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DDH-183 Izumo 22DDH Class

On August 6th, 1945, an atomic bomb destroyed the city of Hiroshima. On 06 August 2013, 68 years later to the day, Japan formally unveiled to the public the first of its 22DDH Class helicopter escort, the Izumo, which is larger than any of the aircraft carriers that Japan employed in the attack on Pearl Harbor. The 22DDH Class helicopter destroyer is Japan's first aircraft carrier since the Great Pacific War. The designation 22DDH is short for helicopter destroyer project, Heisei Year 22. Heisei is the name of the reign of the current emperor. Each emperor's reign is named, i.e. Meiji, Showa, etc. Heisei 22 is the 22nd year of rule by Emperor Akihito. The 22 does not reference the displacement, and in any event Asian navies always disclose empty displacement instead of loaded or full displacement.

On 31 August 2009 it was reported that the JMOD FY2010 budget request included 116.6 billion Yen for a new 22DDH "helicopter destroyer" built to a design signficiantly larger than the 16DDH Hyuuga Class. After Yukio Hatoyama became prime minister in September 2009, new budget requests were submitted in October 2009 -- including 118.1 billion yen for the construction of a helicopter destroyer. The ship would eventually replace the destroyer Shirane, which was scheduled to be decommissioned in fiscal 2014. A request for the helicopter destroyer was first made for the fiscal 2010 budget when the Liberal Democratic Party was in control of government.

It is designed to be a vessel which is conscious of the Chinese Navy, and to support civil disaster relief operation and the United Nations Peace Keeping Operations (PKO). The planned helicopter destroyer will have a length some 25% greater than the 197 meter 16DDH Hyuuga. At 248 meters [813 feet] the 22DDH is comparable to the Italian Cavour of 244 meters [some reports claim 284 meters or 925 feet for the 22DDHH, but this seems to be wrong]. The full-length aircraft carrier type deck extends from the bow to the stern. The light displacement was reported as 19,500 tons, a 44% increase over the 16DDH, while the full loaded displacement is probably comparable to the 27,000 ton displacement of the Italian Cavour.

The "helicopter destroyer" looks like an aircraft carrier, which raised questions that it would violate Japan's pacifist Constitution. As in the Vietnam War and the war in Iraq, aircraft carriers have been a main maritime base of attack for the US military. In light of the constitutional ban in Article 9 on possessing "land, sea and air forces, as well as other war potential," the government in 1988 issued a statement that said, "Because offensive aircraft carriers exceed the war potential needed for a minimum level of self-defense, possession of such ships is prohibited by the Constitution."

As of 2010 the MSDF possessed about 50 major surface combatants, including Small Destroyers [Frigates, Corvettes]. In line with the budget request for the helicopter destroyer, the decommissioning of four other destroyers in addition to the Shirane would be moved up and no replacement ships constructed. The total number of destroyers possessed by the MSDF would decrease, but one high-ranking officer said, "We hope to gain the understanding of the public by not only constructing the necessary ships, but also showing that we are ready to decrease equipment that can be eliminated."

"Helicopters are needed to seek out and keep an eye on submarines as well as to patrol surface ships from as far away as possible outside the range of enemy missiles," a ministry official said. "For those reasons, a large destroyer that can carry many helicopters is necessary." To allow up to five surveillance helicopters to land and take off simultaneously, the bridge of the new helicopter destroyer is on the starboard side to make room for an uninterrupted flight deck.

The new 22DDh is reported to have a capability to transport up to 4,000 people and 50 trucks. It would also be able to refuel other ships. According to the MoD, each of the 22DDH would accommodate nine helicopters simultaneously operating on flight deck [5 more than the 16DDH], and 14 helicopters in the hangar deck [3 more than the 16DDH]. The 22DDH would be fitted with two close-in weapon systems and two Sea RAM missile systems for air defence. The anti-submarine warfare armament includes a mobile decoy and floating acoustic jammer.

The main component of the MSDF fleet is its four destroyer flotillas, each with eight destroyers and eight helicopters. Those numbers were arrived at during the Cold War to counter Soviet submarines plying the waters around Japan. More recently, the Chinese navy has been strengthening its sea attack capabilities. Advanced Chinese destroyers carrying cruise missiles have been spotted near gas fields in the East China Sea.

Another reason for building the large helicopter destroyer is to respond to the expected increase in emergency assistance missions. Participation in international peacekeeping activities was upgraded to a primary task of the SDF, opening the path for more dispatches both in Japan and abroad. Such deployments would become much more efficient, as the new 22DDH helicopter destroyer would be capable of performing as a transport and supply ship. Not only will the helicopter destroyer be able to transport a large number of Ground SDF members and vehicles, but it could also provide fuel to other MSDF ships in its flotilla. That would eliminate the need for ships to drop anchor to refuel. The underway replenishment function is about half that of the existing supply ship.

Japanese officials said the ship would refuel other vessels, transport personnel and equipment, and conduct surveillance of surrounding waters. "Rather than constructing destroyers as destroyers and supply ships as supply ships, building ships that have multiple functions would lead to more efficient use of the budget," a high-ranking Japanese officer explained. "One reason the ship is so large is because we have included a number of functions in it."

A Defense Ministry official explained: "The ship would be a destroyer to transport personnel and supplies in response to major natural disasters in Japan and abroad as well as to carry aircraft necessary for continuous surveillance of waters around Japan. The ship will be incapable of having fighter jets land on and take-off from the deck, and we have no such intentions. It is not an offensive aircraft carrier."

The DDH22 is intended as a replacement to the decommissioning of Shirane-class destroyers, thereby reducing the size of MSDF's overall force. Furthermore, the ship lacks potential offensive capabilities, like a ski-jump ramp which would allow it to be deployed as a light aircraft carrier. The Defense Ministry has also specified the destroyer's mission scope and offensive limitations, insisting that "the ship will be incapable of having fighter jets land on and take-off from the deck".

The 22DDH could possibly use the F-35B carrier-based aircraft, and so might be considered as a light aircraft carrier. First, it is necessary to meet thermal performance of the deck, the condition of the weight of the aircraft carrier take-off and landing is light. Since laying an enhanced deck is possible, the thermal performance of the deck would not be a problem for Japan. The maximum take-off weight of the F-35B will reach 27 tons, but for take-off and landing of large carrier-based aircraft, this is also not an issue. The 22DDH could possibly accomodate 12 or more F-35B carrier-based aircraft. The F-35B fighter has a vertical takeoff and landing capability, so that even though the 22DDH is not equipped with a catapult, there is no problem operating the F-35B with flat deck withouth a ski-jump. The new "22DDH" is larger medium-sized regular aircraft carriers of the former Imperial Navy that attacked Pearl Harbor.

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