Afaik the “wreck” bit was created as part of a comedy skit/trilogy at the 26 March 1926 dedication of the Watchtower on Treasure Island, Nassau. (25.098333,-77.271111) Event of the season.

It's listed as the “Customhouse Watchtower” in the list of works by Howard Van Doren Shaw. He played the part of the pirate in the skit. The tower is still there.

Dolphin Encounters

I've posted the McCutcheon-Sandburg songbook notes and the McCutcheon family song/toast lyrics here: Lyr Add: Canopus. There's a bit more tongue-in-cheek 'history' in the McCutcheon 1927 songbook.