Jade by Sally Watson

Her name was Melanie Lennox, but she preferred to be called Jade. "Swords, adventure, freedom," sixteen year old Melanie cried," and I'll pay any price!" Driven by her courageous, independent spirit and hatred of slavery, Jade attempts to release a ship's cargo of slaves destined for bondage in Virginia. While she is being publicly flogged for her efforts, the ship is captured by pirates, and Jade, undaunted and realizing her opportunity for adventure, decides to join them.

"This exuberant madcap book (who but Sally Watson would end it that way?) fits into the family saga beautifully. It’s a sparkling, stirring off-the-beaten-path of a book." - Horn Book