As the squadron reaches the Oslo Fjord, the ships want to proceed to Oslo without any delay. At 5:20 am the lead ship Blücher
enters the narrowest part of the Fjord, the Dröbak Narrows as the fortress of Oskarborg opens fire with its 28cm (11") guns. The ship is heavily damaged at its superstructure and fire spreads. After two hits by Norwegian torpedo batteries the ship sinks at 7:23 am.
Even today, the wreck is still loosing oil and endangers the environment of the Oslo Fjord.