Stan was a lover of the sea shanty.. If these tunes were ment to be sung without the music they would have been

There is a contradiction here. Surely shanties were sung unaccompanied and a shanty lover would be aware of the virtues of unaccompanied singing.

I know someone who sings this song unaccompanied and very effective it is too. Accompaniment is not essential to effective interpretation of the song.

Personally I don't like this song very much. I am unhappy about some of the sentiments expressed. There is a contradiction at the heart of the song and, maybe, that is what it is about, but I still don't particularly like it.