SINGAPORE - Five Indonesian warships and a helicopter are scanning the waters off the resort island of Bali on Thursday (April 22) for the submarine with 53 crew that went missing during naval exercises.
The last spot where the submarine was detected was 23 nautical miles north of Bali, said the Indonesian Military (TNI) spokesman.
"The Indonesian Navy is currently carrying out a search for the last position the submarine was detected," Major-General Achmad Riad told a press conference from Bali's Ngurah Rai military airbase early Thursday.
Navy chief Yudo Margono said that oxygen supplies onboard the vessel would last 72 hours from the time the submarine went missing, which means that they would run out of air around 3am on Saturday.
According to the Defence Ministry on Wednesday, the KRI Nanggala-402 was to carry out a torpedo drill after it asked for permission to dive early that day. However, it lost contact and could not be reached.
The search operation had begun on Wednesday shortly after the vessel failed to surface as stated in its training schedule, Major-General Achmad said.
"There were oil spills and the smell of diesel fuel in several different locations" he said, but these "could not be concluded to be fuel from the submarine".
Besides oil spills, an underwater movement at a speed of 2.5 knots was also detected.
"The contact was then lost, leaving insufficient data to identify the contact was the (missing) submarine," he added.
According to the Defence Ministry, the Indonesian authorities had also sent out an international distress signal, and several countries including Singapore, Australia and India "have responded and are ready to provide assistance".
Major-General Achmad said Singapore will deploy the submarine support vessel MV Swift Rescue, which departed from Changi Naval Base on Wednesday afternoon and is expected to arrive on site on April 24.
Malaysia will also be sending a vessel, the MV Mega Bakti, which is scheduled to arrive on April 25.
Australian Foreign Minister Marise Payne said Australia would “help in any way we can”, Reuters reported, quoting ABC radio.
“We operate very different submarines from this one, but the Australian Defence Force...will work with defence operations in Indonesia to determine what we may be able to do,” Ms Payne said.
Various countries have also offered support, including the United States, Germany, France, Turkey, and Russia, he said.
The incident was believed to be the first major submarine disaster for Indonesia, which has been moving to upgrade its ageing military equipment in recent years.
The country in the past had a fleet of 12 submarines purchased from the Soviet Union, but now, it has five German and South Korean-built submarines, local media reported.
Indonesia ordered the 1,395-tonne KRI Nanggala-402 in 1977 from Germany, and the submarine joined the Indonesian fleet in 1981. It had undergone maintenance several times, the latest being in South Korea from 2007 to 2012, according to the TNI.
It is powered by four electric diesel engines, and has a speed of up to 21.5 knots when submerged and 11 knots when cruising on the surface. It also has the ability to carry up to 14 SUT torpedoes, TNI added.
The Cabinet secretariat website in 2014 quoted then Cabinet secretary Dipo Alam as saying that Indonesia needed at least 40 submarines to guard its sprawling archipelago, but "currently we have few submarines and all are old".
Defence Minister Prabowo Subianto told a press conference on Thursday that the incident demonstrated the need to modernise Indonesia's main weapons system equipment, known locally as alutsista.
He said he and national armed forces commander Chief Marshal Hadi Tjahjanto are finalising a roadmap for the country's defense system and will submit it to President Joko Widodo in two to three weeks.
“Alutsista is costly, I would even say very costly. The national leaders have always been faced with the dilemma of having to prioritise spending on (soldiers’) welfare and at the same time having to maintain defence capability so that our sovereignty will not be compromised,” he added.
Dr Connie Rahakundini Bakrie, executive director of the Institute of Defence and Security Studies, told MetroTV news channel that she appreciated the Indonesian authorities involving neighbouring countries in the search.
She said: "The faster the better, as we are racing against time."