page_title: Battle of the Atlantic
section_title: 'The Happy Time' (June 1940 – February 1941)
hierarchical_section_title: Battle of the Atlantic / British situation / 'The Happy Time' (June 1940 – February 1941)
context_page_description: 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 of Germany, announced the day after the declaration of war, and Germany's subsequent counter-blockade. The campaign peaked from mid-1940 through to the end of 1943.
  The Battle of the Atlantic pitted U-boats and other warships of the German Kriegsmarine and aircraft of the Luftwaffe against the Royal Navy, Royal Canadian Navy, United States Navy, and Allied merchant shipping. Convoys, coming mainly from North America and predominantly going to the United Kingdom and the Soviet Union, were protected for the most part by the British and Canadian navies and air forces. These forces were aided by ships and aircraft of the United States beginning September 13, 1941. The Germans were joined by submarines of the Italian Regia Marina after Germany's Axis ally Italy entered the war on June 10, 1940.
  As a small island country, the United Kingdom was highly dependent on imported goods.
context_section_description: The early U-boat operations from the French bases were spectacularly successful. This was the heyday of the great U-boat aces like Günther Prien of U-47, Otto Kretschmer (U-99), Joachim Schepke (U-100), Engelbert Endrass (U-46), Victor Oehrn (U-37) and Heinrich Bleichrodt (U-48). U-boat crews became heroes in Germany. From June until October 1940, over 270 Allied ships were sunk: this period was referred to by U-boat crews as "the Happy Time" ("Die Glückliche Zeit"). Churchill would later write: "...the only thing that ever frightened me during the war was the U-boat peril".
  The biggest challenge for the U-boats was to find the convoys in the vastness of the ocean. The Germans had a handful of very long-range Focke-Wulf Fw 200 Condor aircraft based at Bordeaux and Stavanger, which were used for reconnaissance. The Condor was a converted civilian airliner – a stop-gap solution for Fliegerführer Atlantik. Due to ongoing friction between the Luftwaffe and Kriegsmarine, the primary source of convoy sightings was the U-boats themselves. Since a submarine's bridge was very close to the water, their range of visual detection was quite limited.
  The best source proved to be the codebreakers of B-Dienst who had succeeded in deciphering the British Naval Cypher No. 3, allowing the Germans to estimate where and when convoys could be expected.
  In response, the British applied the techniques of operations research to the problem and came up with some counter-intuitive solutions for protecting convoys. They realised that the area of a convoy increased by the square of its perimeter, meaning the same number of ships, using the same number of escorts, was better protected in one convoy than in two. A large convoy was as difficult to locate as a small one. Moreover, reduced frequency also reduced the chances of detection, as fewer large convoys could carry the same amount of cargo, while large convoys take longer to assemble. Therefore, a few large convoys with apparently few escorts were safer than many small convoys with a higher ratio of escorts to merchantmen.
  Instead of attacking the Allied convoys singly, U-boats were directed to work in wolf packs (Rudel) coordinated by radio. The boats spread out into a long patrol line that bisected the path of the Allied convoy routes. Once in position, the crew studied the horizon through binoculars looking for masts or smoke, or used hydrophones to pick up propeller noises. When one boat sighted a convoy, it would report the sighting to U-boat headquarters, shadowing and continuing to report as needed until other boats arrived, typically at night. Instead of being faced by single submarines, the convoy escorts then had to cope with groups of up to half a dozen U-boats attacking simultaneously. The most daring commanders, such as Kretschmer, penetrated the escort screen and attacked from within the columns of merchantmen. The escort vessels, which were too few in number and often lacking in endurance, had no answer to multiple submarines attacking on the surface at night as their ASDIC only worked well against underwater targets. Early British marine radar, working in the metric bands, lacked target discrimination and range. Moreover, corvettes were too slow to catch a surfaced U-boat.
  Pack tactics were first used successfully in September and October 1940 to devastating effect, in a series of convoy battles. On September 21, convoy HX 72 of 42 merchantmen was attacked by a pack of four U-boats, which sank eleven ships and damaged two over the course of two nights. In October, the slow convoy SC 7, with an escort of two sloops and two corvettes, was overwhelmed, losing 59% of its ships. The battle for HX 79 in the following days was in many ways worse for the escorts than for SC 7. The loss of a quarter of the convoy without any loss to the U-boats, despite very strong escort (two destroyers, four corvettes, three trawlers, and a minesweeper) demonstrated the effectiveness of the German tactics against the inadequate British anti-submarine methods. On 1 December, seven German and three Italian 
caption: A U-boat shells a merchant ship which has remained afloat after being torpedoed.
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