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IN DETAIL: The RAN surface fleet in 2023 and beyond

A Nova Systems engineer studies a virtual model of a warship. Will the ‘short and sharp’ review of the RAN’s surface combatant fleet recommend replacing the Hunter-class frigate (top) with a smaller vessel carrying more missiles? Don’t be too sure. Images: Nova Systems and BAE Systems Australia – Maritime

Would the Royal Australian Navy be better off with a bigger fleet of smaller, missile-armed warships?

Interesting question. We’ll know the Navy’s own answer to that question in September when the result of a ‘short and sharp’ review of the RAN’s surface combatant fleet is completed. But the people calling for a radical re-structuring of the RAN’s surface fleet need to understand what they’re asking for, and what they might forego if their wishes are granted.

Its critics say the Navy’s nine planned Hunter-class frigates will be under-armed in this new era of hypersonic missiles. They also say the RAN should have more ships in the water and many more missiles for both air/missile defence and anti-ship work. And they say the Hunter-class is cripplingly expensive. Are they right, though?

The published cost of the Hunter-class frigate program is $45 billion – for nine ships. How does Defence arrive at a figure of $5 billion per ship? Why doesn’t it use a figure that people can understand, and explain properly how it arrived at that figure?

Let Defence’s strange approach to communication with its public go through to the ‘keeper. Let’s talk instead about the ships’ armament: it is under-equipped with long-range anti-aircraft missiles compared with the RAN’s three Hobart-class destroyers, which are real Anti-Air Warfare (AAW) vessels. But it is definitely not under-armed when you compare it with the now-ageing ANZAC-class frigates: the Hunter-class can carry nearly three times as many missiles as the ANZACs.

Table 1: Missile armament of RAN surface combatants (estimated)

Class Mk41 VLS launch cell Short-range AAW missiles Long-range AAW missiles Anti-Ship missiles Total Missile Armament

(8 ships)

8 32 x ESSM 8 x Harpoon/ NSM 40

(320 across the fleet)

Hunter FFG

(9 ships planned)

32 96 x ESSM 8 x SM2

(to be replaced with SM6?)

8 x NSM 112

(1,008 across the fleet)

Hobart DDG

(3 ships)

48 96 x ESSM 24 x SM2

(to be replaced with SM6?)

8 x Harpoon/ NSM 128

(384 across the fleet)

Table 1 shows how many missiles each of these classes carry – bear in mind that the Evolved Sea Sparrow Missile (ESSM) is quad-packed, so each Vertical Launch System (VLS) cell carries four weapons, each with a range of least 50km.  It’s not clear what the breakdown between ESSM and SM2 is on the Hobart-class destroyers and Hunter-class frigates, so I’ve assumed that both of these vessels will carry 96 quad-packed ESSMs in order to protect them, and ships in company, from missile attack. This leaves 24 long-range SM2 missiles (with a range of 185-370km, depending on the type) for the Hobart-class and just eight for the Hunter-class. And the Aegis and CEAFAR2 radars can detect targets  at that range.

By comparison, the Type 26 Anti-Submarine Warfare (ASW) frigate, from which the Hunter-class is derived, has 48 SYLVER cells containing Sea Ceptor missiles (roughly the equivalent of an ESSM) and 24 Mk41 VLS cells designed for other weapons such as anti-ship missiles. But each cell currently contains a single missile, so depending on weapons load the Hunter-class could be significantly better armed than a Type 26.

All three RAN classes carry a battery of eight anti-ship missiles; ANZAC and Hobart are armed with Boeing’s ageing Harpoon, but these will be replaced by Kongsberg Naval Strike Missiles (NSM) which will also arm the Hunter-class. All of the RAN’s surface warships now operate the Sikorsky MH-60R Seahawk ASW helicopter and Mk54 lightweight torpedo to enable detection, localisation and prosecution of contacts at stand-off range.

There remains an uncertainty: how many Tomahawk Land Attack Missiles (TLAM) will equip each ship, and how would they be launched? If from a Mk41 VLS aboard a surface combatant, then we’ll need to sacrifice an SM2 or SM6 or four ESSM to do so – or else we try and fit additional VLS systems.

However, the Hunter-class is very much an ASW design and was selected as such for reasons we explore below. The ship lacks the Anti-Air Warfare (AAW) armament of the Hobart-class destroyers, although it’ll have an AAW sensor suite and combat management system that’s as least as good. Both classes are equipped with the Lockheed Martin Aegis combat system, which has other advantages (see below). Saab Australia was selected to develop the Australian interface to Aegis, based on the 9LV Mk3E combat management system it already builds for the ANZACs – Navy’s intent is to create a common combat system that’s interoperable across the entire fleet. And both the ANZAC currently and the Hunter, in future, will be equipped with the CEAFAR2 L-band Active Phased Array Radar.

So, the Hobarts, ANZACs and Hunter-class ships will have a significant AAW sensor capability. The Hobarts and Hunter-class will be able to build and share with each other a detailed picture of air, surface and submarine movements in their area and defend themselves and ships in company against persistent air and missile attack.

It’s worth taking a moment to think about air and missile attack. Only the Chinese and Russians have the capability at present to threaten our ships with hypersonic missiles. They’d probably be launched from well outside the engagement range of even the SM2 and SM6, hence the AAW sensor suite on the Hunter-class: it can detect both launch aircraft and incoming, high-speed missiles. Every other threat nation would launch manned aircraft and/or high-speed missiles at us from a closer range; many of these attacks could very well result in relatively short-range anti-missile engagements.

The current ESSM/CEAFAR2 combination is about as good as it gets in these circumstances; and if the RAN replaces some or all of its ESSMs with SM6s, which have a reported range of about 240km, CEAFAR2 can detect targets and provide track data at and beyond that range.

But the Hunter-class is designed for a very different threat which will only become more significant with each passing year: submarines. The Indo-Asia-Pacific region will in a few years be home to more than half of the world’s population of nuclear-powered and diesel-electric submarines: Pakistan, India, Bangladesh, Myanmar, Malaysia, Singapore, Thailand, Indonesia, Vietnam, The Philippines, China, Taiwan, Russia, North Korea, South Korea and Japan all have submarines or plan to obtain them. The final figure for Australia’s region could exceed 220 boats by the mid-2030s, not including those of Australia and the United States. And about 130 of these would be North Korean and Chinese, a mix of (mainly) diesel-electric and nuclear-powered boats.

Given the reasons why so many coastal nations say they need submarines – and the mind-bending difficulty of actually detecting them, still less tracking and engaging them – it’s easy to understand why submarines are considered to be a significant threat to both naval and merchant shipping. The resources required to counter a submarine threat can easily stretch a maritime force. In Australia’s case, as an island continent with the country utterly dependent on its Sea Lines of Communication (SLOC), maintaining those SLOCs and deterring or defeating any submarine threat is absolutely essential.

If the submarine threat is significant enough to justify expenditure on a dedicated ASW ship (and I’m assured it is), then selecting a derivative of the Type 26 may have been the logical thing for the RAN to do, purely from the point of view of its operational capabilities. But only the RAN can say, based on its own threat analysis and the ASW performance figures provided by the three bidders.

The selection process was complicated by the need also to establish a sovereign, sustainable – and cost-competitive – continuous naval shipbuilding program in Australia based on the selected design. This was (and still is) both government and Defence policy. So, in seeking value for money the RAN was forced to choose a warship based on two separate criteria, one operational and one based on long-term industry development.

The Hunter-class frigates are designed to be submarine hunters and the two most important things about ASW ships is their sonar suite and their own relative quietness. The Hunter-class and Type 26 are derived from the British Type 23 ASW frigate, arguably the quietest frigate ever built and one of the most effective against submarines. The Royal Navy has long been considered one of the best, if not the best, surface ASW forces in the world. The Hunter is designed to be at least as quiet as the Type 23 and equipped with the same sonars as the Type 26. This is Thales’s CAPTAS (Combined Active-Passive Towed Array Sonar) Type 2087, which has a large, variable-depth towed body and a separate towed array; and, under the bows, the Ultra S2150 hull-mounted sonar.

The relative quietness of the Hunter-class matters to a Navy that is projecting threat development over the next 30 years and beyond.

The Hunter-class’s two rivals were Navantia’s F5000 and Fincantieri’s Modified FREMM. The F5000 is derived from an F100 design that is nearly 35 years old and uses the same Ultra Electronics hull-mounted and towed sonar arrays as Australia’s existing Hobart-class AAW destroyers. The Modified FREMM class would have required modification to carry the Aegis combat system, CEAFAR2 radar, 9LV Mk3E interface and Mk41 VLS. The US Navy selected the Modified FREMM to meet its own FFG(X) general purpose frigate requirement and has replaced the Italian AAW and ASW equipment with its own, except for the CAPTAS sonar; as a result the ship is nearly 600 tonnes heavier, 7m longer and about 20cm broader in the beam.

The Hunter-class ships are heavier than the British Type 26s, but that’s because they are fitted with a world-class (arguably world-best) AAW suite that is much heavier than the less-capable system the British installed on their specialist ASW ships. The RAN has widened the ship by 60cm in order to maintain its stability and seaworthiness margins, but not lengthened it.

One feature of the Aegis combat system which has escaped the notice of many is its Cooperative Engagement Capability (CEC). In simple terms, this enables a warship to detect and track a target – an aircraft, an incoming anti-ship missile, or even a strategic ballistic missile – and then guide a missile launched from a similarly equipped warship (possibly a considerable distance away) to intercept it. This makes jamming an order of magnitude more difficult for an aggressor. It also makes it possible to plan the air and missile defence of a battlegroup on a collective basis, rather than as a collection of individual ships each with their own capability. And it strengthens significantly a country’s Ballistic Missile Defence (BMD) capability.

The United States developed CEC, though France, Israel and India have produced similar systems. The US Navy has shared it with only three other countries: the United Kingdom, Japan and Australia. The CEC doesn’t just make the RAN interoperable with the US Navy and Royal Navy – fitting Aegis to all of its surface combatants would make the RAN fully interoperable with itself.

If we cancel all but three of the Hunter-class ships and instead select a fleet of warships, presumably Military Off The Shelf (MOTS) designs, that are smaller and crammed with offensive and defensive missiles such as the Harpoon, NSM and ESSM, we might be risking a number of things:

  • Do we forego the ability to surveil a huge amount of airspace by putting a world-class AAW suite to sea?
  • Do we lose the vital CEC that comes exclusively with Aegis?
  • Do we leave ourselves vulnerable to hostile submarines by foregoing a world-class ASW capability?
  • If we have lots of smaller ships, where do we find crews for them all?

And are smaller ships also able to carry and deploy fleets of Autonomous Undersea and Surface Vessels (AUV and ASV), and repair and reconfigure them on the high seas?

The point of all this is that the findings of the ‘short and sharp’ maritime review currently being undertaken to support the Defence Strategic Review shouldn’t be considered a foregone conclusion. There are very good reasons why the RAN selected the Hunter-class frigate and there are good reasons why the program should continue, albeit perhaps with a different mix of vessels to strengthen the RAN’s AAW capabilities – perhaps some more Hobart-class ships?

Bear in mind that to maintain commonality across the fleet and maintain the benefits of a fleet-wide CEC fit, whichever alternative ship might be acquired (if any) would still need to be equipped with the Aegis at the very least, and ideally with the CEAFAR2 L-band radar and 9LV Mk3E-based Australian interface/combat management system, which would carry its own risks and costs if anything other than a Hobart-class ship were selected. Without the CEC and AAW sensor commonality there may be no sense in pursuing this course of action.

One thing is certain: the RAN needs more of everything it’s got, and plans to get. But changing things may not be as easy, or as cheap, as some people first thought and may not deliver a better outcome.

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