One of the world’s most prestigious boat brands has changed hands. Oyster Marine, founded by Richard Matthews 35 years ago, has been bought by private equity firm Balmoral Capital. The company already owns the Italian luxury motoryacht builder Canados. Oyster Marine builds a range of luxury yachts from 45 to 125 feet, and its revenues amount to more than $100 million a year. Matthews will remain as chairman and the existing management team will stay on.