The idea of a claim of authorship on 'Roll Down' is nearly
laughable. I mean, look at the thing! I wonder if there's a
phrase or a melodic phrase that's not lifted directly or
re-combined from the original work of one of ten generations
of hard-working deepwater chanteymen (who ploughed the raging
main). And a few shallow-water ones as well.

Make no mistake, it's a brilliant and stirring song, finely
crafted and all. Other than maybe the form seems to be like
hauling and the words sound like heaving. Maybe it's an
'elbow bending' chantey.

But it's also a perfect example of what's broken in intellectual
property laws regarding works that are about 1% the work of the
copyright holder and 99% the work of those who went before.

Works like 'Roll Down' ought to be ceded into the public domain
by their authors, in recognition of the fact that they truly are
the work of a great body of contributors to the culture and
heritage, and not of any one person.

It might make an interesting project to figure out, line by
line, where the bits of 'Roll Down' are derived.

And yes, I know...legally one CAN copyright such a work. But
just because you can do something, doesn't mean you should.
Perhaps, like Linux, you should 'copyleft' it to prevent
others from staking their claim, and make money off of
'service' (i.e., singing it).