A poignant video has emerged showing the crew of a sunken Indonesian submarine singing happily together on board their vessel. The video, filmed a few weeks before the <em>KRI Nanggala 402</em> went down with all hands lost, shows some of the 53-strong crew singing "Sampai Jumpa", an Indonesian hit whose title means "See you later". Submarine commander Heri Oktavian is among those gathered around a seaman strumming an acoustic guitar. "Even though I'm not ready to be missing you, I'm not ready to live without you," the sailors sing. "I wish all the best for you." The video was recorded as a farewell to the departing commander of the navy's submarine corps, whose successor took up his role in early March, Indonesian military spokesman Djawara Whimbo told AFP. The German-built submarine – one of five in Indonesia's fleet – disappeared early Wednesday while it was scheduled to do live torpedo training exercises off Bali. Indonesia's military announced on Sunday it had found the vessel in pieces on the seafloor, about 800 metres below the surface. Indonesian President Joko Widodo sent his condolences to the families of the crew aboard a submarine found at the bottom of the sea just one day earlier. "I send my deepest condolence for the passing of 53 navy members on-board <em>KRI Nanggala 402</em> who had fallen during an assignment in the waters north of Bali." In his address to the nation, the president also said the government would pay for the education of the lost crew members' children. Indonesians mourn the loss of their friends and family members aboard the submarine. One victim's uncle said he hoped the crew members' bodies would be found and returned. "We'd already given our nephew to the government to serve in the military. Now that he has fallen in the operation, we hope the government will return his remains to us after all the official ceremonies, because each of us has our own religion, like Hinduism." The country’s top Navy chief blamed the accident on “forces of nature” and not the crew. More than a dozen helicopters and ships searched the area where contact was lost with the help of the US, Australia, Singapore and Malaysia. Indonesia, South-East Asia's most populous country, has sought to revamp its military, but its ageing equipment has been the cause of several fatal accidents in recent years.