DDH Hyuga / 16DDH "13,500 ton" ton Class
A proposed "13,500 ton" ton helicopter-carrying destroyer, similar in design to a small aircraft carrier, would provide the Maritime Self-Defence Force with greater capability for force projection. This program was initially known as the "13,500-ton" helicopter destroyer (DDH). The Defense Agency formally refers to them as the DDH (helicopter destroyer) follow-on mode. It is temporizing to refer to this type of vessel as a DD (destroyer). There had never been a destroyer that exceeded 10,000 tons. In fact, with a full displacement of about 20,000 tons when equipment fuel, water and weapons are counted in, they essentially can be classified as light aircraft carriers. The ships were later code-named 16DDH (16 as in the 16th year of the Heisei emperor in the Japanese calendar).
The 16DDH in JSDF classification is by no means an aircraft carrier. Its characteristic shape, however, is nothing but. The construction of these next-generation helicopter-carrying destroyers signifies a new direction for the MSDF, in which the service realizes decades-old aspirations.
DDH Hyuga / 16DDH - Program
On 15 December 2001, the Japanese Government approved a new mid-term procurement plan for its Self-Defense Forces totaling 25,160 billion yen (US$223.6 billion) over the next five years. The new procurement plan allows the building of two DDH helicopter destroyer. The first two units are intended to replace the Haruna and the Hiei (both about 5,000 tons) that will be out of service in 2008 and 2009, respectively. They were expected to cost 100 billion yen apiece.
The fiscal 2004 defence budget gave the JMSDF (Japanese Maritime Defence Force) the largest warship Japan has had since the disappearance of its Imperial Navy. The first of the DDH 13,500-ton class ship was approved in 2004 as planned, , with another planned for 2005, with the total cost of 116.4 billion yen (US$1.06 billion). The second ship construction was postponed from its original 2005 plan because missile defense and satellite communication network replaced the prioprities.
IHI Marine United (IHIMU), Japan’s leading shipbuilding company, received an order for the DDH from the Japan Defense Agency in December 2003. The "13,500-ton" DDH 181 Hyuga was launched on 23 August 2007 at the IHI Marine United shipyard in Yokohama, The Hyuga is named for a World War II-era hybrid battleship/carrier that could carry 22 fighters, a decision not lost on defense analysts. The first ship was expected to be completed in March 2009. It was anticipated that at least one additional DDH destroyer will be built in the coming years. As of late 2007 the second 16DDH unit was scheduled to be laid down in May 2008.
A total of four are planned to replace the two Haruna-class and two Shirane-class DDHs in the ASW role. The earlier DDH had an operational life of about 35 years, suggesting that the three further units would be required in the 2015 timeframe.
DDH Hyuga / 16DDH - Aircraft Carrier
The first officially released design was a unique configuration that featured forward and aft helicopter pads with a hanger in the center. However, in the end, the design that most fit the JMSDF's need - aircraft carrying capability - was choosen, which strongly resembled a normal aircraft carrier.
Paragraph 2 of Article 9 of the Constitution provides that "the right of belligerency of the state will not be recognized." The self-defense capability that Japan is permitted to possess is limited to the minimum necessary by the constitutional limitations. However, whether or not the said armed strength corresponds to "war potential" stipulated in paragraph 2 of Article 9 of the Constitution is an issue regarding the total strength that Japan possesses. Accordingly, whether the SDF are allowed to possess some specific armaments depends on the judgment whether its total strength will or will not exceed constitutional limitations by possessing such armaments. But in any case in Japan, it is unconstitutional to possess what is referred to as offensive weapons that, from their performance, are to be used exclusively for total destruction of other countries, since it immediately exceeds the limit of the minimum necessary level of self-defense. Therefore, for instance, the SDF is not allowed to possess ICBMs, long-range strategic bombers or offensive aircraft carriers.
Japan has long wanted to develop an aircraft carrier. As early as 1983, Japan called for the building of a 20,000-ton aircraft carrier, which could carry 20 helicopters or 20 VTOL Sea Harriers. This was not realized owing to opposition from the United States. The US Navy strongly opposed to the plan, and urged Japan to build more destroyers instead. The US Navy had enough flattops to counter the Soviet Navy but lacked destroyers. The MSDF's plan to own a light flattop raised Washington's eyebrow, apparently taken as a subcontractor attempting to strike out on its own.
That did not daunt the Defense Agency or the MSDF. In a Diet budget session in April 1988, then Defense Agency chief Tsutomu Kawara replied, "The Self-Defense Forces are not allowed to possess ICBMs (intercontinental ballistic missile), strategic bombers, or attack aircraft carriers." Until the 1970s in the US Navy, large-scale flattops had been categorized as "attack aircraft carriers" and small flattops as "antisubmarine aircraft carriers." Prohibition of having attack aircraft carries can be taken to mean allowing possession of small aircraft carriers.
With the decline of Russian naval strength, the Self- Defense Forces’ fighting vessels and aircraft rank second in the world, behind the United States. However, the Self-Defense Forces still maintain an ambition to develop an aircraft carrier and nuclear submarine. It is said that the plan to build DDH helicopter destroyer is actually another demonstration of such ambition.
Mention of a light aircraft carrier was first made in the 2001-2005 National Defense Buildup Program Outline (Mid-term Program) that was approved by the Cabinet in December 2000. According to a designer's concept shown by the agency in December 2000, the vessel's bridge was located amidships to bisect the flight deck-a ship design that was effectively identical to its predecessor. But when it became time for the fiscal 2004 budget request in August 2003, the agency came up with a completely new drawing, which showed the bridge on starboard to create a through deck-a design of none other than an aircraft carrier. The agency, however, insists that since this vessel is just an expanded model of any conventional flagship DDH, it ought to be categorized as such.
"The “16DDH”-class ship has attracted significant media and Diet attention, owing to its resemblance to an aircraft carrier. The vessel’s design features a starboard-side island superstructure and an uninterrupted flight deck, prompting observers to speculate that Japan may be eyeing a carrier capable of handling Harrier-like aircraft. Notes one analyst, “The configuration of the Osumi and the new DDH class indicates that Japan is rehearsing carrier-building technology to reserve for itself this potential military option; and thus, that it is considering discarding the constitutional prohibition on the acquisition of power-projection capabilities.” In the meantime, the 16DDH would fulfill many of the peacetime and wartime missions elaborated in the NDPG. As a wartime flagship, the 16DDH would serve as a command-and-control platform, coordinating the activities of other units while its organic helicopters conducted ASW operations. During peacetime operations, or “military operations other than war” (MOOTW), the 16DDH would join the Osumi-class ships for peacekeeping and relief operations, as well as the “diverse situations” Japan foresees confronting on the high seas." [Yoshihara & Holmes, Summer 2006]
It is almost as large as the Imperial Japanese Navy's Tone class heavy cruisers. It matches in size modern small aircraft carriers as Italy's MM Giuseppe Garibaldi (10,100 tons) and Spain's Principe de Asturia (17,188 tons). In terms of displacement, the two destroyers -- not nuclear-powered -- will be in the class of Britain's Invincible, a 20,600-ton light flattop, when they are fully loaded with fuel.
DDH Hyuga / 16DDH Design Features
The new DDH was to be one of the largest naval ships in Japan, with a light displacement of 13,500 tons. The Defense Agency said that in order to simultaneously operate four MH53E jumbo helicopters that are capable of carrying up to 55 people, the displacement of the ships will reach about 13,500 tons. They are equipped with a sonar and ASROC anti-submarine missiles, along with the MK 15 Phalanx CIWS (Close In Weapon System) and 16 MK 41 VLS (Vertical Launch System). Reports that they carry an Aegis-type air defense system are in error, since this capability is provided by DDG escort ships.
In early 2005 Mitsubishi Electric Corporation (Melco) of Japan and Thales Nederland signed a contract for the delivery of a Thales missile control module that will be incorporated in Melco's new FCS-3 radar. The missile control module will add Thales Nederland's revolutionary ICWI technology to the FCS-3 radar. This radar will be installed on the 16DDH, the first of a new class of helicopter carriers for the Japanese Maritime Self-Defence Force.
ICWI (Interrupted Continuous Wave Illumination) is a technology that enables a missile control system to guide several missiles simultaneously to various threats, greatly enhancing a ship's defence capabilities. The performance of ICWI-based missile defence systems was convincingly demonstrated during the live firing trials of the Royal Netherlands Navy's "De Zeven Provinciën" late 2003 and the live firing trials of the German Navy's "Sachsen" mid 2004. Both ships are equipped with APAR, Thales' highly advanced multifunction radar, especially designed to guide ESSM and SM2 missiles to incoming threats.
With this contract the history of co-operation between Melco and Thales Nederland continues. About twenty years earlier the companies already worked together on Thales' well-known WM25 fire control radar. Thales Nederland is proud to continue this relationship through its state-of-the-art ICWI and APAR technology. Both Melco and Thales expected that their good relationship will be strengthened by further co-operation in the future.
In May 2005 GE Transportation's marine gas turbine business announced it will supply Ishikawajima-Harima Heavy Industries, Co. Ltd. (IHI) with four GE LM2500 aeroderivative gas turbines. The engines will power the first of a new class of Japan Maritime Self-Defense Force's (JMSDF) helicopter-carrying destroyers. The 13,500-ton DDH destroyer will use two propulsion trains, each consisting of two LM2500s in a COmbined Gas turbine And Gas turbine configuration (COGAG), driving a propeller through a gearbox. The engines will each provide 25,000 shaft horsepower.
The DDH will be the largest operational naval ship in Japan with a staff of more than 350. Its equipment density will be many times more than that of commercial ships. There will be four helo landing spots on an axial flight deck and supposedly it will carry three SH-60 Seahawk variants for ASW and an EH-101 Merlin for mine warfare, and it is said to have the capacity to carry MH-53E and as many as 11 aircraft.
The design includes two elevators connecting the flight deck and hangar deck. The forward elevator is about 33 feet [10 meters] by 65 feet [20 meters], while the aft elevator is about 45 feet [13.1 meters] by 65 [20 meters] feet. Unofficial artwork shows the F-35B VSTOL strike fighter operating from these ships. The F-35B is has a wingspan of 35.0 ft (10.7 m), and is 50.5-51.1 ft (15.4 m) long. It would seem that there would be more than ample margin on the aft elevator to accomodate the F-35B.
