As has been demonstrated many times and in many places, if a song can be used to provide a working rhythm aboard a vessel (including rowing) it is a chantey. I recently met a retired man who used to live on Bequia (sp?) who used a variant on "Blow the Man Down" for launching whaling boats into the surf. The chorus he gave me was: "Way, hay, gve us some rum" wih the second chorus line "Give us some rum, we'll haul the boat down." This was not aboard ship but it certainly met the requirement of a chantey.