Japanese seaplane carrier sighted at Butaritari, Gilbert Islands according to the U.S. Joint Intelligence Committee. Daily summary dated 19 December 1941

An item referred to the Australian Naval Board reporting that a Japanese converted seaplane carrier was sighted at Butaritari, Gilbert Islands which was now a Japanese air base and probably more suitable for air operations than Tarawa.

Source

Map Room Papers (Roosevelt Administration), 1942 - 1945. U.S. Joint Intelligence Committee. Daily summary No. 9 dated 19 December 1941.