Japan’s Ultra-modern Mogami-Class Frigates Are Headaches For PLA Navy’s Submarine

Amidst a flurry of colorful balloons, Mitsubishi Heavy Industries launched the Mogami from its shipyard in Nagasaki—the lead ship of a new class of versatile 30FFM-type multi-role frigates.  Due to delays caused by a construction accident, the lead vessel launched four months after the second ship laid down in the class, the Kumano, built in Okayama by Mitsui E&S.

The two frigates, both named after rivers, measure 132 meters long and are scheduled to be commissioned into service March 2022. They integrate a wide variety of sophisticated technologies including a high-tech command center, a stealthy hull and mast designed to reduce visibility on radar, mine-hunting aquatic drones and powerful long-range anti-ship missiles

The Japanese Maritime Self Defense Force (JMSDF) eventually plans to procure a total of 22 of the stealth escort frigates (also designated “destroyer escorts”) built at a pace of two per year, at an estimated cost of 50 billion yen ($467 million) each. These will eventually replace eight Asagiri-class destroyers of similar weight and six smaller Abukuma-class escorts.

While the new frigates aren’t quite feature complete (more on that below), they compare well with the U.S. Navy’s infamously troubled littoral combat ships (LCS).

The FFM’s priority design features—speed, small crew size, support for unmanned vehicles, and anti-submarine and counter-mine capability—are also characteristics that guided development of LCSs. In fact, MHI’s earlier, more radical design concepts for the 30FFM resembled the Freedom-class LCS in several respects.

To be fair, these ships weren’t designed to fulfill the same operational requirements, and the LCS can attain uniquely high speeds (47 knots) and carry heavier close-defense weaponry compared to the 30FFM. But the more conservative design MHI settled on is only moderately larger—displacing 3,900 tons standard load, compared to 3,400 for a Freedom-class LCS—slightly less expensive, and all-and-all more versatile and heavily armed.

Stealthy Hull, Star Trek Command Center and Submarine Drones

A high degree of automation allows the 30FFM frigates to function with only 90 crew, compared to 220 on an Asagiri-class destroyer—which is important as Japan’s Self Defense Force must cope with a shortage of personnel. The JMSDF plans to rotate four crews between every three frigates.

Externally, the ‘clean’, flush surfaces of the 30FFM are designed to minimize radar reflectivity, as is the integrated mast combining the vessel’s radar with its electronic warfare system. MHI also claims it has applied technologies it developed for its X-2 Shinshin stealth jet demonstrator into the frigate, possibly referring to incorporation of radar-absorbent materials (RAM).

The frigate’s reduced radar cross-section doesn’t render it undetectable, but does make it seem like a smaller vessel on radar and reduces the range at which it can be tracked.

Ordinarily, the frigate cruises on two fuel-efficient MAN diesel engines, but a supplementary Rolls Royce MT-30 gas turbine can accelerate the boats to a maximum speed “above 30 knots.” A gearbox developed by Kawasaki facilitates the change in reduction gears necessary when surging power input.

The 30FFM’s Combat Information Center has received special attention for its unique circular arrangement evoking the “open office” bridge of a Star Fleet vessel. In addition to 18 multi-function displays and two tactical tables, an overhead screen displays a 360-degree “augmented reality” view around the ship fusing the vessel’s various sensors.

The frigate relies on an X-Band OPY-2 multi-function radar to detect both aircraft and ships, backed up by an OAX-3 electro-optical/infrared sensor system and a NOLQ-3E electronic warfare system combining a self-defense jammer and electromagnetic sensor. The ship’s command system is designed to transmit and receive sensor data and video feeds to ground-based command centers and maritime patrol aircraft.

For surface warfare, the frigates mount four twin-launchers armed with powerful Type 17 anti-ship missiles weighing three-quarters of a ton each. The subsonic sea-skimming weapons can strike targets up to 248 miles away, initially using GPS and inertial navigation guidance before switching to an AESA radar-seeker for terminal guidance.

For close-range encounters (more likely in peacetime confrontations) the ship also mounts a 127-millimeter Mark 45 naval gun and two remote-controlled .50-caliber machineguns. The ship’s radar can direct these to engage both air and sea targets.

For undersea warfare, the 30FFM disposes of three sonars: an OQQ-25 system combining a variable-depth sonar with a towed sonar array for submarine hunting; and a OQQ-11 sonar specialized in detecting mines. The frigate can engage submerged subs with 324-millimeter torpedoes fired from one of its three twin-launchers as well as the SH-60K and L Seahawk anti-submarine helicopters on its flight deck.

Against mines, the frigate can deploy a duo aquatic drones from a docking stations at the ship’s stern. An OZZ-5 submarine drone (or UUV) uses a combination of low- and high-frequency sonars to detect and identify mines; and a separate unmanned surface vehicle (USV) deploys countermeasures to disable the mine.

Currently, the 30FFM’s main weakness is limited air-defense capability, with only a single RIM-116 SeaRAM missile launcher overlooking the rear deck in addition to the guns providing short-range (6 miles) protection from incoming missiles and aircraft.

The 30FFMs are actually built to accommodate 16 missile vertical-launch cells that could carry longer-range surface-to-air missiles, but the two lead ships have been delivered without the launchers installed. That means they can’t really protect nearby ships from air attacks, nor help thin out an incoming attack at a distance.

Eventually, Tokyo is supposed to install Mark 41 launchers in the frigates, though that will presumably raise the effective unit price of the ship. These may be loaded with either U.S.-built RIM-162 Evolved Sea Sparrow Missiles (up to 4 can fit in each Mark 41 cell) or Japanese Type 03 Chu medium-range surface-to-air missiles, and Type 07 anti-submarine missiles; all of which possess ranges exceeding 30 miles.

That would give the 30FFMs local air-defense capability, though even then they may rely on larger vessels equipped with Aegis Combat Systems to provide better radar coverage.

Japan’s Frigate Strategy

Broadly, the 30FFM frigates are intended to allow the JMSDF to field more ships with the same number of personnel to counter the Chinese’s People’s Liberation Army Navy’s increasing presence and capability in the northwestern Pacific.

Elements of the 30FFM’s design like its stealthy hull, drone support equipment and unique bridge, are likely to make their way into future, larger Japanese warships—at least once their viability has been tested operationally in the less costly frigate.

Tokyo is also reportedly working on an export deal with Jakarta to sell eight 30FFM frigates (four built in Japan, four in Indonesia) and transfer relevant technology for $2.9 billion. If the deal goes through it will mark a breakthrough for Japan’s so far very limited defense export market. It would also further Tokyo’s policy of enhancing the naval capabilities of other Asian navies which oppose China’s sweeping claims to waters across the eastern Pacific.

Meanwhile the U.S. Navy has seemingly given up its interest in similarly-sized littoral combat ships, which continue to be plagued by technical problems severely curbing their usability. For example, despite having begun development nearly two decades ago, the mine-countermeasure and anti-submarine packages have yet to complete testing.

 The U.S. Navy is now developing a Constellation-class frigate that’s bigger and more heavily armed than the 30FFM at more than twice the price at an estimated $1.1 billion per ship.

But Japan’s new escort frigates suggest that with a more judicious approach to technological innovation and greater financial discipline, the U.S. Navy could have churned out flexible and hard hitting vessels roughly the size of a littoral combat ship.

Such a vessel might not have included as many exquisite bells and whistles, such as the LCS’s speedy waterjet propulsion system. And of course it would still not be as well protected as an Aegis-equipped missile destroyer. But they might have come out the gate in a useable form—and packing more bang for the taxpayer’s buck

© 2021, GDC. © GDC and www.globaldefensecorp.com. Unauthorized use and/or duplication of this material without express and written permission from this site’s author and/or owner is strictly prohibited. Excerpts and links may be used, provided that full and clear credit is given to www.globaldefensecorp.com with appropriate and specific direction to the original content.

Be the first to comment

Leave a Reply

This site uses Akismet to reduce spam. Learn how your comment data is processed.