The Boarding Party guys often said the shantyman was paid half by management (to encourage a faster pace) and half by the crew (to keep the pace reasonable). Don't know where they got that factoid. Maybe from the late Eric Ilott. I expect the arrangements varied from ship to ship.

"If they are rhythmical, they are shanties..." No. "Sea shanties are just a subset..." Yes (though I'd omit the word "just"). The broader term is work song, and sailors' work songs are called shanties.

I do consider a lot of stevedoring songs as shanties, because they did involve ships and sometimes were sung by the same crews as the deepwater shanties, and they were used to pace work. But most of these were used only for cargo loading/unloading and were not sung aboard ships. Interesting.

Good thread!

Cheers, Nancy