Indonesian navy ships searched Thursday for a submarine that probably sank too deep to be recovered, reducing the chances of survival for the 53 people on board. Authorities said oxygen in the submarine would run out by early Saturday.
The diesel-powered KRI Nanggala-402 was participating in a training exercise on Wednesday when it missed a scheduled report call. Officials reported an oil spill and the smell of diesel fuel near the starting location of her latest dive, some 60 miles north of the resort island of Bali, although there was no conclusive evidence that they were connected to the submarine.
“We hope to be able to save them before the oxygen runs out,” Indonesian Navy Chief of Staff Admiral Yudo Margono told reporters on Saturday.
He said rescuers found an unidentified object with high magnetism at a depth of 50-100 meters and that officials hope it is the submarine.
The military said more than 20 navy ships, two submarines and five aircraft were searching the area where the submarine was last detected. A hydro-oceanographic research vessel equipped with underwater detection capability was also on its way to the site around the oil spills.
Margono said the oil slick may have been caused by a crack in the submarine’s tank after it sank.
Neighboring countries are rushing to participate in the complex operation.
Rescue ships from Singapore and Malaysia are expected to arrive between Saturday and Monday. The Indonesian military said Australia, the United States, Germany, France, Russia, India and Turkey also offered assistance. South Korea also said it had offered help.
The Indonesian Navy said that an electrical failure may have occurred during the dive, resulting in loss of control of the submarine and inability to undertake emergency procedures that would have allowed it to resurface. Thursday was rehearsing for a missile launch exercise, which was eventually canceled.
The navy believes the submarine sank to a depth of 600-700 meters, much deeper than its estimated collapse depth.
Ahn Guk-hyeon, an official with South Korea’s Daewoo Shipbuilding and Marine Engineering who repaired the ship in 2009-2012, said the submarine would collapse if it went deeper than about 200 meters due to the pressure. He said his company has updated much of the submarine’s internal structures and systems, but has no recent information on the ship.
Frank Owen, secretary of the Submarine Institute of Australia, also said the submarine may be too deep for a rescue team to operate.
“Most rescue systems are actually only rated at around 600 meters,” he said. “They can go deeper because they will have a safety margin built into the design, but the pumps and other associated systems may not have the ability to function. So they can survive that depth, but not necessarily function.”
Owen, a former submarine who developed an Australian submarine rescue system, said the Indonesian ship was not equipped with a rescue seat around an escape hatch designed for submarine rescue. He said a rescue submarine would make a waterproof connection to a disabled submarine with a so-called rescue seat-mounted skirt so the hatch could be opened without the disabled submarine filling with water.
Owen said the submarine could be recovered from 500 meters without any damage, but he couldn’t say if it would implode at 700 meters.
Australian Defense Minister Peter Dutton called the incident “a terrible tragedy”. Dutton told Sydney Radio 2GB that the fact that the submarine is “in a very deep part of the water” makes it “very difficult to retrieve or locate.”
Indonesian President Joko Widodo promised a total effort and asked the entire population of the country to pray that the submarine and the crew could be found.
“Our main priority is the safety of the 53 crew members,” Widodo said in a televised speech. “For the families of the crew members, I can understand your feelings and we are doing our best to save all crew members on board.”
The German-built submarine, which has been in service in Indonesia since 1981, was carrying 49 crew members, its commander and three gunners, the Indonesian Defense Ministry said. It had been maintained and overhauled in Germany, Indonesia and South Korea.
Indonesia, the largest archipelago nation in the world with over 17,000 islands, has faced increasing challenges to its maritime claims in recent years, including numerous incidents involving Chinese ships near the Natuna Islands.
Last year, President Widodo reiterated the country’s sovereignty during a visit to the islands on the fringes of the South China Sea, one of the busiest sea routes where China is embroiled in territorial disputes with its smaller neighbors.
In November 2017, an Argentine submarine disappeared with 44 crew members in the South Atlantic, nearly a year before its wreck was found at a depth of 800 meters. In 2019, a fire broke out on one of the Russian Navy’s deep-sea research submarines, killing 14 sailors.