After entering Cam Ranh bay, the Rolldock Storm will be docking in the water in the next few days to wait for experts to tow the submarine into Cam Ranh military port.
Vietnam had inked a deal worth US$2 billion with Russia in 2009 to buy six Kilo-class diesel-electric submarines to strengthen its maritime forces. The contract also includes training programs for Vietnamese crew in Russia.

HQ-186 Da Nang - the fifth Russian-made submarine for Vietnam.

Earlier in 2014 and 2015, Russia had delivered four similar Kilo-class submarines for Vietnam, namely HQ-182 Hanoi, HQ-183 Ho Chi Minh City, HQ-184 Hai Phong and HQ-185 Khanh Hoa.
These submarines have been officially serving under submarine brigade 189 of Vietnam People's Navy.
In early February 2016, the fifth Russian-made submarine, which is expected to be named HQ-186 Da Nang, arrived in Cam Ranh. The sixth and also final submarine will be called HQ-187 Ba Ria-Vung Tau. Flag-raising ceremony for the two submarines will be held in the coming time.
The Kilo-class submarines are built with advanced stealth technology, extended combat range and modern navigation systems. With a displacement of 3,000-3,950 tons, the nearly 74m-long submarine can operate at an average depth of 240 meters and maximum depth of 300 meters, as well as can work for a range of 6,000-7,500 nautical miles for 45 days with 52 crew members.