Twenty of these huge four engine flying boats were built for US navy use in WW2, they arrived too late for wartime service, and only five were completed, serving as transports for a decade. One remains, in use as a water bomber in British Columbia.
Larry Milberry, Aviation in Canada, McGraw-Hill Ryerson 1979
Hawaii Mars in the late seventies, owned by Forest Industries and used for firefighting.
Welam A Shrader; Fifty years of Flight A chronicle of the aviation industry in America 1903-1953 Eaton Manufacturung 1953