Plans for a bridge to link the Derwent River's two shores near Hobart date back to 1832.
The floating bridge was closed to traffic on 17 August 1964, and the following day the locking pin was removed and the two concrete sections towed away.
Today the only reminders of the bridge are the eastern foot of the lifting section which is still in place, and the preserved locking pin.
It was a floating bridge with a lift span, constructed of hollow concrete pontoons, 24 in all, connected together forming a crescent shape curved upstream, and anchored in the middle.
The bridge was constructed in 12-pontoon sections which were then towed out into the river and connected to the banks and to each other in the middle.
The total volume of concrete used in making these pontoons was 8,410 cubic metres (11,000 cu yd).