By Robbin Laird
The Royal Australian Navy is crossing a dangerous bridge. On one side sits the force it has today, three Hobart-class air warfare destroyers, a diminishing number of Anzac-class frigates, and a support structure increasingly strained by the weight of strategic demand. On the other side sits the force Australia intends to build: Hunter-class frigates, general purpose frigates, and eventually nuclear-powered submarines under the AUKUS pathway. The bridge between the two is long, narrow, and if navigated without imagination, a period of genuine strategic vulnerability.
But here is the argument I want to make, and it runs directly against the dominant framing in most of the public commentary on this subject: the hull gap decade is not merely a problem to be endured. It is a strategic opportunity unlike any Australia has had in a generation. The question is whether the Royal Australian Navy, the Australian Defence Force, and the government in Canberra have the institutional imagination to seize it.
Let me be precise about what the gap actually means, because imprecision on this point tends to generate either denial or fatalism, neither of which is useful.
Australia’s surface combatant fleet today consists of three Hobart-class destroyers and eight Anzac-class frigates, a total of eleven principal surface combatants. In practice, however, the number available for operations at any given moment is substantially lower. Maintenance cycles, crew generation, upgrade programs, and the ordinary friction of naval operations mean that a significant fraction of the fleet is unavailable at any time. The Hobart class, Australia’s most capable surface combatants, are three ships. One in maintenance and one in work-up can leave a single destroyer available for sustained operations. That is not a fleet. That is a presence.
The Anzac class is aging out. HMAS Anzac was decommissioned in May 2024 after 28 years of service. HMAS Arunta is due to depart the fleet in 2026. The class that once numbered eight frigates will number six before the first replacement hull enters service. And the replacement timeline is unforgiving: the first general purpose frigate, based on the Mogami design selected in 2025, is not expected to be delivered until 2029 and operational until 2030. The first Hunter-class frigate arrives in approximately 2032. The fleet of the late 2020s will be thinner, more heavily tasked, and less forgiving than the fleet of today.
This is the arithmetic of the gap. It is real, and pretending otherwise serves no one.
The standard response to the hull gap problem is to point toward the future fleet design and argue that quality will compensate for reduced quantity. There is something to this: the Hunter-class and general-purpose frigates, when they arrive, will be more capable than the vessels they replace. Aegis upgrades on the Hobarts will keep those ships credible against demanding threats. The AUKUS submarines, on the timeline measured in decades, will transform Australia’s undersea capability in ways that will matter strategically.
But this response misses the operational reality of the transition decade. It treats the hull gap as a planning category — a phase on a program schedule — rather than as an operational condition with daily consequences. Ships are needed not only for high-end warfighting. They are needed for escort, maritime security, presence, partner reassurance, and the distributed operations that constitute normal naval activity in a contested Indo-Pacific environment. A more capable but numerically reduced fleet still has fewer margins for error, less tolerance for simultaneous commitments, and less ability to persist across multiple theaters under pressure.
The hull gap also creates a deeper institutional risk that is less often discussed. If Australia simply waits for the new hulls to arrive and then attempts to build a hybrid fleet concept, integrating manned and unmanned systems, organizing around mesh networks rather than capital ship hierarchies, operationalizing the kill web rather than the kill chain, it will be learning the new model from scratch while simultaneously absorbing a major platform transition. That is the hardest possible way to transform a force. The history of military modernization suggests that new platforms take roughly five years after entry into service before operators understand how to use them, and close to ten years before they are fully integrated into the wider force. Starting that process after the new hulls arrive, rather than before, is a luxury Australia cannot afford.
This is where the Maritime Autonomous Systems Unit — MASU — and the broader ecosystem of Australian autonomous maritime capability enter the picture as something more than a compensatory measure. They are, if understood correctly, the instrument by which Australia can transform the hull gap from a period of vulnerability into a period of foundational learning.
Consider what is already available. The Ghost Shark large autonomous underwater vehicle is in steady-state production at Anduril Australia under a $1.7 billion contract, with dozens of vessels being delivered annually and a continuous upgrade architecture driven by operational feedback from Navy operators. The Ocius Blue Bottle uncrewed surface vessel is the subject of a Royal Australian Navy production contract for 40 vessels over five years, with operational experience already accumulated through 24/7 Maritime Border Command missions that have driven sustained performance from 30-day to over 100-day deployments.
These are not prototypes. These are not experimental systems waiting for doctrine to catch up. They are operational capabilities available now, being produced now, generating real data about what autonomous systems can do in real maritime environments.
The defense analyst Marcus Hellyer, Head of Research at Strategic Analysis Australia and a former Senior Analyst at ASPI, has made the essential point about the danger of treating these systems as precursors to something better rather than as instruments with present operational value. He reached for the analogy of the bolt-action rifle: if you look at it as a prototype of some future perfected firearm, you miss the utility it offers right now in its own context. The Blue Bottle conducts fisheries surveillance operations. The Ghost Shark can conduct subsurface reconnaissance and intelligence gathering. The question is not whether these systems are ready for something. They are. The question is what that something should be, and whether MASU will rise to meet the operational moment or remain a development cell within Navy’s bureaucracy.
The answer lies not in the systems themselves but in the operational problems Australia already has and can already see coming.
The most important of those problems is the one Hellyer has identified with particular sharpness: protecting the submarines before they arrive. HMAS Stirling, Australia’s primary naval base near Perth, will eventually house some of the most strategically consequential vessels in Australian history. The threat picture facing that base is already diverse and layered: long-range ballistic missiles, autonomous surface and underwater vehicles, drones launched from commercial shipping operating as covert platforms, a pattern with both Iranian operational precedents and Second World War historical analogues. A high-value submarine damaged or destroyed by a low-cost drone launched from a long-range unmanned platform represents a catastrophic return on investment failure for Australia. The defensive architecture needed to prevent it, layered air defense, counter-drone systems, underwater barrier operations, surface surveillance networks, is not futuristic. It is anticipatable and buildable now. HMAS Stirling offers a ready-made development environment, and whatever defensive architecture Australia learns to build around Stirling can subsequently be applied offensively to bottle up adversary forces at strategic chokepoints.
The second operational mission is water space management to Australia’s north. The geometry of the Indo-Pacific is vast, but the objection that Australian autonomous systems lack the reach for strategically relevant operations does not hold up to the evidence. Industry is already producing systems with sufficient range, depending on payload and configuration, to operate from Australian territory into the northern archipelago, from Guam to the Philippines, from the Philippines toward Taiwan. The question is not whether the range is there. The question is whether the operational concepts, the command-and-control architecture, and the integration with crewed platforms and land-based sensing are developed enough to use that reach. That development work takes time. It should begin now, not when the new crewed hulls arrive.
The third mission is the one already being executed by Maritime Border Command through the Blue Bottle operational contract: persistent maritime surveillance at scale. The mesh fleet concept that Ocius has been developing in service — multiple autonomous surface vessels operating as a distributed sensor network, where destroying a single node does not degrade the mesh — is not merely an interesting capability. It is a fundamentally different architecture for maritime surveillance. As Robert Brezniak of Ocius described it, if you lose a Blue Bottle you have lost a pixel on a screen, but the mission continues. You still have your other pixels. This is not how anyone has historically thought about a surface task force, where the flagship or capital ship at the center is both the source of command authority and the primary target. It is an entirely different mental furniture for maritime operations, and it takes time to learn.
This brings us to the central argument of this article. The hull gap decade is the period when Australia should be learning, operationally, institutionally, and doctrinally, how to integrate manned and unmanned maritime assets into a coherent hybrid fleet concept. If that learning happens before the Hunter-class and general-purpose frigates arrive, those new hulls will enter a force that already knows how to leverage what they bring. The operators who crew them will have spent years working alongside autonomous systems, developing intuitions about when to delegate sensing and persistence tasks to unmanned platforms and when to concentrate crewed capabilities on the missions that require human judgment. The CONOPS will be developed. The command-and-control architectures will be tested and refined. The supply chains for autonomous systems will be mature.
David Goodrich of Anduril Australia has expressed confidence that this process has begun. Senior Navy commanders and fleet leaders, he said, understand what is needed. The goal is not to create MASU as a special snowflake off to one side while the “real” Navy continues as before. The intent is integration: Ghost Shark as a normal part of fleet business, generating operational data that continuously shapes what the next year’s upgrade delivers. Royal Australian Navy fleet command, in Goodrich’s assessment, has grasped this.
But the challenge cannot be underestimated. Goodrich was direct about the critical obstacle: “The operational voice needs to be louder than the acquisition voice. At the moment it is always the acquisition voice that has the volume and controls what happens.”
This is the central institutional reform that the hull gap decade requires. Autonomous maritime systems are fundamentally different from capital ships in their procurement logic. They are payload delivery vehicles whose value is driven by the payloads and the data they generate, not by the platform itself. The Blue Bottle you see today will look largely the same on the outside in five years. What will have changed continuously are the sensors, the arrays, the communications architecture, and the software. This requires an acquisition model organized around data services contracts and continuous upgrade cycles, not a model organized around platform delivery with infrequent capability refreshes. The InSitu ScanEagle experience in the United States demonstrated this decisively. When the US Navy later sought to develop the Blackjack system under a platform ownership model rather than a data services model, they found they could not iterate at the speed the system required. Blackjack never achieved operational status.
Australia can avoid that failure by building the right acquisition model now, while the stakes of getting it wrong are lower and the operational feedback loops are already generating the evidence needed to calibrate the approach.
There is a further strategic dimension to acting during the hull gap decade that concerns Australia’s industrial base. The Blue Bottle is built substantially around commercial off-the-shelf components, with a supply chain that is broader, more resilient, and far easier to mobilize than what a capital ship builder requires. When the discussion turns to Australia’s industrial mobilization capacity or the ability to surge production rapidly in a genuine strategic emergency, this architecture matters enormously. You are not dependent on a single specialized vendor for a critical component. The workforce skills required to build and maintain autonomous maritime systems are different from, and in some cases more broadly available than, the highly specialized skills required for capital ship construction. Building those workforce skills, those supply chains, and that industrial depth during the hull gap decade creates a foundation that will serve Australia across multiple contingencies.
This is the point about the hull gap that most commentary misses entirely. It is not only an operational period to be managed. It is an industrial development period in which the choices made will shape what Australia is capable of building and sustaining for the next thirty years. Autonomous maritime systems produced in Sydney by companies like Ocius and in facilities like Anduril Australia’s expanding production base represent an industrial capacity that did not exist five years ago and will not automatically persist unless it is sustained by sustained operational demand. It is as well, a period to determine what is missing and what allied capabilities can and should be added to the fleet to ensure that the mesh fleet being built provides the overall capabilities the fleet needs as it transitions to a hybrid fleet. It is not just a question of supporting local manufacturing as a retired Australian admiral cautioned me.
My conversations with Goodrich, with Hellyer, and with the Ocius team all pointed toward the same essential conclusion. The hull gap decade demands a particular kind of strategic imagination: the ability to treat a period of apparent vulnerability as a period of foundational investment. That is harder than it sounds. Bureaucratic incentives push toward managing the present rather than designing the future. Acquisition processes are organized around platforms rather than capabilities. Public and political discourse tends to frame naval power in terms of hull counts and tonnage rather than in terms of the operational architectures that determine how hulls are actually used.
The forces are in motion that could produce either outcome. Australia has genuine production-scale autonomous maritime capability available right now, with companies delivering against real contracts and accumulating real operational data. It has a Maritime Autonomous Systems Unit that could, with the right institutional backing and mission assignments, become the laboratory through which the hybrid fleet concept is developed and tested at speed. It has new crewed hulls coming that will, when they arrive, need to enter a force that already knows how to think about manned-unmanned integration.
The hull gap decade is the window to do that preparation. It will not come again. The frigates and submarines, when they arrive, will not wait for doctrine to catch up. The question is whether Australia uses the time it has now — the years before those hulls arrive — to build the operational knowledge, the institutional frameworks, the acquisition models, and the industrial depth that a genuinely modern hybrid fleet requires.
That is not a question MASU can answer alone. It is not a question Ocius or Anduril Australia can answer alone. It is a question for the Royal Australian Navy, the Australian Defence Force, the Defence Department, and ultimately the government. The strategic moment is defined. The capabilities exist. The learning has begun. What remains is the will to treat the bridge as a destination as much as a crossing.