UNITED STATES NAVY (UNITED STATES OF AMERICA)

Project history: LCAC are intended to move heavy equipment from beyond the horizon over a beach. An LCAC can also cross a wider variety of beaches than an LCU. In the late 1970s this concept was developed (as JEFF B) in competition with a hard-chine planing craft, which would have been less expensive, but which could not have carried its cargo past the surf zone. The first two were authorised in FY82, for a total of ninety-one; the programme initially envisaged a total of 108. Because an LCAC is substantially larger than an LCU, dock landing ships designed to accommodate several of the latter often cannot accommodate more than one LCAC. The new generation of ships (LHD, LSD 41/49, LPD17) are all sized to take several LCACs.

    Because well deck temperatures can be quite high (and noise levels intense), these craft have separate troop compartments (for a total of 25 troops). Modular troop compartments, to be acquired 1994-95, will accommodate 180 troops or 150 litters. Several LCACs may be used for mine countermeasures, partly because their well decks offer considerable spice to handle gear and partly because the air cushion may reduce the shock effect of mines. M58 Minesweeping modules, comparable to equipment on MH-53E helicopters, are used

Compared to an LCU, an LCAC carries less than half as much weight (75t vs 180t) at much higher speed (50kts vs 11kts). It is also far more expensive, relatively delicate, and far more difficult to repair in the event of battle damage or accident. Its rationale is that a force beyond the horizon can mount assaults over so broad an area that it cannot readily be defended against, at least at the surf line: the assault ought therefore to be unresisted (over the horizon assault also limits the exposure of the valuable big amphibious ships to coast defence missiles).