Well, if I don't love pirates. Especially lesbian pirates.
Here's an idea for you, if you'll indulge me:
You are a corsair of some infamy. Perhaps you are a captain, a commodore, a first mate, or your name might simply be synonymous with a great many crimes worth note. You are a rare woman of the seas, and your prowess (of the blade, over the sea, with a gun, take your pick) proceeds you. Much like your brethren, you think highly of yourself and your deeds, but also are afflicted by superstitions. You might have been hearing rumors of your future demise - perchance an oracle has prophecied your death, or you believe yourself to be cursed. One thing is certain: a sacrifice must be made for whatever reason, a woman, or you will die and your legacy along with you.
Since you are a character of, shall we say, flexible moral fiber, you decide that it would be easy to find yourself a "replacement" to serve your fate. Some unfortunate will do. You might bail out a prisoner, or pay the comparably meager debt of a poor bonded laborer. You choose someone who won't be missed, a maid of some misfortune, unwed and without children or family. She does not know of your plans for her - only that you are her savior.
What unfolds next could be anything: Does your character choose to betray this young innocent for the sake of her own life, or does she take pity on her? Does the relationship become tender, or does your character remain callous and self-serving?
PM me if you're interested in developing this plot. :)