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Asymmetrical Spinnakers: A3 Medium Air Reaching

An A3 on the Express 37 LORA ANN at the start of the Newport to Bermuda Race.

AWA 75°-130°  

AWS 10-20 kts

Mid Girth 85% -95%

Med entry

Med. to heavy cloth

Reaching spinnakers are flatter than running chutes to reduce heeling and so that they can sail tighter wind angles. While an A3 has the same area as an A1, the material on the A3 is heavier to handle the greater loads. While an A1 would be made out of half-ounce or .6 oz. nylon, an A3 would be made out of .75 oz. to .9 oz. cloth.

The heart of faster spinnakers is the construction method. The panel layout UK Sailmakers uses is called Matrix, which is a full radial layout that features narrow panels, each oriented to better align the threads in the cloth with the primary load paths in the spinnaker. This is the most effective way to reduce distortion and make the strongest sail for its weight.

Each panel is shaped on all four sides in order to create a smooth round sail. For one sail to be so versatile, it needs to hold its shape without distorting. Distortion becomes most obvious when close reaching. Spinnakers made with generic nylon cloth stretch in the middle, causing their leeches to harden or hook; which reduces driving power, creates drag, and increases heeling. The only way to prevent distortion, without using too heavy a fabric, is to use performance nylon spinnaker cloth like those made under the Superkote and Airx names. These materials have the same strength and stretch resistance of one weight heavier standard nylon. 

Spinnaker Painting Program

Use this program to create a custom look for your new spinnaker or cruising spinnaker. Click here to go to the Spinnaker Painting Program.

A J/122 sailing with her A3; notice how flat it is.
The Beneteau First 34.7 CIRCA running in heavy air with an A3.

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