Gibb, my "careful methodology" is based on a wide-open imagination. Feel free to add away. I think that it is just fine to have several things going on at once here. I am using your "notion of a "chanty" as a "framework" rather than a "piece," as my baseline. I think juxtaposition generates creativity.

I want to be clear about what you and Lighter are suggesting. Are you saying that a one-pull response is perhaps more basic/earlier in form than a two-pull response, and that a one line call with one line response is perhaps an earlier form than call/response/call/response? What is the difference between a one line call/one line response, with a single pull, and what is usually called a "short haul chanty"? I know this is elemental, but I barely know one end of a rope from the other.

And, if a chanty conforms to single call/single response, with single pull form, then it may be a candidate for an earlier time frame, even if we can't find a proof text to document it. Again, if I am understanding this correctly, it makes sense to me. I'm looking forward to some more examples.