Well, you are certainy correct that the lyrics you found are posted as being from that album, but honestly it's not the same song.

Two other lyrics I checked on that album (Astrapsen, Kitty) were accurate, but then I've never heard those recorded anywhere else, so I can't imagine where else the lyrics could have come from but by listening to it. (I could be wrong -- no time to research here at work.) However, another (Twelve Gates to the City) is actually the Rev. Gary Davis version, not what was on the Baez/Wood/Alizevos album.

I'm thinking that, given Joan's socio-political convictions, it's rather unlikely she would sing a song about weapons-smuggling and piracy on any recording, so I am guessing that the person who submitted those lyrics got them from some other source.

Anyway, about whether it's a chantey -- you don't think so? There are some weird, slow, odd-rhythmed chanteys out there, like one I sing that starts "Have you ever seen them wild geese sailing cross the ocean?" (not Kate Rusby's tune). I think that, if you sped this one up, you could work to it. Rowing comes to mind.

Gotta run...
C