G'day again Malcolm,
Do you have any background information on the terms used in the Bigler song? There are a few that I can't really fathom:
"...our captain he's a shang-a-roosh,"
"Our mate he's a roadstone-prat-inspector,"
As "prat" is standard English for buttocks (as in 'pratfall'), I'm not surprised "He's been seen in many a goal;"!
"Our third hand he's a bushranger,"
Well, we Australians know what we mean by a "bushranger", but what did it mean to Sam Larner? (Unless "He come on deck and received the mail," means he was inclined to pinch anything worthwhile in the crews' mail.)
This group of songs, clustered around the one tune, is a very interesting area.