What is an APA?

Amphibious cargo ships were U.S. Navy ships designed specifically to carry troops, heavy equipment and supplies in support of amphibious assaults, and to provide naval gunfire support during those assaults. A total of 108 of these ships were built between 1943 and 1945—which worked out to an average of one ship every eight days. Six additional AKAs, featuring new and improved designs, were built in later years.They were originally called Attack Cargo Ships and designated AKA. In 1969, they were renamed as Amphibious Cargo Ships and redesignated LKA.

Compared to other cargo ship types, these ships could carry landing craft, were faster, had more armament, and had larger hatches and booms. Their holds were optimized for combat loading, a method of cargo storage where the items first needed ashore were at the top of the hold, and those needed later were lower down. Because these ships went into forward combat areas, they had Combat Information Centers and significant amounts of equipment for radio communication, neither of which were present in other cargo ships.

As amphibious operations became more important in World War II, planners saw the need for a special kind of cargo ship, one that could carry both cargo and the LCM and LCVP boats with which to attack the beach, and that carried guns to assist in anti-air defense and shore bombardment. Specifications were drawn up, and beginning in early 1943, the first 16 U.S. attack cargo ships were converted from Navy cargo ships that had previously been designated AK. During the course of the war, 108 such ships were built; many of them were converted from non-military ships, or started out as non-military hulls.

Attack cargo ships played a vital role in the Pacific War, where many were attacked by kamikazes and other aircraft, and several were torpedoed, but none were sunk or otherwise destroyed. Nine AKAs were present at the surrender ceremony in Tokyo Bay on 2 September 1945.

After the war, many AKAs were put into the National Defense Reserve Fleet. Others were converted for other uses, such as oceanographic surveying, undersea cable laying, and repairing other ships.

Some of the reserve ships were recommissioned for service in the Korean War, and some stayed in service during the Vietnam War.

Six more amphibious cargo ships, somewhat larger and of improved design, were built between 1954 and 1969.

In 1969, the U.S. Navy redesignated all its AKA attack cargo ships as LKA amphibious cargo ships. At the same time, the other "A" designations of amphibious ships were changed to similar "L" designations. For example, all the APAs were redesignated as LPAs.

In the 1960s, both the United States Navy and the British Royal Navy developed amphibious transport docks which gradually took on this unique amphibious role and today have assumed it completely. The last amphibious cargo ship in the U. S. Navy, USS El Paso (LKA-117), was decommissioned in April, 1994.

The Landing Craft Infantry (LCI) were several classes of seagoing amphibious assault ships of the Second World War used to land large numbers of infantry directly onto beaches. They were developed in response to a British request for a vessel capable of carrying and landing substantially more troops than their smaller Landing Craft Assault (LCA). The result was a small steel ship that could land 200 troops, traveling from rear bases on its own bottom at a speed of up to 15 knots. Some 923 were built starting in 1943, serving in both the Pacific and European theaters, including a number that were converted into heavily armed beach assault support ships.

Development

The LCI(L) was designed to carry 200 troops at up to 15 knots and be as capable at landing as the LCA. Since a steel hull would be needed, and steel was already earmarked for building destroyers at home, the U.S was approached. There the plans were developed into the LCI(L) - Landing Craft Infantry (Large). The original British design was envisioned as being a "one time use" vessel which would simply ferry the troops across the English Channel, and were considered an expendable vessel. As such, no troop sleeping accommodations were placed in the original design. The troops were provided benches (similar to a ferry) upon which to sit while they were transported across the channel. This was changed shortly after initial use of these ships, when it was discovered that many missions would require overnight accommodations. The US was able to come up with an easily built and mass-produced design by using non-traditional shipbuilding facilities and equipment. The US established LCI building yards at ten different locations.

Propulsion

All LCI(L) were twin shaft propelled by two banks of Detroit Diesel 6-71 "Quad" Diesel engines that produced a total of 1600 BHP. These engines were a wartime expedient design that utilized existing and readily available engines. Four 2-stroke Detroit Diesel 6-71 (inline 6 cylinder with 71 cubic inch displacement per cylinder) with Roots blower were coupled to create a bank for each of the two propeller shafts. The 4 engines per bank were joined together using individual drive clutches hence the name "Quad Diesel". If a single engine were to fail, the broken engine could be disconnected from the unit via its clutch and repaired while the other 3 engines were still operating. General Motors Corporation Electro-Motive Division supplied the reduction gears, propellers, drive shafts and control units. Each of the two propellers was a reversible pitch propeller, which allowed the propeller shaft to spin only in one direction for either ahead or astern operation. This, coupled with the use of a stern anchor which was dropped as the ship approached the beach, was used to pull the ship off the beach after the troops had disembarked. Two auxiliary Detroit Diesel 2-71's drive the two 30Kw 120V D.C. Ship's Service Generators.

Armament

LCI(L) were armed originally with four to five 20mm Oerlikon automatic cannons. Each gun was mounted inside of a round gun tub with an integral splinter shield. As the war progressed, several LCI(L) were modified into LCI Gunboats. These gunboats, called LCI(G) had three of their forward mounted 20mm Oerlikon cannons removed and replaced with heavier single barrel 40mm Bofors cannons. Also, several LCI(L) had various types of Rocket Launcher racks added in place of their side ramps and inside their well decks. These ships were sometimes designated as LCI(R) for Rocket Ships. Still other LCI(L) were modified to carry three 4.2 inch Heavy Mortars. These were designated as LCI(M).

Construction

There were 3 major types of LCI(L) which differed mostly by the location of the ramps and by the shape of the conning tower. All of these ships had similar hulls. The hull of all LCI(L) were 158 ft (48 m) long with a 23-foot beam, making them relatively long and narrow.

The 3 major LCI(L) types are normally referred to as: a) Square Conning tower, Side Ramp (the original style) b) Round Conn, Side Ramp c) Round Conn, Bow Ramp.

On LCI(L)1-349 class, (Square Conn, Side Ramps) the deck was wider than the prow and two gangways on either side of the bow led onto a pair of ramps that were lowered, and down which troops would disembark. The LCI 350 class had a single enclosed bow ramp with 2 bow doors that swung open. The reason for moving the ramp to the inside was to provide some protection for the troops as they disembarked to the beach, if only by concealing them from enemy sight. Also, the low, squared-off conning tower was upgraded on later models (LCI(L)350 and higher) with a taller, round conning tower which afforded slightly more visibility from the bridge.

The steepness and narrowness of either type of bow ramps made the LCI impractical for landing troops as part of an initial assault against a defended beach, and they were sometimes reserved for the follow-up waves, after the LCA or LCPL boats had landed. However, they were included in the first waves at numerous invasions such as Anzio, Normandy, Southern France, Elba, Saipan, the Philippines, Iwo Jima, Guam, and Okinawa.