Kathy Bray offers the opinion that Brightman may be referring to Alpha, #416.
"When the 'Wasp' was being rigged and fitted out the little centerboarder 'Alpha,' that we have just spoken of, was also completed. Captain Nat had just taken her out for her trial and brought her in to the wharf near the 'Wasp' where Captain Barr was greatly admiring 'Alpha.' Captain Nat, who was always fond of Charlie Barr, said, 'How would you like to take her out for a spin?' Charlie jumped at the opportunity, and calling a couple of his crew from 'Wasp,' boarded 'Alpha.' At the time Charlie was only about twenty-four years old, and all of his experience had been in heavily ballasted Scottish cutters. He ordered one of his men to cast her off and pull the jib to windward. When this was done 'Alpha' turned on her heel like a top, filled her sails, and promptly capsized. It is said she hardly went a boat's length before she was flat on her side and swamped. Of course a light boat like 'Alpha' should be ballasted by her crew moving to windward, and has to be luffed or have her sheet eased in the puffs, but when properly got under way might carry her sail in a fair breeze. Captain Nat used to tease Charlie Barr about that incident in the years to come when Captain Charles Barr had become the greatest of all yacht captains." (Source: Herreshoff, L. Francis. The Wizard of Bristol. The Life and Achievements of Nathanael Greene Herreshoff, together with An Account of Some of the Yachts he Designed. New York, 1953, p. 167-168.)