ronstan Series 55 Orbit Block Swivel Single Becket | Boat Supply Store
For sailors demanding optimized performance and minimal weight, this Ronstan Series 55 block provides the industry's lightest ratio of weight to working load. Its unique orbital design and 2-stage bearing system achieve a class-leading Maximum Working Load (MWL) of 500kg (1,100lbs) with a sheave diameter of 55mm and accommodating up to 10mm rope diameter. It is engineered for mainsail and spinnaker sheets on dinghies, sportsboats, and small keelboats up to 9M (30').
Key Features
- Ultra Lightweight construction minimizes overall rig weight.
- Low friction 2-stage Orbital ball bearing system for superior efficiency.
- Highest working load in its class ensures robust performance under stress.
- Low profile and compact design reduces windage and snagging.
- High performance cleating capabilities for secure line management.
- Swivel shackle head allows unlimited block rotation for optimal lead angles.
- Stainless steel shackle head provides ultimate durability and corrosion resistance.
- Ultra low profile integrated becket for direct load attachment.
Specifications
| Product Specifications | |
|---|---|
| Sheave Diameter | 55mm |
| Max Rope Diameter | 10mm |
| Maximum Working Load (MWL) | 500kg (1,100lbs) |
| Breaking Load (BL) | 1,000kg (2,200lbs) |
| Weight | 88g (3.1oz) |
| Bearing Type | High-compression strength acetal ball bearings, carbon fiber reinforced sheave and stage 2 bearing |
| Frame/Cheeks Material | Glass fiber reinforced nylon |
| Rope Link Material | Dyneema® |
| Head Fitting Material | Grade 316 stainless steel |
Who This Is For
Ideal for sailors of dinghies, sportsboats, and small keelboats up to 9M (30') requiring high-performance mainsail and spinnaker sheet control. It is also suitable for control line applications like halyards, vangs, and backstays on boats up to 8M (26').
How It Compares
| Feature | Ronstan Series 55 Orbit Block Swivel Single Becket | Competitor |
|---|---|---|
| Sheave Ø | 55mm | — |
| Max. Rope Ø | 10mm | — |
| M.W.L. | 500kg (1,100lbs) | — |
| Weight | 88g (3.1oz) | 110g (3.9oz), 95g |
| Bearing Type | 2-stage Ball Bearing | Ball Bearing, Synchro Bearing |
| Head Type | Swivel Shackle | Swivel Shackle, Swivel |
Common Concerns Answered
Is the integrated becket system adaptable for all rigging configurations?
While the integrated becket offers a streamlined, low-profile solution, some custom rigging setups may benefit from the versatility of a separate becket block. Evaluate your specific rigging needs to determine the optimal configuration.
Is this block significantly more expensive than basic alternatives?
The premium materials and advanced 2-stage bearing system contribute to a higher initial price point. However, the substantial weight savings, reduced friction, and enhanced durability offer significant long-term value for serious sailors.
How does the load capacity compare to competitors?
This block boasts a high working load of 500kg (1,100lbs) within its class, though some competitors may offer higher ratings. The Ronstan Series 55 prioritizes an exceptional weight-to-load ratio, making it ideal where weight savings are critical.
Frequently Asked Questions
What is the working load limit (MWL) of the Ronstan Series 55 Ball Bearing Orbit Block™?
The Maximum Working Load (MWL) for the Ronstan Series 55 Ball Bearing Orbit Block™ is 500kg (1,100lbs).
What is the maximum rope diameter this block can accommodate?
This block is designed to accommodate a maximum rope diameter of 10mm.
What are the primary applications for the Ronstan Series 55 Ball Bearing Orbit Block™?
Its primary applications include mainsail and spinnaker sheets on dinghies, sportsboats, and small keelboats up to 9M (30'), as well as halyard, vang, and backstay applications on boats up to 8M (26'). It is also suitable for control lines on larger yachts.
What materials are used in the construction of this block?
The block is constructed with high-compression strength acetal ball bearings, a carbon fiber reinforced sheave and stage 2 bearing, a glass fiber reinforced nylon frame/cheeks, a Dyneema® rope link, and a Grade 316 stainless steel head fitting.
How does the Ronstan Series 55 Ball Bearing Orbit Block™ compare to its competitors in terms of weight and load capacity?
The Ronstan Series 55 is exceptionally lightweight at 88g (3.1oz), often lighter than comparable competitors. While its 500kg (1,100lbs) MWL is substantial, some competitors may offer higher load ratings. However, its unique orbital design maximizes efficiency and minimizes inactive bearing mass, offering an excellent balance of weight and performance.
