Description
The Nautos Line Single Swivel series offers a comprehensive range of high-performance, swivel-mounted single blocks designed for marine rigging systems. Whether you're working with 28 mm, 39 mm, 57 mm sheave diameters — or configurations with fixed head, becket, or ratchet — these blocks deliver reliable performance for Irish boating and sailing environments. Each variant is engineered to provide smooth rotation, strong load capacity and minimal friction—critical for control lines, halyards, traveler and sheet systems exposed to salt spray, tidal shifts and variable weather around Ireland. With Nautos’ proven heritage in sailing hardware, this series supports everything from small craft to larger yachts needing durable, efficient rigging components.
Features
- Individually available in several sheave sizes (28 mm, 39 mm, 57 mm) to match rope sizes and system loads.
- Swivel head design ensures alignment with line direction, reducing side-loading and wear.
- Fixed-head variants keep orientation fixed for consistent line behaviour where required.
- Becket versions provide a fixed eye/loop for anchoring or purchase systems in one unit.
- Ratchet variants add a selectable locking mechanism to control line movement under load.
- High-load aluminium / composite materials ensure marine-worthy durability and low weight.
- Ball or plain bearing options (depending on model) to optimise performance and lifetime.
- Compatible with control lines, halyards, sheets and rigging systems on Irish-based vessels.
Specifications
| Sheave Diameter | Rope Compatibility & Load Data* |
|---|---|
| 28 mm | Max line: ~10 mm, SWL ~120 kg, Break load ~750 kg |
| 39 mm | Sheave: 39 mm; typical max line ~10 mm; SWL ~135 kg, Break load ~820 kg. |
| 57 mm |
Example model: 57 mm sheave, Working load: ~550 lbs (~250 kg), Breaking load ~2,100 lbs (~950 kg). |





