Leech cord tension is very sensitive and can span a wide range. The sheeting point is usually the spinnaker sheet block, although a tweaker might be required. In any case, the halyard needs to be very low stretch and very strong. Some rig builders advise the use of a 2:1 halyard in order to reduce compression on the spar. The sail should set with minimum cloth tension on the luff. Tie it off as short as possible as it is easier to ease than add tension later. When setting the sail, make sure the luff cord is tensioned more tightly than you think would ever be needed. An alternative method is lots of good stopping yarn or zippered snakes. When raising, simply hook up the corners, hoist and release the furling line as the sail is sheeted in. The preferred is a roller furling luff, which allows the sail to be rolled and stowed in a spinnaker box bag. There are two methods of handling Code Zeros. Area limited sails might need longer foots if there is a minimum area requirement that needs to be met. Girth-limited Code Zeros may need shorter foots. The foot is usually close to half the luff length, but also can be governed by handicap, rating or class rules. The leech is designed close to the maximum allowed.
If the sail will set on a furler (recommended), clearance between the drum and the headstay must also be accommodated.
Zeros exert a lot of upward force in order to fly with the luff as straight as possible. These sails are rarely set on conventional spinnaker poles and extreme caution should be used setting a Code Zero on retractable sprit-style poles. Ideally, the tack point is a strong fixture on the boat forward of the headstay. This is determined by measuring the distance from the raised halyard point to wherever the tack will set. (This is in the RRS, as well)ģ)Additionally, asymmetrics are limited to a maximum width (girth limited) or to an area through a formula using luff, leech, foot and mid girthĪ Code Zero luff should be as long as the rig allows. Typically, that means:ġ)The leech must be less than 95% of the luff in length.Ģ)Mid girth must be at least 75% of the foot length. Wind tunnel testing indicates this configuration increases forward force with a lower side force and center of effort than a fuller sail with more normal edge profiles.Ĭode Zero design can be affected by limits placed on them by rating rules, handicaps or class rules. The luff needs to set relatively straight and the leech has a small positive fan (roach). The Zero has more vertical curvature than a genoa and carries a much more twisted flying shape. A typical light genoa’s mid camber is around 16% and a V-Series 1A asymmtric’s mid camber is around 23%. The draft sections are evenly shaped with a mid-stripe camber of around 20%. They are designed with a flatter shape than other asymmetrics, yet still fly without the leech flapping. For racers, a Code Zero wants to measure as close to a genoa as possible while still qualifying as a legal spinnaker. Most boats sailing offshore can put a Code Zero to good use.Ĭode Zeros are closer to a oversized hybrid genoa than they are to a typical asymmetric spinnaker. Code Zeros have also proved effective for reaching in 15-25 knot winds at 80 to 90 degree apparent wind angles.
40-degrees AWA in true wind speeds under 10 knots conditions that are typically slow with conventional sails. not only used by boats that spend a lot of time close reaching in light air, but also in windier conditions and wider angles.Ĭode Zero asymmetrics fit effectively into the crossover gap between a genoa and the ubiquitous 3A asymmetric reacher. A decade later, North “Code Zero” (A0) asymmetrics are versatile members of mainstream inventories. In the opening leg of the 1997-98 Whitbread Around the World Race EF Language unveiled a “secret weapon.” It was a new close-reaching asymmetric developed by North sail designers dubbed the “Code Zero,” and it vaulted EFL to an early lead the team would never relinquish.
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