Soviet guard ship Groza

The Russian Civil War had shut down design and construction of all ships, both naval and commercial from 1917 to 1924, thus Soviet naval architects and shipyards lacked experience when the Soviet Navy decided to replace the few old Tsarist torpedo boats still in service.^[1] The initial requirement was based on that of the later batches of the World War I-era German A-class torpedo boat^[2] that could carry mines as necessary to serve as fleet escorts and conduct torpedo attacks. The Uragans were almost 6 knots (11 km/h; 6.9 mph) slower than designed due to this inexperience and, in their intended role, they "were complete failures – they were too slow for use as torpedo boats and of no value as ASW vessels because of their lack of depth-charge handling equipment and underwater detection devices".^[3]

The Series I Uragan-class ships, officially known as Project 2, displaced 490 metric tons (480 long tons) at standard load and 633 t (623 long tons) at full load. They were 71.5 m (234 ft 7 in) long overall, had a beam of 7.4 m (24 ft 3 in) and a draft of 2.95 m (9 ft 8 in).^[2][4] The ships had 14 main watertight compartments and a double bottom only underneath the machinery and boiler rooms.^[1] In 1943 Groza's crew numbered 114.^[5]

The Uragan-class ships were powered by two Parsons geared steam turbines, each driving one propeller shaft using steam provided by a pair of three-drum boilers. The turbines of the Series I ships developed a total of 5,700 shaft horsepower (4,300 kW) which gave them a speed in service of 21 knots (39 km/h; 24 mph). Groza carried 102–116 metric tons (100–114 long tons) of fuel oil that gave her a range of 850 nautical miles (1,570 km; 980 mi) at 16 knots (30 km/h; 18 mph).^[6]

The main armament of the Uragan-class guard ships consisted of a pair of Tsarist-era 102-millimeter (4 in) Pattern 1911 guns in single mounts, one each forward and aft of the superstructure.^[7] Anti-aircraft defense was intended to be provided by four single 37-millimeter (1.5 in) 11-K AA guns; these were modified versions of the British 2-pounder (40 mm (1.6 in)) guns, but deteriorating relations with the United Kingdom prevented the Soviets from buying any of these weapons. A pair of 7.62-millimeter (0.3 in) Maxim machine guns were fitted in their place.^[8]

A rotating triple mount for 450 mm (17.7 in) torpedoes was fitted between the funnels. The Uragans were fitted with a pair of racks for 22 B-1 165-kilogram (364 lb) and 15 M-1 41-kilogram (90 lb) depth charges. Alternatively up to 20 KB mines could be carried using rails mounted on the main deck. No sonar was fitted so dropping depth charges was largely an act of futility. Two K-1 minesweeping paravanes were fitted on the main deck after the design was finalized. One DM-1 2-meter (6 ft 7 in) rangefinder was mounted above the open bridge and a 1-meter (3 ft 3 in) searchlight was fitted on a small platform abaft the rear funnel.^[7][9][10]

Beginning in 1934, four semi-automatic 45 mm (1.8 in) 21-K AA guns in single mounts were being fitted to the Uragans. The 45 mm guns were generally mounted fore and aft of each of the 102 mm guns. Four years later 12.7 mm (0.50 in) DShK machine guns began replacing the Maxim machine guns. Around the same time ships began exchanging their 21-Ks for three single mounts for fully automatic 37 mm AA guns. These were usually positioned between the forward gun and the bridge, between the searchlight platform and the aft 102 mm gun, and abaft the rear gun. Some ships retained one or two of the 21-Ks into the war. When the Soviets began receiving 12.7 mm Colt-Browning machine guns through Lend-Lease, they began supplementing the DShKs aboard the Uragans, up to a total of six barrels in four mounts, with one twin-gun Colt-Browning mount replacing the searchlight in some ships. Some Uragans had a pair of BMB-1 depth charge throwers installed on the stern in 1941; Groza received hers on 13 August. Beginning in 1942, gun shields for the 102 mm guns were installed. By 1943, the ship had had a British Type 128 sonar installed.^{[11][12][13][14]}