An article in the Malaya newspaper mentioned recently that aside from P-3C Orion aircraft, one other item for possible transfer to the Philippines from Japan is “… a Destroyer or a Frigate type of vessel …” No mention was given on specifically which Destroyer/Frigate were being considered, but speculations point out to at least two types: The Hatsuyuki and the Shirane class Destroyers, and with good reason as both Destroyer classes have either been retired recently, or on its way to being retired soon. So let’s take a close look at both vessels.
’The Hatsuyuki and Shirane Classes’
The Hatsuyuki-class is a class of twelve General Purpose (GP) Destroyers of the Japanese Maritime Self Defense Force (JMSDF) which first entered service in 1982. The dozen ships were made by five different manufacturers, and since then the class has been succeeded by an improved version, the Asagiri-Class Destroyers. Three of the Hatsuyuki ships have been converted into Training Ships starting in 1999 while five have been officially retired since 2013. The remaining four ships were scheduled to be transferred to the Japanese Coast Guard (JCG) starting in 2013, but it seems no English language reference is available to confirm if the transfer has indeed been made.
The Shirane-Class Destroyers on the other hand are a pair of what the JMSDF calls as “Helicopter Destroyers“. The ships were made by the Japanese company IHI Marine United and first entered service in 1980 but has since been succeeded by the much larger and heavier Izumo-Class Helicopter Destroyers. One ship was retired this year (2015) while the other is scheduled for retirement, presumably when the next Izumo class ship enters service.
Below are a comparison of the physical characteristics of both ships, and for added information I also included data for the Oliver Hazard Perry Frigate (OHP) and the PF-16 BRP Ramon Alcaraz as they will be useful for some comparison later.
As we can see the Shirane is a much larger ship and with a much larger Crew and Complement compared to the other three ships, a true “Destroyer” as defined by most countries around the world today. Its size enables it to carry up to three Helicopters, which is probably the main reason why Japan insisted on classifying it as a Helicopter Destroyer. The Shirane and Hatsuyuki ships also illustrate the lack of a standard international naming convention for ships as Japan is the only country I know that uses the term “Helicopter Destroyer”, while the Hatsuyuki class ships would normally be classified as “Frigates” by other countries due to its lighter weight class.
’The Hatsuyuki’s Gas Turbine Engines’
In a previous blog, I had indicated that a ship like the OHP may not be for us because it uses Gas Turbine (GT) engines as its main propulsion which is not as fuel efficient as Diesel Engines, and it turns out that the Hatsuyukis are also using GT engines, so if the OHP was not ideal because of its GT engines, then the Hatsuyuki should not be also since it uses the same engines. However, upon closer inspection, it turns out that there is a big difference between the Hatsuyuki and the OHP despite the fact that they both use GT engines.
The OHP is classified as having a Combined Gas Or Gas (COGOG) engine configuration, meaning it uses EITHER of its two sets of GT engines. But I find this a bit misleading because the OHP uses its lower powered 260 kW GT engines only for maneuvering during docking or undocking, while most of the time when it is at Cruising or at Maximum Speed, it uses the same two 31 MW GT engines. The Hatsuyuki is also classified as having a COGOG propulsion, but it uses two lower powered 7.4 MW GT engines for docking/undocking AND Cruising while it uses its larger 36 MW GT engines only when running at speeds above 20 knots.
The fact that the Hatsuyuki uses a lower powered GT engines most of the time compared to the OHP means that it will have better fuel efficiency, and the range values do support this: The Hatsuyuki can travel 12,975 km which is Sixty Percent (60%) more than the OHP’s range of 7,778 km at the same speed of 20 knots. Of course, the Hatsuyuki’s range is still lower than the Alcaraz’s 19,312 km range at 20 knots (which mainly uses its Diesel Engines for Cruising), but since the Hatsuyuki’s range value is much better than the OHP’s, then IMHO, I think this is a good compromise already despite its use of GT engines.
’The Shirane’s Boiler-Turbine Engines’
As for the Shirane class Destroyer, my major issue about it also concerns its Propulsion System because it uses two Boiler-Turbine (BT) engines, meaning it uses Boiler to generate Steam (powered probably by Diesel) which then turns the Turbine engines to move the ship forward. I find this a little bit unusual because most navies around the world have stopped using CONVENTIONAL BT engines in favor of Internal Combustion Engines (ICEs) like Diesel or GT engines for decades now, and this is simply because ICEs are smaller and lighter, and produces more power per given weight; They are also in general less expensive to acquire and consume less fuel than BT engines.
All nuclear powered ships use BT engines, but this is only because this is the only way we know how to harness the heat generated from Nuclear Fission for power plants, which is by heating water to steam and then using it to drive Turbines. But if you look at the non-nuclear powered ships of the JMSDF, a vast majority of them run on ICEs, with very few only like the Shirane class running on BT engines. Note that the Shirane class itself is composed only of two ships, while the Hatsuyuki class with its GT engines is composed of a dozen ships.
The Shirane is also a much heavier ship than the Hatsuyuki, TWICE as heavy (7,500 tons for the Shirane while only 3,800 tons for the Hatsuyuki) so naturally it would need more powerful engines to drive it, and in fact the Shirane has 50% more powerful engines than the Hatsuyuki’s most powerful engines (52 MW versus 34 MW), and this translates to higher fuel consumption for the Shirane ships.
Both ships are similarly armed for Anti-Air Defence, and both have very good Anti-Air capability, starting with their RIM-7 Sea Sparrow Surface to Air Missiles (SAMs) on eight-shot Mk 29 Launchers. The RIM-7 has a 40 kg warhead and a range of 18 km. The RIM-7/Mk 29 setup is a bit outdated, though, and has since been superseded by the longer ranged (50 km) RIM-162 Evolved Sea Sparrow Missile (ESSM) which are more compact and thus ships can carry more of it on Vertical Launchers. But as it is, the RIM-7 is still very useful.
Both ships also have good redundancy in terms of its Anti-Air defenses as they have not just one (as most ships carry) but two Mk 15 Phalanx Close In Weapons System (CIWS), an automated 20 mm Gatling Gun system with a Rate of Fire of up to 4,500 round per minute and with a range of 3.6 km. The Phalanx acts as a secondary and last line of defense for both ships against missiles and aircraft, and in combination with the RIM-7 gives both ships very solid anti-air capability.
The Hatsuyuki has an OPS-14 Air Search Radar (ASR) with only “2D” capability (meaning it can only provide Distance and Bearing information of air targets) with an estimated detection range of 146 km for a mid-sized fighter aircraft with a 5 m^2 Radar Cross Section (RCS). The Shirane on the other hand has a much more powerful OPS-12 ASR with a detection range of 202 km for the same sized aircraft, and it is more advanced as it has 3D capability (meaning it can provide Distance, Bearing and Altitude information).
Both ships only have short ranged missiles though, so they won’t be able to use much of their radar’s information except for Early Warning or for Surveillance purposes, but it does mean that the Shirane will always have earlier warning of enemy aircraft or missiles, and the information it can share to other assets will be more accurate.
For Anti-Submarine Warfare (ASW) weapons, both ships have Mk 32 Triple Torpedo Tube Launchers for Mk 46 Light Weight (LWT) torpedoes which has a 44 kg warhead and can run at 40 knots at a maximum range of 12 km. Aside from that, both ships also have RUR-5 Anti-Submarine Rocket (ASROC) on eight-shot Mk 16 Launchers. Each ASROC carries a Mk 46 Torpedo out to a range of 19 km, extending the Mk 46’s range and enabling it to reach Submarines faster, dropping almost on top of them.
The Shirane does have several advantages over the Hatsuyuki in terms of ASW capability, and that is first, it has three ASW sensors: An OQS-101 Bow Mounted Sonar (BMS), an SQS-35 Variable Depth Sonar (VDS) and an SQR-18 Towed Array Sonar System (TASS) whereas the Hatsuyuki only has two, a OQS-4 Hull Mounted Sonar (HMS) and a OQR-1 TASS.
The Shirane also has three ASW Helicopters whereas the Hatsuyuki can carry only one. The additional Sensors and Helicopters allows the Shirane to cover more area for ASW and it allows a lot redundancy also, meaning it can still have Sensor or Helicopter capability even if one or two of its Sensors or Helicopters are out of commission for one reason or the other.
On top of that, the Shirane also has a Prairie-Masker system, basically an equipment that generates air bubbles around the Hull and Propeller to mask or silence the ship’s engine and Propeller noise. This makes the Shirane harder to detect by enemy Submarines and Ships. So in total, while the Hatsuyuki has very good ASW capability, the Shirane has OUTSTANDING ASW capability, even better than that of the OHP or the Maestrale class Frigates.
Another big difference between the two is in terms of Anti-Surface Warfare (ASuW) capability. The Hatsuyuki carries a single Oto Melara 76 mm Compact cannon which we are very familiar with as our most modern ships use them also. It has a range of 16 km and a Rate of Fire of 80 rounds per minute. However, the Shirane not only carries one but TWO cannons, and not only does it carry two cannons, they are of higher caliber and more powerful than that of the Hatsuyuki. The Shirane’s Mk 42 127 mm Cannons have a longer range of 23 km but a slower rate of fire of only 28 rounds per minute.
The Hatsuyuki though carries eight RGM-84 Harpoon missiles on two Mk 141 launchers. Each RGM-84 has a warhead of 224 kg, range of around 110 km and a speed of 885 kph. The Shirane, on the other hand, does NOT have ASuW missiles of its own. My guess is that the JMSDF is relegating the use of ASuW missiles to the three Helicopters. However, IMHO it is very possible to remove the two Mk 42 guns (each weighing 66 tons) and replace them with a combination of a smaller and lighter Oto Melara 76 mm Compact Gun (nine tons), two Mk 141 Launchers (each weighing only six tons) for Harpooon missiles and at least two Mk 41 eight-cell Vertical Launch System (VLS, only 26 tons each).
But the conversion would of course entail additional costs, and for a country who have yet to have a Guided Missile ship, the project may well be beyond our capability to manage and supervise, at least for now. Despite the Shirane having more guns and helicopters, I think the Hatsuyuki’s longer ranged and more powerful Harpoon missiles have the advantage when it comes to ASuW.
The Hatsuyuki uses an OPS-18 Surface Search Radar (SSR) while the Shirane uses an OPS-28 SSR, both of which have similar estimated ranges of around 33-37 km for a mid-sized ship with an RCS of 30,000 m^2, which makes them about even in terms of ship detection capability.
’Equipment and Weapons Transfers’
A majority of the Equipment and Weapons that both ships are using are either American-made, or license-built from American designs, hence their transfers will have the same problem we have with the P-3C transfer, and that is they will have to go thru an uncertain Congressional approval process. We just don’t know which Equipment and Weapons the US Congress will approve for transfer, and when they will make that approval.
If the Equipment and Weapons are initially removed before the transfer is made, this will affect more the Shirane than the Hatsuyuki since it is less desirable to have an almost empty larger ship than an almost empty smaller ship as the former will have a higher Operating Cost, but not much capability. With a smaller ship like the Hatsuyuki, at least the cost is minimized until the ship is restocked again.
Despite the uncertainty of getting the Equipment and Weapon systems of these ships if a transfer is made, we at least have an idea of which systems these ships are comfortable of using, and if a system will not be transferred then perhaps we can go out and buy the equivalent systems to enable each ship to function at its full potential.
Summarizing the Pros and Cons between the Hatsuyuki and the Shirane:
– Outstanding ASW Sensors and Equipment.
– Can carry more Helicopters.
– Has more guns which of higher caliber and more powerful.
– Very good Anti-Air capability.
– Better ASR with longer range.
– Bigger and Boiler type engines consume more fuel.
– Larger crew means higher Operating Costs.
– No ASuW missiles of its own.
– Has ASuW missiles.
– Less powerful engines and less crew means lower Operating Costs.
– Very good Anti-Air capability.
– Less ASW capability.
– Carries only one Helicopter.
– Carries only one gun.
– Shorter ranged and less capable ASR.
The bigger Shirane definitely has much better capability overall, it has better ASW capability and longer ranged air search radar, but it is also more expensive to operate. The Hatsuyuki have less capability, but has lower operating costs, and I think that despite its lower capability, it is enough already for us to have good GP ship, so IMHO it would be a better choice for us.
Personally, if we are get a ship as big as the Shirane, I would prefer to have something that carry a lot more missiles, like the Iver Huitfeldt class for example which is slightly shorter and lighter than the Shirane but can carry at least 40 medium sized missiles. At any rate, let’s see which one the PhN will get, assuming of course that it is really down to these two ships in terms of which ship we will get, and if we are really getting a ship from Japan …
^ PH to Get Planes from Japan,
^ Hatsuyuki class Guided-missile destroyer,
^ Coast Guard to pick up retiring Hatsuyuki-class destroyers?,
^ Shirane class Helicopter Destroyer – DDH,
^ The FFG 7 OLIVER HAZARD PERRY – class,
^ The USCGC Hamilton (WHEC-715) Coast Guard Ship of the Future,
^ Oliver Hazard Perry Frigates for the Philippine Navy?,
^ Marine Propulsion Systems,
^ RIM-162 Evolved Sea Sparrow Missile,
^ Mk 15 Close In Weapons System (CIWS),
^ Smarter (and Simpler) Radar in Harpoon,
^ RGM-84 Harpoon missile,
^ Mk-141 Guided Missile Launching System,
^ Vertical Launching System (VLS) Mk 41 – Tactical Length Module,