Thanks for the link. But it should be 'dine beneath the boughs' surely, not 'bows'.

I'd sing it with a bit more oomph, myself, but with the bouncy rhythm it is still fun.

Right enough, I think that a barge of some sort was used to bring the Discovery back to Dundee, but I think it's more likely to be an approximation of 'barca' as suggested earlier.