Dick, your chorus is almost exactly the same as the original Harrigan song, posted near the top of this thread. Listen to Mick Moloney's recording for Braham's tune.

Brian, I don't think the Braham (original) and the Fish tunes are that different really; I feel oral tradition could easily transmutate one from the other. Of course the chorus is a little different.

The Irish Rovers also recorded a song called "Jolly Roving Tar," authored (like most of their songs) by George Millar. This seems to be a different song, though a few phrases are borrowed. A number of years ago it seems I heard a local "Irish Bluegrass" band, Hair Of The Dog, do a version of Jolly Roving Tar, and since they cover a lot of Irish Rovers material I thought it might be this one, but my memory (which may well be at fault) is that it had more similarity to the Fish/Harrigan version. I should track them down and find out.