'TN' (i) was a British naval operation to destroy a German destroyer force at Narvik during 'Weserübung' and leading to the 1^st Naval Battle of Narvik (10 April 1940).

The Narvik campaign was fought from 9 April to 8 June 1940 and comprised a pair of naval battles in the Ofotfjord and a land campaign in the mountains surrounding the port of Narvik in northern Norway. The two naval battles in the Ofotfjord on 10 April and 13 April were fought between British and German naval forces, while the two-month land campaign was fought between Norwegian, French, British and Polish troops against German mountain troops, marooned sailors and paratroopers. Although defeated at sea off Narvik, losing control of the town of Narvik and being pushed back toward the Swedish border, the Germans eventually prevailed because of the Allied evacuation from Norway in June 1940 following 'Gelb', 'Sichelschnitt' and the imminent the Battle of France.

Narvik’s importance to the Germans lay in the fact that it was an ice-free harbour in the Norwegian Sea to which strategically important high-grade iron ore could be transported by rail from Kiruna in neutral Sweden to be loaded onto ships which would then steam to the south in order to reach Germany through the safety of Norwegian territorial waters and the protection afforded by passage though the Leads. Each side had an interest in securing this iron supply for itself and denying it to the other, and this set the stage for one of the first large-scale battles of World War II after the 'Weiss' (i) German seizure of Poland.

Before the German 'Weserübung' invasion of Norway, the British had considered the Narvik for their own use as a possible landing point for an expedition to help Finland in the 'Talvisota' winter war with the USSR. Such an expedition also had the potential of taking control of the Swedish mines and opening the Baltic for the Allies. French politicians were also eager to start a second front as far away from France as possible.

It was on 1 March 1940 that Adolf Hitler ordered the implementation of the 'Weserübung' plan for the invasions of Denmark and Norway. This operation would involve most of the Kriegsmarine, the greater part of whose current strength, together with a number of merchant ships used for transport in the absence of any dedicated naval sealift capability, was divided into five groups for the occupation of six of the main Norwegian ports. Narvik was the objective of the 'Naumburg' sub-operation of 'Weserübung' and, under the command of Kapitän Friedrich Bonte, the vessels involved were Gruppe I, which comprised 10 'Typ 36' and 'Typ 36A' destroyers Georg Thiele of Fregattenkapitän Fritz Berger’s 1^st Zerstörer-Flottille, Wolfgang Zenker, Bernd von Arnim, Erich Giese and Erich Koellner of Fregattenkapitän Erich Bey’s 2^nd Zerstörer-Flottille, and Diether von Roeder, Hans Lüdemann, Hermann Künne, Wilhelm Heidkamp and Anton Schmitt of Fregattenkapitän Hans-Joachim Gadow’s 3^rd Zerstörer-Flottille. Each of these warships carried some soldiers (a total of 1,900 mountain troops) of the 139^th Gebirgsjägerregiment of Generalleutnant Eduard Dietl’s 3^rd Gebirgsdivision. The destroyers were escorted most of the way to Narvik by the battle-cruisers Scharnhorst and Gneisenau.

Early in the morning of 9 April, the destroyers of Gruppe I passed the Vestfjord and arrived at the mouth of the Ofotfjord leading to Narvik, in fog and heavy snow. In the Ofotfjord, they captured the Norwegian patrol vessels Senja, Michael Sars and Kelt, but before being taken Kelt managed to send a message to the coastal defence ship Norge, alerting the local Norwegian naval commander of the incoming vessels. Wolfgang Zenker, Erich Koellner and Hermann Künne then landed their soldiers in the Herjangsfjord, a northern branch of the Ofotfjord, in order to capture a Norwegian regimental supply base at Elvegårdsmoen. Hans Lüdemann and Hermann Künne also landed their troops in order to engage Norwegian forts which did not in fact exist. Diether von Roeder remained in the Ofotfjord in order to ensure German control of the sea. Erich Giese was delayed by engine trouble and did not join the main force for some time.

The main defence of Narvik were the old coastal defence ships Eidsvold and Norge. Alerted by Kelt, both of these Norwegian ships prepared for combat. At about 04.15 the Germans spotted Eidsvold, which immediately signalled the leading German destroyer by lamp and then, after the Germans had failed to respond, fired a warning shot across the German warship’s bow. The Germans had been ordered to occupy Norway peacefully if at all possible, so the German flagship Wilhelm Heidkamp came to a stop and signalled that she would send an officer to negotiate. A small launch ferried Korvettenkapitän Gerlach to Eidsvold, on which he was taken to the bridge to speak to Captain Odd Isaachsen Willoch. Gerlach tried to convince Willoch that the Germans had arrived as friends, but that the Norwegians should surrender their warships to the German armed forces. Willoch asked for time to consult his superior, Captain Per Askim, the commander of Norge. This request was refused by the Germans, but while Willoch had been talking to the German officer the radio officer on board Eidsvold had communicated the events to Askim. Askim’s response to the German demands was negative and order to Willoch was sent immediately: Eidsvold was to open fire. As this was going on, Wilhelm Heidkamp had positioned herself 770 yards (700 m) off Eisvold's port side and trained her torpedo tubes on the Norwegian ship. Gerlach tried another vain effort to convince Willoch to surrender, and as he left Eidsvold fired a red flare, indicating that the Norwegians intended to fight. Eidsvold turned toward the closest German destroyer and accelerated, closing the distance to Wilhelm Heidkamp to just 330 yards (300 m) even as the gunnery officer ordered the port battery of three 150-mm (5.91-in) guns to open fire. Afraid that Eidsvold might ram the destroyer, the Germans launched four torpedoes from Wilhelm Heidkamp: two of these torpedoes struck before the Norwegian ship could open fire, and Eidsvold was blown in two as her ammunition magazine detonated. The forward part of the ship sank in seconds, and the stern followed only a few minutes later, propellers still turning, at about 04.37. Some 175 Norwegian sailors, including Willoch, died in the freezing water, and there were only eight survivors.

Deeper inside the fjord, the explosions were heard aboard Norge, but nothing could be seen until two German destroyers suddenly appeared out of the darkness and Askim ordered his guns to open fire at 04.45. Four rounds were fired from the 210-mm (8.27-in) guns and seven or eight rounds from the starboard 150-mm (5.91-in) guns against Bernd von Arnim at a range of about 875 yards (800 m). As a result of the difficult weather conditions, the guns' optical sights were ineffective: the first salvo fell short and the next salvoes overshot the target. The destroyers waited until they were alongside the pier before returning fire. Bernd von Arnim opened fire with her 127-mm (5-in) main guns as well as smaller-calibre weapons, but the weather was as much of a problem to the the Germans as it had been to the Norwegians. The destroyer also fired three salvoes of two torpedoes each. The first two salvoes missed, but the last struck Norge amidships and the Norwegian ship sank in less than one minute. Ninety of the crew were rescued, but 101 perished in the battle which had lasted less than 20 minutes. The destruction of Norge signalled the end of Norwegian resistance in the port.

On the morning of the German attack, there were four Norwegian ships at anchor in Narvik (4,285-ton Cate B, 1,712-ton Eldrid, 1,758-ton Haalegg and 4,306-ton Saphir) as well as four neutral ships (951-ton Dutch Bernisse and three Swedish ships in the form of the 4,264-ton Boden, 5,613-ton Oxelosund and 5,603-ton Strassa). As well as neutral ships, the warring parties had vessels at anchor in the same port. The British vessels were the 6,582-ton Blythmoor, 5,141-ton Mersington Court, 4,304-ton North Cornwall, 5,378-ton Riverton and 4,887-ton Romanby. As the Germans seized Narvik, there were 11 German merchant vessels present in the form of the 6,388-ton Aachen, 5,398-ton Altona, 4,902-ton Bockenheim, 5,386-ton Hein Hoyer, 4,879-ton Martha Henrich Fisser, 8,096-ton Neuenfels, 5,806-ton Odin, 7,849-ton Lippe, 4,339-ton Frielinghaus and 5,881-ton Planet, as well as the 11,776-ton replenishment oiler and maintenance ship Jan Wellem. This last was a converted whale factory ship, and was awaiting the arrival of the German warships, which she was to refuel. Working in the harbour were two Swedish tugs, the 213-ton Diana and 167-ton Styrbjörn. As the German destroyers entered the harbour, the captain of Bockenheim, who assumed that the intruding warships were British, beached and scuttled his vessel. In total, 25 ore ships had been riding at anchor in Narvik at the outset of the fighting, of which 10 were German.

The German destroyers were now short of fuel and had available to them only Jan Wellem, which had been despatched, according to some sources, from the secret German naval base Basis Nord at Zapadnaya Litsa in the USSR, where she had been based since 4 February, while another source indicates that she departed Murmansk during the evening of 6 April and that Basis Nord was never even established. The oiler had arrived off Narvik from the north on 8 April, having been delayed by British minelaying operations, and had been stopped by the Norwegian patrol boat Kvitøy before being allowed entry to Narvik by the Norwegian regional naval command. In Narvik the ship was inspected, her captain claiming that his vessel was carrying 7,700 tons of fuel oil and 8,098 crates of food provisions, and that she was on her way to Germany.

A second tanker, the 6,031-ton Kattegat, which had sailed to Norway from Wilhelmshaven, had been sunk in the Glomfjord during the evening of 9 April. Kattegat had been stopped by the Norwegian fishery protection ship Nordkapp, which had at first attempted to take the tanker as a prize, but the presence of a large German crew made it impossible for the small Norwegian vessel to control the tanker all the way to Bodø, and Nordkapp finally sank Kattegat by firing four 47-mm rounds into the tanker’s water line.

A third tanker, the 6,031-ton Skagerrak, had also been despatched to Norway, in this instance to support the 'Wildente' landing at Trondheim, but had been intercepted by the British heavy cruiser Suffolk, on 14 April after being redirected by German naval command to a waiting position at sea. When the British warship tried to board Skagerrak, her crew scuttled her. Kattegat and Skagerrak were sister ships, and had been inspected at Kopervik by the Norwegian torpedo boat Stegg on 5 and 7 April respectively. The captain of Kattegat told the Norwegians that he was headed to Narvik for further orders, and the captain of Skagerrak claimed Murmansk as his ship’s destination, and inspections revealed that both tankers had full loads of fuel oil. Skagerrak was also carrying 155 tons of food which, the Germans claimed, was intended for German merchant ships despite being in crates labelled 'Wehrmacht'.

According to the German plan, the destroyers were to have been refuelled by Kattegat and Jan Wellem, each receiving some 535 tons of fuel oil. The flotilla was then to be on its way back to Germany by the evening of 9 April. The plan failed because only Jan Wellem made it to Narvik. Refuelling with just one tanker was difficult, as only two destroyers could be refuelled simultaneously in a process lasting seven to eight hours. On arrival in Narvik, the destroyers were almost out of fuel, and the refuelling was also made more difficult by the fact that Jan Wellem had only improvised refuelling arrangements and inferior pumping equipment. While two destroyers were being refuelled, a third was on guard in fjord, and the other seven were deployed round the area off Narvik. By 04.00 on 10 April, Jan Wellem had managed the full refuelling of only three of the destroyers, and was in the process of refuelling two more.

Meantime British naval forces had tried to engage the German warships involved in 'Weserübung', for the most part without success. On 8 April the destroyer Glowworm engaged the heavy cruiser Admiral Hipper and her two escorting destroyers, and was lost although not before ramming and damaging Admiral Hipper. On 9 April, the battle-cruiser Renown exchanged fire with the German battle-cruisers Scharnhorst and Gneisenau, which were screening the destroyers of Gruppe I, inflicting light damage on Gneisenau. The primary mission of the destroyers had already been completed, however, as they had succeeded in landing the invasion force.

On 10 April the British 2^nd Destroyer Flotilla, under the command of Commodore B. Warburton-Lee and comprising the destroyers Hardy (flag), Havock, Hostile, Hotspur and Hunter, moved up the fjord early in the morning in 'TN' (i). As the British destroyers, all smaller and more lightly armed than their German opponents, attacked at 04.30, Hermann Künne and Hans Lüdemann were alongside Jan Wellem as they took on fuel. Even as the British flotilla approached Narvik, the German picket ship, Diether von Roeder, had left her post in order to be ready to refuel. The British ships were therefore able to surprise and engage a German force at the entrance to the harbour, and sank Wilhelm Heidkamp, on which Bonte was killed, and Anton Schmidt, heavily damaged Diether von Roeder, and inflicted lesser damage on two other destroyers. The British destroyers also exchanged fire with German invasion troops ashore, but did not have a landing force on board and therefore turned to leave. Before the destroyers left the scene, Hostile fired her torpedoes at the merchant shipping in the harbour, and 11 of these (six German, one British, two Swedish and two Norwegian) were sunk during the British sortie into the harbour.

The British flotilla was then engaged by Wolfgang Zenker, Erich Koellner and Erich Giese emerging from the Herjangsfjord under the command of Fregattenkapitän Erich Bey, and then Georg Thiele and Bernd von Arnim emerging from Ballangen bay under the command of Fregattenkapitän Fritz Berger. In the battle which now developed, the British lost the flotilla leader Hardy, which was beached in flames, and Hunter, which was torpedoed and sunk. A third destroyer, Hotspur, was also damaged badly by a torpedo hit. Hotspur and the remaining British destroyers then withdrew, damaging Georg Thiele as they did so.

Now very short of ammunition as well as fuel, the remaining German destroyers did not pursue, and the British ships were able to sink the 8,460-ton ammunition supply ship Rauenfels, which they encountered on their way out of the fjord.

The remaining German ships were soon blockaded in the Ofotfjord by the arrival of British reinforcements, including the light cruiser Penelope. During the night of 11/12 April, while manoeuvring in Narvik harbour, Wolfgang Zenker and Erich Koellner ran aground: the former damaged her propellers and was then limited to a speed of 20 kt, while the latter was more badly damaged and the Germans planned, once she had been repaired sufficiently to move, to moor her at Tårstad in the same capacity as Diether von Roeder, as an immobile defence battery.

As the British destroyers left the Vestfjord outside Narvik, two U-boats, U-25 and U-51, fired torpedoes at them, but German torpedoes at the time had severe problems with their magnetic detonator systems, and all of the weapons either did not detonate at all or detonated well before they reached their targets.

Both the German and British naval commanders, Bonte and Warburton-Lee, were killed in the battle: the former received the Knight’s Cross of the Iron Cross, and the latter the Victoria Cross. The German losses were two destroyers sunk and another four damaged, one ammunition supply ship sunk, six merchant vessels sunk, and 163 men killed or wounded, while those of the British were two destroyers sunk and one heavily damaged. Now unable to escape, the surviving German destroyers awaited the next British attack, which developed three days later as 'DW', otherwise the 2^nd Battle of Narvik.