mg,
To clarify what I was referring to by "rowing songs by non-Blacks":

An investigation that I have been involved with into the songs that hypothetically preceded mid-19th century chanties (the chanties that are handed down to us today) reveals a strong correspondence in form and repertoire between those chanties and songs used for rowing by Blacks in America and the Caribbean. I haven't yet seen any direct correspondence between those other ethnic or linguistic communities' rowing songs, though I'd be happy to learn about them. I think Anglophone "White" rowing songs may have also contributed to chanties, but the evidence so far suggest that was relatively minor.