North Sails NEWS

June 10, 2019


new code sailWhat Is A Code Sail?

The name ‘Code Sail’ means different things to different sailors. What started out as a straightforward but innovative concept has rapidly evolved into a whole new category of sails. While Code Sails may look and perform quite differently from one another, there is one common theme: Code Sails are fast, flat, free-flying sails, designed for close reaching angles.

To understand all the different names and versions, it may help to look back at the origin of these sails. Originally “Code Zeros” were designed to qualify as spinnakers under various rating rules that require the mid-girth to be 75% of the foot length. Volvo Ocean Racers coined the term Code Zero, which fit into the established North Sails coding convention: A1, A2, A3, etc. This design also became popular among handicap racers under Rules like IRC, ORR, and PHRF. As their effectiveness and ease of use became increasingly apparent, Code Sails expanded into cruising as well. Multihull sailors have always called their specialized high performance reaching sails “Screechers”.

Code Sails add a great deal of sail area and power for close reaching angles. Boats with non-overlapping headsails see the biggest benefit from Code Sails, as these sails better fill the inventory gap between upwind headsails and downwind spinnakers.

When purchasing a Code Sail, it’s important to consider your boat’s performance, target wind angles, most common wind speeds, sail handling systems and the right sail material – so the sail can be customized to your specific needs.




code sail size chart



Code Zero Asymmetric Spinnaker – Mid Girth (SMG) >75%

Used for rating rule racing, this sail remains much the same in concept as the original Code Zero. The design requirement is the flattest possible sail with a spinnaker mid-girth of 75%. The challenge of designing and building a Code Zero Asymmetric Spinnaker is meeting the 75% girth measurement while producing a sufficiently flat sail shape. Code Zeros carry unsupported mid-girth sail area that is not aerodynamically efficient for light-air close reaching. Code Zeros can be made in 3Di Downwind or Code style aramid laminates.

Helix is a specialized sail structure evolved from North Sails Load Sharing Technology. Helix is now available for Code Sails, Genoa Staysails, Spinnaker Staysails, Jib Tops, Blast Reachers and other specialty reaching sails. The Helix structure is designed to handle sailing loads while providing sufficient torque for furling. Helix sails are more versatile, from light air close reaching to heavy air broad reaching. Helix structure and optimized shaping results in sails that are furling, self supporting and forward projecting. For more information, please read the Helix Blue Paper.


Code 55 + 65 (SMG 51%-74%)

A Code 55 has a 55% SMG while a Code 65 features a 65% SMG. (SMG is mid-girth as a percentage of foot length). Code Sails with mid-girth between 50% and 75% are highly efficient and versatile sails. However, these sails are sometimes treated unfavorably (if not outright banned) by certain rating rules. For offshore racing, multihull sailing and performance cruising, these Code Sails provide pure reaching performance. A smaller SMG percentage implies a flatter sail for closer wind angles, while a higher SMG percentage implies a slightly fuller sail for wider wind angles. An SMG less than 51% is considered a genoa, while an SMG greater than 74% is considered a spinnaker.

code 65 sail

Free Flying Genoa (SMG<50%)

Not all free-flying furling sails are considered Code Sails. If an overlapping headsail is to be sheeted hard and used upwind, it is a Genoa. Upwind Genoas have leech-oriented sail structure, while offwind Code Sails have luff-oriented sail structure. “Flying” sails are defined by the Equipment Rules of Sailing to be “set with no sail edge attached to the rig.” As a result, upwind flying sails require High Modulus Luff Ropes and Anti- Torsion Ropes when set on furlers.

genoa sail

A3 (Hybrid) Asymmetric Spinnaker – Mid Girth (SMG) 75-85%

This is another popular rating rule sail that tends to be a little more versatile than a Code Zero. The shape is halfway between a Code Zero and traditional A3 and can be built from 3Di Downwind, Code Sail laminates or light polyester spinnaker material. These sails are not necessarily used on a furler. The A3 Hybrid will not sail as close-winded as a Code Zero, but can cover a wide range of angles and conditions.

a3 hybrid asymmetric spinnaker