With every man and his sea-dog being able to afford a basic radar for their fishing boats and pleasure cruisers these days, something was seriously amiss, if nobody on a a vessel of that class spotted, electronically, a thing the size of that commercial ship. Even were it swanning about erratically and being VERY illegal and running without lights, unlike the Fitzgerald.
The RAN has the dubious honour of more post-WW2 sinkings BY an aircraft carrier than any other navy.
HMAS Melbourne collided with and sank, the RAN Daring Class destroyer, HMAS Voyager in 1964, with the loss of 14 officers, including the commanding officer, 67 sailors and one civilian dockyard employee. This happened whilst on an exercise about 20 NM from Jervis Bay.
After repairs, Melbourne went to sea without much happening until 3 June 1969. Melbourne struck the USS Frank E. Evans as she crossed her bows in the the South China Sea. The destroyer was cut in two, with the bow section sinking rapidly. 74 sailors and officers were lost.