Indonesian navy submarine missing off coast of Bali

Indonesia’s navy is searching for a submarine with 53 people on board which has gone missing during a training exercise 26.5 nautical miles northwest of the island of Bali.

The 43-year-old vessel was conducting a torpedo drill on Wednesday but failed to relay the results as expected.

A search is under way for the German-made submarine, KRI Nanggala-402, and its crew.

According to NBC, military chief Hadi Tjahjanto says the KRI Nanggala 402 was participating in a training exercise when it missed a scheduled reporting call.

Tjahjanto says the navy has deployed scores of ships to search the area, including a hydrographic survey ship, and has asked for help from Singapore and Australia, which have submarine rescue vessels.

Local media reports said the navy believes the submarine sank into a trough at a depth of 700 meters (2,300 feet).

The Defence Ministry issued a statement that the submarine lost contact after being granted clearance to dive. That said, a helicopter later spotted an oil spill near the dive’s starting position.

The German-built submarine, which has been in service in Indonesia since 1981, was rehearsing for a missile-firing exercise that was to take place on Thursday.

According to VOA, searchers have spotted an oil slick near where it disappeared.

The oil slick could be evidence of the submarine’s distress from a crack in the hull, says First Adm. Julius Widjojono, a spokesman for the Indonesian Navy. Such cracking is highly unusual but can occur with a sudden change of pressure, naval experts told the New York Times.

The last request made by the submarine was for permission to descend to a deeper part of the Bali Sea in order to fire torpedoes for naval drills, Widjojono says. The area includes valleys that are at least 1,900 to 2,300 feet deep (or roughly 600 to 700 metres).

The request was granted but contact with the submarine was lost after that.

The oil spill is “highly suspected” to have come from the vessel.

“That oil spill location is the last time we had contact with the submarine,” says Widjojono.

According to CNN, Widjojono says the submarine has the capability to dive up to 500 meters below sea level, but authorities estimate it went 100-200 meters below that depth.

He says authorities are holding out hope the crew are safe but acknowledged the situation could be fatal at that depth.

“Let’s pray for them so they can survive,” he told local media on Wednesday.

Several countries, including Australia, India and Singapore, have offered to provide assistance.

Indonesia is deploying four warships to search for the submarine, including a Rigel warship equipped with sophisticated sonar that can precisely detect the vessel’s position, Widjojono says.

Two ships equipped with side-scan sonar, a tool used for mapping the seafloor, began searching the area on Wednesday. The International Submarine Escape and Rescue Liaison Office (ISMERLO), an organisation that facilitates an international response for distressed submarines, is also providing assistance.

Indonesian media reported that the navy believes the submarine sank into a trough at a depth of 700 meters.

The 1,300-ton naval vessel had on board 49 crew members, three gunners and a commander, whose identities are yet to be released.

Indonesia, the world’s largest archipelago nation with more than 17,000 islands, has been improving its military apparatus in recent years as it faces regional maritime challenges involving Chinese vessels near the Natuna islands.