UNITED STATES NAVY (UNITED STATES OF AMERICA)

Project history: A new LSD41 class was proposed to replace the eight Thomastons, but the Carter Administration deferred construction until Congress voted $41m in long-lead items in FY80; the Administration then announced the construction of six ships in alternate years, beginning in FY81. LSD41 has an enlarged well deck, 134.1x15.2m, adapted to carry four air cushion landing craft (LCAC) or twenty-one conventional LCM (6) landing craft; by way of comparison, the LHD will carry only three LCAC. Docking well can be flooded to 1.8m fwd/3.0m aft, when ship takes 12860t of water ballast. Ships also have 64.6x25.3m flight deck for up to CH-53E-size helicopters but with no hangars. 90t of aviation fuel are carried. There is 1214m² of vehicle parking space and 149m³ hold for palletized cargo fwd of the docking well.

    LSD41 was conceived as a near-repeat of Anchorage (LSD36) adapted to LCACs rather than LCMs. That required not only enlargement of the well deck, but also raising the helicopter deck to provide all-round ventilation for LCAC gas turbines. LSD 44-48 are further modified to incorporate collective protection against chemical or biological weapons.

    LSD49 and beyond are a modified Whidbey Island design, officially called the LSD41 Cargo Variant. They were originally requested under the FY88 budget, then withdrawn due to late design changes, and then approved by Congress. The idea originated in an analysis of Marine amphibious assault requirements, which showed that more cargo space was needed, but not in the ratio to LCAC 'spots' implicit in the LSD41 design. LSD49 was conceived as a simple substitution of cargo volume for well deck volume (leaving space for two LCAC or ten LCM).

    Plans called for a total of ten, beginning with LSD49 in FY88, LSD50 in FY90, then one per year after that. The 1992 budget stopped production at LSD51, but Congress included LSD52 in the FY92 programme.