'Very grim': Not much hope for missing Indonesian submarine The Indonesian navy lost contact with the vessel yesterday, while it conducted a torpedo drill about 100km north of Bali. And one of Australia's leading minds on submarines is "very pessimistic" about the fate of 53 Indonesian sailors on board the KRI Nanggala-402. READ MORE: Australian Strategic Policy Institute senior analyst Marcus Hellyer said things were looking "very grim". "There's lots of things that can go wrong on submarines," Dr Hellyer told nine.com.au. "If a submarine has an accident at sea, it tends to be catastrophically bad." An oil slick has been spotted in the spot where the submarine dived from the surface, but aside from that, there is no trace of the KRI Nanggala-402.