What you linked to is not the official debrief. I'm not sure what it is. It appears to be a narrative told later. Here's is what appears to be the official debrief said:
According to this page, the report of the German battery also attributed the sinking of the Corry as due to gunfire, except the German report identifies the Corry as a cruiser. The website where these documents are hosted also reports elsewhere that the commander of the battery have been a former chief instructor of gunnery for the German Navy.
Anyway, the website where these images are posted has a long, badly formatted page that states the Corry was sunk by gunfire, that the report of the Corry being sunk by mine is wrong, and the page provides lots of documentation.
At approximately H-hour, CORRY was hit by a salvo of two or three 8" projectiles that detonated in the engineering spaces and broke the keel, causing the immediate flooding of one engineroom, one fireroom, the usbsequent flooding of the other fireroom, and the breaking in half of the vessel.
According to this page, the report of the German battery also attributed the sinking of the Corry as due to gunfire, except the German report identifies the Corry as a cruiser. The website where these documents are hosted also reports elsewhere that the commander of the battery have been a former chief instructor of gunnery for the German Navy.
Anyway, the website where these images are posted has a long, badly formatted page that states the Corry was sunk by gunfire, that the report of the Corry being sunk by mine is wrong, and the page provides lots of documentation.
Captain Hoffman's official debrief:
http://www.ibiblio.org/hyperwar/USN/ships/logs/DD/dd463-Hoffman.html
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