Singapore Army's HIMARS Featured In Lockheed Martin's Precision Strike Missile Animation

 

Singapore Army HIMARS 21641MID in LMC PrSM animation.

The actual Singapore HIMARS with registration number 21641MID.
Photo : HR586 Emergency Collection via FB

I am not sure how many people noticed this, but Lockheed Martin's concept video for its Precision Strike Missile ( PrSM ) actually featured a Singapore Army HIMARS launching two missiles at what seemed like a S-400 surface-to-air missile battery and a forward arming and refueling point. The dead giveaway is the M1140 truck's vehicle registration number 21641MID which is unique to military vehicles of the Singapore Armed Forces ( SAF ). It is truly befuddling why a US Army deep strike weapon system which is still under development should feature a launch vehicle belonging to a foreign nation. Did Singapore co-sponsor the PrSM program or did it request to buy the PrSM? It seems very unlikely but who knows? You can watch the video below or on Youtube here. Update 2 Jun 2022 : It seems that this video is no longer available on Youtube.

Precision Strike Missile

The PrSM has its origins in the US Army's Long Range Precision Fires Program. It is a next-generation, extended range, all-weather, surface-to-surface missile that will give the ground commander an enhanced capability to attack, neutralise, suppress and destroy critical and time-sensitive point and area targets. 

It is compatible with the M270 Multiple Launch Rocket System ( MRLS ) and the M142 High Mobility Artillery Rocket System ( HIMARS ) family of launchers, complementing existing GPS guided rocket munitions and will ultimately replace the increasing obsolete MGM-140 ATACMS. 

It uses inertial navigation system with GPS for guidance and features insensitive munition propulsion system and payload. It adopts an open systems architecture and modular design for future growth. 

With an official range of 60 to 500+km, the PrSM almost doubles the 300km maximum range of the ATACMS. It is physically narrower and can be packed two to a pod, doubling the ATACMS loadout. Lockheed Martin has since 10th Dec 2019 successfully flight tested the PrSM a total of four times consecutively, with the most recent test on 12th May 2021 at the White Sands Missile Range, New Mexico, demonstrating a 400km range. It is expected to enter service in 2023 and achieve IOC in Q4FY2025.

PrSM Inaugural flight test 10th Dec 2019. 
Photo : LMC

Image : US Army Acquisition Support Center

PrSM Artist's Impression. Image : LMC

Implausible Scenarios

This promotional video is best taken with a huge pinch of salt since it is really just advertisement for Lockheed Martin Corporation ( LMC ) which is the prime contractor for PrSM. It also features another of its product the F-35 Lightning II. 

A pair of F-35 on a deep strike mission discovers a hostile surface-to-air missile ( SAM ) site and a forward arming and refueling point ( FARP ) and designates them as targets. Their coordinates are communicated to the Combat Air Operations Center ( CAOC ). In the true spirit of joint operations, instead of calling for more Air Force assets to attack these targets or diverting the F-35s to deal with them, CAOC sends the fire mission data to a field artillery brigade that is within range using AFATDS ( Advanced Field Artillery Tactical Data System ), the fire support command and control system used by both the US Army and Marine Corps.

As a result a single HIMARS bearing a Singapore vehicle registration number is dispatched and proceeds to launch two PrSM at the designated enemy targets, destroying both in no time with their accurate flight trajectory and their high performance pre-formed fragmentation warheads. 

The main target of the PrSM is a SAM site more than 500km away with what looks like the LEMZ 96L6E Cheese Board multimode acquisition radar for the S-400 Triumf ( NATO reporting name SA-21 Growler ) system, one of the most advanced long range air-defense system developed by Russia. It will be impossible for such valuable assets not to be guarded by a layered air-defense system which will include a tonne of short-range point defense like the Pantsir-S1. Indeed the video shows three domes representing the airspace protected by the hostile short, medium and long-range missiles of the SAM site. It will be totally unrealistic for a single precision strike missile to be able to penetrate a well defended SAM site without being first discovered and subsequently shot down. More likely salvos from multiple HIMARS will have to be launched against such protected sites to have even a remote chance of achieving a kill.

SAM Site 96L6E acquisition radar look-alike.

LEMZ 96L6E Cheese Board acquisition radar.
Photo : Globalsecurity.org

PrSM moments before detonation over what looks like
the 92N6E Grave Stone engagement radar.

PrSM warhead detonation with pre-formed fragments.

The same argument goes for the second target, a FARP which is usually located at or near the forward edge of the battle area to re-arm and refuel helicopters. Would the enemy be so silly to leave it unguarded?

And why would LMC feature a Singapore Army HIMARS in the animation? The SAF does have the HIMARS in its inventory and has recently placed an order for four F-35B stealth fighters but these are for deterrence and defensive purposes only. Singapore is a tiny nation in South-east Asia and cannot afford any armed conflict with its neighbors or any country. It will be very far fetched to imagine the Singapore Army aiding the US in attacking a foreign nation be it China, Russia or Turkey, all of which possess the S-400 SAM system. 

MID Vehicle Registration Number

 

   

All vehicles operated by the SAF are assigned a unique registration number comprising of usually a five digit number followed by a MID suffix, for example 33828MID. MID stands for Ministry of Interior and Defense and is truely a legacy of the past.

Immediately after Singapore gained independence in 1965, the Ministry of Interior and Defense was established and it was responsible for both the internal and external security of the young nation, controlling the Police Force as well as the SAF. It was only in 1970 that the Ministry of Interior and Defense was split into the Ministry of Defense ( MINDEF ) and the Ministry of Home Affairs ( MHA ). 

The MID vehicle number system dates from that era and is still in use for military vehicles today even though the Ministry of Interior and Defense is long gone. So armoured vehicles like tanks and infantry fighting vehicles, utility vehicles like trucks and jeeps, even motorcycles all bear this five digit MID vehicle registration number. The exception will be the limousines for receiving visiting dignitaries and staff cars assigned to high ranking commanders ( battalion commanders and above / commanding officers of ships ). These will have single, double or triple digit numbers followed by the MID suffix, for example 1 MID.

A truck and safety vehicle with typical SAF registration numbers.
Photo : Singapore Army via FB

Another SAF HIMARS on maneuver.
Photo : Singapore Army via FB

  

Just An Animation

The PrSM concept video is just an animation to showcase the potential of LMC's latest surface-to-surface missile. It may not necessarily stick to real world scenarios though it should have, in order to make it as realistic and convincing as it possible to woo prospective buyers. I must however add that the US government is probably the only prospective customer for now.

The inclusion of a foreign HIMARS in the video could be a simple mistake of the animators who might have just taken a photo of the launch vehicle from the internet without knowing that it does not belong to the US Army and copied it wholesale. The SAF's HIMARS are regularly deployed in the biennial Forging Sabre series of exercise with the US military in various locations including Arizona and Utah. So it may not be inconceivable that some could have been mistaken for those belonging to the US Army. You can see some of SAF's HIMARS in action ( 3:42 - 4:56 ) in the video below or here.

On a separate note, the PrSM is a missile system with a huge potential for growth. Unhindered by the 500km range limitation imposed by the now defunct Intermediate-Range Nuclear Forces Treaty, the US is free to develop, test and field a new generation of surface-to-surface missile as it desires. Already, there is talk about giving the PrSM what the US Army terms mid-range capability, defined as 1600km ( 1000 miles ) or more. So we can reasonably expect extended-range PrSM in the near future, just like the ER GMLRS.

The PrSM is currently able to strike only stationary or fixed targets but eventually new multi-mode seekers that can home in on the enemy's communications and radar emissions and perhaps infra-red signatures will be integrated to allow for striking moving targets such as ships at sea or maneuvering land units. The US Army had already began testing this advanced seeker since June 2020. When available this will make the PrSM a very powerful anti-access / area denial weapon for littoral and maritime environments especially in its extended-range iteration. 

Maybe in the foreseeable future, the PrSM might really find its way into the rocket pods of Singapore's HIMARS. Until then, the M30 / M31 GMLRS rockets will have to suffice.

From Singapore 70km GMLRS range covers most of southern Johor.

500km PrSM range covers most of West Malaysia and Sumatra

1600km ER PrSM covers half of South China Sea including the Spratly Islands

Jack-Of-All-Trades : Japan's Mogami-Class Multi-Mission Frigate

JS Kumano ( FFM-2 ) launched 19th Nov 2020.
 Photo : JMSDF

The Japan Maritime Self Defense Force ( JMSDF ) had launched a new class of warship known as the Multi-Mission Frigate ( FFM ) on 19th Nov 2020. Due to some technical mishap during the construction of the lead ship, it was the second-in-class JS Kumano ( くまの ) that was launched first. After a three month delay, the lead ship had finally been launched on 3rd Mar 2021 and was named the JS Mogami ( もがみ ).

These frigates are meant to be compact, stealthy, highly automated to reduce crew requirements and are meant to be scalable for the possibility of export. Their design is a departure from the large destroyers that the JMSDF used to favour and reflects the changing regional security threats and demographic challenges that Japan is facing. A total of 22 frigates have been planned. 

Destroyer Exclusivity No More

The Japanese archipelago is made up of 6852 islands and stretches for more than 3000km from the Sea of Okhotsk to the Philippine Sea. It has a coastline that is 29751km long and an exclusive economic zone of 4470000km2. Due to the vastness of the maritime territory it has to cover, the JMSDF has always required ships with very long range and high endurance. Destroyers have therefore formed the backbone of the JMSDF surface fleet for many decades. Its major combatants are always classified as a destroyer of sorts, helicopter-carrying destroyer ( DDH ), guided missile destroyer ( DDG ), general purpose destroyer ( DD ) and destroyer escort ( DE ). In fact, the JMSDF never had a frigate in its fleet apart from the 18 Kusu-class patrol frigates ( ex-US WWII Tacoma-class ) which it briefly commissioned between 1953 and 1972.

So it might seem like a surprise when after a lapse of almost five decades the JMSDF announced that its next generation warship would be a frigate. However, given the current maritime security situation with the militarization of the South China Sea, a nuclear-armed North Korea and multiple territorial disputes with neighbours including China, Taiwan, South Korea and Russia, it is clear that the JMSDF needs to build up its fleet to meet these challenges, and to do so rapidly and in an affordable manner. By virtue of its smaller size and less sophisticated weapon and sensor systems, a frigate is a lot cheaper to procure and maintain than a destroyer. Frigates also have a smaller complement, an important factor to consider given Japan's declining population and a younger generation unwilling to join the ranks of the JMSDF. 

30FFM

The concept of a high speed multi-mission frigate that is capable of anti-submarine and mine warfare for the JMSDF was first raised in 2005 when the Maritime Staff Office engaged the Japan Association of Defense Industry on a feasibility study based on a vessel similar to the Littoral Combat Ship ( LCS ) of the US Navy. Then the emphasis was on speed and cost. However, the Japanese would soon discover that the cost of building such a ship was prohibitive, even when the specifications were brought down, and the idea was shelved.

It wasn't until late 2013 that saw the frigate being mentioned again, this time in the Defense Guidelines and the H26 Mid Term Defence Plans where the Ministry of Defense wanted to increase the number of escort ships from 47 to 54. The following year, the Japanese government under then Prime minister Abe Shinzo would also end the total ban on arms export and the frigate seemed viable again, perhaps with the help from a potential export market and lowered costs due to maturing technologies. By 2015, Mitsubishi Heavy Industries ( MHI ) had unveiled its proposal, the 30FF, which it had developed using its own funds.

MHI's 30FFM Conceptual Image, annotated

The frigate was originally referred to as the 30FFM as it was promulgated in the defense budget of 2018, the 30th year of the Heisei era. FF is the hull classification for frigate and the M indicates its multi-mission capability but could also refer to the mine laying and mine hunting capabilities of this unique warship. Mine warfare is a highly specialised part of naval warfare and it is usually undertaken by specialised vessels like mine layers, mine sweepers and mine hunters. The conventional duty of a general purpose frigate is to escort other high value vessels like fleet replenishment ships and amphibious landing platforms and to conduct anti-submarine and anti-surface warfare but rarely ever to mine hunt or lay mines. In the FFM the JMSDF intends to create a work horse that is capable of a little of everything, including dealing with mines.

The 30FFM frigates are also frequently referred to as the 3900ton-class escort vessel ( 3900トン型護衛艦 ) as the design called for a ship with a standard displacement of 3900 tons. They are meant to expand the fleet and at the same time replace some of the older destroyers of the Asagiri-class ( 8 in active service ) and the Abukuma-class destroyer escort ( 6 in active service ). 

Each of these frigates will cost 50 billion yen or about US$460 million.

FFM-2 JS Kumano being fitted out at Mitsui's
Tamano yard 9th mar 2021. Photo : @DE224_cookie

30FFM Specifications

Standard Displacement : 3900 tons

Full Load Displacement : 5500 tons

Length : 133m

Beam : 16.3m

Propulsion : CODAG

1 x Rolls Royce MT-30 Gas Turbine

2 x MAN 12V28/33D STC Diesel Engine

2 x variable-pitch propellers

Maximum Speed : Over 30 knots

Power : 70000hp

Complement : 90

Armament :

1 x BAE Systems 62 calibre 5 inch ( 127mm ) Mk 45 Mod 4 gun system

2 x Japan Steel Works RWS with 12.7mm machine gun

1 x Raytheon SeaRAM ship defense system

2 x quadruple canisters for a total of 8 MHI Type 17 anti-ship missiles ( SSM-2 )

2 x HOS-303 triple launchers for 324mm torpedoes

1 x MHI 16-cell Mk 41 VLS ( fitted for but not with )

Mine Warfare :

Simplified Mine Laying Equipment

1 x Unmanned Surface Vehicle ( USV ) with Expendable Mine Disposal System ( EMD )

1 x Unmanned Underwater Vehicle ( UUV ) MHI OZZ-5

C4I : OYQ-1 Combat Management System ( Link 22 compatible )

Sensors : Mitsubishi Electric OPY-2 X-Band multi-function AESA radar

               Mitsubishi Electric OAX-3 Electro-optical / Infra-red sensor system 

               NEC OQQ-25 ship mounted sonar system comprising VDS + TASS

               Hitachi OQQ-11 mine-detecting sonar 

Electronic Warfare : NOLQ-3E electronic warfare system

                                 4 x Mk 137 Decoy launchers

Hangar for 1 x SH-60K Helicopter 

Updated : FFM-1 and FFM-2 ship crests here. Launch of FFM-3 here

JS Mogami being launched on 3rd Mar 2021

The official JMSDF video above on the launching and naming ceremony of the JS Mogami at MHI's Nagasaki yard on 3rd March 2021. 0:22 Kimigayo national anthem 0:48 Naming 0:55 Silver ship launching axe 1:06 cord cutting 1:07 Warship March 1:15 blessing horn

Sporting clean lines and flush surfaces.
The stealthy JS Kumano shortly after launch.
Photo : Hunini via Wikicommons.

Profile view of the sleek and long JS Kumano
shortly after being launched on 19th Nov 2020.
Photo : Hunini via Wikicommons

JS Kumano mid-ship starboard view with
hatches possibly for torpedo launcher.
Photo : Hunini via Wikicommons

JS Kumano superstructure.
Photo : Hunini via Wikicommons

JS Kumano stern and hangar.
Photo : Hunini via Wikicommons

Unique Features

The Mogami-class frigate is radically different from what we would normally expect of a typical JMSDF surface combatant, big powerful ships with towering superstructures and masts full of radar and electronic warfare antenna, with an equally huge complement. 

It is instead relatively smaller, stealthier, highly automated, not as well armed but still very capable, has an advanced combat management system and sensor suite and is intended to be multi-mission capable, including mine warfare.

The flat panels of the OPY-2 AESA multi-function radar
on the tetrahedral mast proper of JS Kumano shortly after
being launched. Photo : Hunini via Wikicommons

Its design has incorporated the latest in stealth technology to drastically reduce the radar cross-section ( RCS ) of the ship. The sides of the frigate are smooth and flush and ship structures are angled to deflect radar waves. The most prominent feature is the single integrated mast combining the ship's radar with its electronic warfare system. The four flat panels of the multi-function OPY-2 radar are mounted on the sides of tetrahedral mast proper, with a tube-like NORA-50 composite communications antennae atop, completely clutter-free. MHI had also indicated that it applied some of the stealth technology from its X-2 experimental fighter on the frigates, presumably radar-absorbent coatings or paint. Simply put, the Mogami-class frigate is probably the stealthiest ship in the JMSDF inventory to date.

FFM-2 JS Kumano's integrated mast being fitted at Mitsui's
Tamano yard 16th Feb 2021. Photo : mineo@youmaydream5

JS Kumano at Mitsui E&S Tamano yard 16th Feb 2021.
Photo : mineo@youmaydream5

A high degree of automation allows the Mogami-class frigate to be operated by a crew of just 90 personnel, a drastic reduction from its predecessor the Asagiri-class destroyer which has a complement of 220. This is an extremely important adaptation as the JSDF as a whole had repeated failed to achieve its recruitment targets since 2014, with the JMSDF fairing the worse among the three services. Declining birth rates and a new generation of youths who cannot live without their always connected smart phones would pose insurmountable challenges. Possibly to reduce the impact of ship deployments on the personal lives of the crew, JMSDF plans to rotate four teams of crew for every three frigates.    

The frigate also has an advanced integrated combat information centre ( CIC ) with a unique circular arrangement and open-bridge concept. It features 18 multi-function displays and 2 tactical tables and overhead screens that can project 360 degree augmented reality views of the ship with the assistance of sensor fusion technology. This will help to increase the situation awareness level of the CIC team.

Although well equipped for anti-surface warfare ( ASuW ) with the new Type-17 AShM and for anti-submarine warfare ( ASW ) with its combination of variable depth sonar, towed array sonar, torpedoes and ASW helicopter, the most unique capability of this frigate is its ability to conduct mine warfare. 

The frigate has the ability to lay sea mines. It can also deploy and retrieve sonar equipped unmanned surface and underwater drones such as the OZZ-5 UUV to hunt and neutralise sea mines from a docking station at its stern. Its USV can also launch the expendable mine disposal system ( EMD ) which are controlled via optical fiber cable for mine hunting and destruction. This video shows how the EMD works. You can also watch it below.

Trainer EMD with dummy warhead in classic
golden-yellow ( 山吹色 yamabuki-iro ) colour
displayed onboard MSO-304 JS Awaji.
Live ordnance would be painted black. 
Image : Wikipedia

          

This mine warfare capability is mostly unheard of in frigates of any navy but it comes at a crucial time when the JMSDF is scaling down its mine countermeasures fleet. So the frigates can pick up the slack left by a dwindling MCM fleet to ensure that the waterways are mine free especially during amphibious operations in the defense of Japan's outer island chains.

Stern of JS Mogami seen just before launch.
The larger opening leads to the USV / UUV docking station.
The smaller opening is for VDS / TASS deployment.
Photo @T_AH19 via twitter

Currently, the frigate's weakness is in its air defense capabilities has it can only rely on the extremely short range SeaRAM close-in weapon system for self-protection against aerial threats. This may change once the 16-cell Mk 41 vertical launch system ( VLS ) is installed. The versatile VLS can pack the longer range RIM-162 ESSM four to a cell or it could accommodate the navalised version of the Type 3 medium-range surface-to-air missile. This will enable it to provide area air defense in an escort mission.

In addition, the Type 7 vertical launch anti-submarine rocket can also be launched from the VLS, boosting the frigate's kill capabilities against submarines. The VL ASROC is basically torpedo with a rocket delivery system that has a reach of 30km.

Celebrating the launch of FFM-2
Image : @gintokii via twitter

Work Horse

With such a multitude of capabilities, the Mogami-class frigates are expected to be involved in the defense of Japan's home waters against surface and underwater threats. They augment the mine laying and mine hunting capabilities of JMSDF's organic mine-countermeasures fleet. They will also be deployed in anti-piracy operations overseas so that larger vessels like destroyers can be left to deal with bigger threats nearer to home, such as the Chinese, Russian and North Korean navies.

They mirror similar developments in other navies worldwide to have multi-mission capabilities built into a single hull and are frequently compared with the Littoral Combat Ship of the USN. The Republic of Singapore Navy's yet to be revealed Multi-Role Combat Vessel will probably share many similarities with the Mogami-class frigate, especially in mine warfare capabilities and emphasis on utilising remotely controlled vehicles.

There are also plans to export these vessels to lower the overall procurement costs. Indonesia is said to be interested in buying up to 8 frigates, with the first four being built in Japan and the remainder constructed in Indonesia. If this comes to fruition it will be Japan's first major arms export since WWII.

 

JS Mogami just after launch.
Photo : JMSDF

JS Mogami at MHI Nagasaki yard 4th Mar 2021.
Photo : @xkVjYrGfhYAOspG via twitter

JS Mogami at MHI Nagasaki yard 4th Mar 2021.
Photo : @xkVjYrGfhYAOspG via twitter

                           

The first-in-class FFM-1 JS Mogami is named after the Mogami River* ( 最上川 ) in Yamagata Prefecture. It is the third vessel to bear that name, the first being the Imperial Japanese Navy's heavy cruiser IJN Mogami and the second was the destroyer escort JDS Mogami ( DE-212 ) of the JMSDF. 

A mishap during the installation of the Rolls Royce MT-30 gas turbine delayed the launch of the lead ship, resulting in the second ship of the series, FFM-2 JS Kumano, being launched first. JS Kumano is named after the Kumano River ( 熊野川 ) in the mountainous Kii Peninsula of Kansai. Both are expected to be commissioned in March 2022.

The naming of the first two ships based on major Japanese rivers suggests that the other twenty might likely have river-based names such as Natori ( 名取 ), Tenryu ( 天竜 ), Kinu ( 鬼怒 ), Mikuma ( 三隈 ), Kiso ( 木曽 ), Tone ( 利根 ), Ishikari ( 石狩 ) and the likes. It follows the JMSDF tradition of naming its destroyers and major surface combatants after natural phenomena, meteorological phenomena, mountains, rivers and landmarks. 

 

View of Mount Gassan from Mogami River.
Ukiyo-e by Utagawa Hiroshige. Wikipedia

* With a total length of 229km the scenic Mogami River is one of the longest and fastest flowing rivers in Japan. It was historically important as a conduit to transport goods from the inland areas of Dewanokuni (出羽国), modern day Yamagata and Akita, to the coastal areas for export. 

The Mogami River was also featured in the hugely successful 1983 NHK serial television drama Oshin ( おしん ), in a snowy winter scene where the protagonist, a 7 year old girl from a poor peasant family, was tearfully separated from her parents and sent by raft down river to Sakata City to work as a babysitter for a timber merchant's family. Mogami River 0:14 - 0:20 in trailer for the 2012 movie adaptation.

    

SSK Soryu's Collision Off Cape Ashizuri : Curse of the Kuroshio?

 

The damaged SSK Soryu at Kochi Port 
9th Feb 2021. Photo : Asahi Shimbun 

Collision At Sea

Collisions at sea involving submarines thankfully do not happen everyday. Even when such unfortunate incidents occur, they tend to take place at remote waters where there are not much media coverage. In any case the need to maintain operational security would ensure very little information whatsoever will be made available to the public on these mishaps.

On 8th Feb 2021, the Japanese attack submarine JS Soryu collided with the Hong Kong registered bulk carrier the Ocean Artemis while it was surfacing during a training deployment in international waters southeast of Cape Ashizuri, Kochi Prefecture. The collision occurred at periscope depth and left the Soryu with extensive damage but fortunately no fatalities.

What was unusual about this incident was the large amount of high resolution images and video footage taken of the damaged submarine after the accident. Once the word was out the Japanese news media even had reporters and cameramen flown out to sea in helicopters to film the stricken submarine, made possible also because of the accident location's proximity to land.

Many theories had been proposed by new agencies and defense web portals as to how and why the accident happened, from poorly trained sonar technicians to equipment failure to thermal layers and even professional negligence. Frequently the opinions of serving or ex-submariners were sought and while they provide a good overview of the matter, none mentioned anything about a local maritime phenomenon that could have played a significant role in causing this incident : the fast moving warm Kuroshio Current that flows northward and eastward off the Pacific coast of Japan.

The Kuroshio Current off the coast of Japan
Here for real time map by earth.nullschool.net

Cape Ashizuri, approximate collision site
and current path of the Kuroshio in red.

The Submarine Soryu

The Soryu is one of the largest and most advanced diesel attack submarine in the world. It is equipped with an air-independent propulsion system. It is also relatively new, being launched as the first-in-class in Dec 2007 and commissioned in March 2009. It has a length of 84m with a displacement of 2900 tonnes surfaced. Its sonar suite comprises of a bow array, flank arrays and a towed array. 

It could make 13 knots on the surface and 20 knots submerged. Its maximum diving depth, though classified, is believed to be between 600m to 800m.

The Soryu is assigned to the 5th Submarine Squadron, 1st Submarine Flotilla operating out of Kure. Her commanding officer is Commander Koji Keisuke ( 恒次啓介 ). The submarine had recently spent considerable time in the ship yard on routine maintenance. She left her home port on 6th Feb 2021 with 90 crew members on a training deployment, most likely for re-certification of her operational readiness.

Soryu-class submarine on surfaced transit.
Photo : JMSDF

The Bulk carrier Ocean Artemis 

The Ocean Artemis is a bulk carrier with a gross tonnage of 51208 tonnes and a dead weight of 93103 tonnes. It was built in 2011. It has an overall length of 229m with a beam of 38m. Its maximum speed is said to be 13.8 knots. It was transporting iron ore from the Chinese port of Qingdao and was heading for the Japanese port of Mizushima, Kurashiki City, Okayama Prefecture when it collided with the Soryu. AIS data suggested that the Ocean Artemis had a draught of 14.9m on the day of the collision.   

Map of Shikoku Island and Kuroshio

The seabed 50km off Shikoku is 
between 1000m to 1500m deep.
Map : Geological Survey of Japan 

Reconstructing The Collision

Based on satellite, oceanographic, meteorological and maritime traffic data, we know that it was a clear but windy day out at sea 50km southeast of Cape Ashizuri on 8th Feb 2021. The wind was gusting at 25 knots from the northwest and whipping up swells with significant wave heights of 1.59m, probably the equivalent of Sea State 4.

The collision site is located over the continental shelf of Shikoku Island and lies over waters about 1000m deep. It straddles not only the main shipping lanes south of Shikoku but also the main path of the warm Kuroshio Current. Despite being winter, the sea surface temperature was about 21C, only dropping to 15C at the 200m depth. The current is strong with a flow speed of about 2 knots and an axis of 070 degrees. 

The Ocean Artemis, laden with ore and riding low in the water, was east bound for the port of Mizushima in the Seto Inland Sea. It would likely be maintaining a course of approximately 060 degrees as she navigates around Shikoku to enter the Inland Sea from the east via the Naruto Straits. 

At 10:58am local time, the Soryu was conducting a surfacing drill when, rising from the deep, she failed to detect the presence of the bulk carrier until she was at periscope depth. It was already too late to take evasive action by the time the surface vessel was seen through the periscope and a collision was inevitable. 

The bow of the bulk carrier struck the starboard side of the submarine's conning tower, denting it and damaging the anechoic tiles covering that area. It also caused severe damage to the starboard hydroplane and the sensor masts, taking out the communications antennae. Three submariners suffered from light injuries like bruises and none required evacuation.

Since the damage occurred mainly on the starboard side of the submarine, it can be deduced that it would have been a glancing blow had the submarine been on a course similar to the bulk carrier or if it were on a reciprocal course. Conversely it would have been a head-on impact had the submarine been maintaining a southerly bearing.

We would later learn that the Ocean Artemis did not report detecting any noise or vibration from the collision and most likely continued with her voyage without even realizing that a collision had taken place.

The loss of communications rendered the Soryu incapable of reporting the incident to the 1st Submarine Flotilla headquarters. Fortunately the Soryu could still move under her own power on the surface and she eventually navigated to an area with cellphone reception. The Ministry of Defense would eventually learn of the accident by 2:20pm. 

Transiting on the surface, the Soryu made it to the port city of Kochi by nightfall. Meanwhile the JCG diverted the Ocean Artemis to Kobe the next day for investigations. There, divers discovered that the impact left multiple scratch marks with black paint residue that presumably matched those from the Soryu on the bulbous bow of the Ocean Artemis. A dent and a 20cm crack corresponding to the point of impact was also found on the bow. This crack had caused some sea water seepage into the vessel.

The black paint residue were collected and had been dispatched to the JCG Research Centre in Tachikawa City, Tokyo, for further analysis and confirmation that they originated from the Soryu.   

Underway enroute to Kochi.
Photo : 5th Regional HQ JCG

Damage to the hydroplane, sensor masts and conning tower 
of the JMSDF submarine Soryu. Photo : Mainichi Shimbun

Moored off Kochi, 9th Feb 2021
Photo : Mainichi Shimbun

Moored off Kochi, 9th Feb 2021
Photo : Mainichi Shimbun

Moored off Kochi, 9th Feb 2021
Photo : Mainichi Shimbun

Moored off Kochi, 9th Feb 2021
Photo : Mainichi Shimbun

The damaged Soryu at Kochi on 9th Feb 2021

Ocean Artemis off Kobe 9th Feb 2021
Photo : Mainichi Shimbun

Divers inspect the bow of the Ocean Artemis
Photo : Asahi Shimbun

Scratch marks on the bow of the Ocean Artemis
Photo : Jiji Press

What Caused The Collision?

Surfacing drills are among the most hazardous submarine operations undertaken during peace time. Even with modern sonar equipment, collisions with surface vessels are always a possibility especially around busy shipping lanes.

Every submarine's forward mounted sonar has blind spots known as the baffles, an area directly behind the submarine where sound detection is not possible. In order to surface safely, a submarine has first to perform a manoeuvre known as clearing the baffles to ensure there are no vessels hiding in the blind spot. It requires the boat to change its course slightly so that the previously hidden areas could now be scanned. Once the baffle is cleared, the submarine will have to execute the ascend to the surface within a specified time of not more than 10 to 15 minutes, any longer and the traffic pattern could have changed.

There is a possibility that the Soryu did not perform a proper baffle clearing or it could have taken too long to ascend after that. Her skipper Cmdr Koji Keisuke had commanded the JS Takashio ( SS-597 ) before assuming command of the Soryu on 15th Oct 2019, so he is not new to his post. However, the Soryu has recently spent considerable yard time on regular maintenance and had just resumed operational training after a long lapse. Perhaps crew proficiency may not be at the peak level and mistakes might be more common.

Clearing the baffle ( sonar blind spot )
Image : Asahi Shimbun

The same trend of thought tells us that the likelihood of the sonar specialists not reporting a surface contact as they should is also possible and could have been made more likely by their long absence from regular training. Having said that, due to the hazardous nature of operating submarines, only the best of the best gets selected to train as submariners, and MSDF personnel have to undergo rigorous training of high standards for their qualification process. So again, professional negligence, though unlikely, cannot be completely ruled out. 

Equipment failure is a remote possibility but Japan's fleet of submarine is young by other navy's standards. Until recently, JMSDF used to retire its submarines after an average of just 20 years! We also know that the Japanese tend to maintain their equipment in tip top condition, and that the Soryu had just completed its regular yard maintenance, so the scenario where there is a catastrophic failure of the sonar system leading to a collision has a low probability. In fact, Chief of the Maritime Staff, Adm Yamamura Hiroshi had already categorically denied any reports of a periscope or sonar malfunction. 

The size and draft of the bulk carrier brings up another possibility to the cause of the accident - the bow-null effect. Simply put, the enormous length of the surface vessel approaching head-on effectively acts as a shield to greatly diminish the acoustic signature from the engine and propellers which are a couple of hundred meters behind the bow. This reduced sound level could have been misinterpreted to be emitted from a source much further away along the same bearing, leading to a potentially disastrous situation. Even veteran submariners have had close shaves due to the bow-null effect. It has also been postulated to be the cause of many collisions between whales and large surface vessels.

Apart from human errors and equipment failures, environmental and geographical factors frequently have a contributory if not causative role to play in such accidents. For submarines, water temperature, depth and to a lesser extend, salinity, will have a huge impact on sound transmission. The existence of shallow thermal layers for example, might create environments with positive sound velocity profile gradients, causing some surface generated sound waves to be deflected upwards. It would result in shadow zones below the layer and make vessel detection from beneath all but impossible. The Kuroshio could have contributed to the creation of such thermal layers.

The Black Tide

The collision took place on a winter's morning in an area known to have high maritime traffic, over the continental shelf extension of Shikoku with depths of approximately 1000m. February is typically the coldest month of the year in the northern hemisphere and being located in the temperate zone one could logically expect the sea surface temperature around Japanese waters to be cold as well, causing thermal layers commonly encountered in warmer months to be greatly diminished or even dissipate altogether. 

That would well be the case if not for the powerful Kuroshio Current which brings warm water from the tropics to the Japanese archipelago all year round. Kuroshio ( 黒潮 ) means black tide in Japanese. It is named because of its nutrient poor, deep blue, clear waters. It is one of the world's major oceanic currents comparable to the Gulf Stream of the Atlantic. The impact of this warm current on Japanese climate and maritime related industries is so great that the Japan Coast Guard monitors its activities constantly and issues daily reports.

JCG Quick Bulletin of Ocean Conditions
Path of Kuroshio & Tsushima Currents
Flow speed is 2 knots south of Cape
Ashizuri on 8th Feb 2021

Sea Surface Temperature off Cape
Ashizuri is about 21C on 8th Feb 2021

Because of the Kuroshio Current, the sea surface temperature south of Cape Ashizuri where the collision occurred remains at 20C to 22C in winter and between 26C to 28C in summer. So even in winter a significant layer of warmer water will exist above the colder water deeper below. How deep is warm layer gets depends on factors such as the current's flow rate, mixing from colder layers below and even eddies that form when the current is deflected by geological features or when it meets another ocean current, like the southward flowing cold Oyashio current from the Kuril Islands. 

It is a well known fact that the salinity and water temperatures can vary considerably especially at the boundaries of the tide, making navigation with sonar extremely tricky. To complicate matters, the path of the black tide is not always fixed and can sometimes shift quite drastically in what is known as the " Great Meandering " ( 黒潮大蛇行 Kuroshio Daidako ) especially off the Kii Peninsula east of Shikoku Island.

Sea Surface Temperature 20.6C
Flow Direction 070
Flow Speed 0.94m/s ( 1.88 knots )

Significant Wave Height 1.59m
Peak Wave Period 5.2s
Direction 305 deg

Surface Wind 25.5 knots
Direction 310 deg

The waters around the collision site is 
approximately 1000m deep.
Bathymetry from Japan's Submission to
the Commission on the Limits of the
Continental Shelf.

Maritime traffic density 2012
Image : shipmap.org

The Aftermath

The JMSDF has not been all forth coming with information on the collision. There were no mention of the incident on its website and social media accounts. The Minster for Defense and the Chief Cabinet Secretary did have press conferences and the MOD had a press release, but that was it. Some of the images and videos came from the JCG but mostly they were from the news media. Investigations are ongoing and hopefully the findings will be released soon. 

Since the Kuroshio Current dominates over almost the entire Pacific coast of Japan, I am convinced that the collision has something to do with it, barring other factors such as human error. Its high flow volume of very warm water creates a perpetual summer-like condition to Kyushu, Shikoku and Western Japan extending eastwards to the Kanto region at times. Its ever changing flow axis with major deviations and meandering and its multitude of eddies and countercurrents where there are deflections by land masses and confluences with other currents means that it is as unpredictable as can be, creating treacherous acoustic environments for submarine navigation. 

As usual, most accidents are caused by cumulative errors committed by all parties involved, but sometimes it can boil down to just pure bad luck, like being at the wrong place at the wrong time. The Soryu unfortunately has quite a long history of mishaps .... from electrocution and burns at the shipyard to attempted suicide and the accidental drowning of three petty officers within the flooded areas of the sail during routine operations in 2012. 

At the time of writing, the Soryu is back in Kobe where the Mitsubishi Heavy Industries Shipyard is located, presumably for damage assessment and repairs. Even though her pressure hull wasn't damaged, it could still possibly be out of active duty for several months and the repairs could cost several tens of millions of dollars.

Cmdr Koji will likely be relieved of his command regardless of the cause of the collision and the outcome of the investigations. His career as a sub-driver or even his future in the JMSDF could already be jeopardised. 

Meanwhile, the MOD decided that a 3.5 hour delay in incident reporting due to communications failure is utterly unacceptable and the JMSDF has pledged to ensure the availability of satellite phones on their vessels and boats.

Cmdr Koji Keisuke
Photo : JMSDF

Foot Note : Cape Ashizuri

It would not be right to end this article without elaborating on Cape Ashizuri. Known in Japanese as Ashizuri Misaki ( 足摺岬 ), this is the southernmost point of Shikoku Island. It is located in the remote western part of Kochi Prefecture where the pristine Shimanto River lies, with rugged coasts and beautiful night skies. 

Cape Ashizuri Lighthouse
Photo : JNTO

I had visited Cape Ashizuri in Feb 2017, after completing the Kochi Ryoma Marathon. Accessibility was an issue as the rail network did not extend to that region and even driving along the winding coastal roads was tedious and time consuming. But the effort was well worth it.

The Cape lies within the Ashuzuri-Uwakai National Park and it has majestic sea cliffs that towers above the vast expense of the Pacific Ocean. I remembered that it was extremely windy when I visited the Cape Ashizuri Lighthouse and walked through the tunnel of camellia which was in full bloom.

Cape Ashizuri is the southernmost
point of Shikoku Island. Statue
of John Manjiro in the Background.
Photo : Author

Another attraction at Cape Ashizuri is the statue of John Manjiro ( 中浜万次郎 ), a Japanese whose remarkable story I first learnt only during that visit. Manjiro had hailed from Nakanohama, an area known today as Tosashimizu, not far from Cape Ashizuri. 

Manjiro came from a poor family and lost his father at a young age. In 1841 when Manjiro was fourteen years old, he left home to work on a fishing vessel to help make ends meet. Unfortunately, due to inclement weather, he was shipwrecked on an uninhabited island off the coast of Japan for six months. Manjiro was eventually saved by the captain of a passing American whaler who named him John and brought him back to his hometown of Fairhaven, Massachusetts, so that he could be educated. 

Statue of Nakahama John Manjiro
at Cape Ashizuri. Photo : Wikipedia

Manjiro stayed in America for ten years, learning English and the science of navigation among other things, becoming the first Japanese to achieve long term residency in America. All that during an era when the ordinary Japanese were forbidden to travel or interact with foreigners! He would later join a whaling ship and work his way up to become the first mate and even participated in the California Gold Rush, earning enough money to fund his journey back to Japan. 

Upon his return, instead of meting punishment for violating the travel ban, the Shogunate government found his knowledge in English and foreign ways valuable and made him an advisor. He was also the translator for Japan's first trans-Pacific delegation to San Francisco and was appointed a lecturer at the Kaisei Institute dedicated to the teaching of foreign languages, science and advanced western technologies, paving the way for the Meiji Restoration and the industrialization of Japan which followed shortly. 

John Manjiro's story is worthy of an article all by itself but fortunately all the details can be found here.