The early phase of the

Battle of the Atlantic The Battle of the Atlantic, the longest continuous military campaign in World War II, ran from 1939 to the defeat of Nazi Germany in 1945, covering a major part of the naval history of World War II. At its core was the Allied naval blockade ...

during which

German Navy The German Navy (, ) is the navy of Germany and part of the unified ''Bundeswehr'' (Federal Defense), the German Armed Forces. The German Navy was originally known as the ''Bundesmarine'' (Federal Navy) from 1956 to 1995, when ''Deutsche Mari ...

U-boat U-boats were naval submarines operated by Germany, particularly in the First and Second World Wars. Although at times they were efficient fleet weapons against enemy naval warships, they were most effectively used in an economic warfare role ...

s enjoyed significant success against the British

Royal Navy The Royal Navy (RN) is the United Kingdom's naval warfare force. Although warships were used by English and Scottish kings from the early medieval period, the first major maritime engagements were fought in the Hundred Years' War against F ...

and its

Allies An alliance is a relationship among people, groups, or states that have joined together for mutual benefit or to achieve some common purpose, whether or not explicit agreement has been worked out among them. Members of an alliance are called ...

was referred to by U-boat crews as "the Happy Time" ("''Die Glückliche Zeit''"), and later the First Happy Time, after a second successful period was encountered. It started in July 1940, almost immediately after the

Fall of France The Battle of France (french: bataille de France) (10 May – 25 June 1940), also known as the Western Campaign ('), the French Campaign (german: Frankreichfeldzug, ) and the Fall of France, was the German invasion of France during the Second World ...

, which brought the German U-boat fleet closer to the British shipping lanes in the Atlantic. From July 1940 to the end of October, 282 Allied ships were sunk off the north-west approaches to

Ireland Ireland ( ; ga, Éire ; Ulster Scots dialect, Ulster-Scots: ) is an island in the Atlantic Ocean, North Atlantic Ocean, in Northwestern Europe, north-western Europe. It is separated from Great Britain to its east by the North Channel (Grea ...

for a loss of 1,489,795 tons of merchant shipping. The reason for this successful Axis period was the British lack of

radar Radar is a detection system that uses radio waves to determine the distance (''ranging''), angle, and radial velocity of objects relative to the site. It can be used to detect aircraft, ships, spacecraft, guided missiles, motor vehicles, w ...

and

huff-duff High-frequency direction finding, usually known by its abbreviation HF/DF or nickname huff-duff, is a type of radio direction finder (RDF) introduced in World War II. High frequency (HF) refers to a radio band that can effectively communicate ov ...

equipped ships which meant that the U-boats were very hard to detect when they made nighttime surface attacks –

ASDIC Sonar (sound navigation and ranging or sonic navigation and ranging) is a technique that uses sound propagation (usually underwater, as in submarine navigation) to navigate, measure distances (ranging), communicate with or detect objects on or ...

(

sonar Sonar (sound navigation and ranging or sonic navigation and ranging) is a technique that uses sound propagation (usually underwater, as in submarine navigation) to navigation, navigate, measure distances (ranging), communicate with or detect o ...

) could only detect submerged U-boats. When it ended is a matter of interpretation, with some sources claiming October 1940 and others extending it to April 1941, after the Germans lost three prominent U-boat commanders:

Günther Prien Günther Prien (16 January 1908 – presumed 8 March 1941) was a German U-boat commander during World War II. He was the first U-boat commander to receive the Knight's Cross of the Iron Cross and the first member of the ''Kriegsmarine'' to r ...

Joachim Schepke Joachim Schepke (8 March 1912 – 17 March 1941) was a German U-boat commander during World War II. He was the seventh recipient of the Knight's Cross of the Iron Cross with Oak Leaves. Schepke is credited with having sunk 36 Allied ships. Durin ...

and

Otto Kretschmer Otto Kretschmer (1 May 1912 – 5 August 1998) was a German naval officer and submariner in World War II and the Cold War. From September 1939 until his capture in March 1941 he sank 44 ships, including one warship, a total of 274,333 tons. For ...

References

Battle of the Atlantic {{Germany-WWII-stub

See also

References