Hugill makes it clear in "Shanties from the Seven Seas" (and still clearer in "Shanties and Sailor Songs") that he altered the last line of nearly every stanza in "Donkey Riding" because the originals were unprintable in the '60s: "the veriest filth," as he says in S&SS.
No doubt he imported the rhyme "Hong-ki-Kong" from the German song to replace something else entirely.