There's a song in Stan Hugill's book "Shanties From the Seven Seas" called "the Chinee Bumboatman." That may be what you're thinking of. It's a horribly offensive song by any modern standards of political correctness. I've only heard it sung publicly once, at a sea chantey sing along in San Francisco, and it was met with a great deal of hissing and "tsk tsk."