True, it could be sailor, and that would correlate Mariner on the marriage certificate. I'm satisfied John was connected to the Callister family living in the Close-y-garey area, but would a person between the ages of 17 and 27 subtract 3 years from his/her age then perpetuate the fallacy till death? Disparity in the Census returns notwithstanding, christening and death dates should and usually do correlate.