The First Test of the 'Channel Type' Supermarine by C.O.B.A.M.

Despite Admiralty reservations, a Civil Aviation Mission was sent to Japan in September 1921. The Master of Sempill led the mission of 30 instructors and further support staff.

The Supermarine Channel was based on the Air Department Flying Boat. In March 1921 one was demonstrated to the Imperial Japanese Naval Air Service when visiting England. Three were purchased and taken to Japan with the Sempill Mission.