There were three officers and 15 sailors on the vessel.
The three officers were Nikhilesh Pal, Alok Kumar and R Venkitaraj.
The 15 sailors were Sanjeev Kumar, KC Upadhya, Timothy Sinha, Kewal Singh, Sunil Kumar, Dasari Prasad, Liju Lawrence, Rajesh Tootika, Amit K Singh, Atul Sharma, Vikas E, Naruttam Deuri, Malay Haldar, Vishnu V and Seetaram Badapalli.
The Navy might take help of a Singapore-based company to salvage INS Sindhurakshak.
"Under the present situation, we may not be having the capability to salvage it. We have to create buoyancy in the deep sea to salvage the submarine. For that, we require help of professionals. The name of a Singapore-based professional firm has come for the consideration and we may hire it for the job," a Naval source told DNA newspaper.
The Navy on Thursday said all the 18 crewmen on board INS Sindhurakshak still remained untraceable.
"No information about the 18 persons trapped in it," Indian Navy spokesman Narendra Kumar Vispute told reporters.
"Heavy duty pumps are being used to pump water out of the submarine," he said.
Navy divers had entered the submarine on Wednesday.
Poor visibility inside the submarine hampered diving efforts, reports said.
In a major setback to the Navy's ambitious modernization drive, the fully armed INS Sindhurakshak, returned by Russia earlier this year after a major refit at an estimated cost of USD 80 million exploded in a Mumbai dock.
Indian Prime Minister Manmohan Singh on Thursday said the country is deeply pained over the loss of INS Sindurakshak in an accident on Wednesday.
"We are also deeply pained that we lost the submarine, INS Sindurakshak in an accident yesterday. Eighteen brave sailors are feared to have lost their lives, " Singh said while addressing the nation on the 67th Independence Day from the Red Fort in New Delhi.
"The accident is all the more painful because the Navy had recently achieved two major successes in the form of its first nuclear submarine, INS Arihant and the aircraft carrier, INS Vikrant," he said.
The submarine was fully loaded with missiles and torpedoes when the explosion led to a massive fire on board INS Sindhurakshak at the Naval dockyard in Mumbai.
INS Sindhurakshak was built in 1997 at Saint Petersburg, for anti-submarine and anti-ship warfare, defending naval bases, securing coasts and sea lanes of communication, reconnaissance and maritime patrol operations.
The vessel had been sent to Russia after the Visakhapatnam accident for a mid-life upgradation in 2010.
The submarine was handed over to India earlier this year after nearly two years of overhaul and refitting in Russia at the cost of 80 million dollars (Rs. 480 crore). The submarine was expected to serve the navy for at least 10 more years.
--IBNS (Posted on 16-08-2013)