How Hitler terrorized the seas with U-boats during World War II
"The only thing that ever really frightened me during the war was the U-boat peril," British Prime Minister Winston Churchill reportedly said while reflecting on the second world war.
By the end of the war, Hitler's Kriegsmarine, the navy of Nazi Germany, had built 1,162 U-boats, which is short for the German word "Unterseeboot," or undersea boat.
In the fall 2015 issue of Weapons of WWII magazine, Marc DeSantis explains how the U-boats were used during World War II.
At the beginning of the war, the commander of the German U-boat fleet, Karl Dönitz, said that if he had 300 U-boats, "he could strangle Britain and win the war."
The Kriegsmarine began the war with just 56 U-boats, but over the course of the war they would build 691 type VII U-boats alone. Here's a photo of a U-35 boat during training exercises in 1936.
The U-boat was not a true submarine in today's sense of the word. It was more of a submersible craft. The diesel engines required air, so while underwater, the craft was powered by 100 tons of lead-acid batteries, meaning it had to surface every few hours when air and battery power were exhausted.
The battery power made the U-boats exceptionally slow underwater, clocking in at 8 knots (9.2 mph), compared to 17.2 knots (19.8 mph) above water on the VII-B models.
The boats were manned by up to 44 men ...
... who shared extremely crammed quarters.
The U-boat featured a fearsome 88-millimeter cannon on the deck, as well as a 20-millimeter antiaircraft gun. Here's the cannon in action:
U-boats were also equipped with torpedoes for underwater attacks. Here's a photo of a German G7 torpedo, the standard torpedo for all German U-boats and surface torpedo-bearing vessels of the war.
However, many early torpedoes fired by U-boats did not function properly, either exploding prematurely or not at all.
By 1943, Allied forces began fiercely hunting U-boats at sea. Here's an Allied pilot bombing a U-boat.
Toward the end of the war, the U-boats were death traps. Of 40,900 men who manned U-boats, some 28,000, or 70%, were killed. Here's a photo of US troops boarding a captured German U-boat.
German U-boats sank more than 2,600 Allied ships carrying supplies during World War II.
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