was a single-step, hydroplaning design with a whaleback upper hull. It was mainly built from duralumin which saved a significant amount of weight, but greatly complicated its use in service because of duralumin's susceptibility to galvanic corrosion in salt water. One captured Soviet torpedo boat commander said that G-5s could only be kept in the water for 5–7 days during the summer and 10–15 days during the winter before it had to be removed from the water and treated with anti-corrosion measures.
The hull was divided into three compartments by two transverse bulkheads. The superstructure was very small to reduce top-heaviness, and crewmen could not stand up inside it.
The G-5 was designed to use a version of the Mikulin AM-34 aircraft engine adapted for naval use as the GAM-34. The two engines were fitted in the forward compartment of the hull. Each engine had its own transmission and drove a bronze propeller .67 m (2 ft 2 in) in diameter. The initial version of the GAM-34 was less powerful than planned at only 675 bhp (503 kW) and the initial Series 7 boats could only reach 45 knots (52 mph; 83 km/h). However the minimum speed was 18 knots (21 mph; 33 km/h) which caused a great deal of trouble when trying to moor and when maneuvering in close proximity.
The gun armament initially consisted of a single 7.62 mm (0.300 in) machine gun, but this was upgraded to a 12.7 mm (0.50 in) DShK machine gun in later models. Some later boats carried two DShKs although the mounts varied; some were placed in a tub in the forecastle, but others carried theirs in a rotating turret behind the superstructure, above the torpedoes. Some boats carried 82 mm (3.2 in) ROFS-82 or 132 mm (5.2 in) ROFS-132 rocket launchers in fixed mounts above and behind the wheelhouse.
Approximately 300 G-5s were built. 152 of the Series 7, 8 and 9 boats were built between 1934 and 1936. 20 Series 10 boats were built in 1937, another 76 in 1938–39 and five in 1939–40. 39 Series 11 boats were built beginning in 1941 and production may have continued during the war. Of all G-5s 73 were lost in the action. Four were exported to the Spanish Republican Navy during the Spanish Civil War and others were transferred to North Korea after the war. Three were captured by the Finns, but only two were used before all three had to be returned to the Soviets after the Moscow Armistice in 1944.