Keep in mind the distinction between shanties and other sea songs. For instance, The Mermaid above is a sea song, but not a shanty.
A shanty is a work song, designed to get all those arms and bodies and legs working together in the right rhythm for the job to be done. I don't think I'd classify Shenandoah as a shanty because it's not a heavy enough, swinging enough rhythm to help with work.

Dave Oesterreich