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World War 2 History: Norway Blocks German Naval Attack On Oslo
Heavy Cruiser Lutzow
Group 5-- The Oslo Group
When the Germans invaded neutral Norway on April 9, 1940-- ending the Phoney War-- their forces were split into six naval groups, each assigned a specific task. Group 5-- also called the Oslo Group-- was to seize Oslo, the capital of Norway, and capture King Haakon, the government and, not incidentally, 50 tons of gold. They expected the Norwegians to be taken by surprise and put up little, if any, resistance.
The Mouth, the Choke Point, and the Prize
The Oslo Group consisted of the heavy cruisers Blucher and Lutzow (formerly known as the pocket battleship Deutschland-- see sidebar below). It also included the light cruiser Emden, a torpedo boat and two minesweepers. The group carried the troops designated to capture Oslo. To get to the capital, the Oslo Group had to navigate the Oslofjord, stretching 60 miles north-to-south. At its southern entrance it was more than 5 miles wide, but, at Drobak Sound, where the tiny island of South Kaholmen split the fjord in two, each channel was only about 2,000 feet wide. On that island, about 15 miles south of Oslo, sat the Main Battery of the Oscarsborg Fortress.
Oscarsborg Fortress: Training Recruits
As the Oslo Group entered the Oslofjord, they passed by Fort Rauoy, which challenged them by firing warning shots, followed by live range-finding shots, but the Germans disappeared into the mist heading north unharmed. They continued up the fjord during the early morning hours of April 9, and approached Oscarsborg Fortress. The Germans didn't think the garrison would be a problem. They thought the Norwegians were too surprised to organize any resistance. Besides, they knew Oscarsborg had been relegated to training recruits and its three main artillery pieces were old and slow to reload. The cruiser Lutzow by itself had eight modern 11-inch guns.
One of the Fortress' 280mm Guns
Antiquated Guns By Krupp and Austro-Hungarian Torpedoes
The fortress was indeed mainly garrisoned by 450 recruits, conscripted only a week earlier. There were only enough experienced gunners to completely man one gun. In charge was 64-year-old Oberst (Colonel) Birger Eriksen. The fortress' Main Battery of three 11-inch guns were all more than 40 years old; they had been made in Germany in the late 1800s by Krupp, the giant armaments firm that had armed Germany in World War 1 and the current conflict. Another battery, the Kopas Battery on the eastern shore of the fjord, had three 8-inch guns.
What the Germans didn't know was that Oscarsborg Fortress also had a torpedo battery with three underwater torpedo tubes and nine ancient torpedoes, made in Austria-Hungary before World War 1.
Oscarsborg Fortress Island
The Oslo Group Approaches Oscarsborg Fortress
Norwegian communications on that day were intermittent at best. Oberst Eriksen knew foreign warships were heading his way, but didn't know their nationality. While Norway was neutral, he knew the Allies were favored over the Germans. By splitting up experienced gunners with recruits, he was able to man two of the three 11-inch guns. When the flagship Blucher appeared just after 4 AM and approached within 2,000 yards, he thought it was German, but couldn't be sure. His last words before giving the order to fire were: "Either I will be decorated or I will be court marshaled”.
Blucher, the Other Heavy Cruiser
The Sinking of the Blucher
The two 11-inch guns fired, their 560 lb high explosive shells both striking the Blucher. The first shell struck a magazine which exploded and started an intense fire. The second knocked out the main electrical system, rendering Blucher's main guns useless. As the ship sailed slowly past the fortress, the Main Battery guns could not be reloaded in time, but her secondary batteries' guns wreaked havoc on the cruiser, suppressing any answering fire from her smaller guns. The Blucher was burning and severely damaged, hit by an additional thirteen 8-inch shells and thirty 2.5-inch shells, but her captain was determined to save her.
Thinking they were beyond the fortress' line of fire, the Blucher unknowingly approached the torpedo battery. When the ship was within 550 yards, two torpedoes were launched in succession. Both hit, but the second hit amidships, causing catastrophic damage. Its engines knocked out, the crew tried to fight the fires raging throughout the ship, but at 6:22 the Blucher slipped below the surface of the Oslofjord. Survivors swam to shore and were taken prisoner, but the Norwegians concentrated on treating the wounded Germans instead of guarding them and many escaped.
The Oslo Group Turns Back
Unaware of the torpedo battery, the commander of the heavy cruiser Lutzow, upon seeing two underwater explosions strike the Blucher, assumed the Drobak Sound was heavily mined and ordered the Oslo Group to turn around. Before the ships got out of range, however, the 8-inch guns of Oscarsborg's Kopas Battery scored three hits on the Lutzow, knocking out its aft (rear) 11-inch turret.
The Oslo Group was forced to land its invasion force out of range of Oscarsborg and march overland north to Oslo instead of sailing into its port.
Deutschland Renamed Lutzow
Originally, the Lutzow was designated as the pocket battleship (“Westentaschen-Schlachtschiffe”) KMS Deutschland, a sister ship of the Admiral Graf Spee . However, Hitler feared losing such a grand-named ship and so it was re-designated as the heavy cruiser KMS Lutzow
Oscarsborg Fortress Bombed
Oscarsborg Fortress Surrenders
Later that day, the Luftwaffe started bombing the fortress. In addition, the Lutzow bombarded it from six miles away, beyond the fortress' range. The bombing continued, on and off, for nine hours and around 500 bombs were dropped.
The Germans adjusted to the situation. Although the Oslo Group's land forces wouldn't arrive at the capital until the next day, additional troops were hastily gathered and airlifted to the outskirts of the city, taking Oslo 12 hours later than planned. In light of Oslo falling and seeing no need for further bloodshed, Oberst Eriksen surrendered Oscarsborg Fortress the next day, April 10, 1940.
The Norwegians suffered no casualties, though most of Main Battery's buildings were destroyed. One German heavy cruiser was sunk; one was damaged. The Germans lost 650 – 800 dead and 550 taken prisoner.
Fortress Commander Eriksen
By holding up the Germans in the Oslofjord, Oslo was given an extra 12 hours. In addition, the troops specifically designated to take the capital had been on the Blucher. This allowed the Royal Family, the cabinet and the Storting (the parliament) to escape Oslo by train. There was also time to load the 50 tons of gold onto trucks. This gave the Storting time to meet and bestow emergency powers on the cabinet to run the government until such time as the Storting could reassemble. By June, the King, the government and Norway's gold were in Britain, a government in exile, but still the legitimate government of Norway. This served to encourage Norwegian resistance throughout the war, tying down extra German divisions in Norway that could have been used elsewhere.
Oscarsborg Fortress Viewed From A Small Drone
© 2012 David Hunt