Gennaker, Screecher, Code One & Asymmetrical Spinnaker

Dear Dan,

Could you please explain the differences between a gennaker, screecher, code one and asymmetrical spinnaker? Is it possible to have a gennaker cut for reaching and another gennaker for running? What would be your recommended sail selection for a performance 55′ catamaran? Thank you, Chris

Hi Chris, Gennaker, Screecher, and Asymmetrical Spinnaker are all names that describe the same type of sail. If you go back about 15 years, most sailmakers offered one model of sail in the Asymmetrical category. I think "Gennaker" was the name that North Sails used to describe their sail and Screecher might have been the name that Ulmer Sails chose (I could be wrong about this). At any rate there were a bunch of marketing names to describe a new product category, and the better names have become part of the confusing sailing lexicon in the same way that face tissues all became known as Kleenex. Today the asymmetrical sail category is much more refined and the models of sails are in general more targeted for specific ranges of apparent wind angle and strength.

Each sailmaking company still has its own nomenclature for A-sails, but most follow the convention established by the Whitbread 60 (later Volvo 60) class, and then adapted by the IACC (Americas Cup) class sailors. A top level race boat with an asymmetrical spinnaker inventory will own 6 A-sails ranging from a Code 0 to a Code 5. The Code 0 is a funny sail that is made to act like a huge Genoa but look like a spinnaker to the rating rule. The Code 1 is for sailing tight angles in light air conditions. The Code 1 is sometimes called a "VMG" sail because it is used in conditions where the boat is gybing back and forth looking for the optimal angle for speed while trying to get downwind. Code 2 and Code 4 sails are runners for medium and windy conditions, respectively. Code 3 and Code 5 sails are for reaching angles in medium and windy conditions. (Lower numbers mean lighter wind strength. Even numbers are runners, odd numbers are reachers.)

For cruising boats there are typically 2 or 3 choices of A-sails. A Cruising Code 0 (or G-0 in North Sails nomenclature) is the same as a Race Code 0 only better because there are no rules that result in contorted edge shapes. The other choices are an all-purpose sail with an emphasis on broader angles (G-2 in North Sails nomenclature) and an all-purpose model with a reaching bias (G-3). If you bought two sails for your catamaran you would probably want a G-0 and a G-2. If you only want to pay for and carry one sail you will be better off with a G-3. Regards, Dan Neri

Posted by admin  (November 30, 1999)

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