Copyright © Fred Vanderbom
On 5 January 1975, the bulk ore carrier Lake Illawarra, carrying 10 000 tonnes of zinc upstream to the Electrolytic Zinc works, hit the pylons of the bridge causing three of its spans to collapse. The roadway landed on the ship causing it to sink within minutes. Seven crew members were drowned because they were below decks at the time.
Five people in four cars that drove off the bridge were also killed as a result of the 45 metre fall into the river. Several other cars just barely stopped in time and ended up with their front wheels dangling over the side.
The loss of the bridge link between the eastern and western sides of Hobart caused some significant social problems. The bridge was re-opened on 8 October 1977, some twenty one months after the collapse. There is a very useful article on the bridge collapse and it's effects on the local community in Wikipedia.