The Indonesian Navy on April 26 assessed options, with aid from local and foreign specialised vessels, on how to salvage its submarine that sunk to a depth of 850m, killing its 53 crew members.

"We will analyse the underwater pictures and video, the current, et cetera, to decide the technology that will be used," First Admiral Julius Widjojono was quoted as saying by Reuters on April 26.

The KRI Nanggala-402 was discovered broken into at least three parts, on the seabed on April 25, four days after it had lost contact during the preparation to launch a torpedo exercise.

A sonar scan detected the submarine at a depth of 850m, which exceeded its capability to withstand external pressure of up to 500m deep.

More than 20 vessels from Indonesia and other countries, including Singapore with its submarine rescue vessel MV Swift Rescue, were deployed in search and rescue operation to detect the location of the submarine.

Grieving relatives of the dead crew members congregated at Celukan Bawang in north Bali coast on April 26 to pray and pay their respects to their beloved ones, local media reported. They also urged the government to retrieve the bodies of the submariners from the sea.

A navy official said that family members of the lost crew will get on board the KRI Soeharso at Tanjung Wangi port in Banyuwangi on April 29 to pray and ceremoniously scatter petals in water.

Zakheus Sortid, a resident of Banywangi, the coastal town in East Java where the KRI Nanggala-402 was stationed, expressed his deep sorrow over the deaths of crew members, saying they were "the chosen people" and among Indonesia’s best military personnel, who had ensure the country’s security from any threat

"Performing the duties underwater is tougher than any other job" in the military, said the 70-year old, who used to be a sailor. "I am praying that their souls rest in peace."

Another resident Daniel Pujiono, 73, said he was very sad and deeply grieved for the death of the submarine crew members.

"This incident is a big tragedy. They passed away while performing their duties. They are national heroes," he said.

Meanwhile, a former Indonesian senior Navy engineer who had worked on the submarine said felt "a big sense of loss" after he heard about the incident.

"Submarine crewmen attend extraordinary training. They are the greatest talent," said Frans Wuwung, who was an engineer on Indonesia's submarines, including the KRI Nanggala-402.

He called for a thorough investigation into the incident to find its cause in order to learn a lesson and avoid the occurrence.

A poignant video of the sailors has emerged filmed singing a song titled Sampai Jumpa (Goodbye), a few weeks before the vessel went down.

President Joko “Jokowi” Widodo offered his condolences to the relatives and vowed that the state would financially support the education of the children of the dead crew members.

THE STRAITS TIMES (SINGAPORE)/ASIA NEWS NETWORK