How to Decide on a New Furling Line for Your Headsail Reefing

When it comes to headsail reefing, the furling line is your lifeline. Choose poorly, and you’ll wrestle with stubborn jams, excessive stretch, or even line failure when you need it most. Select wisely, and reefing becomes a smooth, one-handed affair—even in a blow.

Establishing the Right Length

Before anything else, you must nail down how much line you need. You can often find a manufacturer’s recommendation in your furler’s manual. If not, measure on deck with your headsail furled and add these four elements together:

• The number of wraps you want on the drum
• The distance from the drum back to your cockpit, routed through blocks or fairleads
• The foot length of the sail when fully unfurled
• A tail long enough to reach a winch (plus a small safety margin)

Choosing the Correct Diameter

Most headsail reefing drums are designed for 6 mm line, though you’ll sometimes see 7 mm (rare) or 8 mm on larger yachts. The drum’s capacity ultimately limits your choice, so always verify the maximum diameter in your furler’s spec sheet

Decision-Making Factors

Break Load

If you anticipate winching your furling line under load—whether to overcome friction in the system or to reef in heavy winds—tensile strength becomes critical. Consider:

• Fibre composition, from 100 % polyester up to 100 % Dyneema
• The number of plaits: more plaits mean greater linear strength (8 plait through to 32 plait)

Flexibility

A supple line makes life easier around tight sheaves and blocks. However, flexibility drops off as plait count increases. An 8 plait braid is the most forgiving, while a 32 plait construction will feel stiffer around small-diameter sheaves

Friction and Grip

On a straight winch haul, you want minimal slippage—so good grip is a plus. If your line threads through several fairleads at sharp angles, a slicker finish might actually run more smoothly, though the quality of your blocks and bearings plays a far bigger role. Some ropes blend in dedicated grip fibres (for example, LIROS TopGrip), while others rely on a matte or bright multifilament cover to tune the friction profile

Beyond the Basics

A few other attributes can tip the balance:

• UV resistance and chafe protection for long-term durability
• A soft, easy-to-handle cover that won’t blister your hands
• Colour and diameter contrast for quick identification in a busy cockpit

All these factors add up to a furling line that’s not just strong, but user-friendly—even when the wind pipes up without warning.

Conclusion

By dialing in the correct length and diameter, then matching break load, flexibility, and grip to your sailing style, you’ll transform headsail reefing from grunt work into second nature. Next time a squall hits, you’ll be clipping in reef points before most crews have time to shout “Reef in!” More than just a technical choice, the right furling line is peace of mind at sea—because your headsail deserves nothing less than flawless control.