The new way to cross oceans
Nominated for the 2025 DAME Design Awards.
The IFS Multi Tradewind Sail (also nicknamed the Batman Sail by the online community, after a OneSails video of the black prototype recently went viral on the internet) is an evolution of the traditional twin-headsail system, developed to deliver more power and boat speed with furling simplicity, greatly improved efficiency and control in long-distance downwind sailing.
Building on established trade wind concepts, this sail integrates two structured – luff IFS gennakers on a single furling unit, eliminating the need for heavy, stiff and expensive anti-torsion cables. The result is a lighter, more powerful configuration with a significantly larger sail area and improved aerodynamics compared to conventional twin genoas or spinnakers.
Each section of the sail can be deployed independently or together, adapting seamlessly to all downwind angles.
The system uses standard furling and adjustable clew connections, allowing fast and intuitive operation. It reduces the need for complex sail changes, making it an ideal solution—especially, but not only—for ocean crossings and long-distance cruising, where reliability and simplicity are essential.
This sail is suitable for both multihulls and monohulls. On monohulls, the overall width should be designed according to whether or not spinnaker poles will be used.
Both sails open symmetrically to create a stable and efficient “twin-genoa-like” setup for deep downwind sailing, with TWA between 165° and 180°. Unlike traditional twin genoas, however, these sails can be easily furled, taken down, and stowed in a compact, spinnaker-style bag.
Both sails are set on the same side by simply connecting both clews to the same sheet — they function as a gennaker for reaching angles up to 90° TWA, maintaining consistent power and precise airflow.
Its total surface area can be up to 35% larger than that of a symmetric spinnaker, and since this additional area is concentrated in the lower part of the sail, the boat becomes less prone to rolling and nose-diving.
As a result, it delivers greater thrust, improved stability, and reduced overall load on the upper section of the mast.
The sail is also very safe when running, as easing the clew sheets increases twist in the upper luff sections, providing an effective and simple depowering option.
Sail surface areas in the simulation:
Constructed with advanced materials and featuring a structured luff using OneSails’ exclusive Integrated Furling Structure (IFS) technology, the Multi Tradewind Sail combines lightness, strength, versatility, and durability with the refined craftsmanship that defines all OneSails products.
For over 15 years the OneSails design team have developed exclusive technologies to make one-piece continuous thread sails a reality for cruising and racing boats.
Features like weight, shape control and deformation resistance means better performance compared to traditional panelled sails.
Sails are designed and manufactured to the very highest standards from carefully selected components to ensure the very highest quality and durability. 4T FORTE™ membranes are exclusively made in Italy. All the assembly process is completely made in a unique factory ensuring the meeting of all the required standards.
The best sail shapes are the result of continuous analysis and experience. OneSails is at the forefront of the sailmaking industry, continually investing in research and development to ensure that the very best sail shapes are available. The success of this approach is confirmed by the vast array of racing trophies OneSails clients have won, competing at National, International and World Championship level.
A core activity for every OneSails Loft is providing first class service, support and assistance. As part of our service commitment, each OneSails Loft has a team of experts on hand to ensure that we can deliver on our service pledge. In addition to a growing number of principle lofts, the OneSails Group has an extensive network of service centres strategically placed worldwide’s coast line.
