As I was saying, I'm looking for any documented trad sources for this. I can't get those three extra commonly sung verses ('For seven long years,' 'I'll leave Sal' and 'I thought I heard') back further than Tom Lewis. I too wish breezy had expanded. As to the Civil War aspect, I found the following:

Re chanteys that may have been sung during the Civil War, per Music In The Confederate Navy, by John Townley. Presented at the 10th Annual Mystic Seaport Museum Maritime Music Symposium, June 10, 1989. Posted at http://hmi.homewood.net/alabama.html

A really good candidate, however, is "Bully In The Alley," the chorus of which mentions Shinbone Alley, the heart of sailortown in St. George's, Bermuda.

He offers good logic but not evidence. Any other ideas?