The Oberon Class were built in the 60's
The last Oberon Class in the RAN (Otoma) was decommissioned in December 2000.
There successors, the Collins Class entered service from 1996 onwards.
The Collins Class (6 vessels) are rarely at sea in any great numbers these days, they have been plafued with technical and design problems and the inability to find sufficient qualified personnel.
If a Collins was at a standstill prior to firing a torpedo it is likely that there were insufficient engineers in the engine room
