Re: sideways on anchor?
Is what the Sonata is doing sort of like some boats that "hunt" at anchor, flipping back and forth and tacking around while anchored? Maybe there's some extra windage forward, such as a loosely furled jib? Maybe something such as a small "riding sail" aft would do some good. Also, were you in an area that might have had a noticeable current at an angle to the wind? Does the boat balance and handle well under sail?