By William Langley - NBC News
The time has passed without positive news.
Indonesian authorities reported that the missing submarine had sufficient oxygen for its 53 crew members as of 3pm Eastern Time on Friday.
And that is in case of having survived its sinking in waters perhaps too deep to withstand the pressure.
But so far it has not been found.
KRI Nanggala-402 disappeared Wednesday morning after rehearsing a torpedo drill some 60 miles (96 kilometers) north of the island of Bali.
A helicopter later detected an
oil slick
near the dive's starting position, the Indonesian Navy reported.
[Twelve missing after shipwrecked in a storm off the Louisiana coast]
The Navy originally said it believed the
44-year-old
ship
had sunk more than 2,000 feet;
any depth greater than 1,640 feet could be fatal.
But hopes rose late Thursday when the
strongly magnetic element
was discovered
between 164 and 328 feet underwater.
The Indonesian Navy sent two ships and several helicopters to search that area on Friday.
A rescue ship from the National Search and Rescue Agency sails to join the search for the KRI Nanggala submarine that disappeared while participating in a training exercise on Wednesday, off Banyuwangi, East Java, Indonesia, on Friday, April 23, 2021. .AP
Pentagon press secretary John Kirby said on Twitter Thursday that the United States was
"sending air assets to aid the search"
at the invitation of the Indonesian government.
Singapore, Malaysia, India and Australia have also sent ships or planes to aid in the search.
They joined the 24 Indonesian ships and a patrol plane that mobilized for the search on Friday, focusing on the area where the oil slick was found after the sub's disappearance.
The Nanggala was built in Germany and joined the Indonesian fleet in 1981. It underwent a refit in South Korea that was completed in 2012 and the vessel was said to be in good condition, according to the Reuters news agency.
[One of the largest ships in the world runs aground and blocks the Suez Canal]
Even if the submarine is located, rescuing the ship and its crew will be challenging, Frank Owen, director of the Australian Submarine Institute, told NBC News.
"We know that the submarine is old, we know that it has a depth index of 250 meters, which means that it could probably survive up to 400-500 meters (1,300-1,600 feet)," he said, adding that the ship was in waters of 700 meters (2,300 feet) deep.
Race against time to find a missing submarine with 53 crew members in Indonesia
April 23, 202100: 24
Owen, who is not working on the rescue attempt, said finding the sub in one piece would only be possible if it had managed to stay suspended in the water.
"A submarine that loses propulsion means that it cannot return to the surface. Also, it could be too deep for the introduction of air into the tanks to have any effect in terms of buoyancy. So it could be in the middle of the water and not being able to use any electrical power, "he said.
"But the prognosis is not really good," he added.
