Rescue aircraft and ships scoured the sea north of Bali Friday as the hunt for a missing Indonesia submarine with 53 crew on board reached a critical phase as a result of quickly depleting oxygen supplies.
There are no signs of the missing 44-year-old submarine "Nanggala" and the Indonesia Navy has until Saturday only to rescue the 53 crew before the vessel's oxygen runs out, news reports said Friday.
Officials reported an oil slick near the boat's last known position - around 96 kilometers north of Bali - but there was no conclusive evidence it was linked to the vessel.
Indonesia's President Joko Widodo has instigated an "all-out" search-and-rescue operation in a race against time. The submarine lost contact early Wednesday during a torpedo drill, The Guardian reported.
"I have ordered the military chief, navy chief of staff, search and rescue and other agencies to deploy all the forces and the most optimal efforts to find and rescue the submarine crew," Widodo said.
Six warships, a helicopter and 400 servicemen are involved. Malaysia and Singapore have deployed ships and the U.S., Germany, France and Australia have offered help.
Indonesia navy chief of staff Yudo Margono said the "Nanggala" had enough oxygen to last until Saturday. "The submarine has received a letter of feasibility from the navy. It was ready for battle," Margono told a news conference.
The diesel-powered "Nanggala" is one of five submarines in Indonesia's military. It was built in Germany in the late 1970s and underwent a two-year refit in South Korea in 2012.
Navy officials believe the submarine sank to between 2,000 feet and 2,300 feet - three times more than its safe operating depth. At these depths pressure will start to crush the vessel.
Frank Owen, secretary of the Submarine Institute of Australia, said the submarine might now be too deep under for a rescue. "Most rescue systems are really only rated to about 1,900 feet," he said.
Indonesia has been upgrading its military equipment but much remains old.
A Navy representative said this was the first time Indonesia had lost a submarine, according to the BBC.
