Enns-class river monitor

SMS Enns
Class overview
Name	Sava
Builders	Stabilimento Tecnico Triestino, Linz Ganz Danubius, Budapest
Operators	Austro-Hungarian Navy  Danube Guard  Royal Romanian Navy  Royal Yugoslav Navy  Soviet Navy
Preceded by	Temes class
Succeeded by	Sava class
Built	1912–1915
In service	1914–1958
Completed	2
Lost	1
Retired	1
General characteristics
Type	River monitor
Displacement	540 tonnes (530 long tons)
Length	57.9 m (190 ft 0 in)
Beam	10.3 m (33 ft 10 in)
Draught	1.3 m (4 ft 3 in)
Installed power	2 Yarrow boilers 1,500–1,700 ihp (1,100–1,300 kW)
Propulsion	2 Triple-expansion steam engines
Speed	13 knots (24 km/h; 15 mph)
Range	690 nautical miles (Besarabia, World War II)
Complement	95 officers and enlisted men
Armament	1 × twin 120 mm (4.7 in)/L45 guns 3 × single 120 mm (4.7 in)/L10 howitzers 2 × single 66 mm (2.6 in)/L50 AA guns 6 × machine guns
Armour	Belt and bulkheads: 40 mm (1.6 in) Deck: 25 mm (0.98 in) Conning tower, gun turrets and cupolas: 50 mm (2.0 in)

The Enns-class river monitors were built for the Austro-Hungarian Navy during the mid-1910s. The two ships of the class were assigned to the Danube Flotilla and participated in World War I. The ships survived the war and were transferred to Romania and the newly created Kingdom of Serbs, Croats and Slovenes (later Yugoslavia) as reparations.

The ships had an overall length of 57.9 m (190 ft 0 in), a beam of 10.3 m (33 ft 10 in), and a normal draught of 1.3 m (4 ft 3 in). They displaced 540 tonnes (530 long tons), and their crew consisted of 95 officers and enlisted men.^[1] The Enns-class ships were powered by two triple-expansion steam engines, each driving one shaft, using steam generated by two Yarrow boilers.^[1] The engines were rated at 1,500–1,700 indicated horsepower (1,100–1,300 kW) and were designed to reach a top speed of 13.5 knots (25.0 km/h; 15.5 mph). They carried 75 long tons (76 t) of fuel oil.^[2]

The main armament of the Enns-class river monitors was a pair of 120 mm (4.7 in)/L45^[a] guns in a single turret forward of the conning tower and three 120 mm (4.7 in)/L10 howitzers to the rear, in individual armored cupolas. They also mounted two individual 66 mm (2.6 in)/L50 BAG anti-aircraft guns, and six machine guns.^[1] The maximum range of their Škoda 120 mm (4.7 in)L/45 guns was 15 kilometres (9.3 mi).^[3] Their armour consisted of belt and bulkheads 40 mm (1.6 in) thick, deck armour 25 mm (0.98 in) thick, and their conning tower, gun turrets and cupolas were 50 mm (2.0 in) thick.^[1]

During World War II, Besarabia was the only Romanian river monitor out of seven to be fitted with new turrets. This took place between 1942 and 1943, while she was being completely rebuilt and up-gunned at Galați. Her armament ultimately consisted of two twin 120 mm naval guns, six 37 mm AA guns and four 20 mm AA guns.^[6] She also had a range of 690 nautical miles, more than enough to travel across the greatest East-West extent of the Black Sea, which was 635 nautical miles (the Black Sea was the area of operations of the World War II Romanian Navy).^[7]

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