HMAS Voyager sank after a crash with HMAS Melbourne in the dark of night on Monday, February 10 1964.
The Australian destroyer had a crew of about 300.
The two ships collided during night flying exercises around 9pm, about 15 miles east of Milton off Jervis Bay.
Rescue ships brought 70 survivors of Voyager to Jervis Bay. Some had broken bones, others were suffering from shock.
Melbourne also suffered significant damage in the collision but few details were available right away.
A radio message was broadcast from the HMAS Melbourne: "Voyager sunk".
HMAS Melbourne said that HMAS Voyager had sunk soon after midnight.
Melbourne (20,000 tons) had a crew of about 1000 but the navy did not announce if the casualties were from Voyager or Melbourne or both.
The ships were engaged in a nighttime flying exercise when the Voyager suddenly turned in front of Melbourne.
Other RAN ships on an exercise with Melbourne and Voyager were immediately ordered to the scene.
Two navy search and rescue ships reached the stricken Voyager within an hour of the collision.
By the time the second search and rescue vessel had finished taking on its load of survivors, other navy ships and helicopters reached Voyager before it sunk.
Six helicopters from the Nowra naval air base, HMAS Albatross, took part in the search and rescue operations.
One flew the Officer Commanding the Fleet (Admiral O.H. Becher) from the base to his flagship HMAS Melbourne.
A reporter taken to the scene by a local fishing trawler San Cristafano, said the search area looked like 'one big light' - like a false dawn.
That was caused by the floodlights on ships searching for survivors from Voyager.
As the search went on a fierce electrical storm flashed lightening between the heavy clouds overhead.
But the wind, which had made the seas choppy, had died down significantly.
A skipper from a trawler, Joe Lavelle, said the Voyager almost certainly had sunk beyond the Continental Shelf.
Information provided by Shoalhaven Historical Society.