Lost sub could be too deep to help

JAKARTA, INDONESIA » Indonesian navy ships searched Thursday for a submarine that likely sank too deep to retrieve, making survival chances for the 53 people on board slim. Authorities said oxygen in the submarine would run out by early Saturday.

The diesel-powered KRI Nanggala 402 was participating in a training exercise Wednesday when it missed a scheduled reporting call. Officials reported an oil slick and the smell of diesel fuel near the starting position of its last dive, about 60 miles north of the resort island of Bali, though there was no conclusive evidence that they were linked to the submarine.

“Hopefully, we can rescue them before the oxygen has run out” at 3 a.m. on Saturday, Indonesia’s navy chief of staff, Adm. Yudo Margono, told reporters.

He said rescuers found an unidentified object with high magnetism at a depth of 50 to 165 to 330 feet and that officials hope it’s the submarine.

The navy believes the submarine sank to a depth of 2,000-2,300 feet, much deeper than its estimated collapse depth.

Ahn Guk-hyeon, an official from South Korea’s Daewoo Shipbuilding and Marine Engineering, which refitted the vessel in 2009-2012, said the submarine would collapse if it goes deeper than around 655 feet because of pressure.

He said his company upgraded much of the submarine’s internal structures and systems but lacks recent information about the vessel.

Frank Owen, secretary of the Submarine Institute of Australia, also said the submarine could be at too great a depth for a rescue team to operate.

“Most rescue systems are really only rated to about 600 meters (1,970 feet),” he said. “They can go deeper than that because they will have a safety margin built into the design, but the pumps and other systems that are associated with that may not have the capacity to operate. So they can survive at that depth, but not necessarily operate.”

Owen, a former submariner who developed an Australian submarine rescue system, said the Indonesian vessel was not fitted with a rescue seat around an escape hatch designed for underwater rescues. He said a rescue submarine would make a waterproof connection to a disabled submarine with a socalled skirt fitted over the recue seat so that the hatch can be opened without the disabled submarine filling with water.

Owen said the submarine could be recovered from 1,640 feet without any damage but couldn’t say if it would have imploded at 2,300 feet.

In November 2017, an Argentine submarine went missing with 44 crew members in the South Atlantic, almost a year before its wreckage was found at a depth of 2,625 feet.