Light Air Tight Reacher - A0
What is it?
The smallest Asymmetrical allowed by the IRC rules, the A0 (more commonly known as a the Code 0), is a specialty sail for light air close Reaching, as high as 40 degrees apparent, and as low as 85 degrees apparent.
Code Zero asymmetrics fit effectively into the crossover gap between a genoa and the 3A reacher. They provide additional power in true
wind speeds under 10 knots; conditions that are typically slow with small jibs. Code Zeros have also proved effective for reaching in 15+ knot winds at 80 to 90 degree apparent wind angles. Most
boats sailing offshore and coastal races can often put a Code Zero to good use.
Code Zero Design:
Code Zeros are closer to a oversized hybrid genoa than they are to a typical asymmetric spinnaker. For racers, a Code Zero wants to measure as close to a genoa as possible while still qualifying as a legal spinnaker. To rate as a spinnaker, the leech must be less than 95% of the luff in length and Mid Girth must be at least 75% of the foot length. If the Code 0 has a smaller Mid Girth it will rate as a huge Genoa giving a handicap hard to defend.
They are designed with a flatter shape than other asymmetrics and a more twisted flying shape. The luff needs to set relatively straight and the leech has a small positive fan (roach).
Construction and materials:
Code 0s can be constructed in Nylon or laminate pannels or even membrane laminate.
Nylon sails will have a lower upper range while specialty CZ laminates will allow to carry them with more wind and point higher as will of course a superlight membrane.