Casablanca Conference. Churchill and
Rosevelt decided to give highest priority to the defeat
of the U-boats.
Feb:
Centrimetric radar became operational.
March 1st – 12th:
Atlantic Convoy Conference in Washington.
Allies decided on several initiatives. 20 VLR Liberator
aircraft would be supplied to the Royal Canadian Air Force
to close the Mid-Atlantic air gap. Escort carrier groups
would be introduced. New convoy cycles would be created
and the “huff-duff’ network would be increased.
March 10th:
German navy issued with new code book
for Shark. Station X is temporarily blinded. U-boat operational
strength near it zenith. Wolf packs in the North and Central
Atlantic wreck havoc.
March 10 - 16th:
One of the biggest engagements of the
war, twenty U-boats attacked two slow eastbound convoys
of a total of 100 ships. The U-boats sank 21 ships (with
a combined tonnage of 141,000tons) with the loss of only
one of their own.
Mid – April:
41 VLR Liberators in operation.
RAF Coastal Command had 28 anti-submarine squadrons in
operation.
April:
U-boats engaged in a fierce running
battle with a slow eastbound convoy. They sank 12 ships
but at the cost of seven of their own.
June:
British cryptographers at Station X
(Bletchley Park) crack the German ‘Dolphin’ code
allowing rapid and regular access to U-boat signal traffic
in the Atlantic.
May:
Doenitz lost 43 subs, twice the replacement
rate; only sank 34 Allied ships in the Atlantic.
May 24th:
Doenitz ordered all U-boats out of the
North Atlantic. The 45-month campaign effectively came
to an end. It was not the end of the Battle of the Atlantic
but was the decisive moment of the campaign.
July:
Production rate of merchant shipping
from British and American yards was higher than the rate
at which U-boats were sinking ships at sea for the first
time.
Sept:
Lether group entered North Atlantic
with new anti-radar devices but failed.
Station X was able to break ‘Shark’ codes within 24 hours.
