Bill Stewart was just 11 years old when he became an orphan.

Key points: The deaths of 38 people onboard the SS Iron Crown in 1942 were kept quiet to avoid panic

The deaths of 38 people onboard the SS Iron Crown in 1942 were kept quiet to avoid panic Families of the fallen received medals at the Shrine of Remembrance today

Families of the fallen received medals at the Shrine of Remembrance today Mr Stewart said the service had given him closure about the death of his father

His father Frank was killed aboard the SS Iron Crown when it was torpedoed in Bass Strait in June 1942.

"Sunk by a Japanese submarine, that was all I was told," Mr Stewart said.

Frank Stewart was a fireman on board the merchant navy freighter, which was fully laden with manganese ore destined for the steelworks in Port Kembla.

The torpedo from the Japanese submarine during World War II sunk the ship in just 60 seconds.

There were 43 crew on board, but only five sailors survived by clinging to life jackets and wreckage until they were rescued by the SS Mulbera.

The attack was kept under wraps by the Government to stop people panicking about the tragedy, and the location of the shipwreck remained a mystery.

But Mr Stewart said suppressing the story suppressed the memory of those who died.

Bill Stewart's was one of five families to be presented with medals for their lost relatives. ( By Gemma Hall )

"It always worried me. I always thought he was somewhere off the east coast of Australia but I had no idea where," he said.

"They were the forgotten men of the war, no-one seemed to have been interested in them."

On Tuesday, at least 50 descendants of those who died on board the ship congregated for a service at Melbourne's Shrine of Remembrance.

The service was held as Australia commemorated both the 80th anniversary of Australia becoming involved in World War II and Merchant Navy Day.

Five families accepted medals their relatives had never been given for their service, including Mr Stewart.

Space to play or pause, M to mute, left and right arrows to seek, up and down arrows for volume. Watch Duration: 4 minutes 20 seconds 4 m 20 s The SS Iron Crown was only discovered in April.

Discovery of shipwreck paves way for closure

The 88-year-old only found out where his father's final resting place was in April, when marine archaeologists discovered the wreck 100 kilometres off Victoria's south coast in Bass Strait.

Locating the remains of the ship was a joint project between the Australian National Maritime Museum and the CSIRO.

The project's chief scientist, Emily Jateff, said meeting the descendants of those who died meant a lot to her.

"I've worked on shipwrecks that are hundreds of years old and the fact that this vessel and this wrecking event has a current meaning to families is incredibly significant," she said.

Emily Jateff helped discover the shipwreck. ( ABC News: Gemma Hall )

For Mr Stewart, the discovery meant an end to a life of wondering what had happened.

"It gives me closure, I don't have to think any more about where it went down," he said.

"I'm totally fulfilled with the knowledge of where my dad is and no harm will come to him where he is."