battle of the atlantic1

8/8/2019 Battle of the Atlantic1

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IntroductionIntroductiony As an island Britain needed to bring in a vast amount of

food and military equipment to survive the war.

y The German submarine force (U-boats) severelydamaged the ability to survive the war - henceChurchills quote above when he feared Britain would

starved out of the war.y A great deal of the raw materials came from America

and therefore had to cross the Atlantic. In normal timesthis journey could be hazardous because of theweather but in the war the German submarines lead byAdmiral Raeder proved a very real threat. NaziGermany estimated that they needed to sink 150merchant ships each month to starve Britain out.


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y German submarines hunted in what were called

wolf-packs. British supply ships crossed in

convoys and the ships that brought in the food

etc. were slow and they could barely protect

themselves.

y

After leaving America they were reasonably safewhile in American water and they were also

more safe when they approached British waters

as they got fighter plane cover. It was in the

mid-Atlantic that they were most vulnerable asthe U-boats would run riot.


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y German submarines had direct access to

the Atlantic once France had fallen in the

spring of 1940. Massive submarine pens

were built near Bordeaux.

y 1939 : 222 ships sunk (114 by submarine)

y 1940 : 1059 ships sunk (471 by submarine)y 1941 : 1328 ships sunk (432 by submarine)

y 1942 :1661 ships sunk (1159 by submarine)

y 1943

:597

ships sunk (463

by submarine)y 1944 : 247 ships sunk (132 by submarine)

y 1945 : 105 ships sunk (56 by submarine)


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The UThe U--Boat PerilBoat Perily

The fall of France allowed U-Boats to operate far into theAtlantic from French ports. Nazi shipyards produced about20 new U-boats a months, and British merchant shipping lossesgrew.

y After summer 1940, the U-boats attacked in large wolf-packs when a U-boat came across a convoy, it would radio its

position to a number of other submarines, which would closein on the convoy.

y Then they would wait until nightfall and make surface attacks innumbers. On 18 October 1940, a pack of 6 Nazi U-boatsattacked slow convoy SC7, sinking 15 ships in 6 hours.

y Next day, reinforced by three more U-boats, the pack attacked

the 49-ship convoy HX-79, sinking 12 ships in one night.


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y The Royal Navy did not have enough ships to protect theconvoys properly. In November 1940 convoy HX84 (37ships escorted only by the armed merchant cruiser HMSJervisBay), was attacked by the Nazi battleshipAdmiral Scheer.

Completely outgunned (her shells did not even reach the Naziship) theJervis Bayattacked theAdmiral Scheerto give theconvoy time to escape theJervis Bayand five merchant shipswere sunk.

y The USA tried to help Britain. In August 1940 the US gaveBritain 50 destroyers in exchange for Atlantic naval bases, and,

after August 1941, by an agreement called theAtlantic Charterwhich Roosevelt made with Churchill, convoys were defendedby the US Navy. It had little effect. Losses were huge.

y The worst period was from the beginning of 1942 to March1943 when 7 million tons of merchant shipping was sunk. In

July 1942, 143 ships were sunk in a single month, and in

November 1942, 117 ships were lost.


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1st Phase1st Phase -- September 1939 to Fall of FranceSeptember 1939 to Fall of France

y Doenitz had 57 subs; British had radar, asdic (location

fixed by time of return "ping")

y Sept. 3 - U30 sank British linerAthenia - 1st sinking of the

war by a German Unterseeboot ("U-boat")

y Sept. 5 - Gunther Prien, "Bull of Scapa Flow", sank theBosnia, 1st cargo ship sunk in war

y Sept. 6 - 1st convoy - 36 ships in 9 parallel rows of 4

each, 1 escort in front, left, right

y Oct. 11 SS-Iroquois arrived safely in New York.

y May 5, 1940 - Germany captured HMS Seal, codes for

Bdienst; copied its torpedo design


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Doenitz had 21 operational subs and began wolfDoenitz had 21 operational subs and began wolf--

packs; British increased escort ships to 375packs; British increased escort ships to 375

yJune 22 - fall of France; 1st sub base at Lorientoperated July 6, construction began of thick

concrete pens to protect subs from air attack

y Aug. 17 - Hitler proclaimed total blockade of

England to all shipping

y Oct 18-19 - wolf-pack of 6 subs sank 36 of 79 in

2 convoys - 2 worst days of war

y

Oct. - "The Happy Time" for subs - recordaverage sinking of 60,000 tons per month per sub

y March 11, 1941 - Lend-lease approved; North

Atlantic route became most important


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The Tide TurnsThe Tide Turns

y Eight things helped the Allies to stop the U-boat menace

y The work of the British code-breakers at Bletchley Parkin deciphering the German Enigma code was vital ingiving the Allied navies the edge in the Battle of the

Atlantic.y In February 1942, however, the German code was

improved, resulting in the Drumbeat crisis whenshipping losses were their greatest until March 1943,when the German code was again broken.

y Sonar had been invented before World War I, but after1942 the US Navy Department developed consolesonar which could plot accurate bearings using an echoping. Training of sonar operators was also improved.


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y Radar was improved so that U-boats could even bedetected in bad weather.

y

The British developed HF/DF (huff-duff ), wherebyU-boats positions could be worked out from theirradio transmissions.

y Six aircraft carriers were sent to patrol the Atlantic,and this extended air cover to the whole route

convoys took.y Air depth-bombs were developed so that planes

could attack U-boats under the water.

y Weapons called Hedgehogand Squidwere developed

which allowed attack ships to catapult depth-chargesup to 300 yards in front of the ship.

y The Allies set up hunter-killer groups of ships,including one aircraft carrier with a number ofdestroyer escorts, to hunt down and sink U-boats


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y It was the end of the U-Boat menace 37 U-Boatswere lost in May 1943, and 34 in July. The RAFwas able to intercept and sink many U-boats asthey left harbour. The Nazis gave their U-boatsbetter anti-aircraft guns, and invented a devicecalled Snorkel (which allowed U-Boats to refreshtheir air without surfacing).

y Bottoming tactics allowed U-boats to avoiddetection from sonar and radar. However, afterMay 1943, the U-boats were on the defensive, andAllied shipping losses fell significantly.

y

Nevertheless, it must be questioned whether theAllies won the Battle of the Atlantic between1939 and 1945, 2,753 Allied ships were sunk (grosstonnage 14.5 million) at a cost of 783 Nazi U-boats.


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y

In May 1931 the British captured the U-100, including an Enigma code machine,

which helped the British codebreakers at

Bletchley Park to decipher the Nazi's

Enigma code.y Again, in October 1942, the British

captured the U-559 in the Mediterranean

with a code book that helped the British tobreak the new Nazi Triton cipher.


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3rd Phase3rd Phase -- April 1941 to PearlApril 1941 to Pearl

HarborHarbor

y Doenitz fleet grew to 249 subs with 35operational; British Ultra cracked sub codes, atriumph of WW2 code breaking; "Ultra andthe Campaign against the German U-boat

y Apr. 11 - U.S. destroyer Niblack fired 1st U.S.shot in the war, in widened Security Zone.

y Apr. 17 - Neutral Egyptian freighter Zam Zam

sunk by German cruiser Atlantic, 138Americans rescued.


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y May 9 - British destroyer Bulldogsouth of

Iceland captured U-110 sub and itsEnigma machine

June 20 - FDR speech on the SS Robin

Moorsunk by U-69 May 21; sub 0-9 lost in

accidentMay 27 - HX129 convoy first to be

escorted "end-to-end" across Atlantic;

Canadian Navy joins


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yJuly 1 - FDR includes Iceland in the security zone,sends marines, crosses the threshold to

undeclared naval war in the Atlanticy Aug. 1 - first convoy to Murmansk - Atlantic

route doubly important, helped Russians andBritish

y

Sept. 16 - HX150 from Halifax was the firstconvoy with American escorts to Iceland

y Oct. 19 - SS Lehigh sunk off African coast by U-126

y

Oct. 31 - U.S. destroyer Reuben James sunky Dec. 7 - U.S. built Audacity-class escort carriers,

Liberty ships, B-24 with 24 depth charges

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