A through deck destroyer or cruiser, without a well dock and extensive facilities of an LHD, as well as being significantly smaller, would be substantially cheaper (to own and operate) and infinitely more flexible. The RAN already has two LHDs, ships so large and capable that the question arises, what would a third, larger version, actually carry? Are we going to double the size of the army to give the extra large amphib something to do? Add Choules and the much needed LCH replacements there is probably little justification in a third LHD, let alone a larger derivative.
A smaller through deck ship, as stated previously is cheaper to own and operate, has higher performance, smaller crew, lower operating costs, carries more aircraft for its size, can be acquired in greater numbers meaning its capabilities can be in more places at any given time than the LHDs. Potentially they would be more survivable through superior sensor and armament suits in addition to the capabilities provided by the aircraft carried, AEW, ASW, CSAR, ARH and even MCM helicopters, rotary and fixed wing UCAVs, they can even function as an LPH if required. You likely wouldn't send a. strategic asset such as an LHD to the Persian Gulf or East Africa but one of these ships would be ideal. They would complement and support the major surface combatants, even significantly add to the capability of any force escorting an LHD. Then if you add a half dozen or more F-35B to the mix the impact goes through the roof.
On OPV to OCV to light frigate, initially the ACPBs should be replaced by OPVs and possibly OCVs with provision for multi-mission modules (preferably USN spec as developed for the LCS program). The thing is we have eight ship sets of sensors and weapons from the ANZACs that will be surplus once the new frigates / destroyers start to come on line, as well as systems removed from the Adelaide class FFGs as they were / are retired. Why not pull them through to a light frigate that shares a high level of commonality with the OPV / OCV? Some would be base OPVs, some would be multi-mission OCVs and some would be corvettes / light frigates using ANZAC ASMD and / or FFGUP systems.
Instead of throwing useful kit away, or worse paying to keep it in storage even though it will never be used again, why not just use it? What I am looking at is ways to enhance capability within a limited budget and reusing capable systems is one way to do this. The Japanese, Italians and many others are convinced of the benefits of supporting as many helicopters as possible at sea. Experience has proven that a through deck design is superior for operating and supporting helicopters than a hybrid helicopter carrier, let alone a surface combatant with a hanger for only one or two helicopters. Such a setup is without a doubt superior for supporting UAVs and UCAVs as they evolve and inevitably grow in size and platform impact.
Just my two cents, but as I see it we have our big LHDs, our purple assets and our low end patrol vessels, what we need is actual warships, vessels to add to and if possible multiply the fleets offensive and defensive capabilities.
