Sassinak (The Planet Pirates Series)

That was the right age: old enough to be useful, and young enough to be broken. But Sassinak was a little different from the usual slave girl. Maybe it was her physical strength. Or her spirit. Or her friendship with the captured Fleet crewman. Whatever it was, it wouldn't let her resign herself to life as a slave. When the right moment came, she escaped. That was the beginning. Now Sassinak is a Fleet captain with a pirate-chasing ship of her own and only one regret: not enough pirates.