Sorry to come in so late on this one. We used to play at the Melbourne Maritime Museum where you can pick up all sorts of things, including information and rumours. The version we used to sing began, "Were you ever in Quebec stowing timber on the deck
something something something else riding on a donkey. An old guy there in the eighties told me this was a song from the timber hauling ships. If I remember it correctly, there was some sort of a large trapdoor at the bow that could be opened to get the timber on board. It was loaded through this by a crane and either for bravado or to help guide it (which I doubt due to the weights involved) men often would ride the load of timber onto the ship. This was called riding the donkey, possibly due to the use of the donkey engines running the cranes. Of course this could all be pure bullshit but that's how folk legends are made.