From Joanna Colcord, Roll and Go:
Another beautiful song, but more of the "quarter-deck" than the "fore-castle" variety, was never so far as I know current ashore. The original version was a North Country ballad about the little port of Amble in Northumberland. W. E. Henley took it and rewrote it, giving it Falmouth for a home port. In the British version, the expected son "will live to serve his King,With his dirk and his hat and his little jacket blue ." That had to be changed for Yankee consumption. Whether sung by British or Americans, no song so tenderly expresses the homesick longing of the sailor in foreign parts.
Shay identifies this with the "many-versioned Bell-Bottom Trousers of the clubhouses and bull sessions".