So it would appear that "The Pearl Diver" is a parody of "The Rich Man Rides By." The late 1920's seem a good fit for this song. Billy, could you check the tune with this link and tell me if it sounds similar?The Pearl Diver

It's possible that Dennis picked this song up at some waterfront pub when he was sailing in the South Pacific in the 1930's.

Cheerily,
Charley Noble