I'd heard a slightly different version of the "Cliffs of Dover" story before. It sounds like Old Stormy was a composite of every nautical hero.
My follow-up question: does Stormy actually have anything to do with General Taylor (presumably Zachary Taylor) or are the General Taylor lyrics just later additions to the Shantey? I can imagine after hauling on a capstan for a few hours, you'd be singing just about anything that came into your head, so it's hard to tell whether the addition of Mr. Taylor is at all topical.
-MudWeasel