The five bodies were found by naval divers from the 2,300 tonne INS Sindhurakshak, which was recently refurbished in Russia and which suffered explosions and fire as it went down after Tuesday midnight.
"Efforts to trace and retrieve the other 13 bodies of sailors are underway on a war footing and we are hopeful of further recoveries by late this evening," an official said.
These five were among the 15 sailors and three officers who got trapped in the submarine berthed at the Mumbai dock once disaster struck. Eight of the sailors were married.
The bodies were sent to the government-run Sir J.J. Hospital for autopsy, DNA and other tests to ascertain their identity.
The search operation has slowed down as only one diver can work at a time owing to the cramped space inside the submarine.
Also, all equipment in the deep sea fighter vessel has shifted from their original location.
The navy said "the state of (the bodies) and conditions within the submarine leads to the firm conclusion that finding any surviving personnel is unlikely.
"The damage and destruction within the submarine around the control room area indicates that the feasibility of locating bodies of personnel in the forward part of the submarine is also very remote as the explosion and very high temperatures, which melted steel within, would have incinerated the bodies too," the statement added.
The bodies extricated from the submarine "are severely disfigured and not identifiable due to severe burns", the navy said, adding they have been sent to INHS Asvini, the naval hospital, for possible DNA identification.
This "is likely to take some more time". It said the boiling waters inside the submarine prevented any entry till Wednesday noon.
"Access to the inner compartments of the submarine was made almost impossible due to jammed doors and hatches, distorted ladders, oily and muddy waters inside the submerged submarine resulting in total darkness and nil visibility ... even with high-power underwater lamps.
"Distorted and twisted metal within very restricted space due extensive internal damage caused by the explosion further worsened conditions for the divers.
"This resulted in very slow and laboured progress," the statement said.
After hours of "continuous diving effort in these conditions", navy divers finally reached the second compartment behind the conning tower early Friday.
The navy said it was concentrating on reaching the interiors of the submarine to "locate and extricate any remaining bodies that may still be trapped within".
"Salvage of the submarine would only be attempted thereafter for which many alternatives including deploying professional salvers are also being considered.
"However, presently, gaining access to the submarine and locating bodies is the top priority," the navy said.
The heat of the explosion had melted parts of the internal hull deforming the submarine hatches, preventing access to different compartments.
Heavy duty pumps were used to pump out the seawater from the submarine.
The families of the 18 personnel were being provided regular updates.
The navy feels that some of the armaments inside the deep sea fighter vessel, stored on the rear side may be recovered undamaged as the flames did not completely gut that portion of the submarine.
--IANS (Posted on 16-08-2013)