Lewis and Clark-class (T-AKE-1)

The Lewis and Clark class comprises 14 dry cargo/ammunition ships (T-AKE) operated by Military Sealift Command for the United States Navy. General Dynamics NASSCO received the detailed design and construction contract in October 2001, and the ships were built at the company's San Diego yard between 2001 and 2012. The class replaced eighteen ships: the Mars- and Sirius-class combat store ships and the Kilauea-class ammunition ships. Operating together with a Henry J. Kaiser-class replenishment oiler, the Lewis and Clarks also took over the role of the Sacramento-class fast combat support ships. Serial production reduced build effort across the run: T-AKE-7 required fewer than half the worker-hours of T-AKE-1 and 37 percent less total construction time.

The ships were built to commercial American Bureau of Shipping standards rather than military standards, a decision taken to hold down cost and to test competitive construction on the civilian market. Additional features were incorporated to improve survivability, including an advanced degaussing system to reduce the magnetic signature against mines, shock hardening of selected equipment, emergency power and communications, and expanded damage control provisions for firefighting and stability. Atomic, biological and chemical countermeasures are fitted, along with AN/SLQ-25 Nixie torpedo countermeasures; an acoustic trial by T-AKE-4 off San Clemente Island demonstrated that Nixie could mask the ship's acoustic signature. Because the ships are civilian-crewed, active self-defence is limited to .50 calibre machine guns, with space, weight and power reserved for a close-in weapon system. Sensors comprise an I/J-band surface search radar and an I-band navigational radar. Propulsion is integrated electric, with two Fairbanks-Morse/MAN Diesel 8L48/60A and two 9L48/60A diesel engines feeding a 6.6 kV high-voltage system with GE Power Conversion generators, motors and drives, driving a single shaft through tandem propulsion electric motors. Cargo capacity is 1,388,000 cubic feet plus 23,450 barrels of fuel, and the flight deck and hangar support two vertical replenishment helicopters.

As part of the Naval Fleet Auxiliary Force, the T-AKEs deliver ammunition, provisions, stores, spare parts, potable water and petroleum products to carrier strike groups and other naval forces, working as shuttle ships or station ships. In the station-ship role they pair with a Henry J. Kaiser-class oiler (T-AO 187) to provide direct logistics support within a carrier strike group. USNS Lewis and Clark (T-AKE-1) and USNS Sacagawea (T-AKE-2) were assigned to one of the two active Maritime Prepositioning Ship squadrons, forward deployed in the Western Pacific and Indian Ocean, tasked with selective offload of cargo to sustain U.S. Marine Corps forces ashore; they are otherwise identical to T-AKE-3 through T-AKE-14.

Lewis and Clark was placed in service in June 2006 and returned to Naval Station Norfolk, Virginia, on 8 February 2008 from a six-month deployment to the U.S. Central Command area, resupplying ships in the Persian Gulf, around the Horn of Africa and along the Somali coast. Richard E. Byrd (T-AKE-4) entered the 7th Fleet area of operations on 24 July 2008, the first of the class to do so. Sacagawea began its first deployment to the 5th Fleet area on 11 December 2008. The final ship, USNS Cesar Chavez (T-AKE-14), was delivered on 24 October 2012. All 14 remain in service.