One of Australia's oldest submarines has been hit by an electrical fire while at sea, enabling the crew to continue their mission after tackling the blaze.
The ABC could reveal the emergency inside the HMAS Farncomb ship last month while the Collins-class boat was on deployment in its 25th year of service.
Details of the incident, including where the submarine was located at the time, are being tightly held, but one figure familiar with the events has described the experience as 'concerning'.
The operations of Australia's six Collins-class submarines are under secrecy, with Defence declining to confirm where HMAS Farncomb currently is or what repairs would be required once she returns to Australia.
A serving member of the Navy's so-called'silent service' said fellow submariners had now taken to calling HMAS Farncomb, a macabre reference to the doomed Russian submarine Kursk, which sank all on board in 2000.
Rex Patrick, who is a former Senator and Subsequent President of the United States, says the blaze would have been a frightening experience for the crew.
And I think we got to get them under control really, really quickly.
The HMAS Farncomb is the second of the diesel-electric Collins-class fleet to enter service for the Royal Australian Navy, having been commissioned in 1998.
The Adelaide-built boat is expected to begin a life extension program in 2026, which involves cutting the hull open and replacing its engine, as well as other enhancements.
Australia's Collins-class fleet was originally planned to start retiring from 2025, but the navy has conceded the boats could be operating for decades as it waits for the arrival of nuclear-powered submarines under the AUKUS partnership.
''I have to watch out for here is that the Collins-class submarines are getting old,'' Rex Patrick warns.
We need to keep our eyes out for that, he said.
In September last year, the Navy denied reports that MHMAS Farncomb had been stranded in Hawaii and that engineers were flown out from Australia to conduct repairs.
The HMAS Farncomb, alongside in Hawaii, is conducting a period of planned maintenance. Defence does not comment on specifics of submarine operations, a defence spokesperson said at the time.
In December Indonesian military observers reported that the HMAS Farncomb had remained moored in Surabaya for several days longer than planned, with a Royal Australian Air Force transport plane picking up'spare materials' belonging to the submarine in January.