Reclassified as a coastal defence ship in 1921 , Asahi was disarmed two years later to meet the terms of the Washington Naval Treaty , after which she served as a training and submarine depot ship . She was modified into a submarine salvage and rescue ship before being placed in reserve in 1928 . Asahi was recommissioned in late 1937 , after the start of the Second Sino @-@ Japanese War , and used to transport Japanese troops . In 1938 , she was converted into a repair ship and based first at Japanese @-@ occupied Shanghai , China , and then Cam Ranh Bay , French Indochina , from late 1938 to 1941 . The ship was transferred to occupied Singapore in early 1942 to repair a damaged light cruiser and ordered to return home in May . She was sunk en route by the American submarine USS Salmon , although most of her crew survived .