The sinking of the Blücher in the Drøbak Narrows

In the early hours of 9 April 1940, at the narrowest point of the Oslofjord, in the Drøbak Narrows some 30 kilometres south of the Norwegian capital, the brand-new German heavy cruiser Blücher went down. She was hit by shells from old guns and by two torpedoes from Oscarsborg fortress, which had guarded the approach to Oslo since the days when Norway was still in union with Sweden. The ship was leading a force that was to seize the capital by surprise and capture the king and the government. Her loss halted the seaborne expedition for many hours, and that time decided that Norway, unlike Denmark, occupied the same day, did not capitulate but fought.

Kampfgruppe 5 in the Oslofjord

Under the directive of 1 March, the capture of Oslo was the heart of the whole of Operation Weserübung. The Germans reckoned that if they took the capital at once and the king and government fell into their hands, the country would accept a “peaceful occupation” without a shot being fired. The task was given to Naval Group 5 (Kampfgruppe 5) under Rear Admiral Oskar Kummetz. His flagship was the Blücher, the second of the Admiral Hipper-class heavy cruisers, named after the Prussian field marshal Gebhard Leberecht von Blücher. She had been commissioned only on 20 September 1939; in the winter ice on the Baltic had interrupted her training, and she was declared ready for operations on 5 April 1940 – three days before she put to sea. Her crew, commanded by Captain Heinrich Woldag, was raw and inexperienced.

Behind the Blücher sailed the panzerschiff Lützow, recently reclassified as a heavy cruiser, the light cruiser Emden, three torpedo boats (Albatros, Kondor and Möwe), minesweepers and two armed launches. The force carried some 2,000 soldiers, mainly of the 163rd Infantry Division. Aboard the flagship, besides some 1,400 sailors, were several hundred soldiers, the divisional staff with its commander, Generalmajor Erwin Engelbrecht, and officials and specialists who were to take over the ministries, communications and the central bank. The ship also carried plans and documents for the occupation administration.

Surprise was lost before the force entered the fjord. At about 11 p.m. on 8 April, at the entrance to the Oslofjord, it was challenged by the small Norwegian patrol vessel Pol III. Her commander, Captain Leif Welding-Olsen, according to most accounts rammed the torpedo boat Albatros, fired alarm flares and sent a report. Fired upon, he was killed, the first Norwegian to fall in the war. A few minutes later the batteries on the islets of Rauøy and Bolærne fired warning shots and a few live rounds, without scoring hits in the fog and darkness. Shortly after midnight, on the orders of the admiral commanding the Norwegian navy, the lighthouses and navigation lights were extinguished. Kummetz transferred some of the soldiers to the minesweepers, which were to seize the battery islets and the naval base at Horten, while he led the main ships on so as to be in Oslo at dawn, as the timetable required.

Oscarsborg fortress

Oscarsborg stands on the two islets of Kaholmen (North and South) beside the island of Håøya, where the fjord narrows to a few hundred metres. The fortress was built in the mid-nineteenth century, and its main armament consisted of three 280 mm guns supplied by Krupp in the early 1890s. The gunners gave them biblical names: Moses, Aron and Josva (Moses, Aaron and Joshua). On the eastern side of the narrows, by the small town of Drøbak, stood auxiliary batteries: three 150 mm guns at Kopås and two 57 mm guns at Husvik. The most valuable asset, however, was the torpedo battery hidden in the rock of North Kaholmen, with three underwater tubes and Whitehead torpedoes from Fiume, bought from Austria-Hungary around the turn of the century. German intelligence knew nothing about it and regarded the whole fortress as an obsolete training establishment.

In April 1940 it was indeed largely a training centre. Most of its garrison consisted of some 450 conscripts called up on 2 April. No minefield had been laid in the narrows, because laying it had been planned as an exercise for the recruits a few days later. There were enough trained gunners to crew one gun, so they were divided between two and made up with cooks and other untrained soldiers. The commandant was the 64-year-old Colonel Birger Eriksen, a coastal artilleryman six months short of retirement. On the evening of 8 April, when news arrived of fighting in the lower fjord, he summoned to the torpedo battery the 60-year-old Commander Andreas Anderssen, a retired officer from Drøbak who had commanded it years before and was standing in for its sick commander. Anderssen crossed the narrows by boat in his old uniform.

Shots at 4.21 a.m.

Eriksen had no clear orders and no certainty about whose ships were coming up the fjord. Norway was neutral, and he knew that in the event of war the government would sooner side with the British. Before dawn, however, he received reports that German was being spoken aboard the ships. At 4.21 a.m. Norwegian time, when the searchlights picked out of the darkness the silhouette of the Blücher, moving slowly right beneath the fortress, Eriksen ordered his guns to open fire – without the warning shots that pre-war regulations required. He reasoned that the ships had already been warned by the fire of the batteries in the lower fjord. Asked whether he really meant to fire live rounds, he answered with words every Norwegian knows: “Either I will be decorated, or I will be court-martialled. Fire!”

Moses and Aron each fired one round from a range of about a kilometre. There was no time to reload, and Josva had no crew at all. Both shells hit. Accounts differ in detail, but one struck the superstructure and mast, killing some of the crews of the fire-control positions, and the other exploded in the area of the seaplane hangar, where fuel, aircraft bombs and the landing troops’ ammunition were stowed. A great fire broke out and engulfed the midships section. Immediately afterwards the batteries at Kopås and Husvik opened fire. According to Norwegian findings the Blücher took about thirteen 150 mm and about thirty 57 mm shells. One of them wrecked the steering gear, and to avoid running aground the ship could now be steered only by her engines. The fire of her anti-aircraft guns went too high, and her main armament found no target. The exchange of fire lasted five to seven minutes.

The badly damaged cruiser then entered the field of fire of the torpedo battery. At about 4.30 a.m., from a range of a few hundred metres, Anderssen fired two torpedoes two or three minutes apart. Both hit, the second in the engine room, and the ship lost propulsion. The third tube was held in reserve for the following ships.

The sinking

The Blücher struggled a little further north and dropped anchor off the Askholmene islets, out of range of the fortress guns. For an hour the crew fought the fire, launching their own torpedoes so that they would not explode aboard. At about 5.30 a.m. the fire reached the magazine of the anti-aircraft guns. The explosion tore open the side and the boiler-room bulkheads, and the fire spread to the fuel tanks. At 6.22 a.m. Norwegian time (7.22–7.30 by German clocks, since summer time had been in force in the Reich since 1 April) the ship capsized to port and sank bow first. Oil on the water caught fire. There were not enough lifejackets, because the mission had been kept secret, and the fire had destroyed the boats. Sailors gave their lifejackets to soldiers, who often could not swim.

The number of dead is uncertain. Estimates range from about 320 (125 sailors and 195 soldiers, according to the German historian Jürgen Rohwer), through 600–1,000 (according to the military historian Henrik Lunde), to more than 800 in some German studies. Some 1,400 men survived, among them Kummetz and Engelbrecht, who swam ashore. About 1,200 survivors came ashore in the municipality of Frogn near Drøbak. A company of the Norwegian King’s Guard concerned itself chiefly with the wounded and, withdrawing in the evening, left the prisoners unguarded. Kummetz and Engelbrecht reached Oslo only at about 10 p.m. The Norwegian batteries did not lose a single man in the action.

The captain of the Lützow, Captain August Thiele, seeing the torpedo explosions, concluded that the narrows were mined. At 4.40 a.m. the force turned back, and as she withdrew the Lützow took three hits from Kopås, which put one of her two main turrets out of action. The troops were landed on the eastern shore of the fjord, well away from the fortress, and continued on foot. Throughout the day Oscarsborg was bombed by the Luftwaffe, including Junkers Ju 87s from Kiel. Several hundred bombs fell, and not one of the garrison was killed. In the evening, when the Germans had taken the Kopås battery and landed on the mainland at Son, and Oslo was already in their hands, Eriksen concluded that without infantry further defence was pointless. On the morning of 10 April, at about 9 a.m., he handed the fortress over to the Germans undamaged.

A few hours that saved the state

The Germans took the capital anyway, but not as they had planned. Once the fleet had turned back, there was no one to enter Oslo. Transport aircraft carrying infantry landed at Fornebu airfield before noon, despite the fog and the resistance of Norwegian fighters. The infantry entered the city only in the early afternoon, few in number and without the divisional command, which was stranded on the shore of the fjord with the Blücher’s survivors.

The Norwegians made use of those hours. At about 7.30 a.m. a special train left Oslo East Station for Hamar carrying the royal family, King Haakon VII, the government of Johan Nygaardsvold and members of the Storting, the Norwegian parliament. That same day parliament met at Hamar, and during the night, at Elverum, it granted the government full powers to act in wartime. Early in the morning lorries carrying the country’s gold reserve, almost 49 tonnes in fifteen hundred crates, left Norges Bank. The last of them left the city at about 1 p.m., when the Germans were already at its gates. The gold was hidden first at Lillehammer and then, over several weeks, moved by road, rail and sea to Britain and North America. The evacuation was possible because the men who were to seize the bank, and the plans for taking it over, had gone to the bottom with the Blücher.

Significance

The sinking of the Blücher was the German navy’s most painful single defeat on the first day of the campaign. One of the Kriegsmarine’s newest ships was lost on her first operational voyage, beaten by guns and torpedoes older than most of her crew. The political consequence, however, mattered more. The plan that had worked within hours in Denmark failed in Norway, because the king and the government remained at liberty. That evening Vidkun Quisling proclaimed himself prime minister on the radio, but in the following days the lawful authorities rejected the German demands and for two months waged war alongside the Allies. When on 7 June the king and the government sailed from Tromsø to Britain, they took the legitimacy of the state with them: Norway never capitulated as a state, and its government-in-exile in London had at its disposal the gold and a huge merchant fleet that served the Allies until the end of the war.

Captain Woldag was killed a few days later in an air crash. Kummetz later commanded, among other things, the force that lost the Battle of the Barents Sea in December 1942. After the war Eriksen was questioned by the commissions investigating the events of April 1940, which charged him with surrendering the fortress too early, but both cleared him, and in 1945 he and Anderssen received the War Cross with Sword, Norway’s highest military decoration. In 1995 King Harald V unveiled a monument to him at Oscarsborg. The wreck of the Blücher still lies in the Drøbak Narrows. In 1994 more than a thousand tonnes of oil were pumped out of it, and in 2016 it was designated a protected memorial site and war grave.