Балтийский завод
The boats were built at Barnet Yard in Vancouver, British Columbia, Canada as knockdown kits. The kits were transported by ship to Vladivostok and over the Trans-Siberian Railroad to European Russia. The boats were assembled at the Baltic Shipyard in Saint Petersburg and its subsidiary in Nikolayev by the Black Sea (now Mykolaiv, Ukraine). Like some of the British H-class boats (of the same design), they were equipped with Fessenden transducers, an early form of sonar.