Image courtesy of NOAA Ocean Exploration, Shakedown, Calibration, and Testing in the Main Hawaiian Islands. Download larger version (jpg, 1.1 MB).
On December 7, 2016, on the 75th anniversary of the bombing of Pearl Harbor, NOAA Ocean Exploration led a dive to explore a Japanese mini submarine sunk by Navy destroyer USS Ward on the morning of December 7,1941. The shots fired to sink this submarine marked our nation's entry into World War II.
From: NOAA Ship Okeanos Explorer: Shakedown, Calibration, and Testing in the Main Hawaiian Islands.