Operationsbefehl Hartmut

Operationsbefehl Hartmut(literally "Operation Order Hartmut" ) was thecode wordto begin Germansubmarineoperations duringOperation Weserübung-Nazi Germany's invasion ofDenmarkandNorway.Occasionally these operations are termedOperation Hartmut.The orders involved submarine screening actions for the German invasion fleet andreconnaissance- particularly offNarvikandTrondheim.The orders also resulted in a number of attacks onAllied forces- particularly in or near thefjordsof the Norwegian coast.

The operation's reconnaissance and screening objectives succeeded for the most part, however Hartmut is notable for the large number of faultytorpedoesfired and four U-boats sunk. These problems came at a time when thewar in the Atlanticwas still going exceptionally well againstBritain.The deployment of U-boats during Operation Weserübung is occasionally criticized as a waste of manpower andmaterielfor this reason. The use ofmagnetic pistolsand operations in cold weather rendered theG7e torpedoless effective. Coastal operations may have also hampered commanders used to the open sea. Speculation persists that massive torpedo failure during this campaign provoked Germannaval high commandinto improving the weapon's performance. U-boat commanders likePrien,SchultzeandSchützehad the only patrols of their careers without anytonnagesunk.

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.BdUKarl Dönitzintermittently sent ships to reconnoitre areas of the Norwegian coast and to try to locate portions of theBritish fleet.

Due tosubmarines' 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 theWeser riveron the morning of 7 April. Twenty U-boats went out on 3, 4 and 5 April.

Hartmut preparations

Preparations in the German submarine forces (U-bootwaffe) began in early March. On 4 March 1940Karl Dönitzreceived orders from his superiors in Berlin:

1. Further U-boat sailings are to be stopped. U-boats which have already sailed are not to operate off the Norwegian coast.
2. All Naval forces to be ready for operations as quickly as possible. No special degree of readiness.

Dönitzmobilizedany vessel that could dive. Only 12 largerType VIIandType IXsubmarines capable of operating in theAtlantic Oceanwere fit for the operation. One older ocean-goingType IAwas also included. 12 smallerType IIU-boats were called up, despite that the Norwegian coast limited their operating time. The operation subsequently disrupted training exercises in theBaltic Seaas six outdated Type IIA training submarines were brought into theNorth 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. 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."

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

U-4sank theBritish T-class submarineHMSThistle.

U-13

U-13sank the British steam merchantSwainbyoff the Shetland islands with one torpedo on 17 April.

After docking inBergenfor a short time,U-13then sank the Danish vesselLilythat had been taken as aprizeby the British after the Germanoccupation of Denmark.The first torpedo failed to arm, but the second broke the ship in half.A few days laterU-13damaged another British ship before returning to port.

U-37

U-37sank one Swedish tanker, one Norwegian freighter and one British freighter equalling 18,715 tons of shipping between 10 and 12 April.

U-38

There were two navalbattles of Narvikon 10 April 1940 and 13 April 1940.U-38andU-65were positioned at the entrance of the fjord. When the Royal Navy arrived,U-38fired atHMSValiantand atHMSSouthamptonmissing both. In the second battle, U-38 fired atHMSEffinghambut the torpedoes detonated prematurely.

U-47

U-47underGünther Prienencountered "a wall of ships" on 15 April.A Britishfleetofcruisersandtransport shipswere anchored nearNarvikoffloading 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 torpedoesU-47had no success. One detonated underwater after hitting a rock, well off course.

After leavingOfotfjord,U-47spotted and attackedHMSWarspite.One torpedo detonated ahead of the battleship, while another detonated far behind.U-47spent the next hours submerged under persistentdepth chargeattack.

U-48

U-48underHerbert Schultzemade 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-48attacked HMSWarspitebut both torpedoes failed to detonate.Warspite's destroyer screen fired on the vessel andU-48was depth charged, but escaped destruction.

U-51

U-51attacked a destroyer, but the torpedoes detonated prematurely. On 19 April, commanderDietrich Knorrattacked the French cruiserÉmile Bertin,but both torpedoes missed.

U-65

Hans-Gerrit von StockhausencommandingU-65attacked 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.

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 themagnetic pistolsfailed 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 suitableoperating 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.

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

• U-25- one of only twoType IAsubmarines in theKriegsmarine.Under the command ofViktor Schütze,U-25had no success during Hartmut.
• U-46- aType VIIBunderHerbert Sohlerwith IWOErich Topp.U-46had no success during Hartmut.
• U-51- a Type VIIB underDietrich Knorr,who failed to sink any vessels during Hartmut.
• U-64- aType IXBunderGeorg-Wilhelm Schulz.U-64was the first U-boat sunk by aircraft in the war. While anchored nearBjerkvik,British forces including aFairey Swordfishlaunched fromHMSWarspitesank the boat on 13 April.Schulz and other surviving crew were rescued from the water by German troops in Norway.
• U-65- aType IXB,which patrolled in the North Sea for 36 days without sinking any ships.

U-Boat Group Two

Patrol Area: Trondheim, Namsos, Romsdalsfjord

• U-30- a Type VIIA underFritz-Julius Lemp,who was responsible for sinking theSSAthenia,the first ship sunk during the war. His patrol along the coast of Norway during Hartmut was uneventful.
• U-34- a Type VIIA, which torpedoed the scuttled Norwegian minelayerHNoMSFrøyaon 13 April.

U-Boat Group Three

Patrol Area: Bergen, Aalesund, Shetland Islands

• U-9- aType IIBcommanded byWolfgang Lüth.WhileU-9had a relatively successful career, she sank no ships during Hartmut.
• U-15- a Type IIB successfully commanded byHerbert Wohlfarth,but which failed to sink any ships during Hartmut.
• U-56- a Type IIC with an uneventful patrol.
• U-60- a Type IIC with an uneventful patrol.
• U-62- a Type IIC with an uneventful patrol.

U-Boat Group Four

Patrol Area: Stavanger

• U-1- a Type IIA brought into frontline service. The submarine was sunk by mines, probably on 6 April.
• U-4- a Type IIA brought into frontline status before returning to her role as a training boat. Sank theBritish T-class submarineHMSThistle.

U-Boat Group Five

Patrol Area: East of the Shetland Islands, Vagsfjord, Trondheim

• 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 Hartmannsank three freighters.
• U-38- a Type IXA underHeinrich Liebe.U-38engaged multiple ships, but was plagued with premature torpedo detonations and misses.
• U-47- a Type VIIB underGünther Prienand IWOHans-Werner Kraus.
• U-48- a Type VIIB underHerbert Schultzeand IWOReinhard Suhren- both who ended the war as successfulU-Boat aces,but had no success on this patrol.
• U-49- a Type VIIB underKurt von Gosslerwas sunk on 15 April bydepth chargesfrom the BritishdestroyersHMSFearlessandHMSBrazenwith one dead and 41 survivors.
• U-50- a Type VIIB was sunk by mines on 6 April en route to her patrol area.

U-Boat Group Six

Patrol Area: Pentland, Orkney islands, Shetland Islands

• U-13- a Type IIB commanded byMax-Martin Schulte.She sank two ships and damaged another during the operational time period.During this patrol,U-13docked in recently occupiedBergenfor a short time on 19 to 21 April.
• U-57- a Type IIC underClaus Korth.U-57sank a British tanker in late March, but had no success during Weserübung.
• U-58- a Type IIC underHerbert Kuppischhad one long patrol during the entire operation, but no ships sunk.
• U-59- a Type IIC commanded byHarald Jürst,which sank one Norwegian vessel on 6 April.

U-Boat Group Seven

Never assembled. Group Seven was designated to patrol the Eastern entrance to theEnglish Channel,but was cancelled.

U-Boat Group Eight

Patrol Area: Lindesnes, Egernsund

• U-2- a Type IIA brought to frontline status for two patrols during the operation before returning to her role as a training boat.
• U-3- a Type IIA also brought into frontline service for the operation.
• U-5- a Type IIA brought into frontline service for one patrol.
• 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.

• U-7- a Type IIB, which was on patrol west of the Norwegian Coast when Dönitz first received orders to prepare for Hartmut.U-7conducted three patrols during March/April 1940.
• U-10- a Type IIB that sank a Norwegian vessel in February, but nothing on patrol during Hartmut.
• U-19- a Type IIB that sank four Danish merchants on 19 and 20 March.

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.

• U-17- a Type IIB for frontline training; until late AprilU-17was not on war patrol.
• U-23-Otto Kretschmer's former Type IIB. The submarine had no success during Hartmut.
• U-24- a Type IIB that began operations in late April without success.
• U-61- a Type IIC under the command ofJürgen Oestenwent on patrol in mid-April, but did not have any success.

Other submarine actions

• U-26- a Type IA - one of only two in the Kriegsmarine (the other beingU-25from Group One).U-26delivered supplies to German troops in Trondheim, before going on patrol and sinking one British supply ship on 21 April.
• U-29- a Type VIIA also tasked with delivering supplies to Trondheim, but with an uneventful subsequent patrol.
• U-32- a Type VIIA that delivered supplies to Trondheim in early May.
• U-43- a Type IXA, which also delivered supplies to Trondheim. On her return journey she was bombed by two BritishHudsonaircraft on 22 April, suffering light damage on the return journey to Wilhelmshaven.

See also

• Operation Weserübung
• Battles of Narvik
• Battle of the Atlantic

External links

• U-Boats during Operation Weserübung[In German]
• U-boat Archive - BDU's KTB