North Sails NEWS

TOP-DOWN FURLING IS BACK

The Helix Luff Cord Changes Everything

North Sails and Future Fibres co-engineered the Helix Luff Cord, the latest advancement in Load Sharing Technology. This exciting new product was designed and manufactured by North Sails partner Future Fibres, who took their vast experience and technical expertise in torsion cable and furler integration to the next level on this shared R&D project. 

Designed to work exclusively with North Helix sails, this innovative product brings top-down furling back to self-supporting Code sails. The Future Fibres Helix Luff Cord is a very light, thin, and pliable engineering solution that brings the benefits of top-down furling to Load Sharing sails. The cords are built to the precise tensile stiffness which allows for optimal Load Sharing between the cable and the sail. As the sail trim changes the cord to sail load ratio remains the same. The onboard benefit is a safe and reliable top-down furl while reaping the benefits of a free-flying, forward projecting Helix sail.

North Sails Head of Engineering and Design JB Braun and Future Fibres Project Manager Seth Cooley employed Future Fibre design tools in combination with the North Design Suite, validating the Helix Luff Cord Concept, and then understand the details aeroelastic coupling through a range of sailing conditions. Membrain, the North exclusive load analysis software, helped the team understand the loads on the boat, mast and sails, right down to the specific Load Sharing ratios between cord and sail. The designs were then run through Flow, which analyzed wind pressures across the sail as cord and sail load up together. 

“As the Helix concept has grown exponentially over the past year and a half, it became clear that bottom-up furling of 75% mid-girth sails was unreliable at best,” says North Sails President Ken Read. “It would have been easy to simply retrofit standard torsion cables back into Helix, but that isn’t our style. We needed to develop a system that incorporated lightweight and ease of handling along with clear sail shape and performance advantages. A tall task. Fortunately, JB, Seth and our teams came up with a product that is a true revolution.”

The Helix Luff Cord allows for “top-down” furling at a fraction of the size, weight, and stiffness of past luff cables. This, in turn, allows the Load Sharing and shape of the Helix sail structure to fly unencumbered by the stiffness, weight, and diameter of a conventional cable.  

The Helix Luff Cord (right) delivers reliable top-down furling at a fraction of the size, weight, and stiffness of traditional anti-torsion cables (left).

“This is the next step in the evolution of Load Sharing Technology,” JB Braun explains. “The Helix Luff Cord and sail work together, as opposed to a heavy anti-torsion cable which is designed to hold the rig up. And the same sail/cord load ratio is maintained through changes in sail trim. This allows the sails to change shape through tack line adjustment while maintaining optimum luff tension.”

Since its introduction, Helix has become the choice for cruisers, racers, and Grand Prix sailing because it offers superior flying shapes with less overall loading. Code Sails, laminate A-Sails, reaching headsails, and staysails have all benefited from the North exclusive Helix designs, and the Helix Luff Cord adds easier and more dependable Code sail-handling to the many other benefits of Load Sharing Technology. 

“Anyone can furl, unfurl, hoist and drop our Helix Code Zero now, at any apparent wind angle,” says Sam Richmond, sales manager for North Sails UK. “We have been developing and testing luff cords on Jethou throughout the past five months, mainly on our Helix Code Zeros. The Helix Luff Cord allows us to reap the benefits of the Helix design with its forward-flying luff and a radical reduction in loads on the bowsprit and mast, all while adding the safety and reliability of top-down furling. We no longer have to worry about losing boat lengths during a furl or unfurl, or the danger of handling big sails with bottom-up furling.”

To find out more about Helix and the new Future Fibres Helix Luff Cord contact a North Sails representative near you. The Helix Luff Cord is exclusive to North Sails, part of our mission to make sailing better for all types of sailors.

Read more about the Helix Luff Cord here.