: Prien used high tide to clear the blockships, entering the anchorage at approximately 12:58 a.m..

: Although much of the Home Fleet was at sea to avoid aerial attacks, the aging World War I-era battleship HMS Royal Oak remained at anchor. II. The Attack and Sinking

: At 1:04 a.m., Prien fired a spread of torpedoes. One struck the bow, but the damage was so localized that the crew initially believed it was an internal explosion in the paint store or aviation fuel store.

: The ship listed to 15 degrees, quickly submerged its open portholes, and capsized. It sank within 13 minutes of the second strike. III. Casualties and Aftermath

: After reloading, Prien fired a second salvo of three torpedoes. All three struck the battleship amidships at 1:16 a.m., causing catastrophic flooding and igniting a magazine.

: Prien returned to Germany as a national hero, nicknamed the "Bull of Scapa Flow" . He became the first German submarine officer to receive the Knight's Cross of the Iron Cross.

: The shock of the raid forced immediate security changes, most notably the construction of the Churchill Barriers —massive concrete causeways built to permanently seal the eastern entrances to Scapa Flow.