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{{Short description|Code word to begin German submarine in WWII}}
'''Operationsbefehl Hartmut''' (literally "Operation Order Hartmut") was the [[Code word (communication)|code word]] to begin German [[U-boat|submarine]] operations during [[Operation Weserübung]] - [[Nazi Germany]]'s invasion of [[Denmark]] and [[Norway]]. Occasionally these operations are termed '''Operation Hartmut'''. The orders involved submarine screening actions for the German invasion fleet and [[reconnaissance]] - particularly off [[Narvik]] and [[Trondheim]]. The orders also resulted in a number of attacks on [[Allies of World War II|Allied forces]] - particularly in or near the [[fjords]] of the Norwegian coast.

The operation's reconnaissance and screening objectives succeeded for the most part, however Hartmut is notable for the large number of faulty [[torpedo]]es fired and four U-boats sunk. These problems came at a time when the [[Battle of the Atlantic|war in the Atlantic]] was still going exceptionally well against [[United Kingdom|Britain]]. The deployment of U-boats during Operation Weserübung is occasionally criticized as a waste of manpower and [[materiel]] for this reason. The use of [[magnetic pistol]]s and operations in cold weather rendered the [[G7e torpedo]] less effective. Coastal operations may have also hampered commanders used to the open sea. Speculation persists that massive torpedo failure during this campaign provoked German [[Oberkommando der Marine|naval high command]] into improving the weapon's performance. U-boat commanders like [[Günther Prien|Prien]], [[Herbert Schultze|Schultze]] and [[Viktor Schütze|Schütze]] had the only patrols of their careers without any [[tonnage]] sunk.

==Hartmut's execution==
First hints of an impending invasion of Norway and Denmark came in March 1940. By early April, most of the U-boats to be used for Operation Hartmut as part of Operation Weserübung were ready. [[Befehlshaber der U-Boote|BdU]] [[Karl Dönitz]] intermittently sent ships to reconnoitre areas of the Norwegian coast and to try to locate portions of the [[Royal Navy|British fleet]].

Due to [[submarine]]s' generally slow surface speed compared to surface vessels, many of the U-boats specifically assigned to perform in Operation Weserübung departed before the main surface fleet left from the mouth of the [[Weser river]] on the morning of 7 April. Twenty U-boats went out on 3, 4 and 5 April.<ref>{{cite web | url=http://www.uboatarchive.net/BDUKTB30262.htm | title=F.d.U./B.d.U.'S War Log, 1–15 April 1940 | access-date=10 May 2010 | archive-url=https://web.archive.org/web/20130819210938/http://uboatarchive.net/BDUKTB30262.htm | archive-date=19 August 2013 | url-status=dead }}</ref>

===Hartmut preparations===
Preparations in the German submarine forces (U-bootwaffe) began in early March. On 4 March 1940 [[Karl Dönitz]] received orders from his superiors in Berlin:

<!-- "Auslaufen weiterer Boote zunächst stoppen. Kein Einsatz auch bereits ausgelaufener U-Boote an Norwegens Küste. Verwendungsmöglichkeit aller Seestreitkräfte beschleunigt herstellen. Keine besondere Bereitschaft."/"Cease launching submarines on patrol for the time being. Do not assign missions near Norway's coast to submarines already at sea.  Quickly make all naval forces fit for action."-->
# Further U-boat sailings are to be stopped.  U-boats which have already sailed are not to operate off the Norwegian coast.
# All Naval forces to be ready for operations as quickly as possible.  No special degree of readiness.<ref>{{cite web | url=http://www.uboatarchive.net/BDUKTB30261.htm | title=F.d.U./B.d.U.'S War Log , Appendix 1 to B.d.U's War Log, 1–31 March 1940 | access-date=10 May 2010 | archive-url=https://web.archive.org/web/20130820025556/http://uboatarchive.net/BDUKTB30261.htm | archive-date=20 August 2013 | url-status=dead }}</ref>

Dönitz [[Mobilization|mobilized]] any vessel that could dive. Only 12 larger [[Type VII]] and [[Type IX]] submarines capable of operating in the [[Atlantic Ocean]] were fit for the operation. One older ocean-going [[German Type I submarine|Type IA]] was also included. 12 smaller  [[German Type II submarine|Type II]] U-boats were called up, despite that the Norwegian coast limited their operating time. The operation subsequently disrupted training exercises in the [[Baltic Sea]] as six outdated Type IIA training submarines were brought into the [[North Sea]].

At this point, commanders and crews were simply ordered into the North Sea. A sealed envelope aboard each of the U-boats held their official orders. The envelope was to be opened upon receiving the radio code word "Hartmut" (hence the attributed name Operation Hartmut).

Dönitz predicted spectacular results for his submarines. <!-- "Sicherlich würde der Gegner auf die Anlandung deutscher Truppen in Norwegen scharf reagieren. Seine Unternehmungen konnten sich dann gegen die von uns besetzten Häfen richten oder die Einrichtungen eigener, das heißt englischer Stützpunkte zum Ziel haben... Auch der Gegner war an die engen Fahrwasser der Fjorde gebunden, seine Schiffe mussten also die U-Boote in naher Entfernung passieren. Dies konnte nur bei sehr unruhiger Wetterlage ungesehen geschehen. Bei Aufstellung mehrerer U-Boote in tiefer Staffelung war es deshalb wahrscheinlich, dass sich Schussgelegenheiten ergeben würden." -->In his memoirs he wrote, "Undoubtedly the enemy would react sharply to the landing of German troops in Norway. Their operations could be directed at our occupied ports or their own facilities - that is, strategically important sites for the English... The enemy was also bound to the narrow waterways of the fjords; their ships would have to pass near the U-boats. They could only go unseen in very turbulent weather. The deployment of multiple U-boats in staggered formation would likely yield more shooting opportunities."<ref>{{cite web | url=http://www.u-boote-online.de/krieg/unternehmen_weseruebung.html | title=Die U-Boote bei dem "Unternehmen Weserübung"}}</ref>

By the beginning of April 1940, 31 U-boats were ready for operations between England and Norway. On 6 April, the codeword "Hartmut" was transmitted and German submarines began their designated operations.

===Attacks on Allied vessels===
German submarines operating near the Norwegian coast made numerous attacks on British ships, although many proved unsuccessful due to faulty torpedoes.

====''U-4''====
[[German submarine U-4 (1935)|''U-4'']] sank the [[British T-class submarine]] [[HMS Thistle (N24)|HMS ''Thistle'']].<ref>{{cite web | url=http://uboat.net/boats/u1.htm | title=Type IIA U-4}}</ref>

====''U-13''====
[[German submarine U-13 (1935)|''U-13'']] sank the British steam merchant ''Swainby'' off the Shetland islands with one torpedo on 17 April.<ref>{{cite web | url=http://uboat.net/allies/merchants/ships/312.html | title=Swainby}}</ref>

After docking in [[Bergen]] for a short time, ''U-13'' then sank the Danish vessel ''Lily'' that had been taken as a [[Prize (law)|prize]] by the British after the German [[occupation of Denmark]]. The first torpedo failed to arm, but the second broke the ship in half.<ref>{{cite web | url=http://uboat.net/allies/merchants/ships/314.html | title=Lily}}</ref> A few days later ''U-13'' damaged another British ship before returning to port.<ref>{{cite web | url=http://uboat.net/boats/patrols/patrol_5119.html | title=Patrol of U-Boat U-13 from 21 Apr 1940 to 2 May 1940}}</ref>

====''U-37''====
[[German submarine U-37 (1938)|''U-37'']] sank one Swedish tanker, one Norwegian freighter and one British freighter equalling 18,715 tons of shipping between 10 and 12 April.<ref>{{cite web | url=http://uboat.net/boats/patrols/patrol_256.html | title=Patrol of U-Boat U-37 from 30 Mar 1940 to 18 Apr 1940}}</ref>

====''U-38''====
There were two naval [[battles of Narvik]] on 10 April 1940 and 13 April 1940. {{GS|U-38|1938|2}} and {{GS|U-65|1940|2}} were positioned at the entrance of the fjord. When the Royal Navy arrived, ''U-38'' fired at {{HMS|Valiant|1914|6}} and at {{HMS|Southampton|83|6}} missing both. In the second battle, U-38 fired at {{HMS|Effingham|D98|6}} but the torpedoes detonated prematurely.<ref>Blair, Clay (1996). Hitler's U-Boat War. London: Weidenfeld & Nicolson, pg 155. {{ISBN|0-297-84076-2}}.</ref>

====''U-47''====
[[German submarine U-47 (1938)|''U-47'']] under [[Günther Prien]] encountered "a wall of ships" on 15 April.<ref>{{cite web | url=http://www.u-boote-online.de/krieg/torpedokrise_u0047.html | title=Priens erfolgloser Angriff auf die britische Landungsflotte}}</ref> A British [[Naval fleet|fleet]] of [[cruiser]]s and [[Troopship|transport ships]] were anchored near [[Narvik]] offloading troops and war materials. Prien targeted two cruisers and two transports with the four forward torpedoes but none detonated. An hour and a half later after a thorough inspection of the tubes and torpedoes, Prien tried again. Again, with a textbook surfaced attack from 750m away using four torpedoes ''U-47'' had no success. One detonated underwater after hitting a rock, well off course.

After leaving [[Ofotfjord]], ''U-47'' spotted and attacked [[HMS Warspite (03)|HMS ''Warspite'']]. One torpedo detonated ahead of the battleship, while another detonated far behind. ''U-47'' spent the next hours submerged under persistent [[depth charge]] attack.<ref>{{cite web | url=http://uboat.net/boats/patrols/patrol_324.html | title=Patrol of U-Boat U-47 from 3 Apr 1940 to 26 Apr 1940}}</ref>

====''U-48''====
[[German submarine U-48 (1939)|''U-48'']] under [[Herbert Schultze]] made multiple attacks on a fleet of three cruisers on 10 April, but the torpedoes failed to arm or detonated prematurely. Later on 14 April, ''U-48'' attacked HMS ''Warspite'' but both torpedoes failed to detonate. ''Warspite''{{'}}s destroyer screen fired on the vessel and ''U-48'' was depth charged, but escaped destruction.<ref>{{cite web | url=http://uboat.net/boats/patrols/patrol_334.html | title=Patrol of U-Boat U-48 from 3 Apr 1940 to 20 Apr 1940}}</ref>

====''U-51''====
[[German submarine U-51 (1938)|''U-51'']] attacked a destroyer, but the torpedoes detonated prematurely. On 19 April, commander [[Dietrich Knorr]] attacked the French cruiser [[French cruiser Émile Bertin|''Émile Bertin'']], but both torpedoes missed.<ref>{{cite web | url=http://uboat.net/boats/patrols/patrol_349.html | title=Patrol of U-Boat U-51 from 11 Mar 1940 to 22 Apr 1940}}</ref>

====''U-65''====
[[Hans-Gerrit von Stockhausen]] commanding ''U-65'' attacked a group of British destroyers, but the torpedoes missed or failed to arm. The U-boat subsequently suffered moderate damage when the same destroyers depth charged her.<ref>{{cite web | url=http://uboat.net/boats/patrols/patrol_454.html | title=Patrol of U-Boat U-65 from 9 Apr 1940 to 14 May 1940}}</ref>

===Operational results===
U-boats succeeded in reporting some Allied fleet movements, but Dönitz' greatest interest was sinking ships - a portion of Hartmut where the U-boats performed underwhelmingly. In general, submarine attacks in the Norwegian waters proved ineffective. Nearly two-thirds of the [[magnetic pistol]]s failed by either detonating too early, not arming, or running too deep.

Despite orders to cease using magnetic pistols in late 1939, Dönitz had authorized commanders to use either magnetic or impact pistols on their torpedoes during Operation Weserübung. Cold water in the North Sea and Norwegian fjords hampered the use of electric torpedoes used at the time, which required heating to reach suitable [[operating temperature]].

Other speculation has pointed to the unfamiliar conditions of the campaign for the abnormally large number of torpedo failures. Most commanders were used to operating at sea where the effect of tides and currents over short distances is negligible between a boat and its target. Underwater movement may have significantly affected torpedoes, by throwing them off course or making them run too deep - potentially explaining at least part of the missed shots and torpedo failures.<ref>Trompelt, Heinz (2006). Eine andere Sicht. Norderstedt: Books on Demand GmbH, pg 137-140. {{ISBN|3-8334-4481-9}}</ref>

Four submarines were also lost - three ocean-going submarines consisting of two VIIBs and one IXB along with one older IIA.

==Submarine order of battle==
Operation Hartmut engaged nearly every submarine in Germany's navy - most notably, both older Type IA submarines and all six of Germany's IIA coastal submarines, which were operating as training boats in the Baltic. Boats which were initially unavailable for action at the beginning of the operation took part in ferrying supplies or patrolling later on.

When Hartmut was issued on 6 April 1940 the German plan designated the U-bootwaffe into eight groups (along with a further Group Seven, which was cancelled).

===U-Boat Group One===
Patrol Area: Narvik, Harstad, Westfjord, Vagsfjord
* [[German submarine U-25 (1936)|''U-25'']] - one of only two [[German Type I submarine|Type IA]] submarines in the [[Kriegsmarine]]. Under the command of [[Viktor Schütze]], ''U-25'' had no success during Hartmut.
* [[German submarine U-46 (1938)|''U-46'']] - a [[German Type VII submarine|Type VIIB]] under [[Herbert Sohler]] with IWO [[Erich Topp]]. ''U-46'' had no success during Hartmut.
* [[German submarine U-51 (1938)|''U-51'']] - a Type VIIB under [[Dietrich Knorr]], who failed to sink any vessels during Hartmut.<ref>{{cite web | url=http://uboat.net/boats/patrols/u51.html | title=War Patrols by German U-Boat U-51}}</ref>
* {{GS|U-64|1939|2}} - a [[German Type IX submarine|Type IXB]] under [[Georg-Wilhelm Schulz]]. ''U-64'' was the first U-boat sunk by aircraft in the war. While anchored near [[Bjerkvik]], British forces including a [[Fairey Swordfish]] launched from {{HMS|Warspite|03|6}} sank the boat on 13 April.<ref>{{cite web | url=http://uboat.net/boats/u64.htm | title=The Type IXB boat U-64}}</ref> Schulz and other surviving crew were rescued from the water by German troops in Norway.
* {{GS|U-65|1940|2}} - a [[German Type IXB submarine|Type IXB]], which patrolled in the North Sea for 36 days without sinking any ships.<ref>{{cite web | url=http://uboat.net/boats/patrols/patrol_454.html | title=Patrol of U-Boat U-65 from 9 Apr 1940 to 14 May 1940}}</ref>

===U-Boat Group Two===
Patrol Area: Trondheim, Namsos, Romsdalsfjord
* [[German submarine U-30 (1936)|''U-30'']] - a Type VIIA under [[Fritz-Julius Lemp]], who was responsible for sinking the {{SS|Athenia|1922|6}}, the first ship sunk during the war. His patrol along the coast of Norway during Hartmut was uneventful.
* [[German submarine U-34 (1936)|''U-34'']] - a Type VIIA, which torpedoed the scuttled Norwegian minelayer [[HNoMS Frøya|HNoMS ''Frøya'']] on 13 April.<ref>{{cite web | url=http://uboat.net/boats/patrols/patrol_244.html | title=Patrol of U-Boat U-34 from 3 Apr 1940 to 30 Apr 1940}}</ref>

===U-Boat Group Three===
Patrol Area: Bergen, Aalesund, Shetland Islands
* [[German submarine U-9 (1935)|''U-9'']] - a [[German Type II submarine|Type IIB]] commanded by [[Wolfgang Lüth]]. While ''U-9'' had a relatively successful career, she sank no ships during Hartmut.
* [[German submarine U-14 (1936)|''U-15'']] - a Type IIB successfully commanded by [[Herbert Wohlfarth]], but which failed to sink any ships during Hartmut.
* [[German submarine U-56 (1938)|''U-56'']] - a Type IIC with an uneventful patrol.
* [[German submarine U-60 (1939)|''U-60'']] - a Type IIC with an uneventful patrol.
* [[German submarine U-62 (1939)|''U-62'']] - a Type IIC with an uneventful patrol.

===U-Boat Group Four===
Patrol Area: Stavanger
* [[German submarine U-1 (1935)|''U-1'']] - a Type IIA brought into frontline service. The submarine was sunk by mines, probably on 6 April.<ref>{{cite web | url=http://uboat.net/boats/u1.htm | title=Type IIA U-1}}</ref>
* [[German submarine U-4 (1935)|''U-4'']] - a Type IIA brought into frontline status before returning to her role as a training boat. Sank the [[British T-class submarine]] [[HMS Thistle (N24)|HMS ''Thistle'']].<ref>{{cite web | url=http://uboat.net/boats/u1.htm | title=Type IIA U-4}}</ref>

===U-Boat Group Five===
Patrol Area: East of the Shetland Islands, Vagsfjord, Trondheim

* [[German submarine U-37 (1938)|''U-37'']] - a Type IXA, one of the few boats to survive to be scuttled near the war's end. During Hartmut, ''[[K.Kapt.]]'' [[Werner Hartmann]] sank three freighters.<ref>{{cite web | url=http://uboat.net/boats/patrols/patrol_256.html | title=Patrol of U-Boat U-37 from 30 Mar 1940 to 18 Apr 1940}}</ref> <!-- 1 tanker (Swedish) 9076 APR10; 1 freighter (Norwegian) 5128 APR10; 1 freighter  4511(British) APR12 -->
* [[German submarine U-38 (1938)|''U-38'']] - a Type IXA under [[Heinrich Liebe]].<ref>{{cite web | url=http://uboat.net/boats/u38.htm | title=The Type IX boat U-38}}</ref> ''U-38'' engaged multiple ships, but was plagued with premature torpedo detonations and misses.
* [[German submarine U-47 (1938)|''U-47'']] - a Type VIIB under [[Günther Prien]] and IWO [[Hans-Werner Kraus]].<ref>{{cite web | url=http://uboat.net/boats/patrols/patrol_324.html | title=Patrol of U-Boat U-47 from 3 Apr 1940 to 26 Apr 1940}}</ref>
* [[German submarine U-48 (1939)|''U-48'']] - a Type VIIB under [[Herbert Schultze]] and IWO [[Reinhard Suhren]] - both who ended the war as successful [[List of successful U-boat commanders|U-Boat aces]], but had no success on this patrol.<ref>{{cite web | url=http://uboat.net/boats/patrols/patrol_334.html | title=Patrol of U-Boat U-48 from 3 Apr 1940 to 20 Apr 1940}}</ref>
* [[German submarine U-49 (1939)|''U-49'']] - a Type VIIB under [[Kurt von Gossler]] was sunk on 15 April by [[depth charge]]s from the British [[destroyer]]s {{HMS|Fearless|H67|6}} and {{HMS|Brazen|H80|6}} with one dead and 41 survivors.<ref>{{cite web | url=http://uboat.net/boats/u49.htm | title=The Type VIIB boat U-49}}</ref>
* [[German submarine U-50 (1939)|''U-50'']] - a Type VIIB was sunk by mines on 6 April en route to her patrol area.<ref>{{cite web | url=http://uboat.net/boats/u50.htm | title=The Type VIIB boat U-50}}</ref>

===U-Boat Group Six===
Patrol Area: Pentland, Orkney islands, Shetland Islands
* [[German submarine U-13 (1935)|''U-13'']] - a Type IIB commanded by [[Max-Martin Schulte]]. She sank two ships and damaged another during the operational time period.<ref>{{cite web | url=http://uboat.net/boats/u13.htm | title=Type IIB U-13}}</ref> During this patrol, ''U-13'' docked in recently occupied [[Bergen]] for a short time on 19 to 21 April.
* [[German submarine U-57 (1938)|''U-57'']] - a Type IIC under [[Claus Korth]]. ''U-57'' sank a British tanker in late March, but had no success during Weserübung.<ref>{{cite web | url=http://uboat.net/boats/u13.htm | title=Type IIC U-57}}</ref>
* [[German submarine U-58 (1939)|''U-58'']] - a Type IIC under [[Herbert Kuppisch]] had one long patrol during the entire operation, but no ships sunk.
* [[German submarine U-59 (1939)|''U-59'']] - a Type IIC commanded by [[Harald Jürst]], which sank one Norwegian vessel on 6 April.<ref>{{cite web | url=http://uboat.net/boats/patrols/patrol_418.html | title=Patrol of U-59 from 31 Mar 1940 to 7 May 1940}}</ref>

===U-Boat Group Seven===
Never assembled. Group Seven was designated to patrol the Eastern entrance to the [[English Channel]], but was cancelled.

===U-Boat Group Eight===
Patrol Area: Lindesnes, Egernsund
* [[German submarine U-2 (1935)|''U-2'']] - a Type IIA brought to frontline status for two patrols during the operation before returning to her role as a training boat.
* [[German submarine U-3 (1935)|''U-3'']] - a Type IIA also brought into frontline service for the operation.
* [[German submarine U-5 (1935)|''U-5'']] - a Type IIA brought into frontline service for one patrol.
* [[German submarine U-6 (1935)|''U-6'']] - a Type IIA brought into frontline service for one patrol.

===U-Boat Group Nine===
Patrol Area: Bergen, Shetland Islands; SW of the Norwegian Coast.
* [[German submarine U-7 (1935)|''U-7'']] - a Type IIB, which was on patrol west of the Norwegian Coast when Dönitz first received orders to prepare for Hartmut.<ref>{{cite web | url=http://www.uboatarchive.net/BDUKTB30261.htm | title=Appendix 1 to B.d.U's War Log, 1–31 March 1940 | access-date=10 May 2010 | archive-url=https://web.archive.org/web/20130820025556/http://uboatarchive.net/BDUKTB30261.htm | archive-date=20 August 2013 | url-status=dead }}</ref> ''U-7'' conducted three patrols during March/April 1940.<ref>{{cite web | url=http://uboat.net/boats/u7.htm | title=Type IIB U-7}}</ref>
* [[German submarine U-10 (1935)|''U-10'']] - a Type IIB that sank a Norwegian vessel in February, but nothing on patrol during Hartmut.
* [[German submarine U-19 (1936)|''U-19'']] - a Type IIB that sank four Danish merchants on 19 and 20 March.<ref>{{cite web | url=http://uboat.net/boats/u19.htm | title=Type IIB U-19}}</ref>

===Unassigned===
These U-boats began patrols during the timeframe of Operation Weserübung, but were not fit for service (either due to damage, command changes or other reasons) during the beginning of Hartmut. These submarines generally operated in the area of the Orkney islands, Shetland Islands, and near Bergen.
* [[German submarine U-17 (1935)|''U-17'']] - a Type IIB for frontline training; until late April ''U-17'' was not on war patrol.<ref>{{cite web | url=http://uboat.net/boats/patrols/u17.html | title=Patrols of U-17}}</ref>
* [[German submarine U-23 (1936)|''U-23'']] - [[Otto Kretschmer]]'s former Type IIB. The submarine had no success during Hartmut.<ref>{{cite web | url=http://uboat.net/boats/patrols/u23.html | title=Patrols of U-23}}</ref>
* [[German submarine U-24 (1936)|''U-24'']] - a Type IIB that began operations in late April without success.
* [[German submarine U-61 (1939)|''U-61'']] - a Type IIC under the command of [[Jürgen Oesten]] went on patrol in mid-April, but did not have any success.

==Other submarine actions==
* [[German submarine U-26 (1936)|''U-26'']] - a Type IA - one of only two in the Kriegsmarine (the other being ''U-25'' from Group One). ''U-26'' delivered supplies to German troops in Trondheim, before going on patrol and sinking one British supply ship on 21 April.
* [[German submarine U-29 (1936)|''U-29'']] - a Type VIIA also tasked with delivering supplies to Trondheim, but with an uneventful subsequent patrol.
* [[German submarine U-32 (1937)|''U-32'']] - a Type VIIA that delivered supplies to Trondheim in early May.
* [[German submarine U-43 (1939)|''U-43'']] - a Type IXA, which also delivered supplies to Trondheim. On her return journey she was bombed by two British [[Lockheed Hudson|Hudson]] aircraft on 22 April, suffering light damage on the return journey to Wilhelmshaven.<ref>{{cite web | url=http://uboat.net/boats/patrols/patrol_286.html | title=Patrol of U-Boat U-43 from 12 Apr 1940 to 23 Apr 1940}}</ref>

==See also==
*[[Operation Weserübung]]
*[[Battles of Narvik]]
*[[Battle of the Atlantic]]

==References==
{{reflist}}

==External links==
*[http://www.u-boote-online.de/krieg/unternehmen_weseruebung.html U-Boats during Operation Weserübung] [In German]
*[http://www.uboatarchive.net/BDUKTB.htm U-boat Archive - BDU's KTB]

{{DEFAULTSORT:Hartmut, Operation}}
[[Category:Naval battles of World War II involving France]]
[[Category:Naval battles of World War II involving Germany]]
[[Category:Naval battles of World War II involving Norway]]
[[Category:Naval battles and operations of the European theatre of World War II]]
[[Category:Code names]]
[[Category:U-boats]]