The Australian surface combatant review’s recommendations around Tier 2 general purpose frigates pose interesting questions for New Zealand, writes maritime capability specialist and former Royal New Zealand Navy Officer Andrew Watts.

In a way this article isn’t particularly timely given that Cabinet is currently considering a new Defence Capability Plan that will hopefully address options for the renewal of New Zealand’s naval capability when the current fleet reaches the end of its life of type in the early to mid-2030s.

Having said this, the recently completed Australian Surface Combatant Review has no doubt had a bearing on the options presented to government, and it’s possible to reflect on the implications of Australian intentions without pre-judging the DCP process.

The public version of Enhanced Lethality – An Independent Analysis of Australia’s Surface Combatant Capability (the Review) was released on 20 February this year. The Review is an outgrowth of the Australian Defence Strategic Review released in 2023, the latter having determined that the issues around surface combatant capability requirements were so broad as to require further detailed study that could not be completed in time for DSR submission and release.

The overriding theme of the Review is that the current surface combatant fleet is not fit for purpose given Australia’s strategic circumstances, specifically the emergence of regional strategic competition. In the assessment of the Independent Analysis Team that conducted the review, the fleet is too small and insufficiently capable to address potential threats, and that significant re-orientation is required.

The Australian government has accepted almost all of the review recommendations. The Hunter class frigate program will terminate at six units instead of the nine currently planned, the Hobart class air defence destroyers will be significantly upgraded, and six optionally crewed surface platforms will be acquired to provide magazine depth for the Hunter and Hobart classes in the form of additional vertical launching silos for advanced air defence and strike missiles.

Tier 2 general purpose frigates

The review recommendation of most interest to Aotearoa New Zealand, however, is that at least seven and optimally eleven “Tier 2” general purpose frigates optimised for undersea warfare will be acquired to secure maritime trade routes, defend Australia’s northern approaches, and escort military assets.

Tier 1/2/3 capability descriptors were introduced by the Australian Chief of Naval Staff in 1986, but have seldom been used since. However, they are useful differentiators in the programmatic sense, particularly for people who – with some justification – find naval nomenclature somewhat confusing.

Tier 1 equates to highly capable multi-function combatants such as the US Arleigh Burke class and the Australian Hunter and Hobart classes. These ships are capable of sustained, high intensity combat operations.

“In sum, we can be confident that the outcome of this analysis in terms of the number and type of Tier 2 capabilities required by Australia is both valid and relevant to our own requirements.”

Tier 2 ships are less capable and more affordable combatants generally intended for lower intensity operations. However, the emphasis in the review on undersea capabilities suggests that in this dimension, the capabilities of the projected Tier 2 combatant could approach Tier 1 levels. The post Frigate Systems Upgrade Project Anzac class frigates fall into the Tier 2 category, although they are not optimised for undersea warfare.

Tier 3 ships are those acquired for purely constabulary functions, including resource and border protection. They are not capable of operations of greater intensity than that required for law enforcement. The RNZN Offshore and Inshore Patrol Vessels are in this category.

In arriving at the Tier 2 requirement, the Independent Analysis Team commissioned extensive modelling and simulation events to determine the best mix of overall surface combatant capability, taking into account the capabilities of the nuclear powered submarine force that will enter service from the early 2030s and other Australian and allied defence capabilities.

Simulation events would have used a variety of scenarios drawn from strategic analysis. The nature of the events and the simulation outcomes will be highly classified. Nonetheless, we can assume that the modelling and simulation capabilities used were advanced given the investment that Australian Defence has made in this area over many years. We can also assume that the event scenarios were focused on the region in which we share strategic interests with Australia.

In sum, we can be confident that the outcome of this analysis in terms of the number and type of Tier 2 capabilities required by Australia is both valid and relevant to our own requirements.

In determining solutions to the Tier 2 requirement, speed to capability appears to be the overriding consideration. To this end, Australia’s Head of Naval Capability, Rear Admiral Hughes, has announced that the Tier 2 design selected will not be altered from its original configuration in any way.

This is a significant decision, greatly reducing the integration and design risks that have emerged in other projects where base designs have been altered to incorporate Australian capability choices. On the debit side, the Tier 2 ships will introduce many new supply chains and training system requirements.

Advantages to NZ of Tier 2

The advantages that might accrue to Aotearoa New Zealand from joining the Australian Tier 2 program are threefold. Firstly, we would be acquiring surface combatants fully compatible with, and credible to, our only formal ally. We could be assured that the design selected is a good fit with regional requirements on the basis of the modelling and simulation commissioned by the Independent Analysis Team.

Secondly, it will be a large program offering attractive economies of scale – unit procurement prices will be reduced still further should New Zealand join the program.

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Thirdly, capability sustainment systems including logistical and engineering support and training could be shared with Australia, dramatically reducing through life sustainment cost and risk for New Zealand.

It is theoretically possible that a similar program of cooperation with a navy other than Australia would yield similar benefits. However, given the closeness of the Australia – New Zealand defence and economic relationship and the depth of the relationship between the two navies on every level, the benefits delivered by cooperation with another navy would need to be spectacular in order to stack up.

The challenges of Tier 2

In any event, a number of factors on the other side of the balance sheet need to be considered. The first and most significant concerns our ability to recruit and retain a naval combat work force.

Operational research conducted by Victoria University Wellington (and subsequently validated by the Defence Technology Agency) demonstrated that given typical workforce attrition and the training throughput governed by the number of bunks available for trainees in an Anzac frigate, a viable naval combat work force required a minimum of three ships, and even then, deterioration was likely over time. A greater number of training bunks in the Tier 2 frigate would alleviate this problem, as would a reduced attrition rate.

However, work force issues aside, a naval combat force of only two ships (as at present) cannot provide for the full-time availability of a single ship for operational contingencies. In my view this is inconsistent with our defence policy statements, and a minimum force of three combat ships is required to ensure the full-time availability of one ship at an acceptable level of readiness for contingencies.

Secondly, the mission systems of the exemplar Tier 2 designs detailed in the review are tightly coupled to platforms in the traditional warship design sense. This means that at some point they are likely to require an expensive and technically risky midlife upgrade that will take them out of service for lengthy periods, especially if there is a need to incorporate disruptive new technologies.

“… the potential benefits of a fleet based on modular mission capable platforms are such that they must be examined and compared to the Tier 2 approach, noting that a viable Tier 2 force will require a minimum of three platforms.”

In addition, our appetite for such upgrades could well be markedly different from the Australians, who may at some point seek to incorporate Australian sourced systems such as the CEAFAR radar and Saab combat management system. In a recent interview at the Combined Naval Event in Farnborough, UK, Rear Admiral Hughes hinted that this might occur. If we do not or cannot follow suit, our ships will again be orphans, which creates a raft of sustainment challenges.

Thirdly, and allied closely to the second point above, these ships will not be modular to any meaningful degree. They will be effective across the entire spectrum of conflict from resource and border protection through to combat, but they will only be efficient over the combat arc of the spectrum.

Employing these ships on low intensity patrol operations will consume service life and reduce readiness for deterrent and combat operations. It may be possible to re-task them for critical missions, such as humanitarian assistance/disaster relief, mine countermeasures, and environmental assessment, but they will not have the capacity and flexibility across these missions that a modular design would have.  

Finally, a modular design would allow capability upgrades without taking ships out of service for half-life refits, as obsolescence is managed within the capability modules by upgrading systems or by replacing the modules wholly. The ships themselves would remain available for operations excepting those that require the individual module undergoing upgrade or replacement.

Modularity

A patrol/combatant design based on modular concepts would provide greater through life mission flexibility and technological adaptability than the proposed Tier 2 combatant.

It could also enable new workforce concepts whereby some people are coupled to a mission module as opposed to a ship, which could reduce personnel operating tempos and allow greater focus on career specialisation and accomplishment – the module and its people would only be embarked in ships when required for operations and training.

If people intensive capabilities such as boarding operations are modularised, onboard automation might provide opportunities for reducing the numbers required to operate the platforms and allow multi-crewing concepts to be adopted.

“There is an understandable aversion within New Zealand Defence to being the first to adopt breakthrough technological concepts.”

However, in assessing the viability of a force structure based on modularity, there is a very large elephant in the room, which is that despite the wide recognition of the merits of modularity (the Royal Navy’s Maritime Modularity Concept signals it as the way ahead for force design), no-one else has adopted it as a cornerstone fleet design concept.  

There is an understandable aversion within New Zealand Defence to being the first to adopt breakthrough technological concepts. As the ‘technological approach’ future force design principle states, “The Defence Force will seek opportunities to adopt technologies earlier in their lifecycle once proven, and in line with what our partners are doing. Defence will not seek to be at the leading edge.”

However, like all such principles, this should be considered a guide as opposed to an inflexible rule. The advantages that could accrue to a small, resource strapped navy with a broad range of missions are such that modularity must be fully investigated and compared with alternative options, such as acquiring Tier 2 general purpose frigates in conjunction with Australia. The relative risks, benefits, and opportunities must be studied and quantified.

To go somewhat further, the Offshore Patrol Vessels need to be replaced in a similar time frame to the Anzac frigates. It might be possible to replace them with a modular platform and a range of modules for humanitarian assistance/disaster relief, mine countermeasures, and resource and border protection missions.

This would provide evidence of the workability or otherwise of modularity before resources are committed to more expensive combat mission modules, and could be achieved within a similar cost bracket as like for like replacement of the current ships with dedicated OPV. The worst possible outcome is that the navy would be equipped with two highly flexible ships to replace the current OPV.

The potential outcome is that Navy will have a tested modular platform and organisational concept that could be expanded to encompass the combat missions currently performed by frigates. Platforms would thus be standardised, greatly simplifying logistics and training systems, and the benefits of modularity would realisable across the entire fleet.

The Tier 2 general purpose frigates that Australia is acquiring will be highly capable ships well suited to New Zealand’s geostrategic circumstances. A joint acquisition would enhance interoperability with Australia and allow both countries to share logistical, engineering development, and training systems, to the particular benefit of New Zealand.

However, the potential benefits of a fleet based on modular mission capable platforms are such that they must be examined and compared to the Tier 2 approach (or any other involving non-modular platforms), noting that a viable Tier 2 force will require a minimum of three platforms. When force projection and sealift capability requirements are added to the need to consider combat and patrol requirements, the scale of the task facing NZ Defence can be seen. I’m confident that the people concerned will be guided by objective evidence framed by the future force design principles, and not by inviolable Golden Rules.