The upper component, Mercury, was a twin-float, four-engine seaplane crewed by a single pilot and a navigator, who sat in tandem in an enclosed cockpit. It could carry  of mail and  of fuel.
Mercury, the top section, was a twin-float, four-engine seaplane manned by a solo pilot and co-pilot who sat together in a glass-enclosed cabin. The aircraft had a capacity for transporting  pounds of postal goods and  gallons of aviation fuel.