Admiral Yudo Margono, the Indonesian Navy Chief of Staff, said the submarine has enough oxygen for 72 hours, based on calculations since the ship lost contact during a military exercise on Wednesday.
The German-made KRI Nanggala-402 requested permission to dive or submerge on Wednesday at 3 a.m. local time before losing contact, authorities said. Margono said the submarine had just fired two torpedoes – one with real ammunition and another with a training head – as part of training drills in the Bali Strait, a stretch of water between the islands of Java and Bali that connects to the Indian Ocean. and Bali Sea.
Margono answered questions about the submarine’s condition before participating in the war simulation, saying that the KRI Nanggala-402 and all its crew are well prepared. It was last docked for maintenance in 2020 in Surabaya, a port city on the island of Java, he said.
The army suspects that an oil leak observed on Wednesday during air surveillance near the dive point came from the vessel. Margono said the Navy also found an object at a depth of 50-100 meters (about 164-328 feet) that was magnetic, meaning it likely came from the submarine.
Margono said there are two possibilities to explain the oil spill on the surface: the submarine tank could leak because it dived too deep, or the submarine released liquid on board in an attempt to rise to the surface.
The Indonesian Navy spokesman, First Admiral Julius Widjojono, said the submarine is capable of diving up to 500 meters (about 1,640 feet) below sea level, but authorities estimate it went 100-200 meters below that depth.
Two ships equipped with side-scan sonar, a tool used to map the seafloor, began searching the area on Wednesday, the Department of Defense said, while a Rigel warship equipped with advanced sonar monitoring the position of the accurately detect the vessel, it is en route from Jakarta. according to Widjojono.
Authorities hope the crew is safe, but recognize that the situation at that depth could be fatal.
“Let’s pray for them so they can survive,” Widjojono told local media on Wednesday.
The International Submarine Escape and Rescue Liaison Office (ISMERLO), an organization that facilitates an international response for ailing submarines, is also providing assistance, the Department of Defense said.
The 1,395-ton KRI Nanggala-402 was built in 1977 by the German shipbuilder Howaldtswerke-Deutsche Werft (HDW) and joined the Indonesian Navy in 1981, according to a statement from the ministry.
The submarine underwent a two-year refit in South Korea that was completed in 2012, the Indonesian cabinet secretariat said.
In the past, Indonesia operated a fleet of 12 submarines purchased from the Soviet Union to patrol the waters of the vast archipelago. But now it has a fleet of just five, including two German-built Type 209 submarines and three newer South Korean ships.
Indonesia has tried to improve its defense capabilities, but some of its equipment still in use is old and there have been fatal accidents in recent years, most notably with obsolete military transport aircraft.
CNN’s Kara Fox contributed to this report.