The chanty itself -- that is, aside from the engine idea -- is pretty interesting.

How did it relate to "Highland Laddie," which was one of the early documented capstan songs and a cotton-stowing chant?

And how did it relate to "Powder Monkey Jim," a non-chanty whose chorus it partially shares?

How do all three relate?

If "Donkey" got the "golden crown" bit from "Powder Monkey"... where did "Powder Monkey" get the "Were you ever in XYZ" theme from (which is part of "Highland Laddie")?

Is the "Were you ever in XYZ" theme a contribution to chanty "language" from the old Highland Laddie? If so, is it in that sense a sort of Scottish contribution to chanty language? Or is the non-narrative, non sequitur style of "Were you ever in XYZ" an inspiration of African-American style of versifying?

My current feeling is that, yes, "Were you ever in XYZ" comes from "Highland" and possibly a wider set of songs from that tradition (Northern Britain, etc), so it is very interesting how it fits into and was developed into a mode of work-song that I would claim is more African-American.

Lots of big questions!