Piratica - Tanith Lee

Trapped in the dreary Angels Academy for Young Maidens by her tyrant father, 17-year-old Artemesia Blastside (Art to her friends) dreams of the seafaring life she once led with her mother, a notorious pirate, killed six years before by an untimely cannonblast.

Unaware that her memories of glamorous characters and high adventure are not what they seem, she seizes her chance to escape. Now she's off in search of her mother's old crew, her heart set on the High Seas, the Blue Indies of the Caribbean, and on treasure Beyond the Dreams of Avarice. Careering through the haunts of highwaymen, pirates and smugglers Art sweeps a motley and unwilling crew into the treasure hunt of all time, and does her best to win her mother's crown as the feared and famous PIRATICA.