Mogami frigate – ‘fast and stealthy, like a ninja’

During a pre-Christmas visit to Japan, a small group of Australian journalists were given unprecedented access to one of two contenders for SEA 3000 – the Mogami FFM frigate, the upgraded version of which is being offered to the RAN.  The ship is impressive, with high levels of crew automation and a stealthy design that will make it difficult to detect and target.

The government of Japan has guaranteed delivery of the first ship to Australia in 2029 – one of the key requirements for the General Purpose Frigate (GPF) project.  Prime contractor Mitsubishi Heavy Industries (MHI) is in the process of delivering an initial batch of 12 Mogamis to the Japanese Maritime Self-Defense Force (JMSDF) – and we witnessed the launching ceremony of the 10^th in the series in Nagasaki on December 19.

A second batch of 12 upgraded Mogamis are expected to be under contract in the 2024 Japanese financial year, which ends on March 31, 2025.  Construction will begin almost immediately with the first ship delivered in 2027.  If Japan is chosen, Australia will receive the third ship of the new series – or the 15^th Mogami overall – which will be launched in mid-2028.

Throughout the visit a number of themes were stressed.  Perhaps the most important was that Japan sees Australia as a key strategic partner in the Indo-Pacific region, now at the same level of trust as the extremely close relationship it has with the US.  It is for this reason that Japan is prepared to sell a ship loaded with a variety of advanced technologies and stealth features to the RAN – a decision that would not have been approved for many other countries.

Another point was that the bid is a combined effort of the Japanese government and industry.  There is a perception that Japan missed out on the SEA 1000 Collins submarine replacement project in 2016 because while the government wanted the deal, the same prime contractor – MHI – was observed to be less motivated.

This has completely changed with MHI and the government now showing a united and enthusiastic front.  On December 13 Japan announced the formation of a joint industry-government committee to promote the Mogami bid, co-chaired by the Vice Minister for Defense Kazuo Masuda and MHI President Seiji Izumisawa.

A number of ministries are involved in addition to Defense, including Foreign Affairs, and Finance as well as the companies MHI, Mitsubishi Electric, Hitachi, NEC and Japan Marine United.  It is the first time that Japan has used this structure in support of a defence technology sale and is a sign of the importance being attached to the deal.

The upgraded Mogami class – that Japanese officials say is an evolution of the original design – have a number of important changes from the current ships.  These include:

• Change of full load displacement from 5,200 tonnes to about 6,200 tonnes
• Length increase from 133m to 142 metres
• Beam increase from 16.3m to 17m
• 32 Mk 41 VLS cells – up from 16 for the earlier Mogamis (some were launched without VLS cells, but all are in the process of being refitted)
• Radar mast enlarged and rotated to 45 degrees from the ship’s centreline
• An improved hull-mounted sonar suite

Other features of the upgrade are: improvements in crew habitability; SSM launcher area expansion (to fire the new Type 17 SSM, replacing the Type 12); increased generator capacity; AESA radar upgrade; and an increase in the size of the Combat Information Centre (CIC).  Collectively, these changes:

• Improve Anti-Air Warfare (AAW) and Anti-Submarine Warfare (ASW) capabilities;
• Increase survivability;
• Incorporate lessons learned from the first Mogami series.

All the mine warfare features of the first batch of Mogamis are being retained.  These involve the use of uncrewed surface and subsurface craft that can search for mines and neutralise them.  The ships can also lay mines.

The stealthy shaping of the ship has been influenced by MHIs experience in the design and manufacture of advanced combat aircraft.  While signature details are classified, the radar cross section of a sleek Mogami is probably two orders of magnitude less than a similar sized ship with a conventional layout.  They are designed to have a 40 year life-of-type made possible by a philosophy of designing for hardware and software upgrades.

Another important stealth feature is the lack of a funnel – which is also a physical vulnerability in a warship. Instead, exhaust gas comes out of several vents behind the radar mast and from outlets in the hull, dramatically reducing the ship’s IR signature by eliminating major hotspots.

For mine detection the Mogami class has a hull mounted sonar – and for ASW missions carries a TACTASS (TACtical Towed Array Sonar System) and a Variable Depth Sonar (VDS).  The winch and the sonar systems are mounted below deck at the stern of the ship and can be installed and removed via standard 20ft access hatches allowing for a containerised approach to the equipment.

These upgrades have been driven by the changing threat environment – particularly from China.  Also when the contract for the first 12 Mogamis was signed in 2018 the defence budget was very constrained – hence building the first 6 without a Mk 41 VLS – but those circumstances have changed.

In late 2022, Japan committed to a major increase in defence spending to about 2% of GDP by 2027, up from a historical average of around 1% of GDP.  This means that funding of the Mogami upgrade is not an issue – along with spending on a number of other defence capability improvements.

The need for the upgrades was explained by RADM Touri Sasaki – who is also responsible for a number of memorable quotes, including the “ninja” reference in the headline. He is the Deputy Director (Naval Systems) in the Acquisition, Technology and Logistics Agency (ATLA).  ATLA was created in 2015 to coordinate defence projects and also R&D – so something akin to a combination of CASG and DSTG.

Asked if Japan was responding to a growth in China’s military capability, RADM Sasaki explained:

“Yes, that’s exactly correct.  As the international security environment worsens, we need to adapt our own systems and strategies to change in response – and that includes our ships.”

The first morning of the visit was taken up with an extensive tour of the JMSDF Kumano, the second Mogami frigate, launched in November 2019.  The ship was built by Mitsui – now a subsidiary of MHI – in Tomano, with all remaining eleven in the initial batch of ships constructed in Nagasaki by MHI.

The contract for the next 12 upgraded FFMs will be split between three yards: MHI as prime contractor; Mitsui and Japan Marine United (JMU) Corporation.  The first Australian ship will be produced by JMU with the build location of RAN ships two and three yet to be decided. MHI believe this distributed build between yards in Japan is evidence of their ability to transition construction to Henderson in Western Australia for ship four and onward – though the company understands there are sizable industrial and workplace cultural differences between the two countries.

First impressions of Kumano are of a slim, stealthy, extremely advanced and well laid out warship.  The walkways are spacious, and most piping and cabling is behind covers making everything look clean, neat and new.  The integrated bridge provides the first evidence of automation and draws heavily on commercial shipbuilding experience, reducing the number of crew required from the usual eight down to four.

The heart of Kumano is the Combat Information Centre (CIC), which has an unusual but functional circular layout.  Or to be more exact, the main consoles face forward, and they are surrounded by a 360 degree large flat panel display more than a metre high that can show everything from a complete panoramic external view from the ship, navigational data, machinery control, damage control, communications data and ship status information.

A further 14 consoles face outward towards the display, forming a complete circle of operator stations which have multiple screens of their own.  Another two are inside the circle facing forwards, along with two large map tables and a steering and ship control position. No photography was permitted in the CIC.  All of the workstations are modern and multifunctional with each operator having at least 3 large screens displaying data.

A study of the CIC and bridge explains why Mogami frigates have achieved such small crew numbers – and it is not just due to high levels of automation but also alterations to how the ship is managed.  The two best examples are that Kumano has neither a separate radio room or a damage control centre, the former usually directly behind the bridge and the latter buried deep in the bowels of the ship in a spot least likely to be hit during combat.

For the Mogami class, damage control and communications are run from the CIC.  This has come about for two main reasons – the effectiveness of new generation Chinese anti-ship missiles, coupled with careful analysis of the sinking of the 12,000 tonne Russian cruiser the Moskva by one or two Ukrainian missiles on April 14, 2022.  Japanese analysists believe that the Moskva was a highly capable, well defended ship but noted that it sank within a few hours of being attacked.

At the same time, China has been fielding more powerful anti-ship missiles of their own.  Japanese officials declined to name exactly which missiles are the ones now giving planners a major headache, but the suggestion is that some of them have larger or more effective warheads – or both – than earlier generation weapons.

The conclusion is that if a modern well protected 12,000 tonne warship can succumb to a strike from a Neptune missile with a 150kg warhead, the chances of survival of a 4-5,000 tonne class ship such as a Mogami are minimal.  The PLA(N) equivalent of the Neptune (both are derived from Russian missiles) is the YJ-12, which is understood to have a larger warhead of up to 500kg.

The calculation is simple: there is no need for the Mogami class to have a separate damage control centre because if the ship receives a major hit to the CIC – including from future hypersonic missiles – there will be no point in trying to continue operating.  The most likely outcome of such a scenario is that the surviving crew will be heading for the life rafts.  This also explains why the ship is without an emergency CIC, with further savings in personnel numbers.

According to RADM Sasaki, the crew of 90 is the maximum needed to run the ship and in wartime the JMSDF will cut that number to 60.  This is because with a three watchkeeping system, at any one time 20 sailors at the controls are sufficient.  This does not include the team for the embarked MH-60K helicopter – functionally the same as the RAN’s MH-60R Sea Hawks – which is an additional 10 people made up of aircrew and maintainers.

Discussing the level of automation, RADM Sasaki said:

“The most important change that has been needed is the change of mindset. In the past, if a part had been broken it has been up to us to put a hand in and fix it. We need to change that – we need to understand that it’s now up to the machines to do that. Our change in mindset has been from not doing it ourselves but using the available tools to do it even better.”

A separate radio room has also been deemed unnecessary given that the Mogami has advanced to an integrated, automated communications mast containing a number of systems in a stealthy antenna.  The system is known as UNICORN for UNIfied COmplex Radio aNtenna and has the following features from top to bottom:

• Electronic Support-Radar antenna
• Electronic Support -Communications antenna
• Wi-fi Band antenna
• Link 16 antenna
• UHF Band T/R antennas
• IFF response antenna
• UHF Band VRF Band T/R antenna
• TACAN antenna

There are few details about the combat management system (CMS), though it is also produced by Mitsubishi.  Importantly for potential Australian operators, the use of the English language software is embedded in the CMS because the JMSDF uses both Link 16 and Link 11 to maximise interoperability with the USN.  All displays and symbology are to USN standards.

The CIC is likely to need some modifications to be suitable for RAN service.  Some of the JMSDF networks are in Japanese – these have been designed by NTT – and that means some software and a few hardware changes will be needed.  The ships will also need connectivity to ADF networks.  Other companies involved in the CMS are Mitsubishi Electric, Fujitsu and NTT.  All are understood to have visited Australia to find local partners.

Japan has taken a pragmatic approach to the Australian bid, delivering exactly what they have been required to produce.  Asked if they had offered the Saab 9LV CMS currently used by the RAN on all their surface ships the answer was no because – inexplicably – Australia did not request that option.  The implication is that 9LV could be fitted – perhaps being incorporated when construction shifts to Australia – but this will only happen if the customer asks for it.

The small crew numbers raise the issue of how trainees can be taught when there are so few spare bodies on board to do the mentoring.  RADM Sasaki explained that the JMSDF gave the issue a great deal of thought:

“We designed the ship with the fewer numbers in mind and knew this would be an issue, but what we’ve done is arrange for most of the education and training to be done prior to the crew boarding the ship. There are packages of education delivered in the classroom, and a lot of simulation is involved, so we’ve designed the entire training system to cope with the fact that the ship is different.”

The level of crew comfort looks to be good. One member of our party who is 1.94m tall (6’4”) tested the junior officer bunks and could comfortably fit in them – exploding the usual trope that large Australian sailors would be unable to fit in beds designed for Japanese people.  All on board dine in the same mess. The captain has a small conference room, a washing machine and a compact bath, in addition to a bed and small office.  On average, 10% of the crew are female and they have separate accommodation and facilities.

The above-water sensors are a four panel OPY-2 AESA radar suite and also fixed and gimbled EO/IR cameras.  The latter are designated OAX-3 and are in two configurations: several sensors fixed to the radar mast below UNICORN to provide a constant 360 degree picture for harbour surveillance; navigation support – especially at night and during poor visibility – and air and surface target detection. There is a separate rotating OAX-3 above the bridge. The ship also has a small navigation radar.

The gallium-nitride OPY-2 is a multifunction radar that is an improved version of the OPY-1 phased array that currently equips JMSDF 6,800 tonne Asahi class destroyers. In turn, this radar was based on an earlier FCS-3 system that had two separate antennas: one in C-Band for surveillance and tracking, and another in X-Band for fire control.  The OPY-2 not only detects air and surface targets but also has a periscope detection function.

For armament, in addition to the Mk 41 VLS cells and SSM canisters the ships have a 5” main gun identical to that used by the RAN and USN; a Raytheon SeaRAM launcher that fires Rolling Airframe Missiles (RAM) and two remotely controlled 12.7mm machine guns.  The ship carries Japanese-designed Type 97 (G-RX4) lightweight ASW torpedoes (not to be confused with Type 97 World War 2 torpedoes) launched from HOS-303 tubes. The SH-60K helicopter also carries the Type 97 and can drop depth charges.

Propulsion is a CODAG system made up of a single Rolls Royce MT30 gas turbine engine made under license by Kawasaki and two 12-cylinder supercharged MAN V28/33D diesels.  This gives the ship a top speed in excess of 30 knots (56 kmh).  The MT30 is also the gas turbine that will equip the future Hunter class frigates.  The average length of a Mogami deployment is 150 days at sea; longer missions sometimes occur.

The final event of the tour was attending the launch and naming ceremony for the 10^th FFM, the Nagara, at MHI’s massive yard in the city of Nagasaki, and it was the first time foreign journalists had been allowed on site. History buffs might be interested to learn that this yard, which was established in 1857, built the super-battleship Musashi – sister of the mighty Yamato, the largest battleship ever built – and it was the aiming point for the second atomic bomb, which drifted slightly off target and destroyed much of the city on August 9, 1945.

The launch was a happy, loud and colourful occasion with the JMSDF Sasebo Band very professionally belting out a series of upbeat tunes.  In attendance were various political and military dignitaries – including two RAN representatives – shipyard workers and a sizable contingent of Japanese media.  Accompanied by exploding fireworks, streamers and cheering, a banner was pulled aside revealing the name Nagara painted on the side of the hull.

As with other FFMs, it takes only 12 months to go from keel laying to launch – a world-competitive speed. During a subsequent shipyard tour it was explained to us that the secret sauce is to QR code all pipes – of which there are a multitude in any modern warship – palletise them accurately and use a highly trained, experienced workforce to put it all together. Nagara will spend another year at Nagasaki for final outfitting and sea trials before commissioning.

In the last 30 years, MHI has never been late in delivering a warship – and hence the extreme confidence on the part of all Japanese officials that the first Australian ship will be ready in 2029.  This of course depends on the RAN resisting the urge to constantly change everything about the ship, which at the moment is limited to alterations to make the design fully compliant with all Australian maritime rules and regulations.

The next article will examine further details of the Mogami design as well as look at the growing Australia-Japan strategic relationship.

(Disclaimer: the author travelled to Japan as a guest of MHI and the Japanese Ministry of Defense.  It is impossible to thank everyone for their assistance, but special mention must be made of RADM Touri Otani Sasaki – father of the Mogami class – who must have had far more important things to do than graciously assist a group of Australian journalists gain a better understanding of the ships and the finer points of Japanese culture.)

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