U-20 class submarine
Encyclopedia
The U-20 class was a class
Ship class
A ship class is a group of ships of a similar design. This is distinct from a ship-type, which might reflect a similarity of tonnage or intended use. For example, the is a nuclear aircraft carrier of the Nimitz class....
of four submarine
Submarine
A submarine is a watercraft capable of independent operation below the surface of the water. It differs from a submersible, which has more limited underwater capability...
s or U-boats built for and operated by the Austro-Hungarian Navy
Austro-Hungarian Navy
The Austro-Hungarian Navy was the naval force of Austria-Hungary. Its official name in German was Kaiserliche und Königliche Kriegsmarine , abbreviated as k.u.k. Kriegsmarine....
during World War I
World War I
World War I , which was predominantly called the World War or the Great War from its occurrence until 1939, and the First World War or World War I thereafter, was a major war centred in Europe that began on 28 July 1914 and lasted until 11 November 1918...
. The class is sometimes referred to as the Havmanden class because it was based upon the design of the Royal Danish Navy
Royal Danish Navy
The Royal Danish Navy is the sea-based branch of the Danish Defence force. The RDN is mainly responsible for maritime defence and maintaining the sovereignty of Danish, Greenlandic and Faroese territorial waters...
's 1911 Havmanden class submarines
Havmanden class submarine (1911)
The Havmanden class was a class of six submarines built for the Royal Danish Navy from 1911 to 1914. Also later known as the A class, the boats were designed by the Austro-Hungarian firm Whitehead & Co. of Fiume...
, three of which were built in Fiume.
With a small fleet of six U-boats at the beginning of World War I, two of which were not operational, the Austro-Hungarian Navy acted to bolster its fleet. They reluctantly ordered four U-20 boats in 1915 because construction could start immediately, even though the Havmanden-class design was largely obsolete by the beginning of the war. Political considerations caused the order to be split between Austrian and Hungarian firms, which contributed to construction problems and delays, keeping any of the boats from being operational until the middle of 1917.
The class boats were just over than 127 feet (38.7 m) long and were armed with two front torpedo tubes, a deck gun
Deck gun
A deck gun is a type of artillery cannon mounted on the deck of a ship or submarine.The deck gun was used as a defensive weapon against smaller boats or ships and in certain cases where torpedo use was limited. Typically a crew of three; gunner, loader, and layer, operated the gun, while others...
, and a machine gun
Machine gun
A machine gun is a fully automatic mounted or portable firearm, usually designed to fire rounds in quick succession from an ammunition belt or large-capacity magazine, typically at a rate of several hundred rounds per minute....
. The engines for the boats were unreliable, which compounded handling problems with the design. The U-20 class did not claim any wartime successes, yet lost two of the boats—U-20 and U-23—to enemy action during the war. The remaining two were delivered as war reparations
War reparations
War reparations are payments intended to cover damage or injury during a war. Generally, the term war reparations refers to money or goods changing hands, rather than such property transfers as the annexation of land.- History :...
and broken up. The conning tower
Conning tower
A conning tower is a raised platform on a ship or submarine, often armored, from which an officer can con the vessel; i.e., give directions to the helmsman. It is usually located as high on the ship as practical, to give the conning team good visibility....
from U-20, which was raised and salvaged in 1962, is on display in a military museum in Vienna
Vienna
Vienna is the capital and largest city of the Republic of Austria and one of the nine states of Austria. Vienna is Austria's primary city, with a population of about 1.723 million , and is by far the largest city in Austria, as well as its cultural, economic, and political centre...
.
Background
The Austro-Hungarian NavyAustro-Hungarian Navy
The Austro-Hungarian Navy was the naval force of Austria-Hungary. Its official name in German was Kaiserliche und Königliche Kriegsmarine , abbreviated as k.u.k. Kriegsmarine....
's U-boat fleet at the beginning of World War I
World War I
World War I , which was predominantly called the World War or the Great War from its occurrence until 1939, and the First World War or World War I thereafter, was a major war centred in Europe that began on 28 July 1914 and lasted until 11 November 1918...
consisted of six largely experimental submarines, two of which were not operational. and were in drydock awaiting diesel engine
Diesel engine
A diesel engine is an internal combustion engine that uses the heat of compression to initiate ignition to burn the fuel, which is injected into the combustion chamber...
s to replace their inadequate gasoline engines. See: Gardiner, pp. 340–41. When it became apparent that the war would not be a short one, Austria-Hungary moved to bolster their U-boat fleet by seizing the plans for the Danish Havmanden class submarines
Havmanden class submarine (1911)
The Havmanden class was a class of six submarines built for the Royal Danish Navy from 1911 to 1914. Also later known as the A class, the boats were designed by the Austro-Hungarian firm Whitehead & Co. of Fiume...
, three of which had been built at Whitehead’s in Fiume. Although the Austro-Hungarian Navy was not happy with the design, which was largely obsolete, it was the only design for which plans were available and which could be begun immediately in domestic shipyards. The Austro-Hungarian Navy unenthusiastically placed orders for four boats on 27 March 1915.
Design and construction
Before construction could begin, the Navy found itself in the midst of political situation because the Hungarian government demanded that a substantial portion of the submarine contracts be allocated to Hungarian firms. After intricate negotiations, the order was split into two orders of two submarines each, with U-20 and U-21 built at the Pola Navy Yard, and U-22 and U-23 built at the Hungarian UBAG yard at Fiume. The subcontracts were also divided between Hungarian and Austrian firms, with about two-thirds going to Hungarian companies and one-third to Austrian companies. This allocation of contracts, while politically expedient, exacerbated technical problems that resulted in numerous modifications and delays.
Beam (nautical)
The beam of a ship is its width at the widest point. Generally speaking, the wider the beam of a ship , the more initial stability it has, at expense of reserve stability in the event of a capsize, where more energy is required to right the vessel from its inverted position...
of 13 feet (4 m) and a draft
Draft (hull)
The draft of a ship's hull is the vertical distance between the waterline and the bottom of the hull , with the thickness of the hull included; in the case of not being included the draft outline would be obtained...
of 9 feet (2.7 m). For propulsion, they featured a single shaft, a single 450 bhp diesel engine
Diesel engine
A diesel engine is an internal combustion engine that uses the heat of compression to initiate ignition to burn the fuel, which is injected into the combustion chamber...
for surface running, and a single 160 shp electric motor for submerged travel. The boats were capable of 12 knots while surfaced and 9 knots while submerged. Although there is no specific notation of a range for the U-20 class, the Havmanden class, upon which it was based, had a range of 1400 nautical miles (2,592.8 km) at 10 knots, surfaced, and 23 nautical miles (42.6 km) at 8 knots submerged. The U-20 class boats were designed for a crew of 18.
The U-20 class boats were armed with two 45 cm (17.7 in) torpedo tubes located in the front and carried a complement of two torpedoes. They were also equipped with a 66 mm/26 (2.6 in) deck gun
Deck gun
A deck gun is a type of artillery cannon mounted on the deck of a ship or submarine.The deck gun was used as a defensive weapon against smaller boats or ships and in certain cases where torpedo use was limited. Typically a crew of three; gunner, loader, and layer, operated the gun, while others...
and an 8 mm (0.31496062992126 in) machine gun
Machine gun
A machine gun is a fully automatic mounted or portable firearm, usually designed to fire rounds in quick succession from an ammunition belt or large-capacity magazine, typically at a rate of several hundred rounds per minute....
. The first of the class to be launched was U-21, when it slid down the ways on 15 August 1916; the final boat launched was U-22 on 27 January 1917. The boats entered service between August and November 1917.
Class members
During their active service, the boats of the U-20 class suffered from unreliable engines which compounded the already poor handling characteristics of the boats. None of the class had any successes and two of their number were sunk during the war. U-23 was the first sunk when she went down on 21 February 1918 from an explosive paravaneParavane (weapon)
The paravane is a form of towed underwater "glider". It was developed by Cdr Usborne and Lt Burney financed by Sir George White, founder of the Bristol Aeroplane Company....
in the Straits of Otranto. U-20, the lead boat
Lead ship
The lead ship or class leader is the first of a series or class of ships all constructed according to the same general design. The term is applicable military ships and larger civilian craft.-Overview:...
of the class, sank in July 1918 when she was torpedoed by the Italian submarine F-12 in the Tagliamento estuary. The remaining two boats were surrendered at war's end, with U-21 being ceded to Italy in 1920, and U-22 to France; both were broken up.
SM U-20
Lead ship
The lead ship or class leader is the first of a series or class of ships all constructed according to the same general design. The term is applicable military ships and larger civilian craft.-Overview:...
of the class, was laid down on 29 September 1915 at the Pola Navy Yard. She was launched on 18 September 1916. During diving trials in March 1917, U-20 was accidentally rammed by the Austro-Hungarian Navy light cruiser , which required seven months of repairs for the U-boat. U-20 was commissioned
Ship commissioning
Ship commissioning is the act or ceremony of placing a ship in active service, and may be regarded as a particular application of the general concepts and practices of project commissioning. The term is most commonly applied to the placing of a warship in active duty with its country's military...
on 20 October, and operated out of Pola and Trieste
Trieste
Trieste is a city and seaport in northeastern Italy. It is situated towards the end of a narrow strip of land lying between the Adriatic Sea and Italy's border with Slovenia, which lies almost immediately south and east of the city...
. She was in the estuary of the Tagliamento river in early July 1918 when she was spotted by the surfaced Italian submarine F-12. U-20 was hit by one torpedo at a range of 650 yards (594.4 m) and sank with all hands west of Trieste
Trieste
Trieste is a city and seaport in northeastern Italy. It is situated towards the end of a narrow strip of land lying between the Adriatic Sea and Italy's border with Slovenia, which lies almost immediately south and east of the city...
near position 45°29′N 13°02′E.Sources report the date of the attack as being variously on the night of 4/5 July, on 6 July, or on 9 July. The wreck of U-20 was raised and salvaged
Marine salvage
Marine salvage is the process of rescuing a ship, its cargo, or other property from peril. Salvage encompasses rescue towing, refloating a sunken or grounded vessel, or patching or repairing a ship...
in 1962. Remains of her crewmen were interred on the grounds of the Theresian Military Academy
Theresian Military Academy
The Theresian Military Academy is an academy, where the Austrian Armed Forces train their officers. The Academy is located in the castle of Wiener Neustadt in Lower Austria.- History :...
at Wiener Neustadt
Wiener Neustadt
-Main sights:* The Late-Romanesque Dom, consecrated in 1279 and cathedral from 1469 to 1785. The choir and transept, in Gothic style, are from the 14th century. In the late 15th century 12 statues of the Apostles were added in the apse, while the bust of Cardinal Melchior Klesl is attributed to...
. The conning tower
Conning tower
A conning tower is a raised platform on a ship or submarine, often armored, from which an officer can con the vessel; i.e., give directions to the helmsman. It is usually located as high on the ship as practical, to give the conning team good visibility....
and a midship section were donated to the Heeresgeschichtliches Museum
Heeresgeschichtliches Museum
The Heeresgeschichtliches Museum is a military history museum located in Vienna, Austria. It claims to be the oldest and largest purpose-built military history museum in the world...
in Vienna
Vienna
Vienna is the capital and largest city of the Republic of Austria and one of the nine states of Austria. Vienna is Austria's primary city, with a population of about 1.723 million , and is by far the largest city in Austria, as well as its cultural, economic, and political centre...
, where they are on display. U-20 did not sink any ships during her service.
SM U-21
SM U-21 was built at the Pola Navy Yard and was launched on 15 August 1916, and was the first of the class to be launched. U-21 was damaged in a diving trial in January 1917, requiring seven months for repairs. The U-boat was commissionedShip commissioning
Ship commissioning is the act or ceremony of placing a ship in active service, and may be regarded as a particular application of the general concepts and practices of project commissioning. The term is most commonly applied to the placing of a warship in active duty with its country's military...
on 15 August 1917. In early October, U-21 conducted patrols off the Albania
Albania
Albania , officially known as the Republic of Albania , is a country in Southeastern Europe, in the Balkans region. It is bordered by Montenegro to the northwest, Kosovo to the northeast, the Republic of Macedonia to the east and Greece to the south and southeast. It has a coast on the Adriatic Sea...
n coast, but a mid-October Mediterranean patrol was cut short by a leaky seal on her main hatch
Trapdoor
A trapdoor is a door set into a floor or ceiling .Originally, trapdoors were sack traps in mills, and allowed the sacks to pass up through the mill while naturally falling back to a closed position....
. After an additional eight months of repairs, U-21 again conducted patrols off Albania. A broken piston in her diesel engine cut short her war career. At Pola at the war's end, U-21 was ceded to Italy in 1920 as a war reparation and broken up. U-21 did not have any successes during the war.
SM U-22
SM U-22 was built at the Hungarian UBAG yard and was launched on 27 January 1917, the last of the class to be launched. The still-incomplete boat sank in the harbor at Fiume in June 1917, but was raised, repaired, and relaunched in October. From her November commissioning, U-22 conducted patrols off the Po RiverPo River
The Po |Ligurian]]: Bodincus or Bodencus) is a river that flows either or – considering the length of the Maira, a right bank tributary – eastward across northern Italy, from a spring seeping from a stony hillside at Pian del Re, a flat place at the head of the Val Po under the northwest face...
estuary and, later, northern Adriatic patrols from Trieste
Trieste
Trieste is a city and seaport in northeastern Italy. It is situated towards the end of a narrow strip of land lying between the Adriatic Sea and Italy's border with Slovenia, which lies almost immediately south and east of the city...
. After three months of repairs for her failed electric motor in mid 1918, U-22 resumed service, patrolling the Montenegrin
Montenegro
Montenegro Montenegrin: Crna Gora Црна Гора , meaning "Black Mountain") is a country located in Southeastern Europe. It has a coast on the Adriatic Sea to the south-west and is bordered by Croatia to the west, Bosnia and Herzegovina to the northwest, Serbia to the northeast and Albania to the...
coast out of Cattaro. In port at Cattaro at war's end, she was ceded to France as a war reparation and broken up. U-22 sank no ships during the war.
SM U-23
SM U-23 was laid down on 8 December 1915 at the Hungarian UBAG yard and was launched on 5 January 1917. She was commissionedShip commissioning
Ship commissioning is the act or ceremony of placing a ship in active service, and may be regarded as a particular application of the general concepts and practices of project commissioning. The term is most commonly applied to the placing of a warship in active duty with its country's military...
on 1 September and initially patrolled off the Italian towns of Rimini
Rimini
Rimini is a medium-sized city of 142,579 inhabitants in the Emilia-Romagna region of Italy, and capital city of the Province of Rimini. It is located on the Adriatic Sea, on the coast between the rivers Marecchia and Ausa...
and Ancona
Ancona
Ancona is a city and a seaport in the Marche region, in central Italy, with a population of 101,909 . Ancona is the capital of the province of Ancona and of the region....
. After being transferred to Cattaro in late December, U-23 departed on her final patrol on 20 February 1918. The following day, Linienschiffsleutnant Klemens Ritter von Bézard, U-23s only commanding officer, guided the boat in an attack on the Italian transport in the Straits of Otranto. U-23 then came under attack from the Italian destroyer
Destroyer
In naval terminology, a destroyer is a fast and maneuverable yet long-endurance warship intended to escort larger vessels in a fleet, convoy or battle group and defend them against smaller, powerful, short-range attackers. Destroyers, originally called torpedo-boat destroyers in 1892, evolved from...
Airone; after first trying to ram the U-boat, the destroyer deployed an explosive paravane
Paravane (weapon)
The paravane is a form of towed underwater "glider". It was developed by Cdr Usborne and Lt Burney financed by Sir George White, founder of the Bristol Aeroplane Company....
. When the paravane came into contact with the submerged U-23, it blew debris into the air, sinking the submarine with all hands. Like all of her sister boats, U-23 had no wartime successes.