Steve, I've had the same thought since I first read that the rhythm was "irregular."

Which seafaring collectors other than Hugill have actually connected "Shenandoah" with the windlass anyway? (He could have uncritically accepted someone else's erroneous information.)

But, as he used to say: "Different ships, different long splices." If somebody felt like using it at the windlass, he could probably have found a way to do it.