If you are basing YOUR arrangement of the words on any of the broadside versions (or your own devisings from them) and you are playing and singing YOUR arrangement of any of the traditional versions of the tune, the resulting arrangement is YOURS and nobody else's. Copyright in THAT version is YOURS and nobody else's. Of course if you then put up a recording on YouTube, you're handing them a deal of rights in THAT production (your choice!)

If you are copying somebody else's work, none of the above applies.

Ross