Hartmann ' s wolfpack Hartmann ’ s wolfpack was a formation of the German Navy in World War II , a " wolfpack " of U - boat s that operated during the early stages of the Battle of the Atlantic . Background . Hartmann ’ s wolfpack was the first essay by the German Navy during the Second World War in its wolfpack tactic against allied convoys . Its operations were in October 1939 , during the earliest stage of the Atlantic campaign . The name " Hartmann " was unofficial , taken from that of its commander , Werner Hartmann . Unlike later packs which had specific code names this formation was left without an official designation . The original intent of the U - boat Command ( BdU ) was to organize two packs of five boats each ; one composed of Type VIIB ’ s from 7th ( " Wegener " ) flotilla and the other of the larger Type IX ’ s of 6th ( " Hundius " ) flotilla . In the event , several boats were unavailable , so the operation was adjusted to form a single pack comprised six boats . This arrangement meant forming a unit of different type of vessel , who had not previously operated together . The whole force was commanded by Hartmann , flotilla commander of the Hundius flotilla . Operations . The first five boats sailed independently in October 1939 from bases in NW Germany , sailing northabout around the coast of Scotland in order to reach the Western Approaches . The last boat , , which was delayed in departing , was ordered to take the southabout route through the Channel ; this was more dangerous , but was deemed practicable . In the event " U – 40 " became trapped by the Allies ' Channel defences , the Dover Barrage ; on 13 October she struck a mine and was destroyed . The remaining five boats under Hartmann ’ s command took station in the Western Approaches . The German signals intelligence branch , " B - Dienst " , which had penetrated British naval codes , was able to give notice of a convoy ( KJF 3 ) from the Caribbean and BdU instructed the pack to intercept . Three boats found the convoy and attacked , while a fourth failed to make contact . The fifth , , met a freighter sailing independently ; she attacked , but was counter - attacked by two destroyers that came to the scene and was destroyed . The attack on KJF 3 was an ad hoc affair ( Blair describes it as " an uncoordinated free for all " ) ; though four ships were sunk , one of the attacking boats , was destroyed by the convoy escorts . A second convoy , HG 3 from Gibraltar , was detected by " B - dienst " and Hartmann ’ s boats were again ordered to intercept . made contact and shadowed while the other two closed . The attack sank three ships without loss to the attackers . Following this the boats were relieved , and returned home . Aftermath . This first attempt at operating a wolf pack was , over all , not a success . In the course of the operation Hartmann ' s skippers had sunk seven ships from two convoys and another four ships sailing alone ( stragglers and independent sailings ) . However three of the six U - boats had been destroyed , some 10 % of the available Type VII ( sea - going ) and Type IX ( ocean - going ) vessels the U - boat Arm had . The original pack tactic envisaged that command and co - ordination would be exercised at sea ; however while this had worked on exercise in the Baltic and North Seas it was unworkable in the wider reaches of the Atlantic . Hartman reported it was impossible to maintain an overview of the situation from his U - boat in the midst of the ocean and equally impossible to maintain contact with his charges . The experience was also soured by the continuing torpedo problems that the U - boat Arm suffered during the first years of the conflict . Following this , wolfpack tactics were shelved until the following year , when they were tried again with more success during the so - called " Happy Time " .