Steve,

I remember you also mention somewhere that the foreman of the stevedores was also called a 'chanteyman'. Are there more than these 2 contemporary references to the use of chanty in other contexts than shipboard?

Nordhoff is the famous source that gives us "chantyman" prior to chanty/shanty/etc., and calls the songs "chants."

As for the details of how it all lays out (to my knowledge), the best I could say (cogently) is my article about "chanty" etymology. If you don't have a copy and would like it, email or private message me.

My most intriguing argument (if I may say so!) is that "chantyman" may have preceded "chanty" and that "chanty" (specifically) was derived from "chantyman" rather than the other way around.

Another point is that "chantyman" had some overlap in meaning with, well, "stevedore who sings." I argue that it was lingo more employed among stevedores before becoming widely used among sailors. Of course, there was overlap.

Before a rather late period when "chanty" is documented to have much currency (it is documented from the 1850s, but doesn't become REALLY noticeable until 1870s), the songs we recognize were called "songs," "chants," "chaunts," etc.

"Chant," I argue, had both the connotation of 1) a "small" song, relatively monotonous, relatively constrained in tonal range AND 2) an "uncouth" song, something of "the folk" or of "Others." In the case of #2, it often sounded like #1 anyway. Those "others", further, were often African Americans. That is, there was a notable practice of describing songs as "chants" if the singers were Black -- though by not exclusively so. Another dimension is insider vs outsider terms; most of the terminology comes from the outside. Too complicated to rehash here, but just to give an idea that "chant/chaunt" was part of the linguistic landscape, carrying certain connotations, for some time. "Chanty" didn't suddenly spring up as a new idea but rather gained momentum eventually as a mutation.