NORTH ATLANTIC,
JANUARY 1941/JUNE 1943
By the end of 1942, the future course of
Allied strategy —every hope and every
plan — hung in the balance of a long,
bitter, groping battle fought out
between U-boat and convoy escort in
the grey battlefield of the Atlantic.
Throughout, the Allies were hampered
by their inability to concentrate all
their naval resources on this one battle.
But when victory came to them it was
with astonishing speed and complete
ness, only weeks after one of their most
disastrous reverses at sea
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By the beginning of 1941 the difficulties and
complexities of the Battle of the Atlantic
were really starting to make themselves felt.
The severe merchant ship losses in 1940 —
2,186,158 tons were sunk by the U-boats
alone —had in part been met by wartime
redeployment of peacetime shipping, but
from 1941 on there was no hope of meeting
further losses by this means. By this time
merchant shipping had been stretched to
its limit, and future losses could be made
good only by new construction.
There were several factors which were to
single out 1941 and 1942 as the years of
special peril in that swaying, groping battle
against the U-boats. The most immediate of
them was the rapid build-up in numbers of
the U-boats themselves, for the increased
building programme put in hand by Ger
many at the outbreak, of war was, by 1941,
beginning to take effect. From the beginning
of 1941 to the middle of 1943, the rate of
building far exceeded the rate of loss, so
that each succeeding month saw more and
more U-boats in the Atlantic.
There were other factors in this battle
which also came to the aid of the U-boats.
An important one was the length of time a
convoy took to cross the Atlantic. Allowing
for diversions, weather, and other delays,
the average time of passage of an Atlantic
convoy throughout the whole of the war was
just over 15 days; convoys to and from Free
town took four days longer. These long
passages in effect presented the U-boats with
more targets as the merchant ships made
their laborious voyages across the ocean.
Another important factor was the short
sea endurance of British escort vessels. At
the outbreak of war, escort for convoys could
only be provided up to a distance of about
500 miles from the British coast; beyond
that the merchant ships were on their own.
The occupation of Iceland after the disastrous
land campaign of 1940 provided the oppor
tunity of increasing the range of escort by
the provision of a refuelling base on the
island, but it was not until April 1941 that
the first base there was fully in commission.
Simultaneously, the Canadian navy de
veloped bases in Newfoundland and eastern g
Canada, and by the use of these bases the°
range of surface escort was pushed even*
farther out into the Atlantic. By April 1941 £
it was as far as 35 W, a little more than
half-way; two months later the first convoy
with end-to-end surface anti-submarine
escort sailed across the Atlantic. But be
cause of the shortage of escort vessels, the
average strength of escort was, in 1941, no
more than two ships per convoy. It was not
until the new long-range escorts, laid down
just before the war, began to join the fleet
that the strength of escort could be increased,
in 1942 and 1943, to more adequate numbers.
As important as the surface escorts were
those of the air, for of all the enemies of
the U-boat the one most feared was the air
craft. Their range of vision and speed of
attack were both vastly superior to those of
the surface escorts, and an aircraft circling
a convoy would force every U-boat within
attacking range to submerge, thus condemn
ing them to their low underwater speed and
a much reduced range of vision. But here
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