Why add a Code Zero?

Originally created to give non-overlapping rigs genoa-like punch on a reach, the Code Zero measures as a spinnaker yet behaves like a high-efficiency reaching headsail. Perfect for windy coasts, club racing, and distance legs where most miles are reached—not run.

Furling Options

Other Sails To Consider

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Old

The Code Zero was originally designed to give boats with non-overlapping jibs the power of an overlapping genoa when reaching. Upwind, high-aspect sail plans offered efficiency and rating advantages, making the lack of an overlapping genoa worthwhile. However, for boats optimized for windward-leeward racing that also tackled distance races, a challenge emerged: most distance race legs are reaches, and boats with non-overlapping jibs often have a significant gap between their jib and their flattest spinnaker. The Code Zero provided an ingenious solution—a very flat reaching sail that functioned like an overlapping jib but measured as a spinnaker. To qualify as a spinnaker, its mid-girth must be at least 75% of the foot length.

Today’s Code Zeros have advanced even further. They are now available with ISL (Integrated Structural Luff) technology, combining a Titanium lens luff with Code Zero laminate throughout the sail body. This construction enhances luff load management and reduces the need for oversized anti-torsion cables. Optimized for reaching, Code Zeros perform best at apparent wind angles between 45° and 70° and in wind speeds of 0–10 knots, making them a versatile and efficient option for both racing and cruising.

Code Zeros are a must for distance racing on modern boats with non-overlapping headsails. Boats with small jibs are at a major disadvantage when jib reaching — conditions when it is too close to carry a spinnaker, but the boat is not hard on the wind. Boats with overlapping genoas can get a lot more speed when they ease out their big genoas and they have the option of changing to an overlapping high-clewed jib top. Boats with non-overlapping jibs don’t have enough sail area for reaching.

The Code Zero is more than twice the size of a non-overlapping genoa. The pictures above show the same boat sailing with a jib and her Code Zero. Code Zeros takes the place of a high-clewed overlapping jib top.

Origin of the Name “Code Zero”

Racing spinnakers have a number coding where odd numbers designate reaching spinnakers and even numbers are for running spinnakers; e.g., Code 1 for a light air reacher, Code 2 for medium air runner, Code 3 for medium/heavy reacher, etc. Those codes were already in place the Code Zero was invented by the sailmakers for the 1997 Whitbread Round the World Race winner EF LANGUAGE. Since they created a sail for closer reaching than Code 1, the new sail jumped in front and was named Code Zero.

Furler Options

There are three different methods for controlling a Code Zero. For boats 33 feet and smaller, sails are small enough that a furler is not necessary. For mid-sized boats 33-44 feet, a simple direct furler is the best option; for boats over 42 feet, you’ll need a top-down furler to handle the Code Zero, which is getting quite big. There are many different companies making innovative furling units for Code Zeros. Talk to your local UK Sailmakers representative to find out which one will work best for your boat and budget..

Top-Down furlers work better with large Code Zeros and asymmetrical spinnakers because they roll up the roach and upper leech first. By rolling up the top of the sail first, the rest of the sail becomes blanked by the mainsail and as a result rolls up very tightly. Having a tight roll allows the sail to unroll better and a tight roll presents less windage so that it can be raised sooner without hurting your sailing performance.

Explore More Spinnakers

Asymmetrical Spinnakers

Code Zero — The Reaching Weapon

Fill the gap between your jib and your spinnaker with a flat, furling reacher that supercharges light-air performance and distance-race legs. Optimized for apparent wind angles ~45–70° and 0–10 knots.

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Why add a Code Zero?

Originally created to give non-overlapping rigs genoa-like punch on a reach, the Code Zero measures as a spinnaker yet behaves like a high-efficiency reaching headsail. Perfect for windy coasts, club racing, and distance legs where most miles are reached—not run.

Light-Air Horsepower

Take off in 5–8 knots

When it’s too close for a runner and too open for the jib, the Zero keeps boats moving, accelerating quickly out of tacks and lane changes.

Easy Handling

Furl & go

Set on a continuous furler for simple hoists, takedowns, and gybes. Stow cleanly on the bow and redeploy in seconds.

Rating-Smart

Measures as a spinnaker

Mid-girth ≥ 75% of foot length means it rates as a spin while acting like a reaching jib—ideal under common handicap systems.

UK Sailmakers Advantage: ISL Structured Luff

Upgrade your Code Zero with ISL (Integrated Structural Luff)—our lens-luff technology that shares forestay load into the sail, reducing cable size and improving furling and shape stability. Pair with our Titanium construction for a lighter, faster reaching package.

Straighter luff under load Smaller anti-torsion cable Tighter, cleaner furl

Learn about ISL

Ideal Range & Crossover

Apparent Wind Angle

Sweet spot for a classic racing Code Zero:

≈ 45°–70° AWA

Wind Speed

Designed for acceleration in light stuff:

0–10 kts TWS

Crossover

Bridges the gap between your non-overlapping jib and your flattest asym.

Angles shift by boat type and rig geometry—talk with your local UK designer for a target cut and luff profile that match your program.

Furling Options

Boats ≤ 33’

Smaller sails may be flown without a furler for minimum weight and cost.

33’–44’

Direct-drive continuous furlers are simple, fast, and reliable.

≥ 42’

Top-down furlers roll the roach first for tight, low-windage snakes and cleaner redeployments.

Materials & Build

True Code Zeros use low-stretch laminate with aramid/X-ply inserts to keep the sail flat and fast. We tune film, taffeta/LiteSkin®, and fiber layout to your boat’s righting moment and target wind range.

• Laminate body with strategic aramid inserts
• Optional taffeta/LiteSkin® for durability
• ISL upgrade for structured-luff performance

See the Difference vs. a No.1 Jib

Bigger Driving Area, Flatter Shape

On non-overlapping rigs, the Zero is dramatically larger than a No.1, but flatter than an A1—delivering genuine reaching grunt and point while staying rating-friendly.

Spec My Code Zero

FAQs

Why is it called “Code Zero” and how does it measure?

To qualify as a spinnaker under common rules, the mid-girth must be at least 75% of the foot length. The “Zero” label came from round-the-world programs that needed a closer-reaching “Code 1”—so the new sail jumped to “zero.”

How is this different from Code 55 / Code 65 terms I see online?

Those names describe geometry (mid-girth as % of foot). A classic Code Zero sticks to spin measurement (≥75%). UK will design to your rule, angles, and target modes.

Can I cruise with a Code Zero?

Absolutely. On furlers with UV options and the right laminate spec, it’s a low-drama power boost for close reaches and light air days.

Ready to reach faster?

Work with your nearest loft to choose luff structure, material, and furling that fit your boat and rating.

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