Indonesian navy detects object during search for missing submarine

Indonesian military chief Hadi Tjahjanto, points to the debris found in the waters today

Indonesian President Joko Widodo had ordered all-out efforts to locate the submarine and asked Indonesians to pray for the crew's safe return.

A former US Navy submariner walked Insider through what can make finding one so challenging.

"With the authentic evidence we found believed to be from the submarine, we have now moved from the "sub miss" phase to "sub sunk", Margono said at a press conference.

The vessel's status has been deemed "subsunk", military chief Hadi Tjahjanto said, "because shards have been found and the last location of the ship is at a depth of 850 meters".

Not every submarine can carry out every mission, but regardless of the vessel's mission and capabilities, stealth is generally regarded as important. While they suspect it is the missing submarine, this is yet to be confirmed.

The pinger, while it does not necessarily guarantee recovery, is invaluable because it allows search-and-rescue teams to use passive sonar to scan a larger swath of the ocean in complement with other tools. Clark, a defense expert at the Hudson Institute, speculated that were the boat making noise, it would have probably already been located.

Kirby also said Secretary of Defense Lloyd Austin was meeting with his counterpart in Indonesia - Prabowo Subianto - to pursue other means of worldwide assistance.

Communication with the submarine was lost on Wednesday, as it was conducting a torpedo drill in waters north of the island of Bali. It added that a helicopter later spotted an oil slick near the dive's starting position.

"(The items) would not have come outside the submarine if there was no external pressure or without damage to its torpedo launcher".

Experts like Koh say Indonesia will have to expand the area of search again if the magnetic anomaly is proven not to be the vessel and warn that if the submarine is lost at an "extreme depth", it might not be possible to retrieve.

Singaporean rescue ships were also expected later Saturday, while Malaysian rescue vessels were due to arrive Sunday, bolstering the underwater hunt, Indonesia military spokesperson Djawara Whimbo said earlier Saturday. The Bali Sea can reach depths of more than 1,500 metres.

Searching for things around the ocean floor is also rather challenging, Clark said.

Pentagon spokesperson John Kirby announced Thursday evening on Twitter that at Indonesia's request, the USA was "sending airborne assets to assist in the search for the missing submarine". In November 2017, an Argentine submarine went missing with 44 crew members in the South Atlantic, nearly a year before its wreckage was found at a depth of 800 metres (2,625 feet).

The navy said the submarine would have enough oxygen to last about 72 hours, meaning supplies could run out at around 3 a.m. on Saturday, local time.

"But if the submarine is in a 700-metre sea trough, it will be hard for them to survive because underwater pressure will cause cracks and ruptures of the steel hull", Connie Rahakundini Bakrie said.