Asymmetrical keels perfect for multihulls

I recently read Chuck Husick’s article on winged keels and, as always, found it well written and informative. Unfortunately, it lacked any mention of multihulled vessels. This is not uncommon in most articles, but in this case the discussion lent itself to thoughts about multihulls. "Most boat keels are therefore symmetrical, equally curved on port and starboard. Obviously these keels are not as efficient as they might be if they were asymmetrical." These statements lend themselves to a discussion of catamarans that can be designed with asymmetrical centerboards for increased performance, with or without winglets. Why is it that so many designers and writers limit themselves in their discussions to just monohulls? Jon Rosenthal lives in Somers, Conn.