|Background - Russia is a land with numerous rivers that have been used for hundreds of years to transport goods when not frozen over during the
frigid winter months. The more famous among them include the Don, Dnieper, Neva, Dvina and the mighty Volga, which is Europe's longest river at
almost 2,300 miles/3,700 kilometers long. Early is Russia's history these waterways were used for military purposes, but in a very limited sense. It
wasn't until the reign of Peter the Great that the need for a modern navy was recognized and real efforts made to build not only a seagoing fleet but a
river based flotilla. During the Second Azov campaign of 1696 against the Ottoman Empire, the Russians employed for the first time a large number of
ships and boats built on the Voronezh River. In the early 20th century, the Russian road system was still very primitive and difficult to move along.
Because of this, fighting during the Russian Civil War mainly followed the networks of rivers and railroads. Rivers played an important role not only as
supply routes but were also good natural defensive barriers. The latter led to the building of flotillas of armored river gunboats. Larger naval warships
were disarmed and their guns were fitted on any suitable platform that could carry them. Heavier guns, some as large as 6 inches, were placed on non-
self-propelled barges and smaller guns on tug boats and other civil craft. During the 1920s and early 1930s, the river flotillas fell into disrepair. Older
vessels were scrapped and civilian craft commandeered for military use were returned to their original uses. In 1934 the Red Navy issued a request for a
new river monitor design that could be massed produced using as many common components as possible with the tanks of the 1931 program. The new
vessels should have two turrets, armor protection for their vital spaces and a draft of only 0.5 meters or about 1foot 8 inches.
Yuliy Benoit, the chief engineer for this project, said it would be impossible to build a two-turret armored boat only drawing a half-meter. Instead he
proposed a smaller one-turret vessel that would meet the shallow draft requirement. That proposal was approved and two designs were submitted from
Benoit’s bureau. The larger design was called BKA (bronirovannyie katera, or armored cutter) 1124 and had two T-26 tank turrets mounting 45mm
guns. This boat displaced 42 tons, was 25 meters (82 feet) long and had 12mm of armor on its “citadel” protecting the engines and other vital spaces.
With a draft of 0.80 meters, it still could operate in very shallow waters. The smaller version, known as BKA 1125, only drew 0.5 meters and displaced
29 tons. They carried one turret, were slightly shorter (22.6 meters or about 74 feet) and had less armor protection. The compact size of both the 1124
and 1125 designs made it possible to transport them on railways cars to move them from one front to another.
Production began in 1935 at small shipyards along the Soviet Union’s inland rivers. When construction began, the T-26 turret was replaced by the 76.2
mm short-barreled gun and turret used in the T-28 medium and T-35 heavy tanks. To provide anti-aircraft defense, the 1125 was fitted with two 7.62
mm machine guns in mounts. Later in the war, the main gun was replaced with a long barreled 76.2mm T-34 turret and the aft machine gun mount was
replaced by a Katiusha rocket launcher, which increased firepower and effectiveness. By the time of the Nazi invasion in June 1941, 85 boats had been
delivered with 68 more under construction. They saw action very early on, with boats of the Danube flotilla supporting the landing of troops on June
24, routing Romanian soldiers defending the Danube delta. On June 26, boats of the Pinsk flotilla took part in the Soviet counter-attacks against German
positions along the Berezina River. The BKA 1125 was used throughout the war in attacks against German troops and armor on all fronts, including
Stalingrad. Towards the end of the war, these armored boats were used for bombardment of fortifications and cities in support of Soviet troop
advancements. The Austrian capital city, Vienna, was bombed by a flotilla of BKA 1124 and 1125 boats in 1945.