1924  Up aloft in a conning tower is Dr. Grenfell with the "scunner" as he is called. . . .
1953  We found that Stephen was at the wheel, and Jimmie was the Scunner.
1956  From the seal-fishery we get . . . scunn, to direct a sealing vessel from the barrel, hence scunner, assistant to the master of a watch. . . .