Sorry, DH. As Gibb suggests, logic (and 21st century sensibilities about what 19th century seamen would have wanted to sing about in shanties) has little to do with it.

Not to mention that there's absolutely no evidence that Taylor's position on slavery had anything to do with the song. If it had, the words would say so, and they don't. The simplest explanation is that "Santy Anna" is already in the song and is more fun to pronounce than "General Taylor."

We have no idea when SA replaced GT anyway. It could have been long after the Mexican War - or the Civil War for that matter.

But who am I to let facts get in the way of a good story, dreamed up 150 years later, about enslaved crews singing shanties in code to fool their masters - and everybody else for the next century and a half.