HMAS Australia (ex-HMS Hermes CATOBAR)
In this alternate Cold War timeline, Australia secures a new carrier — but not without a twist of history.
In reality, plans to replace HMAS Melbourne had begun not long after she had entered service. Built from a WW2 era light escort carrier design, she had limited potential for growth and upgrades as technology rapidly advanced in the early Cold War. She did however provide valuable experience for the Royal Australian Navy in fixed wing aviation. In 1968, brand new Australian A-4G Skyhawks successfully practised landing on the deck of HMS Hermes during an exercise. With Britain under financial strain, her shrinking navy meant that HMS Hermes was offered as an option for a new RAN carrier. Ultimately the RAN declined the offer due to costs to operate the carrier and manpower constraints. Melbourne would soldier on long term as the RANs primary carrier until being decommissioned in 1982 with no replacement, while Hermes would serve on in the Royal Navy with various configurations until the early 1980s, finally ending up serving with the Indian Navy until 2017.
But what if circumstances were different?
In this alternate timeline, however, with increased investment in the RAN and heightened strategic concern in the Cold War era Indo-Pacific—especially with an active involvement in the Vietnam War—Australia reassesses its priorities. The Royal Navy, offers Hermes to Australia on highly favourable terms, including a refit and a complement of Gannet AEW.3 aircraft to provide a new capability for the RAN on its new carrier, airborne early warning and control. 849 Squadron RAN is created to pilot these new aircraft.
The order for the A-4G Skyhawks is increased to equip 805 Squadron with enough aircraft to field a carrier air wing of 16 aircraft, while the S-2 Trackers and Wessex helicopters transfer to the new carrier. She is recommissioned into the Royal Australian Navy in early 1970 as HMAS Australia (R22).
The carrier becomes the centrepiece of Australia’s fixed-wing naval aviation. Her air wing evolves with newer aircraft and she will later receive refits. Over the next three decades, Australia serves in both peacetime and combat deployments, including Vietnam War service, regional interventions and future contributions to coalition operations in the Middle East and elsewhere. Her longevity, maintained with spares over time from decommissioned Centaur class carriers and later upgrades, allows a long service life.
- 1970 – Baseline Configuration: Received with original sensor suite and Seacat missile systems, A-4G Skyhawk, S-2G Tracker, Gannet AEW.3 and Wessex helicopters. Focused on air defence, strike and ASW,
- 1984 – First major refit: Major overhaul replaces the Seacat launchers with the Sea Sparrow BPDMS and its associated fire control systems. A significant upgrade is the replacement of the original sensor suite with American AN/SPS-48C and AN/SPS-49(V)5 radars and American AN/SLQ-32 ESM/ECM systems. Commonwealth Aircraft Corporation license built A-4AU Super Skyhawk and licence built Gannet AEW.7, Sea King Helicopters have replaced the Wessex since the late 1970s. Phalanx CIWS are added to the defensive weapons suite in order to protect the flagship from missile swarm attacks.
- 1999 – The Modern Era: Fully realized multirole strike carrier with PGM-capable A-4AU Mk.3 fighters with ECM pods and precision strike laser-designator pods. Upgraded ASW Sea King Mk50B+ & S-2T Turbo Trackers. Continued use of the Gannet AEW.7. Phalanx CIWS upgraded to Block 1A standard and upgraded RIM-7P missiles keep the defensive suite up to date. Continued sensor upgrades include the AN/SPS-48E and AN/SPS-49A(V)1 radars and ESM/ECM systems kept up to date.
The ship would have required significant investment however if done so it would have allowed the RAN to maintain a very powerful blue water capability into the 21st century, also retaining and may have led to continued carrier based aviation.
In this alternate history, the Commonwealth Aircraft Corporation (CAC) was given new life and partnered with Douglas to refurbish surviving A-4G airframes and license-build new airframes for the RAN. The resulting Super Skyhawk (A-4AU being the unique Australian designation) featured an upgraded lightweight pulse-doppler radar derived from the AN/APG-66 radar, avionics, expanded weapons compatibility (AIM-7M Sparrows, AIM-9L Sidewinders, Mavericks, Rockeyes, Shrikes and Harpoon anti-ship missiles), and a more powerful J52-P-408 turbojet engine for better range and reliability — ensuring strike capability into the 1990s.
I have tried to keep the loadouts relative to the aircraft’s size. This concept is inspired by real life upgrades to the Skyhawk like the A-4K Kahu and similar upgraded Skyhawks but geared towards performing as a multirole fighter.
The Fairey Gannet AEW.7 was a proposed advanced development of the AEW.3, created to extend the aircraft’s frontline service life into the late Cold War. Retaining the basic twin-engine, turboprop, carrier-based layout, the AEW.7 introduced a twin tail arrangement with modernized avionics and a revised ventral radome housing a more capable pulse-Doppler radar system. These upgrades provided improved detection ranges, better tracking of fast jet and sea-skimming targets, and enhanced reliability for sustained carrier operations. In Royal Australian Navy service the AEW.7 operated from HMAS Australia during the 1980s and 1990s, forming the backbone of the fleet’s airborne early warning capability until its eventual replacement by more modern AEW platforms. RAN specifications for the Commonwealth Aircraft Corporation licence-built version required a Radar Warning Receiver and Chaff countermeasures included in the design.
✅ Three fully realized variants spanning 1970–1999, with the final variant very capable out into the 2000’s and beyond
✅ Evolving squadrons reflecting RAN-specific upgrades
✅ Eventual improvement of defensive weapons suite
✅ Ideal for Cold War or Pacific flashpoint scenarios
✅ Pair with the HMAS Melbourne ’84 or ’98 mods to create a powerful two-carrier RAN force, for interesting what-if Australian carrier based naval resurgence and alt-history scenarios, with Australian naval independence and the opportunity to make big contributions in larger conflicts with allied navies
✅Pair the 1999 variant with the Gallipoli Class DDG mod to give her a powerful AAW escort
Hermes model, Gannet AEW models and custom RAN skins – by petrouvis01
Skyhawk, Tracker and Wessex models – by skyblazer
RAN and RCN Sea Kings MOD – by plasm@n
New Threat Upgrade – by nuclearstonk
(You will need to look these up on YouTube, the automated content checker can have issues with links)
Simple Install Guide by Skyblazer
Sealifter and Anchor Chain guide by Brothermunro
Required items:
Click the title to search on this site.
Anchor Chain — Steam Workshop
SeaLifter — Steam Workshop
New Threat Upgrade — Steam Workshop
