The Headquarters of Commander Marianas on Guam and of the Commander
Philippine Sea Frontier on Leyte kept Operations plotting boards on which were plotted the positions of all vessels with which the headquarters were concerned. However, for ships as large as
Indianapolis, it was assumed that they would reach their destinations on time, unless reported otherwise. Therefore, their positions were based on predictions, and not on reports. On 31 July, when she should have arrived at Leyte,
Indianapolis was removed from the board in the headquarters of Commander Marianas. She was also recorded as having arrived at Leyte by the headquarters of Commander Philippine Sea Frontier. Lieutenant Stuart B. Gibson, the Operations Officer under the Port Director, Tacloban, was the officer responsible for tracking the movements of
Indianapolis. The vessel's failure to arrive on schedule was known at once to Lieutenant Gibson, who failed to investigate the matter and made no immediate report of the fact to his superiors. Gibson received a letter of reprimand in connection with the incident. The acting commander and operations officer of the Philippine Sea Frontier also received reprimands, while Gibson's immediate superior received a letter of admonition
In the first official statement, the Navy said that distress calls "were keyed by radio operators and possibly were actually transmitted" but that "no evidence has been developed that any distress message from the ship was received by any ship, aircraft or shore station Declassified records later showed that three stations received the signals; however, none acted upon the call.
One commander was drunk, another had ordered his men not to disturb him and a third thought it was a Japanese trap.
Immediately prior to the attack, the seas had been moderate, the visibility fluctuating but poor in general, and
Indianapolis had been steaming at 17 kn (20 mph; 31 km/h). When the ship did not reach Leyte on the 31st, as scheduled, no report was made that she was overdue. This omission was due to a misunderstanding of the Movement report system. or moverep as we called it
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FUBAR and SNAFU all rolled into one
no radar sonar or escort. a sittin' duck