Furling drums
Our range of furling drums is specified for technically demanding sail handling systems, including Code Zero, gennaker, staysail and structural headsail furlers. Designed for continuous line furling under high torsional loads, these furling drums from Ronstan, Bamar, Morfrac and Facnor integrate with anti-torsion cables and top swivels to deliver controlled, repeatable furling performance on cruising and performance yachts. Read more...
Furling Drums for Continuous Line Furling Systems
Furling drums are the primary drive component within any continuous line furling system. They convert line input into rotational torque at the sail’s tack, enabling controlled furling and unfurling under load. In modern sailing applications—particularly Code Zero, asymmetric spinnaker and staysail configurations—the mechanical efficiency and load capacity of the furling drum directly determine system reliability.
Unlike conventional headsail reefing drums integrated into forestay systems, standalone furling drums are typically specified for flying sails operating on anti-torsion cables. These systems depend on efficient torque transmission from drum to swivel via the cable. Poor drum design results in delayed sail response, uneven furling or torsional loss in the luff cable. For medium to large yachts, particularly above 40ft LOA, correct drum sizing is critical to avoid slippage or line override under peak loads.
Our category includes furling drums engineered for:
- Code Zero furling systems
- Asymmetric spinnaker furlers
- Staysail and solent furling
- Structural furlers for detachable inner forestays
- Retrofit furling upgrades
Each furling drum is selected based on safe working load (SWL), maximum luff cable diameter, line diameter compatibility and bearing configuration.
Mechanical Design and Load Considerations
Technically advanced furling drums incorporate several key engineering features:
High Load Bearing Systems
Modern furling drums use Torlon or high-grade composite bearings, often in stacked or multi-race configurations, to reduce friction under axial and radial loads. For larger sail areas, sealed bearing systems minimise contamination and extend service intervals—particularly important for offshore cruising.
Structural Materials
Hard anodised aluminium, marine-grade stainless steel and composite hybrid constructions are standard. The drum body must resist deformation under torsional load while remaining weight-efficient to reduce pitching moment at the bow. Ronstan and Facnor systems, for example, focus on strength-to-weight optimisation for performance cruising and race applications.
Line Management Geometry
The drum diameter and line groove depth determine furling line grip and prevent override. Larger diameter furling drums reduce required input load but increase overall system weight. Correct specification balances ergonomic handling with mechanical advantage.
Integration with Anti-Torsion Cables
Efficient furling requires precise alignment between drum, anti-torsion cable and top swivel. Morfrac and Bamar furling drums are frequently integrated into complete structural or modular furling assemblies, ensuring consistent torque transmission through the luff.
| Brand | Model Range (Typical Series) | Safe Working Load (kN) | Max Luff Cable Ø (mm) | Typical Sail Type | Typical LOA Range |
|---|---|---|---|---|---|
| Ronstan | Continuous Line Series 80–160 | 15 – 45 kN | 8 – 14 mm | Code 0 / A2 / Gennaker | 30 – 55 ft |
| Bamar | RLG / GX Series | 20 – 60 kN | 10 – 16 mm | Code 0 / Staysail / Solent | 40 – 65 ft |
| Morfrac | MF Structural Series | 30 – 80 kN | 12 – 18 mm | Structural Staysail / Code | 45 – 75 ft |
| Facnor | FX+ / Structural Range | 12 – 60 kN | 8 – 16 mm | Gennaker / Code 0 / Solent | 30 – 65 ft |
Furling Drum Key Brands
Ronstan
Ronstan furling drums are widely specified for performance cruising and race yachts. Their continuous line drums are engineered with low-friction bearing arrays and compact geometries suited to Code Zero and gennaker furling. Load ratings are clearly defined, allowing accurate matching to sail area and cable diameter.
Bamar
Bamar offers modular furling drum systems that integrate with both structural and removable cable configurations. Their engineering emphasis lies in mechanical durability and serviceability, making them suitable for offshore and bluewater installations. Many Bamar drums are compatible with electric or hydraulic drive retrofits in larger yacht applications.
Morfrac
Morfrac furling drums are typically specified in structural and high-load applications. Known for precision-machined components and high working load tolerances, they are frequently selected for larger Code sails and staysails on performance cruisers and race yachts.
Facnor
Facnor’s FX and structural drum systems are commonly used in flying sail furling. Their continuous line drums are engineered for ease of installation and compatibility with removable anti-torsion cables. Facnor furling drums are frequently chosen for retrofit projects due to their modular design and clearly defined load bands.
Applications of Furling Drums Onboard
Furling drums are not limited to downwind sails. Correctly specified units are used across multiple sail handling systems:
Code Zero Systems
High luff tension and torsional loads demand a furling drum capable of transmitting consistent torque without distortion. Larger diameter drums reduce line effort when furling under residual load.
Asymmetric Spinnakers and Gennakers
Lightweight furling drums are preferred to minimise bow weight. Efficient bearings are critical to avoid friction when furling in marginal breeze.
Staysails and Solent Sails
Structural furling drums used with inner forestays allow controlled sail deployment without the complexity of permanent forestay reefing gear.
Removable Furling Systems
Many furling drums are designed for quick installation and removal, making them suitable for performance yachts that wish to minimise windage when sails are not in use.
Selection Criteria for Furling Drums
When specifying furling drums, technically minded owners should assess:
- Maximum safe working load (SWL)
- Breaking load margin relative to sail luff tension
- Anti-torsion cable compatibility
- Furling line diameter and length
- Bearing type (sealed vs open race)
- Overall drum diameter and weight
- Serviceability and spare parts availability
Overspecification increases weight unnecessarily, while underspecification risks torsional inefficiency and premature bearing wear.
Furling Drim Installation and Integration
Correct installation of furling drums is essential for consistent performance:
- Ensure axial alignment between drum and swivel
- Avoid lateral load from misaligned tack fittings
- Maintain correct luff cable tension
- Use low-stretch continuous furling line
- Regularly inspect bearing condition and line groove wear
For larger yachts, furling drums may integrate with bowsprits, padeyes or structural tack fittings designed to handle peak loads generated by Code sails.
A Technical Approach to Furling Drums
For medium to high net worth yacht owners who prioritise mechanical reliability and precise sail handling, furling drums are not generic components. They are load-bearing drive systems that directly affect sail control, safety and deck workflow.
Our selection of furling drums from Ronstan, Bamar, Morfrac and Facnor focuses on engineering integrity, defined load ratings and compatibility with modern furling architectures. Whether upgrading an existing Code Zero system or specifying a structural staysail furler, accurate drum selection ensures predictable, repeatable performance offshore and inshore alike.
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