Japanese whaling factory ship loaded with aircraft sighted according to the U.S. Joint Intelligence Committee. Daily summary dated 7 August 1942

Tonan Maru No. 2-3

An item reported that aircraft sighted in the Rabaul area a Chonan Maru type vessel (19,5000 tons whaling factory ship) (1) loaded with aircraft lying in the harbour. It was the first time that such vessel was reporting while carrying aircraft. Until now were such vessels due to their large oil capacity and 15 knots speed used as tankers.

Source

Map Room Papers (Roosevelt Administration), 1942 - 1945. U.S. Joint Intelligence Committee. Daily summary No. 240 dated 7 August 1942.