In February 1937, the Gloster Gladiator ^[1] biplane entered service with the Royal Air Force. It was already obsolescent; Hawker Hurricanes ^[2] began operational service late that year. Gladiators were effective early in World War II, but were rendered obsolete by the arrival of the Luftwaffe’s Messerschmitt Bf 109s. A little more than eight years after the Gladiator began service, Gloster’s jet-engined Meteor ^[3] joined the RAF, signalling the end of the era of propeller-driven monoplane fighters.

It seems increasingly probable that the application of light-metal battery technology to conventional submarine design will be as disruptive and transformative as these turning points in 20th century airpower were. One of the questions Defence Minister Linda Reynolds should ask about the Attack-class program is how to avoid spending $4 billion apiece on a 21st-century maritime equivalent of the Gladiator.

The goal of the Attack-class program is to produce a ‘regionally superior’ submarine. But that objective is now under challenge. As we noted in part 2 ^[4], Japan has launched a submarine with a lithium-ion main battery, South Korea has approved construction of lithium-ion-battery-powered submarines and Naval Group is developing a lithium-ion battery system that will become available in derivatives of its Scorpene ^[5] class.

In perhaps a little over a decade, several East Asian nations will have acquired submarines capable of high speed and ‘zero indiscretion’ in defensive operations thanks to lithium-ion batteries.

Pitting a lead–acid battery submarine (such as Australia’s Collins-class vessels and, when built, HMAS Attack) against a lithium-ion battery submarine would be risky business. Important tasks, such as gathering intelligence on regional naval activity (which is often shared with allies) might become untenable, compromising the influence that Australia currently enjoys.

The performance of lithium-ion batteries has accelerated since 2016 and storage systems comparable in capacity and power to large submarine main batteries have been operating for long enough to confirm their technical viability. The modular, digitally monitored, multiple-small-cell configuration of batteries in large land-based storage systems can be scaled to fit submarines. This modular configuration simplifies upgrades throughout the life of a vessel and allows for evolving battery performance to be relatively easily transferred to submarines. This is a paradigm shift from heavy-metal battery technology, where a new design is required to improve submarine performance.

Reynolds should seek analyses of the expected rate of increase in lithium-ion battery performance and of the submarine programs using them and make an assessment of the R&D required to have this technology incorporated in the Attack-class program.

Submarine planners and builders in East Asia have determined that requisite levels of operational fire safety can be achieved and sustained for lithium-ion main batteries. They have also conducted the research to build broad confidence in lithium-ion-battery-powered propulsion.

The minister will have to be prepared to approve spending to confirm those judgements, ensure adequate diligence on safety, and provide guidance for employing lithium-ion batteries in an Australian operational environment. Defence R&D into lithium-ion propulsion will have to expand into something equivalent to South Korea’s technical readiness assessment process, under which some 11 research institutes combined to verify the characteristics of lithium-ion batteries in a submarine environment. It was this 30-month program that underwrote the decision to build the KSS-III batch 2 ^[6], and a similar pathway in Australia will be needed if the Attack-class program is to succeed.

As currently planned, the Attack-class program faces a central problem. Its build schedule doesn’t allow the introduction of lithium-ion batteries until the 2030s.

HMAS Attack will be built with a heavy-metal main battery, a process already initiated by a contract signed by Naval Group and MTU Friedrichshafen ^[7] for diesel generator sets.

HMAS Attack will be trialled and evaluated until the mid-2030s, before approval of the design of subsequent vessels. The need to verify construction and engineering is unavoidable, but the timing of the process will compromise the operational effectiveness of the RAN submarine force. Adoption of Naval Group’s LIBRT system will move the Attack-class design onto lithium-ion-battery-driven propulsion, but the proposal to start with batch 2 construction ^[8] does little to solve the problem.

By the time evaluation of HMAS Attack is sufficiently advanced to allow approval of further construction, the boat itself will be obsolescent. Worse, we expect that the technology to build a megabattery submarine will become available at about this time, rendering the Attack obsolete and challenging the response of the design team. Then, if technological advances in light-metal batteries follow predictions, the gigabattery submarine will follow about a decade later.

The probability that the gigabattery submarine will be emerging as the standard for conventional design before the end of construction of the 12-boat Attack class means that the program can’t produce the regionally superior submarine that is its objective and therefore can’t be completed as currently envisaged.

Nor was it ever intended to be. The acquisition strategy for the Attack class was planned from the beginning to incorporate reiterations of the design, with boat 12 expected to be substantially different from the Attack. A sovereign submarine capability is therefore central to the program and fundamental for the future development of the Australian submarine force—because it will supports the creation of the deep knowledge essential for any organisation to manage innovation.

The evolution of the capacity of light-metal batteries will allow submarine performance to improve significantly several times during the construction of the Attack class. It won’t be the only change. Enhanced performance will open new modes of operation that might lead to changes in the CONOPS. Unrestricted electricity supply will allow submarines to operate diverse systems that may lead to changes of role. These in turn will feed back into the design of later submarines.

Consequently, the defence minister would do well to review the intellectual power of the Attack-class program, the state of its access to intellectual property, and the requirements of its training and recruitment programs. These are the elements that will help the program confront its challenges—and help keep the minister out of hot water.