My plan to keep the industry going in the 60s would be to build additional River Class and develop a DDG version of the Daring locally. Build the Rivers exclusively at Williamstown, twelve would be ideal to replace the WWII River and Bay Class, as well as the Tribal and Q conversions, but at least eight or ten. Ideally, all four Darings would have been built, providing six large modern destroyers, with a program of DDG versions, minimum six, preferably eight, built to supplement, then replace the earlier ships into the 70s.
At this point twenty to twenty-five years was considered to be a good service life for a warship.
Assuming our alt history starts in the 1st of January 1970, that changes things. The industry has already been gutted, CODOC and Williamstown are each building a River Class DE in slow time as the DDL is evolving from a gun armed sloop, maybe with a Seacat, into a helicopter-equipped frigate with Tartar/Standard, there are discussions on a collaborative build of a modified Type 21 due to the popularity of the various Vosper Thornycroft fast frigate exports in recent years.
There is a shortage of designers and draftsmen, more so than trades. This is in part due to the drawdown of shipbuilding, but also due in part to professionalisation, with the moves to restrict anyone who hasn't completed a four-year degree at a university from working as an engineer. This was devastating as many naval architects, designers, draftsmen, and technical specialists who had come up through trade, trained at institutes of technology, trained basically as engineering apprentices in what was called "pupillage".
Harmful but not insurmountable, for starters, just hook in to the Royal Institute of Naval Architects certification system assessing and certifying people as competent.
Assign the DDL to CODOC and Amazon to Williamstown, ordering four of each.
Order an additional four Amazons from Williamstown going into the early 80s and three to five modified, enlarged Vosper Thornicroft Harrier Carriers from CODOC being built from the late 70s into the mid 90s.
That's the ships laid down in the 70s, later examples would not be completed and commissioned until the 80s or 90s, but the first four Amazons and four DDLs should be done by the early 80s. They would have high levels of commonality, i.e. Olympus and Tyne GTs, Mk-45 5" gun, and many common subsystems. The Harrier Carriers would also have many common systems. This could justify local production of the GTs.
These ships would increase numbers and replace the last of the gun destroyers, as well as Sydney and Melbourne.
The program for the 80s would be six to eight Type 22 to replace the River Class, leading into a DDG and DDL replacement built at CODOC and an Amazon replacement kicked off in Williamstown in the 90s, completing in the 2000s, leading into the carrier and ASW frigate program in the 2010s. This would see a switch to Spey in place of Olympus.
