If a mermaid met a woman pirate...

In alot of stories i see a mermaid meeting a man and seducing him or capturing him with her seductiveness. then she pulls him off the ship to drown or to whatever doom she has planned.

but....

i wondered what would happen if a mermaid came ready to attack and popped up out of a water to see a woman staring back her. would her seductive charms work, if the woman was heterosexual? or what would happen? would they get along or would the human woman have a clue and shoot her in the face with a musket or something? or why would there even be a woman on a ship because they're suppose to be bad luck. i'm thinking pirates of the Ccaribbean world and time frame.

The woman pirate and the mermaid would exchange tips for how to keep their eternally greasy hair so clean in the salty air. Or even tips on how to attract men and render them helpless.

Beware of the mermaid trained by the woman pirate. She probably can board the ship unencumbered by her fish tail and wield a cutlass with the best of them.

What's the chance that the woman pirate meets a really hot merman? Or do merman stay home to raise the kids while mermaids bring home the long bacon?

They should form a partnership.

For a pirate, the help of a mermaid who can serve as a spy or as a distraction would be invaluable, not even to mention that the mermaid would probably leave her male crewmembers alone (preventing such awkward incidents like the one when the bosun suddenly went missing due to mermaid influence) and might encourage other mermaids not to target that particular ship (if mermaids have any sort of society at all and aren't solitary creatures). Having the help of a mermaid would also come in handy if the pirate ever finds herself marooned or thrown overboard.

As for what the mermaid gets out of the deal: If the pirate is primarily interested in looting the ships, she certainly would not mind handing over all the prettiest sailors to the mermaid (if that is what the mermaid wants). Having a ship as a safe haven to retreat to could also be useful (perhaps mermaids are threatened by predators like sharks or orcas - and who knows if preying on unsuspecting humans is all right in mermaid society, or if a mermaid who does such things is their equivalent of an outlaw and might need to hide at times?).

You can make whatever you want to happen.

As Dennis said, you can have the ladies share tips (although I took it as more of a joke, mind you).
As you suggested, they could have a fight. Considering the mermaid surfaced to collect dinner I suppose it would just be harder than seducing a man, but she still needs to feed her kids (or whoever...).
OR maybe mermaid's powers DO work on a lady, although I'm not sure if you've ever watched Sinbad but in that movie all the male pirates were affected, but the dog and the lady weren't. You might want to research a bit about the mermaids, see if the legends say they stick to men only. Although now that I think about it, you could have the fact that they knew how to seduce both genders and there was a time when both mermaid and merman surfaced to fetch dinner, but because the ships carried men, throughout the years things changed and mermen stayed at home. Because of that, through generations they lost their power to seduce the women and now we've got a human female and a mermaid sprawling to the death, because she can't be fooled? :3