Melbourne-Voyager collision: The aircraft carrier HMAS Melbourne collides with and sinks the destroyer HMAS Voyager off the south coast of New South Wales, Australia, killing 82.

HMAS Voyager was a Daring-class destroyer of the Royal Australian Navy (RAN), that was lost in a collision in 1964.

Constructed between 1949 and 1957, Voyager was the first ship of her class to enter Australian service, and the first all-welded ship to be built in Australia. During her career, Voyager was deployed to the Far East Strategic Reserve on six occasions, but never fired a shot in anger.

During the night of 10 February 1964, Voyager and the aircraft carrier HMAS Melbourne collided off Jervis Bay, when the destroyer passed in front of the carrier during post-refit sea trials. Voyager was cut in two by the collision, sinking with the loss of 82 of the 314 people aboard. This was the largest loss of Australian military personnel in peacetime, and the subsequent investigations resulted in the holding of two Royal Commissionsthe only time in Australian history this has occurred.

The Melbourne–Voyager collision, also known as the Melbourne–Voyager incident or simply the Voyager incident, was a collision between two warships of the Royal Australian Navy (RAN); the aircraft carrier HMAS Melbourne and the destroyer HMAS Voyager.

On the evening of 10 February 1964, the two ships were performing manoeuvres off Jervis Bay. Melbourne's aircraft were performing flying exercises, and Voyager had been given the task of plane guard, and was positioned behind and to port (left) of the carrier in order to rescue the crew of any ditching or crashing aircraft. After a series of turns effected to reverse the courses of the two ships, Voyager ended up ahead and to starboard (right) of the carrier. The destroyer was ordered to resume plane guard position, which would involve turning to starboard, away from the carrier, then looping around behind. Instead, Voyager began a starboard turn, but then came around to port. The bridge crew on Melbourne assumed that Voyager was zig-zagging to let the carrier overtake her, and would then assume her correct position. Senior personnel on Voyager were not paying attention to the manoeuvre. At 20:55, officers on both ships began desperate avoiding manoeuvres, but by then a collision was inevitable.

Melbourne struck Voyager at 20:56, with the carrier's bow striking just behind the bridge and cutting the destroyer in two. Of the 314 aboard Voyager, 82 were killed, most of whom died immediately or were trapped in the heavy bow section, which sank after 10 minutes. The rest of the ship sank after midnight. Melbourne, although damaged, suffered no fatalities, and was able to sail to Sydney the next morning with most of the Voyager survivors aboard – the rest had been taken to the naval base HMAS Creswell.

The RAN proposed a board of inquiry to investigate the collision, but a series of incidents during the 1950s and 1960s had led to a public mistrust of Navy-run investigations, and as proposals for an inquiry supervised by a federal judge were not acted upon, a full royal commission became the only avenue for an externally supervised inquiry. The four-month Royal Commission, headed by Sir John Spicer, concluded that Voyager was primarily at fault for failing to maintain effective situational awareness, but also criticised Melbourne's captain, John Robertson, and his officers for not alerting the destroyer to the danger they were in. Robertson was posted to a shore base and banned from serving again at sea; he resigned soon afterwards. Opinions were that the Royal Commission had been poorly handled and Robertson had been made a scapegoat.

Increasing pressure over the results of the first Royal Commission, along with allegations by former Voyager executive officer Peter Cabban that Captain Duncan Stevens was unfit for command, prompted a second Royal Commission in 1967: the only time in Australian history that two Royal Commissions have been held to investigate the same incident. Although Cabban's claims revolved primarily around Stevens' drinking to excess, the second Royal Commission found that Stevens was unfit to command for medical reasons. Consequently, the findings of the first Royal Commission were based on incorrect assumptions, and Robertson and his officers were not to blame for the collision.