Many lessons learned from the 2017 incident when near- tragic blaze ignited a boat in Darwin

The fire extinguishers failed, the crew had to call for help on mobile phones because they had no training on the radios and firefighting breathing apparatus could not be recharged due to a power failure.

These were just some of the problems the crew on the HMAS Maryborough faced when the engine room of their Armidale Class boat exploded into flames just before midnight off Vernon Island in the Beagle Gulf in 2017.

While the 31-person crew have been praised for their reactions that night on the stricken vessel about 50km northeast of Darwin, investigative reports reveal issues relating to training and equipment that could have resulted in a major tragedy.

The boat was heading back to Darwin at about 22 knots when a loose bleed screw in the engine room blew out, spraying more than a hundred litres of diesel onto the exhausts, according to the investigation report obtained through Freedom of Information.

The oily mist caused the engine room to burst into flames, destroying the CCTV camera and handicapping the ability of the crew to monitor the fire.

With the temperature spiking above the maximum 100C, a crew member opened the hatch to the engine room but was forced back by the heat and thick black smoke, which then spread.

Visibility went down to 30cm and fire extinguishers couldn’t be discharged due to inability to see any flame, said the report.

The dense smoke complicated the response to the incident, restricting movement within the vessel and requiring increased use of breathing apparatus. An officer ordered the triggering of the ship’s CO2 system in order to starve the blaze of oxygen.

But it failed and the engine room temperatures increased. The crew member pressed the buttons to try another drench and this time the CO2 system worked and the temperature dropped.

But within 10 minutes it rose again, and a crew member wearing breathing apparatus went into the smoke-affected compartment containing the CO2 cylinders to trigger a manual drench.

The ship anchored and the fire was declared extinguished about two hours after it started.

While the crew succeeded in extinguishing the fire, various problems were noted, including the fact the crew had to call for help on a mobile phone.

The report said the Maryborough had limited external communications systems working and crews were supposed to use portable HF and UHF radios.

But the Navy did not provide training on the use of these portable radios, said the report. It also noted the system used to recharge the firefighting breathing apparatus failed because it was connected to the main power supply, which was shut down.

The Navy this week said it was satisfied all material, training and procedural issues identified from the investigation had since been resolved.

A spokesman said all the vessel’s CO2 system cylinder head hoses had been replaced and all were regularly inspected. He said formal training in use of the Harris radios was now provided for all RAN communications personnel as part of initial entry training.