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The nuclear submarine
USS Nautilus
The modern conventional submarine
Inside German WW2 submarines
The Type VIIC submarine
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Submarines in service on 1 September 1939
France - 59 units
9 oceanic units Requin class (1926-28), 4 coastal units Sirčne class (1927), 6 minelayer units Saphir class (1930-37),
30 oceanic units Redoutable class (1931-39), 9 coastal units Diane class (1932-34), 1 cruiser unit Surcouf class (1934).
Germany - 55 units + 18 in construction
30 coastal units Type II (1935-), 18 oceanic units Type VII (1936-), 7 oceanic units Type IX (1938-).
Great Britain - 46 units + 12 in construction
9 oceanic units Odin class (1927-30), 6 oceanic units Parthian class (1930-31), 4 oceanic units Rainbow class (1930-32),
3 oceanic units Thames class (1932-35), 12 oceanic units S class (1932-35), 6 minelayer units Porpoise class (1933-39),
3 oceanic units Triton class (1938-), 3 oceanic units Undine class (1938-).
Italy - 107 units + 1 in construction
5 coastal units H class (1916-17), 2 minelayer units X class (1917), 5 oceanic units Balilla class (1928-29),
4 oceanic units Mameli class (1929), 4 oceanic units Pisani class (1929), 4 oceanic units Bandiera class (1930),
1 oceanic unit Fieramosca class (1930), 4 oceanic units Squalo class (1930-31), 2 minelayer units Bragadin class (1931),
2 oceanic units Settembrini class (1932), 7 coastal units Argonauta class (1932-33), 12 coastal units Sirena class (1933-34),
4 oceanic units Galilei class (1934-35), 2 oceanic units Glauco class (1935), 1 minelayer unit Pietro Micca class (1935),
3 oceanic units Calvi class (1935-36), 10 coastal units Perla class (1936), 17 coastal units Adua class (1936-38),
2 oceanic units Argo class (1937), 3 minelayer units Foca class (1937-39), 5 oceanic units Brin class (1938-39),
10 oceanic units Marcello class (1938-39).
Japan - 55 units + 13 in construction
3 oceanic units Ro-57 class (1922-23), 2 oceanic units Ro-26 class (1923-24), 3 oceanic units Ro-29 class (1923-27),
9 oceanic units Ro-60 class (1923-27), 1 cruiser unit I-51 class (1924), 9 cruiser units I-153/I-156 class (1924-30),
1 cruiser unit I-152 class (1925), 4 cruiser units I-1 class (1926-29), 6 minelayer units I-121 class (1927-28),
3 cruiser units I-61/I-162 class (1929-30), 1 cruiser unit I-5 class (1932), 3 cruiser units I-165 class (1932),
8 cruiser units I-168/I-174 class (1934-38), 2 oceanic units Ro-33 class (1935-37).
Poland - 5 units
3 oceanic units Wilk class (1929-31), 2 oceanic units Orzel class (1938-).
Soviet Union - 167 units + 76 in construction
5 coastal units Amerikansky Golland class (1918-23), 6 oceanic units Dekabrist class (1930-31), 1 oceanic unit L55 class (1931),
17 oceanic units Leninets class (1933-), 58 coastal units Malyutka class (1933-), 74 coastal units Shchuka class (1933-),
3 oceanic units Pravda class (1936), 3 oceanic units Srednyaya class (1936-).
United States - 88 units + 10 in construction
19 coastal units R class (1918-20), 38 coastal units S class (1919-25), 3 cruiser units Barracuda class (1924-26),
1 cruiser unit Argonaut class (1928), 2 cruiser units Narwhal class (1930), 1 cruiser unit Dolphin class (1932),
2 cruiser units Cachalot class (1933-34), 10 oceanic units Porpoise class (1935-37), 6 oceanic units Salmon class (1937-38),
6 oceanic units Sargo class (1939-).
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Surcouf
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Narwhal
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I-15
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Length (meters)
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110.00
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112.95
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108.60
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Width (meters)
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9.00
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10.13
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9.30
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Draft (meters)
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9.07
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4.80
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5.10
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Displacement in surface / immersion (tonnes)
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3270 / 4250
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2730 / 3900
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2590 / 3655
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Engine power in surface / immersion (PS horsepower)
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7600 / 3400
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5400 / 2540
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12400 / 2000
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Speed in surface / immersion (knots)
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18 / 8.5
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17 / 8
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23.5 / 8
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Range in surface / immersion (nautical miles/knots)
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10000 at 10 / 59 at 5
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18000 at 10 / 48.6 at 5
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14000 at 16 / 100 at 3
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Torpedo tubes
(*) In orientable mountings
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4 internal afore (55 cm)
4 external * afore (55 cm)
4 external * astern (40 cm)
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4 afore (53.3 cm)
2 astern (53.3 cm)
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6 afore (53.3 cm)
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Cannons
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2 x 203 mm
2 x 37 mm
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2 x 152 mm
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1 x 140 mm
2 x 25 mm
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Aircraft
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1 x Besson M. B. 411
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-
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1 x Yokosuka E14Y1
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Complement
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118
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89
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100
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Submarine warfare in the Atlantic
In some way, it could be argued that the outcome of submarine warfare during the Second World War was sentenced
beforehand with the defeat of the German, regardless of their notable technical and tactical innovations besides their
partial victories. A proof of it would be the following thoughts from whom back then was the Chief of the Navy's
High Staff, Grand Admiral Karl Doenitz: "In the first months we were still far from possessing the required amount
of units which would allow to turn the Atlantic into the decisive theater of the war. These units which we needed
were the submarines. I, personally, fought since years before so their numbers were increased. It was perfectly
clear that only by means of submarines we had the possibility of defeating England. But my requests and those from
the German Navy were not heard in Berlin. If I had had 300 oceanic submarines, instead of the 23 which were ready at
the beginning of the war, things would have been different from the beginning. Hitler preferred to produce tanks
and aircraft. On the other hand, this strategy was a strictly continental one. He did not understand the importance
of the sea. Until 1943 he did not grant to me a number of submarines equivalent to the third part of what I requested
in 1939. But it was already too late."
Regardless of his apparent lack of optimism, Doenitz and his small submarine fleet were a true headache for the
Allies during the first half of the Second World War. Not even the modern tanks and infantry which, combined in the
famous Panzer Divisions, overran the enemies throughout Europe, to the west and east of Germany, or the Luftwaffe,
which caused aerial terror in the area of London, would have the repercussion of the lonely submarine "wolf packs"
which were close to surrender the British military power and thus to decide the outcome of the conflict in the
early 1940s. The German submarines would sink a total of 14 millions of tonnes of Allied and neutral ships. These
losses were close to jeopardize the supplies of warfare materials, raw materials and victuals which were
indispensable in the desperate fight against the annihilating force of the Third Reich. Once the conflict had ended,
Winston Churchill referred to Doenitz's weapon this way: "The only thing that truly frightened me during the war
was the threat from the U-Boot."
Some naval experts argued that submarine warfare had ended in the autumn of 1917, with the arrival of new defensive
tactics in the convoys and the technical development of depth charges and the ASDIC, a detection device which was
very improved during the interwar period and which would put many submarines in trouble. These beliefs, along with
the restrictions imposed by the Versailles Treaty, imbued the victorious nations with a sense of safety as well as
oblivion in respect of the 18 millions of tonnes sunk by the German submarines during the First World War. When they
faced the reconstruction and modernization of their fleets, the submarine weapon was left in the background. The
German of the Weimar Republic did not think the same and thus they continued the development of the submarine
weapon.
The outbreak of the largest conflict in History takes place with the German invasion of Poland the 1st September 1939.
Parallely, the German start the Battle of the Atlantic and cause surprise among the enemies with their new strategy.
The Kriegsmarine, knowing that its war fleet is incapable of facing the British Home Fleet, tried to strangle the
maritime commerce of the Allies, allocating its main assets in the Baltic and in the Atlantic: the pocket battleships
of the Deutschland class, the light cruisers of the Emden class and the submarines of the types IIC, VIIA and VIIB.
The German began the war with ten coastal submarines of the Vesikko type for training the crews in the school at Kiel,
twenty of the same type in the North Sea and twenty-seven of medium size in the Atlantic.
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Since before the outbreak of the war the three types of submarines that the Kriegsmarine considered to be necessary were
the short-range Type II, the medium-range Type VII and the long-range Type IX.
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Class
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Remarks
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Type II
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The Type II was the first submarine class designed by Germany during the interwar period. These were coastal submarines
of great prestations which however were too restricted by their small size. 50 exemplars were built until 1941 (six IIA,
twenty IIB, eight IIC and sixteen IID).
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Type VII
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The Type VII was the most widespread submarine class in the Kriegsmarine, built by hundreds throughout the war. These medium-range
oceanic submarines had good prestations but they excelled due to the tactics used and the excellent training of their crews.
They were deployed in the North Atlantic with the main purpose of intercepting the maritime traffic in route to England.
703 exemplars were built until the end of the war and the Type VIIC alone encompasses 568 of them, along with ten VIIA,
twenty-four VIIB, ninety-one VIIC/41, six VIID and four VIIF.
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Type IX
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The Type IX was a class of long-range oceanic submarines which was basically a enlarged version of the Type VII. Since the beginning
of the war the submarines of the Type IX operated in the western and southern Atlantic and later, when United States joined the war,
they fought the maritime traffic in the eastern coast of United States and in the Antilles. 194 exemplars were built until the end of
the war (eight IXA, fourteen IXB, fifty-four IXC, eighty-seven IXC/40 and thirty IXD).
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Type X
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The Type X was a class of minelayer submarines fitted with vertical mine tubes. The Type XA was a large vessel with a displacement of 2500
tonnes, which never entered service because the large size was considered to be a vulnerability. The Type XB was a smaller vessel which
had six tubes in the bow and twelve smaller tubes at each side. Only eight exemplars of this type were built.
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Type XI
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The Type XI was a class of cruiser submarines which never entered service. These vessels were planned to have a length of 111 meters,
a displacement of 3140 tonnes in surface, a speed of 23 knots in surface, two 127-millimeter cannon mountings and a seaplane. Not even
a single exemplar of this type was completed.
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The German submarine fleet was organized in groups which were called "wolf packs" and shortly after the beginning of
the conflict these vessels inflicted serious pain to the the Royal Navy. The 17th September the U-29 sank the
22,000-ton aircraft carrier HMS Courageous and the 14th October the U-47 sank the 29,000-ton battleship HMS Royal
Oak, when this one was anchored inside the highly protected British base at Scapa Flow. Later, the victory of the
Wehrmacht upon France granted the Kriegsmarine the free utilization of several French ports, which would serve as
bases from where the submarines could harass with increased efectiveness the Allied maritime routes. From 1941,
these bases would be fortified with numerous bunkers to protect the U-Boot from the Allied aviation.
The balance after the first year of war was 28 losses for the U-Boot (a 46 percent of their force) and a total of
353 Allied ships sunk (for a total of 1,513,390 gross tonnes). Twenty-eight new units would replenish the losses,
so the second year of the war would begin with the same number of submarines (57) than the previous, with only 33
of them being operational. The first large battles of submarines against convoys, which took place between
September and October 1940, proved the success of the group attack strategy developed by Doenitz from 1935. The
time of individual attacks had ended because the new combat rules set by the Allies in 1918 had rendered them
ineffective.
Radio communication devices were a fundamental help for organizing the "wolf packs" and the success against the
convoys is a proof of this. The 20th September contact is made with the HX 72 convoy and subsequently five U-Boot
arrived to the location, among them the U-47 and the U-49; during the night from the 21st to the 22nd this group
would sink almost a dozen of merchant vessels. During the night from the 16th to the 17th October 1940 another
convoy is located; in the attack is present as well the leader of German submarine aces, Frigate Captain Otto
Kretschmer, who arrives aboard the U-99 (yet another Type VIIB submarine), and that night one of the greatest
successes of submarine warfare is achieved: 20 merchant vessels recognized by the British.
The 19th October, the U-47, always commanded by the acclaimed Gunther Prien, spots the HX 79 convoy; this time
the "pack" congregated by Prien would sink twelve ships. The year 1940 ended with a total of 520 ships sunk
(for a total of 2,462,867 tonnes) at the expense of losing 25 submarines. The highest score was achieved in the
months between September and November, in which twelve submarines sank 764,000 tonnes, which in average amounts
to 64,000 tonnes per U-Boot. The time of the greatest hunts (from June 1940 to May 1941) had not yet ended when
the German submarines lost in a single month three of their aces: Gunther Prien, who disappeared with his whole
crew the 7th March after being attacked the U-47 by the destroyer HMS Wolverine; Joachim Schepke, who died the
17th March onboard the U-100 when this one was sunk by the destroyer HMS Vanoc; and Otto Kretschmer, the greatest
submarine ace of the Second World War (with 283,000 tonnes in his tally), who was captured when the U-99 was
boarded by the destroyer HMS Walker, after being forced to emerge to avoid being sunk by depth charges.
The slowdown in the delivery of new submarine vessels turned the scales in favor of the Allies, who never cease
in tuning new countermeasures, increasing the escorts and intensifying the aerial patrols. In the months between
September and December 1941 the "wolf packs" sank 123 ships for a total of 552,035 tonnes, but at the expense of
20 submarines lost, which means an average of 6150 tonnes per submarine, a number which would continue decreasing.
The U-Boot would still enjoy a second happy time, but at an increasingly high cost. The American, at the time of
declaring the war to Germany, did not have an effective system for defending their coasts and the convoys departed
without protection and in a disorderly way, which rendered them an easy prey for the U-Boot, which in turn began
to attack in a lonely way, in overt contradiction with the doctrine created by Doenitz. Their decadence was
proven when they incurred in the mistakes committed during the First World War. All of these circumstances
inexorably signaled the beginning of the end of their legendary effectiveness.
Notable IXB boats include the U-107 commanded by Günther Hessler, which had the most successful
single mission on the Battle of the Atlantic, with close to 100,000 gross tonnes sunk, and the U-123 commanded by
Reinhard Hardegen, which began the campaign of submarine attacks in the eastern coast of United States in the
early 1942.
In the last trimester of 1942 the U-Boot reached one of the highest amounts of sinkings, 375 ships for a total of
2,185,262 tonnes, but the counterpart is also terrible: 44 submarines. The second glorious time of the submarine weapon
during the 20th century was ending. The Allies, as it had happened during the First World War, had finally developed
the tactics and the technology necessary for fighting this clamorous resurgence of the submarine threat. From August
1943 the losses became unbearable: in eight months 176 submarines were lost. Eventually, in September of that same year,
the numbers are reversed: 53 Allied ships sunk at the expense of 65 submarines. However, the worst was yet to come:
from January to April 1944 the Allies lost 50 ships whereas the German lost 84 submarines. The situation had become
completely untenable.
Multiple factors contributed to that disaster. These include: the entry into service of long-range aircraft, which covered
the whole Atlantic while harassing the enemy submarines day and night, hindering so the rest of their crews and the reload
of torpedoes; the introduction of high-frequency radar devices, which were undetectable for the German submarines and so
effective that they could notice something as small as a snorkel; the new tactics used by convoys; the secret capture of
the U-505 in June 1944 in front of the African coast, which gave the Allies access to the Enigma encrypting machine and
the new Triton code; and, not less importantly, the lost of great aces like Gunther Prien and Otto Kretschmer.
The defeat is almost absolute at the beginning of 1944, but Doenitz still has time for trying a last trick in the attempt
of giving a 180-degree turn to the conflict: the entry into service of the Type XXI, the most advanced submarine ever built
so far. The last action of the U-Boot took place the 8th May 1945, when the U-2336 sank two British ships in the mouth
of the river Forth. That was an innovative Type XXIII submarine with a displacement of 230 tonnes, which had not been yet
notified about the surrender of Germany.
The Type XXI submarines had these characteristics: length, 76.7 meters; beam, 6.6 meters; displacement
in surface, 1621 tonnes. The highly hydrodynamic hull and the powerful electric motors fed by large battery banks allowed to
reach a speed of 17.5 knots in immersion.
[1] Out of the four Type XI submarines (from U-112 to U-115), planned in a time when cruiser submarines
were still booming, only three exemplars were laid down and none of them would be completed, for the necessity of this
kind of units diminished. [2] The Type IX project achieved excellent results on its diverse versions which always operated
at increasing distances. [3] The profile of the Type XXI, optimized for underwater prestations, was different from that of
previous submersible vessels.
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