LHD

LHD
Name	LHD
Type	Amphibious assault ship / helicopter destroyer

LHD

LHD denotes a class of amphibious assault ships often described as helicopter carriers or helicopter destroyers that combine aviation, amphibious, and command capabilities. These vessels bridge expeditionary United States Marine Corps expeditionary operations, Royal Navy carrier doctrine, and Japan Maritime Self-Defense Force maritime strategy, enabling power projection, humanitarian assistance, and crisis response. They appear alongside other capital ships such as aircraft carriers, amphibious transport docks, and dock landing ships in modern fleets.

Definition and Overview

LHDs are large-deck warships configured to operate rotary-wing aircraft, tiltrotor platforms, and amphibious landing craft while supporting embarked marine or marine-equivalent forces. Design philosophies link to developments in Amphibious Ready Group concepts, Expeditionary Strike Group organization, and doctrines influenced by operations like Operation Enduring Freedom, Operation Iraqi Freedom, and Humanitarian assistance and disaster relief operations such as responses to 2011 Tōhoku earthquake and tsunami. Their roles often overlap with vessels such as Wasp-class amphibious assault ship, Izumo-class helicopter destroyer, and Mistral-class amphibious assault ship.

Types and Variants

Variants of LHD-type ships reflect national priorities and industrial capabilities. Notable families include designs derived from Tarawa-class amphibious assault ship lineage, the Juan Carlos I multi-purpose amphibious assault ship concept, and derivative classes influenced by HMS Ocean conversions and Hyūga-class destroyer developments. Differences appear between pure aviation-centric decks, hybrid well-deck-equipped models like some Wasp-class designs, and "flat-top" ships optimized for V-22 Osprey tiltrotor operations and short takeoff/vertical landing (STOVL) jets such as the F-35B Lightning II.

Design and Technical Features

Typical features include full-length flight decks, aircraft elevators, hangar decks, command centers, medical facilities, and amphibious well decks to launch LCAC and conventional landing craft. Propulsion ranges from conventional diesel-electric plants to combined gas and gas (COGAG) systems found in larger aircraft carrier designs; survivability elements often borrow from Aegis Combat System-equipped ships for sensor and command integration. Aviation systems accommodate helicopters like the CH-53 Sea Stallion, tiltrotors like the Bell Boeing V-22 Osprey, and STOVL jets such as the Lockheed Martin F-35B. Defensive armament may include close-in weapon systems exemplified by Phalanx CIWS, surface-to-air missile launchers like Sea Sparrow, and electronic warfare suites akin to those on Type 45 destroyers.

Operational History

LHD-type vessels gained prominence during late 20th- and early 21st-century expeditionary operations, supporting amphibious assaults, non-combatant evacuation operations (NEO), and multinational exercises with partners including NATO, United Nations, and regional coalitions. They were integral to amphibious operations in contexts related to Persian Gulf conflicts and humanitarian missions during crises such as Hurricane Katrina responses and seismic disasters in the Indian Ocean. Modern deployments emphasize joint interoperability with forces from nations like Australia, France, Japan, and South Korea through bilateral and multilateral drills.

Role and Tactics

Operational doctrine for LHD-type ships emphasizes combined-arms amphibious assault, sea-basing for expeditionary units, and aviation-centric maneuver employing helicopters, tiltrotors, and STOVL aircraft for vertical envelopment. Tactics integrate amphibious assault from over-the-horizon using assets such as Landing Craft Air Cushion and AAVP-7A1 amphibious vehicles, supported by shipboard aviation and command-and-control nodes linked to formations including Carrier Strike Group and Expeditionary Strike Group. They also serve as afloat forward staging bases akin to ESB conversions for special operations and as platforms for humanitarian relief with onboard hospital facilities comparable to those on Hospital ship USNS Comfort-class missions.

Notable Examples and Operators

Prominent examples and operators include: - United States Navy: Wasp-class amphibious assault ship, America-class amphibious assault ship. - French Navy: Mistral-class amphibious assault ship. - Spanish Navy: Juan Carlos I (L61), Juan Carlos I-class amphibious assault ship. - Italian Navy: Cavour (550), Giuseppe Garibaldi (551) derivatives. - Royal Navy / Japan Maritime Self-Defense Force influences: HMS Ocean, Izumo-class helicopter destroyer, Hyūga-class destroyer. - Royal Australian Navy: Canberra-class landing helicopter dock. - Republic of Korea Navy: Dokdo-class amphibious assault ship. - Brazilian Navy: São Paulo (A12) derivatives and acquisition programs. - Spanish Navy and Turkey have operated or designed variants linked to Navantia and Sedef Shipyard projects.

Category:Amphibious warfare ship types