German cruiser Blücher Blücher was the second of five heavy cruiser s of the German Kriegsmarine , built after the rise of the Nazi Party and the repudiation of the Treaty of Versailles . Named for Gebhard Leberecht von Blücher , the victor of the Battle of Waterloo , the ship was laid down in August 1936 and launched in June 1937 . She was completed in September 1939 , shortly after the outbreak of World War II . After completing a series of sea trials and training exercises , the ship was pronounced ready for service with the fleet on 5 April 1940 . Assigned to Group 5 during the invasion of Norway in April 1940 , " Blücher " served as " Konteradmiral " Oskar Kummetz ' s flagship . The ship led the flotilla of warships into the Oslofjord on the night of 8 April , to seize Oslo , the capital of Norway . Two old coastal guns in the Oscarsborg Fortress engaged the ship at very close range , scoring two hits . Two torpedoes fired by land - based torpedo batteries struck the ship , causing serious damage . A major fire broke out aboard " Blücher " , which could not be contained . After a magazine explosion , the ship slowly capsized and sank , with major loss of life . The wreck remains on the bottom of the Oslofjord . Construction . " Blücher " was ordered by the Kriegsmarine from the Deutsche Werke shipyard in Kiel . Her keel was laid on 15 August 1936 , under construction number 246 . The ship was launched on 8 June 1937 , and was completed slightly over two years later , on 20 September 1939 , the day she was commissioned into the German fleet . As built , the ship had a straight stem , though after her launch this was replaced with a clipper bow increasing the overall length to . A raked funnel cap was also installed . As launched " Blücher " was long overall and had a beam of and a maximum draft of . The ship had a design displacement of and a full load displacement of . " Blücher " was powered by three sets of geared steam turbines , which were supplied with steam by twelve ultra - high pressure oil - fired boilers . The ship ' s top speed was , at . As designed , her standard complement consisted of 42 officers and 1 , 340 enlisted men . " Blücher " s primary armament was eight SK L / 60 guns mounted in four twin gun turret s , placed in superfiring pairs forward and aft . Her anti - aircraft battery consisted of twelve L / 65 guns , twelve guns , and eight guns . The ship also would have carried a pair of triple torpedo launchers abreast of the rear superstructure . The ship had four triple torpedo launchers all on the main deck next to the four FLAK range finders . The ship was equipped with three Arado Ar 196 seaplanes and one catapult . " Blucher " never had more than two seaplanes onboard and en route to Oslo one had to rest at the catapult as one of the hangars was used storing bombs and torpedoes . " Blücher " s armored belt was thick ; her upper deck was thick while the main armored deck was thick . The main battery turrets had thick faces and 70 mm thick sides . Service history . " Blücher " spent the majority of November 1939 finishing fitting out work and finishing additional improvements . By the end of the month , the ship was ready for sea trials ; the ship steamed to Gotenhafen in the Baltic Sea . Trials lasted until mid - December , after which the ship returned to Kiel for final modifications . In January 1940 , the ship resumed exercises in the Baltic , but by the middle of the month , severe ice forced the ship to remain in port . On 5 April , the ship was deemed to be ready for action , and was therefore assigned to the forces participating in the invasion of Norway . Operation " Weserübung " . On 5 April 1940 , " Konteradmiral " Oskar Kummetz came aboard the ship while it was in Swinemünde . An 800 - strong detachment of ground troops from the 163rd Infantry Division also boarded . Three days later , on 8 April , " Blücher " left port , bound for Norway ; the ship was the flagship for the force that was to seize Oslo , the Norwegian capital . Organized as Group 5 of the invasion force , the heavy cruiser " Lützow " and light cruiser " Emden " , and several smaller escorts steamed alongside " Blücher " . While steaming through the Kattegat and Skagerrak , the British submarine spotted the convoy and fired a spread of torpedoes . The Germans successfully evaded the torpedoes , however , and proceeded with the mission . Night had fallen by the time the German flotilla reached the approaches to the Oslofjord . Shortly after 23 : 00 ( Norwegian time ) the flotilla was spotted by the Norwegian patrol boat " Pol III " . The German torpedo boat " Albatros " attacked " Pol III " and set her on fire , but not before the Norwegian patrol boat raised the alarm with a radio report of being attacked by unknown warships . At 23 : 30 ( Norwegian time ) the south battery on Rauøy spotted the flotilla in the searchlight and fired two warning shots . Five minutes later , the guns at the Rauøy battery fired four shots at the approaching Germans , but due to poor visibility , scored no hits . The guns at Bolærne fired only one warning shot at 23 : 32 . Before " Blücher " was targeted again , she was out of these shore guns ' firing sector and was no more be seen either from Rauøy or from Bolærne after 23 : 35 . Shortly after midnight , Norwegian searchlights in the coastal artillery batteries on the islands of Bolærne and Rauøy illuminated the ships , though the guns held their fire . The German flotilla steamed at a speed of . Shortly after midnight ( Norwegian time ) an order from the Commanding Admiral to extinguish all lighthouses and navigation lights was broadcast over NRK . The German ships had been ordered to fire only in the event they were directly fired on first . Between 00 : 30 and 02 : 00 , the flotilla stopped and 150 infantrymen of the landing forces were transferred to the escorts " R17 " , " R21 " from " Emden " and " R18 " , " R19 " from " Blücher " . The R - boats were ordered to engage Rauøy , Bolærne and the naval port and city Horten . Despite the apparent loss of surprise , the " Blücher " proceeded further into the fjord to continue with the timetable to reach Oslo by dawn . At 04 : 40 , Norwegian searchlights again illuminated the ship . Forty - one minutes later , the coastal guns placed at the Oscarsborg Fortress opened fire on " Blücher " , beginning the Battle of Drøbak Sound . The coastal guns scored several hits on her port side at very close range . The first two 28 cm shots were on " Blüchers " port side . The first hit was high above the bridge , hitting the battle station for the commander of the anti - aircraft guns , killing AO II " Kapitänleutnant " Hans - Erich Pochhammer . The main range finder in the top of the battle mast was set out of alignment , but " Blücher " had four more major rangefinders ( B - turret , bridge roof , aft battle station ( Nachtstand ) and C - turret ) and many smaller on the bridge and the four rangefinder stations for the AA . The commander in the D - turret , " Oberstückmeister " Waldeck stated that the first 28 cm hit had no influence on the battle ability of the 20 . 3 cm turrets . " Blücher " immediately returned fire , each battery shooting at their own target . The second 28 cm hit caused serious damage : it hit near the aircraft hangar and started a major fire . As the fire spread , it detonated explosives carried for the infantry , further hindering firefighting efforts . The explosion set fire to the two Arado seaplanes onboard : one on the catapult and the other in one of the hangars . The explosion also probably knocked a hole in the armored deck over turbine room 1 . Turbine 1 and generator room 3 stopped due to lack of steam and only the outboard shafts from turbineroom 2 / 3 were operational . The Germans were unable to locate the source of the gunfire . " Blücher " increased speed to in an attempt to move past the Norwegian guns . The guns on Drøbak , some on " Blücher " s starboard side , opened fire as well . At a distance of 500 meters " 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 " Leitende Ingenieur Fregattenkapitän Dip . Ing . " 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 75 meters amidships , between B - turret and C - turret . However , all scores were 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 . Normally the rudder is controlled electrically from the bridge to the motors forward of the " Handsteuerraum " ( hand steering room ) deep under the armored deck , forward of the rudder . In an emergency it can be switched within seconds to hand steering , but steering orders from the bridge to the rudder may be delayed . At 05 : 30 , Norwegian land - based torpedo batteries scored two hits on the ship . The targeting device in the torpedo battery was very primitive . The speed of the torpedo was known and set , but the speed of the target had to be set by guessing . According to Admiral Kummetz ' report , the first torpedo hit Kesselraum 2 ( boiler 2 , just under the funnel ) and the second hit Turbinenraum 2 / 3 ( the turbine room for the side shafts ) . Boiler 1 was already destroyed by gunfire . Only one boiler remained , but all steam pipes through boiler 1 and 2 and turbine room 2 / 3 were damaged and turbine 1 for the main shaft lost its power . By 05 : 34 , the ship had been severely damaged , but had successfully passed through the firing zone ; the Norwegian guns could no longer train to engage the ship . The 15 cm guns in the Kopås battery are all standing in open positions with a wide sector of firing . After the torpedo hits , " Blücher " was still within reach . The battery asked for orders , but Eriksen concluded : " The fortress has served its purpose " With all propellers stopped , about 60 % of the electric power gone , Blucher quickly lost speed and about 04 : 50 dropped anchors at Askoholmene . The ship ' s rudder was jammed to port , however , and the port shaft had to be stopped and the starboard shaft had to be run at full speed back so the ship could remain on a straight course . After passing the gun batteries , the crew of the " Blücher " , including the personnel manning the gun batteries , were tasked with fighting the fire . By that time she had taken on a list of 18 degrees , though this was not initially problematic . The fire eventually reached one of the ship ' s 10 . 5 cm ammunition magazines between turbine room 1 and turbine room 2 / 3 , which exploded violently . The blast ruptured several bulkheads in the engine rooms and ignited the ship ' s fuel stores . The battered ship slowly began to capsize and the order to abandon ship was given . " Blücher " rolled over and sank at 07 : 30 , with significant casualties . Naval historian Erich Gröner states that the number of casualties is unknown , but Henrik Lunde gives a loss of life figure ranging between 600 to 1 , 000 soldiers and sailors . Jürgen Rohwer meanwhile states that 125 seamen and 195 soldiers died in the sinking . The loss of " Blücher " and the damage done to " Lützow " caused the German force to withdraw . The ground troops were landed on the eastern side of the fjord ; they proceeded inland and captured the Oscarborg Fortress by 09 : 00 on 10 April . They then moved on to attack the capital . Airborne troops captured the Fornebu Airport and completed the encirclement of the city , and by 14 : 00 on 10 April the city was in German hands . The delay caused by the temporary withdrawal of " Blücher " s task force , however , allowed the Norwegian government and royal family to escape the city . " Blücher " remains at the bottom of the Drøbak Narrows , at a depth of . The ship ' s screws were removed in 1953 , and there have been several proposals to raise the wreck since 1963 , but none have been carried out . When " Blücher " left Germany , she had about of oil on board . She expended some of the fuel en route to Norway , and some was lost in the sinking , but she was constantly leaking oil . In 1991 the leakage rate increased to per day , threatening the environment . The Norwegian government therefore decided to remove as much oil as possible from the wreck . In October 1994 the company Rockwater AS together with deep sea divers drilled holes in 133 fuel tanks and removed of oil ; 47 fuel bunkers were unreachable and may still contain oil . After being run through a cleaning process , the oil was sold . The oil extraction operation provided an opportunity to recover one of " Blücher ' s " two Arado 196 aircraft . The plane was raised on 9 November 1994 and is currently at the " Flyhistorisk Museum , Sola " aviation museum near Stavanger . Footnotes . Notes Citations