Not folklore, not myth, maybe legend, but HISTORY. This is a brilliant presentation of history that we English have largely deleted. I have visited Clew Bay, I bought Anne Chambers' book, I regularly listen to Shaun Davey's suite of music, 'Granuaile'. I fell in love!
They cut out the most important part. Her father's excuse for not letting her sail with him, was that her hair would get caught in the shipping ropes. So she shaved her head, earning the knickname Grainne Mhaille- Bald grainne
There hasn't been 56 generations since Grace O'Malley lived. She may be your ancestor but she would be more like your 15th (give or take a couple generations) great grandmother.
Wouldn't it be fascinating if Xena was a heroine or warrior queen who truly existed in the pages of history, and I don't mean - Syfy history. Ha ha ha...