SOLVED. Pirate story [s]

[Marsha]

I remember that the cover featured a black-haired pirate woman looking in bemusement at the male minstrel seated at her feet. That was the main story: a female pirate captures a minstrel and starts a relationship with him. I believe the pirate may have been called Blackhair.

[Juels]

Maybe the Bard series by Keith Taylor.

Bard
Bard III: The Wild Sea
"I am called Felimid mac Fal. I am a bard of the old blood, a lesser degree of Druid. Where I come from, bards have been knows to sing armies to defeat or victory and kings off their throne or on to them. Descended from the faery folk, the Tuatha de Dannann, my line's been poets and harpers in Erin since the world was new, and magic's in our heart-marrow.
She is called Gudrun Blackhair...as well as names a good deal less polite. She is the most dangerous pirate on the open seas, master of the enchanted ship Ormungandr, and the woman of my heart. If you wish to know more than that, ask the ballad singers and gossip mongers at any tavern. Half of what you hear will be fact, half will be lies, and even I can no longer separate the two. Yet this story, perhaps the strangest of them all, of shapeshiters and sorceresses and the sea-dwelling Children of Lir, is naught but the gods' own truth...on my honor as a bard."

[Marsha]

The cover is not what I remember. But the description seems absolutely right! So it looks like you got it. I'll make a note to look for it and mark this as SOLVED.