After checking the logs, my impression is that Imperial Japanese Navy was not serious about discovering Earhart and her partner in the huge Pacific Ocean. Japanese ships were busy about their daily routine, after all.
The log of IJN special-service ship Koshu (特務艦 膠州) with reference code: C11083156000 & C11083156100 & C11083156300 & C11083156400 at
JACAR tells -
General:
Routine job: Observation of upper air by baloon, sea water (streaming, depth, transparency etc) by instruments, laundry, military exercise, lecture, cleaning, maintenance etc.
Off-time entertainment: movie, show-time etc.
July 2 1937 Palau-Ponape
1745 Recognized Greenwich atoll
July 3 Palau-Ponape
0605 recognized Greenwich atoll
0815-0828 Halt. Rescue exercise using a cutter and a launch.
0831-1353 Delivery of supplies & shift member(s) to observatory on Greenwich atoll
1615 Left atoll
July 6-9 Ponape
Loaded coal and water.
July 10 Ponape-Jaluit
0915-0945 Fire‐fighting exercise
July 14-19 Jaluit
Joined athletic games in the stadium, baseball and party.
July 20-23 Jaluit-Ponape
July 24-27 Ponape
Loaded coal and water. Joined exercise.
July 28-August 10 Ponape-Saipan
August 11-20 Saipan
August 21 Left Saipan for Palau
View attachment 377783