The term U-boat is derived
from the system used by the Kriegsmarine (German Navy) to name its submarines:
U- followed by a number, where the U stood for Unterseeboot (literally, undersea boat), the German word for
submarine. The main area of use for the U-boat was the Battle of the Atlantic,
and its main objective was targeting the merchant convoys which were bringing
supplies from the United States to Europe. During the early stages of the war,
the U-boats were highly successful in this objective, and destroyed a great
amount of Allied shipping. This intended effect of destructive power was
prophesied by Kaiser Wilhelm II, issuing orders to some of the first U-Boat
commanders during World War I, in February of 1917:
We will frighten the British flag off
the face of the waters
and starve the British people until
they, who have
refused peace, will kneel and plead for
it.
The German admiral of the
U-boats, Karl Doenitz, who helped design the system of cutting off Allied
systemthe system of economic waralso advocated the U-boat technique known as
the wolfpack, in which teams of U-boats would gang up on convoys and
overpower the accompanying defense warships.
After
the fall of France, the Kriegsmarine had immediate access to the Atlantic Ocean
and the English Channel, which meant even more pressure for the RAF and RN. In
addition, large fortified concrete ports to cover the U-boats were built, which
could resist any successful bombing (this lasted through the entirety of the
war). Most of the German fleet was moved to these protective bases; such strong
air cover was another difficulty for the British. The structure, technology,
and brutally-inventive engineering behind the U-boats were perhaps their
biggest asset. Throughout the course of the war, the Kriegsmarine were
constantly improving upon the design, producing many different types of U-boats
as technology evolved. Landmarks in the development were the Type II, Type VII,
and the Type IX U-boats.
The
Type II was the second iteration of Germanys second-generation U-boats (they
were stripped of all their U-boats after WWI, but in the 1920s and 30s rebuilt
their fleet). It was designed as a coastal submarine, and its defining
characteristic was its tiny sizeit was referred to as the Einbaum (dugout canoe) and had huge advantages of maneuverability
over larger boats, as well as the ability to roam shallow waters and dive more
quickly. They were effective within their intended role, but had limited cargo
space and could only carry a couple torpedoes; they were a first step towards
re-armament for the Germans, and provided the Kriegsmarine with an example to
train and lay the foundation for larger boats to build upon.
Type II U-boat
Displacement: 279 to 329 tons (submerged)
Length: 140 ft; Beam: 13 ft; Crew: 25
Speed: 13 knots (surface), 7 knots (submerged)
Much
more powerful than the Type II, the Type VII were more agile on the surface,
carried larger crews, could hold 3 more torpedoes and had a more advanced
mounted deck-gun. The second-generation Type VIIB boats were built with better
fuel capacity, which added significant amounts of range, and increased speed.
Two rudders increased agility. Though the real workhorse for the German effort
was the Type VIIC, a larger and heavier boat which increased armaments. Perhaps
the famous Type VIIC was the U-96, which had a feature-role in the movie Das
Boot.
Type VIIB U-boat
Displacement: 753 to 857 tons (submerged)
Length: 218 ft; Beam: 20.25 ft; Crew: 44
Speed: 17.25 knots (surface), 8 knots (submerged)
The
culmination of high speed, innovation, and heavy armament was the Type XXI,
also known as the Elektroboots. The XXI was the first submarine design to
operate entirely submerged underwater, instead of a system of repeated surfacingsa
much less awkward mode of operation. Among the advancements was a hydraulic
torpedo reload system that could reload all six torpedo tubes faster than the
Type VIIs could reload a single tube. Better batter design made underwater
range and speed enormous.
This
method of constant improvement and implementation repeatedly increased the
difficulties that American merchant marine and the RAF and RN were forced to
face, adding to the general sense in the early stages of the war that the
U-boats of the Nazi Navy would bring Germany eventual victory over the Allied
Powers.
Type XXI Elekroboot
Displacement: 1819 to 2100 tons (submerged)
Length: 251 ft, Beam: 27 ft; Crew: 60
Speed: 15.6 knots (surface), 17.2 knots (submerged)
It
should not be overlooked, of course, that all of these U-boat successes were
before certain circumstances turned the tide of the U-boats and the German
hopes in the war indefinitelyfor example, the breaking of the German Enigma
code. In the end, the U-boat fleet suffered heavy amounts of loss, with 743
U-boats sunk and approximately 30,000 submariner casualties. U-boats were
considered by much of the naval world as a poor-mans weapon: seek-and-destroy
hunters of merchant ships used only by cowards. To read about some of the other
naval vehicles used by the Germans in World War II, link to Boats.
U-234 is torpedoed by the USS Sutton
* * *
The U-boats were obviously the
main element to the Axis Powers submarine force. However, the Pacific theater
of the war was one in which the sea was significant. As explained in the Allied Submarines section, Japans role in
this theater was certainly one of defeat. However, beginning with Pearl Harbor,
submarines served a large role in the Japanese Navy. For example, in a quirky
example, the midget submarine was an interesting vehicle used in the attack on
Pearl Harboralbeit unsuccessful. At a mere 79 ft length and height of 6 ft,
the midget submarine was hypothetically intended for agile search-and-destroy
missions. Click on the image below to link to the interesting story of the
Japanese midget Ha-19.
[1] Image sources: left, www.spartacus.schoolnet.co.uk/ FWWgermanN.htm; right, http://online.mepl.co.uk/cgi-bin/dwsrun?PWACQ.DWO&dl=9&page=26
[2] Image source: www.hq.wwiionline.com/ profiles/uboats.shtml
[3] Image source: http://www.hq.wwiionline.com/profiles/uboats.shtml
[4] Image source: http://www.subnetitalia.it/ubootXXI.htm
[5] Image source: http://www.uboatarchive.net/U-234.htm