Sunday, April 19, 2015
The German navy in World War II was largely a submarine fleet, especially after Karl Dönitz took over naval command from Erich Raeder. Although the Treaty of Versailles barred Germany from producing or operating submarines, in 1935 the nation defied the treaty by building the Type II, of which a total of 50 (Type IIA through Type IID) were built before production was ceased in 1941. The Type II was a coastal submarine, intended mainly for short-range defense. In the IID configuration, it displaced only 314 tons surfaced and 364 tons submerged. It was 144 feet long, with a beam of 16 feet and a draft of 12 feet 9 inches. Two diesels delivered 700 bhp and two electric motors delivered 410 hp. Surfaced speed was 13 knots, submerged a very slow four knots. The boats were armed with one to four 20- mm AA guns and three 21-inch torpedo tubes. They were crewed by 25 officers and men.
Type VII. The Type VII was originally built for Germany by Finland during the 1930s. Five iterations were produced: Type VIIA through Type VIIF. (A Type VIIE was planned but never produced.) In contrast to the Type II, the Type VII was designed as a seagoing submarine-although it was still small by World War II standards. It displaced 769 tons surfaced and 871 tons submerged, was 218 feet long, with a beam of 20 feet 4 inches and a draft of 15 feet 7 inches. Two diesels delivered 2,800 bhp, and two electric motors made 750 hp. Surface speed was 17.5 knots, submerged speed 7.5 knots. Armament consisted of one 88 mm gun, one 37 mm AA gun, and two (later eight) 20 mm AA guns. The boat had five 21-inch torpedo tubes and was crewed by 44 officers and men.
Type IX. The Type IX was available at the outbreak of the war and was a long-range (15,535- mile) submarine displacing 1,120 tons surfaced and 1,232 tons submerged. It was 251 feet long with a beam of 22 feet 2 inches and a draft of 15 feet 5 inches. Two diesels delivered 4,400 bhp, and two electric motors made 1,000 hp. Surface speed was 18.2 knots; submerged top speed was 7.5 knots. The submarine was armed with one 105 mm gun, one 37 mm AA gun, one 20 mm AA gun, and six 21-inch torpedo tubes. The ship's complement was 48 officers and men.
Type XB. This was the German navy's mine-laying submarine. It displaced 1,763 tons surfaced and 2,177 tons submerged. The Type XB was 294 feet long with a beam of 30 feet 2 inches and a draft of 13 feet 6 inches. Two diesels delivered 4,200 bhp, and two electrics 1,100 hp. Top surface speed was 16.5 knots; submerged speed was 7 knots. The minelayer had a long range of 21,375 miles. It was armed with a single 105 mm gun, a 37 mm AA gun, and as many as four 20 mm AA guns. It carried two 21-inch torpedo tubes and 66 mines.
Type XVII. This small coastal submarine was a daring experiment in high-speed underwater propulsion. As Allied antisubmarine air operations became increasingly sophisticated, it was becoming too risky for submarines to use their high surface speeds for attack. To get around this limitation, the Germans experimented with the Walter closed-cycle propulsion system, which used volatile hydrogen peroxide to produce a combination of steam and free hydrogen, which drove a turbine at very high speed. The Type XVII was able to cruise at nine knots on the surface and to blast away at 21.5 knots underwater, using its Walter engine. The only drawback was that the hydrogen peroxide-hydrogen mix was extremely unstable and explosive, making these vessels inherently unsafe.
The Type XVII displaced just 312 tons surfaced and 357 tons submerged. It was 136 feet long with a beam of 11 feet 2 inches and a draft of 14 feet. A 210 bhp diesel was used on the surface. A 77 hp electric motor could push the boat along at five knots underwater when the Walter engine was not being used. The Walter delivered 2,500 hp for the top speed of 21.5 knots. Armament consisted of two 21-inch torpedo tubes. The boat was crewed by 19 officers and men.
Type XXI. This highly advanced design was double-hulled and had three different engines: diesels for surface propulsion, electric turbines for high-speed submerged propulsion, and small electric motors for creeping propulsion underwater. The submarine displaced 1,621 tons surfaced and 1,819 tons submerged. It was 251 feet 8 inches long, with a beam of 21 feet 9 inches and a draft of 20 feet 4 inches. The diesels delivered 4,000 bhp for a top speed of 15.5 knots. The turbine electrics delivered 5,000 hp for a 16-knot submerged speed. The smaller electrics made just 226 hp and produced a top speed of 3.5 knots. Armament consisted of four 30 mm or 20 mm AA guns and six 21-inch torpedo tubes. The submarine was crewed by 57 officers and men.