of surprise, the Blücher proceeded further into the fjord to continue with the timetable to reach Oslo by dawn. At 04:20, Norwegian searchlights again illuminated the ship and at 04:21 the guns of Oscarsborg Fortress opened fire on Blücher at very close range, beginning the Battle of Drøbak Sound with two hits on her port side. The first was high above the bridge, hitting the battle station for the commander of the anti-aircraft guns. The main range finder in the top of the battle mast was knocked out of alignment, but Blücher had four more major rangefinders. The second 28 cm shell struck near the aircraft hangar and started a major fire. As the fire spread, it detonated explosives carried for the infantry, hindering firefighting efforts. The explosion set fire to the two Arado seaplanes on board: one on the catapult and the other in one of the hangars. The explosion also probably punched a hole in the armored deck over turbine room 1. Turbine 1 and generator room 3 stopped for lack of steam and only the outboard shafts from turbine room 2/3 were operational. The Germans were unable to locate the source of the gunfire. Blücher increased speed to in an attempt to get past the Norwegian guns. The guns on Drøbak, some on Blüchers starboard side, opened fire as well. At a distance of Blücher entered the narrows between Kopås and Hovedbatteriet, the main battery, at Kaholmen. The Kopås battery ceased firing at Blücher and engaged the next target, Lützow, scoring multiple hits. First engineer Karl Thannemann wrote in his report that the hits from the guns on Drøbak, which were fired on the starboard side, were all between section IV and X in a length of amidships, between B-turret and C-turret. However, all damage was on the port side. After the first salvo from the 15 cm batteries in Drøbak, the steering from the bridge was disabled. Blücher had just passed Drøbakgrunnen (Drøbak shallows) and was in a turn to port. The commander got her back on track by using the side shafts, but she lost speed. At 04:34 two torpedoes from a concealed and unknown battery at the Oscarsborg fortress scored hits on the ship. According to Kummetz's report, the first torpedo hit Boiler Room 2, just under the funnel, and the second hit Turbine Room 2/3 (the turbine room for the side shafts). Boiler