Ghosts of the Sargasso — Bill Craig

When their steamship back to England is sent off course and marooned, Hardluck Hannigan and his friends find themselves trapped in the mysterious ‘graveyard of ships' known as the Sargasso Sea. Soon they discover that they must battle not only the elements for survival, but a renegade pirate tribe living aboard the derelict ships and a deadly menace from beneath the waves that threatens all of Humanity!