T.O.M. -- all the versions you posted say "I'd send it by the waters where the islands overflow" which is slightly but noticeably different from "I'd send it by the waters that don't overflow".

As to the provenence of the song, would it be fair to say that while it is related to "Bunclody" et al, "Pretty Saro" in the versions we've seen, is an American song?

Cheers,
Michael