 Following its return to Astoria , the USS PC @-@ 815 was ordered to escort a new aircraft carrier to San Diego , where the subchaser was to participate in exercises . On June 28 , Hubbard ordered his crew to fire four shells from the ship 's 3 @-@ inch gun and a number of rifle and pistol shots in the direction of the Coronado Islands , off which the ship anchored for the night . He did not realize that the islands belonged to Mexico , an ally , nor that he had taken the USS PC @-@ 815 into Mexican territorial waters . The islands were garrisoned by Mexican Navy personnel during the war . The Mexican government complained and two days later , Hubbard found himself before a naval Board of Investigation in San Diego . He was found to have disregarded orders by carrying out an unsanctioned gunnery practice and violating Mexican waters . He was reprimanded and removed from command , effective July 7 . Rear Admiral Frank A. Braisted commented , in a fitness report written shortly after the Coronado incident , that he " consider [ ed ] this officer lacking in the essential qualities of judgment , leadership and cooperation . He acts without forethought as to probable results . He is believed to have been sincere in his efforts to make his ship efficient and ready . Not considered qualified for command or promotion at this time . Recommend duty on a large vessel where he can be properly supervised . " 
