Thanks for that important context, TomB.

I have been finding that the statements of Hugill and Doerflinger about a "creative period" (or what I called "generative period" etc) are supported by the evidence. So I am hoping to take that as a starting point, and see how it is born out as we look at the evidence again and find more. In addition, I'd like to break down that "creative period" into chunks to really see the trajectory.

If anyone can speak specifically to the mechanics of sailing at specific moments, that contribution would be most welcome. I myself am unclear whether the shift in sailing methods -- specifically with respect to raising yards -- was a matter of new vessels or of new conditions aboard those vessels. In other words, did the packet ships in and of themselves (in their design) require/inspire a different approach to raising yards (e.g. due to size)? Or was it the conditions aboard them: smaller crews and the need for speed? And, in which years precisely did this kind of shift begin? I realize that generally it is after the War of 1812, and that 1815 is often a date used to mark the beginning of this new "Golden Age." However, specifics would be helpful. I think it is quite probable that when Robert Hay heard the Jamaican stevedores sing "Grog time of day," there was not yet any precedent aboard ship with which to compare it.

To add to the 1810s:

I forgot to note the other Jamaican stevedore song from 1811, in HAY:

Two sisters courted one man,
CH: Oh, huro, my boys
And they live in the mountains,
CH: Oh, huro boys O.

Next,

In SERVICE AFLOAT (published 1833), a British sailor describes observations from during his service during the Napoleanic Wars. So, 1815 or earlier (probably not much earlier). In Antigua, he observed a song for rowing. It was another version of "Grog time of Day," showing that that song was spread through the West Indies. His transcription gives a better idea of the complete form of this work song:

Massa lock de door, and take away de key
Hurra, my jolly boys, grog time a day
CH: Grog time a day, my boys, grog time a day,
       Hurra, my jolly boys, grog time a day

To give a sense of how that form MAY have worked, I've created this example (no melody was given, but I set it to the matching tune of "Doodle Let Me Go":

Grog Time of Day

And in the Virgin Islands, the same author observed another boatmen's song:

Jenny go to market for buy me yarrow prantin,
Heigh me know, bombye me takey.
      Chorus—Heigh me know &c.
               Heigh me know &c.

Me nebur know before Jenny bin a bad gal,
Heigh me know, bombye me takey.
    Chorus—Heigh me know, &c.
             Heigh me know &c.

Remarking on the practice of New World Blacks, the author has this commentary. Note that he describes the basic call and response format of a chantey, though he does not compare it to anything in his own tradition.

Some of their airs are exceedingly plaintive, and the manner of singing in chorus evinces no small degree of natural taste : rowing in boats or other kind of labour, when a simultaneous effort is required, they have generally a song formed of extempore verses, the improvisatore being the stroke oar, the driver, or one supereminent among the rest for the talent. He in a minor key gives out a line or two in allusion to any passing event, all the rest taking up the burthen of the song, as a chorus, in a tenor, and this produces a very pleasing effect.

Note also the emphasis on improvisation. This is important to note re: the aesthetic of this music as well as something to remember when looking for references.

It would be great to find more references to work-songs (maritime, or, of similar form) in the 1810s. With the slim evidence so far, my contention would be that work-songs of this type had not yet found their way aboard ships in the early 1810s. It doesn't say much, but is notable nonetheless, that the British Naval officer does not compare the songs to practice on his ships even by the time of publication, 1833.