Although this is no help to the original poster's question, I think I can clear up one anomaly on this thread. I happened to cross paths with Dan Aguiar over the weekend, and now have his permission to post his answer to my question following EBarnacle1's post above.

Dan says:
"No, Eric actually has the process backward. I heard the song on a live
concert tape that I made at one of Gordon's Long Island concerts in the
early 70's. I loved Gordon's intro mentioning bootleggers sly methods of
stashing booze in false bilges, adding Allison airplane engines to
slow-looking vessels and the song's story of the rumrunners carrying paint
around to disguise a boat overnight and John Townley also had several
stories of rumrunners' evasive techniques from his days sailing down in
the Carribean on his parents' boat and he liked the song too so we put it
on one of our albums as "The Rumrunner." However, I misheard the boat's
name and recorded it with "Bellanena" instead of "Bellamena."
"I have a postcard somewhere with Gordon scolding me for not
checking with him first for the correct words which he would gladly have
given me. The boats in his version were Bellamena, Mystery, and Nagua."

So the X-Seaman had it from Gordon Bok.

I agree with Kath (for what my opinion's worth) that the Belafonte song was probably a rewrite of an earlier song. I say this with no evidence whatsoever other than facts presented in this thread, not having heard the Belafonte or the Blind Blake version as far as I remember (less and less as the years go by).

As a final note, Kath does have the spellings correct in her post above. Inagua is an island group in the Bahamas (also rendered as 'Nagua in GB's lyrics).