Wasp-class amphibious assault ship

The Wasp class is a class of Landing Helicopter Dock (LHD) amphibious assault ships operated by the United States Navy. Based on the Tarawa class, with modifications to operate more advanced aircraft and landing craft, the Wasp class is capable of transporting almost the full strength of a United States Marine Corps Marine Expeditionary Unit (MEU), and landing them in hostile territory via landing craft or helicopters. All Wasp-class ships were built by Ingalls Shipbuilding, at Pascagoula, Mississippi, with lead ship USS Wasp (LHD-1) commissioned on 29 July 1989. Eight Wasp-class ships were built, and, all eight are active.

Design
The Wasp class is based on the preceding Tarawa-class design. The design was modified to allow for the operation of AV-8B Harrier II aircraft and Landing Craft Air Cushion (LCAC) hovercraft, making the Wasp class the first ships specifically designed to operate these. The main physical changes between the two designs are the lower placement of the ship's bridge aboard the Wasps, the relocation of the command and control facilities to inside the hull, the removal of the 5-inch Mk 45 naval guns and their sponsons on the forward edge of the flight deck, and a lengthening of 24 ft to carry the LCACs.

Each Wasp class ship has a displacement of 41150 MT at full load, is 253.2 m long, has a beam of 31.8 m, and a draft of 8.1 m. For propulsion, most of the ships are fitted with two steam boilers connected to geared turbines, which deliver 70,000 shaft horsepower (33,849 kW) to the two propeller shafts. This allows the LHDs to reach speeds of 22 kn, with a range of 9500 nmi at 18 kn. The last ship of the class, USS Makin Island (LHD-8), was instead fitted with two General Electric LM2500 geared gas turbines. The ship's company consists of 1,208 personnel. The ships are the largest amphibious warfare vessels in the world.

Amphibious operations
The LHDs can support amphibious landings in two forms: by landing craft, or by helicopter. In the 81 by well deck, the LHDs can carry three Landing Craft Air Cushion, twelve Landing Craft Mechanised, or 40 Amphibious Assault Vehicles (AAVs), with another 21 AAVs in the vehicle deck. The flight deck has nine helicopter landing spots, and can operate helicopters as large as the Sikorsky CH-53 Sea Stallion and Boeing Vertol CH-46 Sea Knight. The size of the air group varies depending on the operation: a standard air group consists of six Harriers and four Bell AH-1W SuperCobras for attack and support, twelve Sea Knights and four Sea Stallions for transport, and three to four Bell UH-1N Iroquois utility helicopters. For a full assault, the air group can be maxed out at 42 Sea Knights, while a Wasp operating in the sea control or 'harrier carrier' configuration carries 20 Harriers (though some ships of the class have operated as many as 24), supported by six Sikorsky SH-60 Seahawk helicopters for anti-submarine warfare. The CH-46 is being replaced by the MV-22 Osprey on a squadron-by-squadron basis, with expected full conversion within all aviation combat elements by 2019. Two aircraft elevators move aircraft between the flight deck and the hangar; in order to transit the Panama Canal, these elevators need to be folded in.

Each ship is capable of hosting 1,894 personnel of the United States Marine Corps; almost the full strength of a Marine Expeditionary Unit (MEU). A Wasp-class vessel can transport up to 2860 m2 of cargo, and another 1858 m2 is allocated for the MEU's vehicles, which typically consists of 5 M1 Abrams battle tanks, up to 25 AAVs, eight M198 howitzers, 68 trucks, and up to 12 other support vehicles. An internal monorail is used to shift cargo from the cargo holds to the well deck.

Each Wasp-class ship has a hospital with 64 patient beds and six operating rooms. An additional 536 beds can be set up in an "Overflow Casualty Ward" as needed.

Armament and sensors
The armament of the first four Wasp class consists of two Mark 29 octuple launchers for RIM-7 Sea Sparrow missiles, two Mark 49 launchers for RIM-116 Rolling Airframe Missiles, three 20 mm Phalanx CIWS systems, four 25 mm Mark 38 chain guns, and four .50 BMG machine guns. The next three ships, USS Bataan (LHD-5), USS Bonhomme Richard (LHD-6), and USS Iwo Jima (LHD-7), have a slightly reduced weapons outfit to their preceding sister ships, with one Phalanx and one Mark 38 gun removed.

Countermeasures fitted to the ships include four to six Mark 36 SRBOC launchers, an AN/SLQ-25 torpedo decoy, AN/SLQ-49 chaff buoys, a Sea Gnat missile decoy, and an AN/SLQ-32 Electronic Warfare Suite.

The sensor suite fitted to each ship is made up of an AN/SPS-48 or AN/SPS-52 air-search radar backed up by an AN/SPS-49 air-search radar, an SPS-67 surface search radar, an AN/URN-25 TACAN system, along with several other radars for navigation and fire control.

Construction
All Wasp-class ships were built by Ingalls Shipbuilding, at Pascagoula, Mississippi. The first ship of the class, USS Wasp (LHD-1), was commissioned on 29 July 1989.

The fifth ship of the class, USS Bataan (LHD-5), was constructed through a process of modular assembly and pre-fitting out, which meant that the LHD was almost 75% complete when launched. Bataan was also the first LHD built to house female personnel (as opposed to modified after completion), with dedicated berths for up to 450 female Navy or Marine personnel.

Ships and homeports

 * USS Wasp (LHD-1), Norfolk, Virginia
 * USS Essex (LHD-2), San Diego, California
 * USS Kearsarge (LHD-3), Norfolk, Virginia
 * USS Boxer (LHD-4), San Diego, California
 * USS Bataan (LHD-5), Norfolk, Virginia
 * USS Bonhomme Richard (LHD-6), Sasebo, Japan
 * USS Iwo Jima (LHD-7), Norfolk, Virginia
 * USS Makin Island (LHD-8), San Diego, California