On the night of 13/14 October 1939, having conned U 47 into the main anchorage on the surface via the channel between Lambs Holm and the mainland, Günther Prien lined up his four bow tubes at the Royal Oak, and launched three torpedoes at 0058, one tube having malfunctioned. Of the three torpedoes, two missed, but one struck Royal Oak right forward in the bows.
The shock and noise of the explosion woke the crew, but it was thought the problem was in the inflammable store right forward. A submarine attack was not suspected. One must ask why not, and presumably the mindset of the ships’ officers was turned towards the air threat, thinking that the blockships and boom defence would prevent entry of a submarine. Prien turned and launched one torpedo from his stern tube, but that also missed. Reloading the three empty bow tubes, he came round and at 0113 fired a salvo at Royal Oak, and this time all three torpedoes exploded against the starboard side of her hull.
The cordite in a 6in magazine ignited, and a ball of fire quickly engulfed the open spaces of the ship, while she took on a serious list to starboard. At 15 degrees, water entered through her open portholes, she continued to roll over and capsized, just minutes after being hit. The death toll in the freezing water was extremely high: of Royal Oak’s crew of almost 1250 officers and men, no less than 833 were killed, including Rear Admiral Blagrove. More than a hundred of the victims were boy seamen less than eighteen years of age, mirroring the tragedy of the boy seamen lost in Weddigen’s attack on the ‘live bait’ squadron at the start of the Great War.
In a typically belated move to bolt the stable door, the eastern entrances to Scapa Flow were eventually blocked by the ‘Churchill barriers’, concrete causeways built mainly by Italian PoWs, and which replaced the inefficient blockship and boom defences of 1939.
NORWAY, TREACHERY AND RETRIBUTION I: OSLOFJORD
Operation Weserübung was the German codename for the invasion of neutral Norway. Hitler was concerned that the Allies were about to attempt to cut Germany off from its vital source of iron ore in Sweden, carried by rail to the port of Narvik and from there by ship through neutral Norwegian waters to Germany. In fact, the British had determined to carry out a ‘peaceful’ occupation of Norway to do just that, and also in order to come to the aid of the beleaguered Finns under attack by Russia.
The British and French started out first, but the Germans had a shorter distance to cover, and arrived first. The Norwegians had been warned of German intentions when the Polish submarine Orzel torpedoed and sank the German transport Rio de Janeiro. Norwegian ships picking up survivors were shocked to learn that most were in fact armed German soldiers on their way to invade their country. Still the Norwegian government prevaricated. But time was running out.
In the night of 8/9 April 1940, German Group V under Admiral Kummetz entered Oslofjord with orders to proceed to the Norwegian capital, and land troops to seize the Royal Family and members of the Parliament. Kummetz’s flagship was the new heavy cruiser Blücher, followed by the ‘pocket battleship’ Lützow and the light cruiser Emden, plus three torpedo boats and smaller vessels. In addition to her normal crew, Blücher was transporting over eight hundred soldiers for the occupation of the capital, plus a group of Gestapo agents whose role would be to seize the Royal Family.
After sinking a small Norwegian patrol vessel, the whaler Pol III at 2300 on the 8th, Group V landed troops to seize the Norwegian forts defending the entrance to the fjord and swept on to the north. At 042 °Colonel Eriksen, the commander of the Oscarsborg Fortress, observed the Blücher passing in front of his guns. Correctly estimating the range at 1200m (1310yds), one minute later he gave the order to open fire with the only two 28cm guns which the few men at his disposal could man.
Both high-explosive shells struck the Blücher, the first at the base of the bridge superstructure, severing the controls to the steering and knocking her secondary armament fire control out of action. The second hit the aircraft hangar, loaded with petrol and bombs, and started a major fire. At that moment, from the opposite side of the fjord, the three 15cm guns of the Kopås Battery and the three 57mm guns at Husviktangen opened fire at the German flagship, scoring forty-three hits between them.
With his ship badly damaged by shells, on fire and out of control, Captain Heymann attempted to steer by throwing her starboard engines into reverse to avoid the island of Kaholmen. At that moment Blücher crossed the sights of Captain Andreas Anderssen, commander of the Kaholmen torpedo battery. Of the nine Whitehead Mk Vd torpedoes with 120kg (264lbs) warheads at his disposal, he ordered six to be loaded into the firing frames, having decided to fire two at each of the three larger German warships.
The first torpedo aimed at Blücher was fired from the southern № 1 shaft, and the second from the middle № 2 shaft. With their 40-knot speed, at a range of 500m (545yds) he could hardly miss. The first torpedo hit the forward part of the ship, and the second hit amidships. Blücher lost all steam and electric power, her torpedoes were launched to avoid them exploding, and the anchors were let go. When the fires reached a 10.5cm magazine and it exploded, blowing out a large part of the hull, the doomed ship capsized and sank by the bow. Heavy casualties were suffered by her passengers and crew, and it is rumoured the entire Gestapo contingent drowned.
Lützow and Emden briefly duelled with the shore batteries but their commanders, believing the flagship to have run into a minefield, retreated back down the fjord. Oslo was not captured until later in the day, allowing the Royal Family and the government to evacuate to safety, not before having finally sent out general mobilisation orders — by post!
The wreck of Blücher still lies where she sank in Oslofjord, fully loaded with ammunition, and threatening to pose an environmental hazard from leakage of her fuel oil. The torpedo battery, rearmed during the Cold War with British Mark VIII torpedoes, was demilitarised in 1993, and is now part of the Oscarsborg Museum complex.