Every serious review is based on geography as well as perceived strategic threat.
The geography drives how many ships we need and the environmental conditions they need to operate in. The strategic threat dictates the defensive and offensive capability the ships require.
Australia needs a minimum number of ships to provide the required presence in our local waters, through our region and globally as required. They need a minimum level of endurance and seaworthiness to reach and operate where they are needed.
We have always had around 25 or 30 combatants. Ideally they would have been, depending era, battlecruisers, cruisers and sloops; heavy cruisers, light cruisers and sloops; DLGs, DDGs and DEs; CGs/DDGs, FFGs, light frigates/corvettes.
What we have had this century is FFGs, FFHs, and patrol boats.
Since the late 60s the lower end has been inadequate PBs, with no combat capability to mention, culminating in the basically useless Armidale and Cape class constabulary patrol boats. These craft are so pathetic they need to be supplemented by frigates during the monsoon because they are too fragile and unseaworthy to be operated during monsoonal weather conditions. That is their class rules, specifically prevent them from going to sea in certain conditions because they are too fragile by design.
These make up just over half of our combatant numbers and they are incapable of actually doing the job they were acquired to do throughout the year. As such, they need to be supplemented by major surface combatants.
This is why we ordered the arafuras. Ships that were large enough and seaworthy enough to do the limited constabulary job the PBs were never good enough for. But because they are bigger, more durable and more seaworthy there is pressure to turn them into pocket battleships.
Yep, we finally get a constabulary vessel that is large enough, durable enough and seaworthy enough to do the bare minimum, close to zero threat level job required, and it gets recast as a replacement for the ANZACs and Hunters.
