The black banner - Helen Hart

1719, and the high seas are plagued by the lawless. Pirates rule the crystal waters of the Caribbean, hunting heavily-laden merchant ships with savage ferocity. Entire crews are condemned to die beneath a cutlass blade unless they swear allegiance to the black banner.
Penniless Becky Baxter crops her hair, dresses in breeches, and leaves the dangerous backstreets of Bristol far behind. She embarks on a new life of adventure and fortune as the youngest deckhand on a merchant ship, the Bonny Marie. But she quickly discovers that there are far more dangerous enemies than her drunken Ma and evil Mr Crudder.
Pirates!