When I was in the Navy, "Fou Fou", or "Foo Foo " was definitely "powder, talcum, perfumed, balls (not cannon), for the drying of" as per messrs Johnson, Yardley, et al.

It might be worth looking at a few films to see what their take on period sailing-ship music might have been (real or imagined)---for example, in the rip-roaring British navy yarn "Damn the Defiant" starring Alec Guinness, Dirk Bogarde, and Anthony Quayle, the crew are shown on deck taking exercise by "rapping" to the tune we often know as "Chase Me Charlie", or "Aunty Mary Had A Canary” etc. The Gey Gordons?? (Note the correct spelling of "gey”!!).

Otherwise, I’d have thought that they'd have been too tired, too busy, too fatigued, too poxed up, too thrashed, and too dispirited with malnutrition, piles, scurvy, and generally having a shit time, to bother with singing & dancing.