Soviet armoured river and coastal gunboats – the BKA and MBK types

Given its huge size and enormously varied geography, the USSR – like the Imperial Russia it succeeded in 1917 – found that there was considerable scope for the use of gunboats on the country’s many large rivers, major lakes, and even its shallow coastal waters (such as the Sea of Azov and the Gulf of Finland). This was as true in Eastern Siberia, where the Amur river Flotilla was created as part of the Soviet defence against Japanese territorial ambitions, as it was in European Russia – where there were river and lake flotillas on many of the larger rivers (inc. the Volga, Dniepr, and Pripyet) and lakes (such as Ladoga).

Many of the areas in which these lakes rested and rivers flowed lacked much in the way of overland communications by road or rail, but were often desired in their own right by adversaries for their agricultural or material wealth – and the fact that they offered axes of advance toward major cities. Thus, there was considerable advantage to the Soviets possessing river and lake flotillas, where their vessels’ guns could serve as mobile artillery for intervention in land warfare, and could prevent a European use of Russian coastal and inland waters for logistics.

The USSR therefore built and operated large numbers of BKs (bronekater, or armoured motor boat) craft. Initially produced in modest numbers during the 1930s as prototypes, production of the ships escalated in WWII for operational use. The type was pioneered by the 18-ton Type N and 20-ton Type K boats, each built only in small numbers. The first carried one 16-mm machine gun and several lighter machine guns, had a maximum speed of 19 kt on 90 bhp (67.1 kW) and was crewed by eight men, while the latter carried two 76.2-mm (3-in) guns and several machine guns, had a maximum speed of 21 kt on 800 bhp (596 kW) and was crewed by an unspecified number of men.

Production ordered

Experience with these prototypes helped to finalise Soviet decision-making, and by January 1940 orders had been placed for 85 such craft – the majority of them for service on the rivers. Designed during the period of the 2nd Five-Year Plan, the craft were built by the many smaller yards on Soviet rivers and lakes, and protection was provided by the addition of comparatively thin armour plating over the conning position and machinery spaces.

The two first riverine gunboat classes to emerge from this process were the Type 1124BKA and Type 1125BKA. Production of the Type 1124BKA and the Type 1125BKA boats began in about 1935, primarily in small inland yards. The early craft were armed with the turret of the T-28 medium and T-35 heavy tanks: this turret was armoured to a maximum of 20 mm and fitted with a 76.2-mm (3-in) L/20 gun, but with the advent of the classic T-34 medium tank from 1939, the turret of this tank was made available for riverine gunboats: the turret was initially fitted with a 76.2-mm (3-in) F-34 L/30.5 gun, upgraded in 1940 to the 76.2-mm (3-in) L/41.2 gun and had a maximum frontal armour thickness of 50 mm (2 in). Some of the Type 1124BKA craft were also revised in the course of the war to carry a ROFS-82 multiple rocket launcher in place of the turret.

The 42-ton Type 1124BKA had a length of 25.00 m (), beam of 3.80 m () and draught of 0.80 m), propulsion by two petrol engines delivering 1,600 hp (1193 kW) to two shafts for a speed of 28 kt, protection by 12.7-mm (0.5-in) armour for the belt and conning position, a crew of 17 men, and an armament of two turrets, each fitted with one 76.2-mm (3-in) gun and two 12.7-mm (0.5-in) machine guns.

The 29-ton Type 1145BKA had a length of 22.60 m, beam of 3.50 m and draught of 0.50 m, propulsion by one petrol engine delivering 720 hp (537 kW) to one shaft for a maximum speed of 20 kt, protection by light plate on the sides and conning position, a crew of 10 men, and armament of one turret fitted with a 76.2-mm (3-in) gun, one 12.7-mm (0.5-in) machine gun and two 7.62-mm (0.3-in) machine guns.

By the time of the German invasion of June 1941, 85 boats of these two types had been ordered and 68 were under construction, and on 18 January 1941 another 110 units had been ordered. All of this occured before the end of the war in May 1945.

Enlarged development

A third type of gunboat, better suited to estuarine and also coastal operations, was developed during the war as the MBK. Its design was developed shortly before the outbreak of war as an enlarged version of the Type 1124. Construction of the prototype was started in Leningrad in 1941, and this was completed in 1943. Other examples were delivered in 1944, and though initially intended for use in the shallow waters of the Baltic, they were instead employed for a wide range of duties. Whereas the Type 1124BKA and Type 1125BKA had been designed to carry the turret of the T-34/76 tank, the BKM was conceived round the turret of the later T-34/85 armed with the longer 85-mm (3.35-in) ZiS-53 gun and finally a 100-mm (3.94-in) gun.

The data for the 150-ton MBK included a length of 36.00 m, beam of 5.40 m and draught of 1.50 m, propulsion by two Diesel engines delivering 1,000 hp (746 kW) to two shafts for a maximum speed of 18 kt, protection by 50-mm (2-in) plate on the sides and conning position, a crew of 38 to 42 men, and armament of two turrets each fitted with one 85- or 100-mm (3.35- or 3.94-in) gun, one 37-mm L/67 cannon and four 12.7-mm (0.5-in) machine guns.

All three types were very successful. At least 270 were built between 1935 and 1945, and of these some 90 were lost.

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