The tank landing ship (LST, for "Landing Ship, Tank") was created during World War II to support amphibious operations by carrying significant quantities of vehicles, cargo, and troops directly onto an unimproved shore. More than a thousand of these ships were laid down in the United States during WWII.
The British evacuation from Dunkirk in 1940 demonstrated to the Admiralty that the Allies needed relatively large, ocean-going ships capable of shore-to-shore delivery of tanks and other vehicles in amphibious assaults upon the continent of Europe. As an interim measure, three medium-sized tankers, built to pass over the restrictive bars of Lake Maracaibo, Venezuela, were selected for conversion because of their shallow draft. Bow doors and ramps were added to these ships which became the first tank landing ships (LSTs). They later proved their worth during the invasion of Algeria in 1942, but their bluff bows made for inadequate speed and pointed up the need for an all-new design incorporating a sleeker hull.
At their first meeting at the Argentia Conference in August 1941, President Franklin Roosevelt and Prime Minister Winston Churchill confirmed the Admiralty's views. In November 1941, a small delegation from the Admiralty arrived in the United States to pool ideas with the Navy's Bureau of Ships with regard to development of the required ship. During this meeting, it was decided that the Bureau of Ships would design these vessels.
Within a few days, John Niedermair of the Bureau of Ships sketched out an awkward looking ship that proved to be the basic design for the more than 1,000 LSTs which would be built during World War II. To meet the conflicting requirements of deep draft for ocean travel and shallow draft for beaching, the ship was designed with a large ballast system that could be filled for ocean passage and pumped out for beaching operations. The rough sketch was sent to Britain on 5 November 1941 and accepted immediately. The Admiralty then requested the United States to build 200 LSTs for the Royal Navy under the terms of lend-lease.
The preliminary plans initially called for an LST 280 feet (85 m) in length; but, in January 1942, the Bureau of Ships discarded these drawings in favor of specifications for a ship 290 feet long. Within a month, final working plans were developed which further stretched the overall length to 328 feet (100 m) and called for a 50-foot (15 m) beam and minimum draft of 3.8 feet (1.2 m). This scheme distributed the ship's weight over a greater area enabling her to ride higher in the water when in landing trim. The LST could carry a 2,100-ton (1,900 t) load of tanks and vehicles. The larger dimensions also permitted the designers to increase the width of the bow door opening and ramp from 12 to 14 feet (3.7 to 4.3 m) and thus accommodate most Allied vehicles. Provisions were made for the satisfactory ventilation of the tank space while the tank motors were running, and an elevator was provided to lower vehicles from the main deck to the tank deck for disembarking. By January 1942, the first scale model of the LST had been built and was undergoing tests at the David Taylor Model Basin in Washington, D.C.
In three separate acts dated 6 February 1942, 26 May 1943, and 17 December 1943, Congress provided the authority for the construction of LSTs along with a host of other auxiliaries, destroyer escorts, and assorted landing craft. The enormous building program quickly gathered momentum. Such a high priority was assigned to the construction of LSTs that the keel of an aircraft carrier, previously laid in the dock, was hastily removed to make place for several LSTs to be built in her stead. The keel of the first LST was laid down on 10 June 1942 at Newport News, Va., and the first standardized LSTs were floated out of their building dock in October. Twenty-three were in commission by the end of 1942.
The LST building program was unique in several respects. As soon as the basic design had been developed, contracts were let and construction was commenced in quantity before the completion of a test vessel. Preliminary orders were rushed out verbally or by telegrams, telephone, and air mail letters. The ordering of certain materials actually preceded the completion of design work. While many heavy equipment items such as main propulsion machinery were furnished directly by the Navy, the balance of the procurement was handled centrally by the Material Coordinating Agency—an adjunct of the Bureau of Ships—so that the numerous builders in the program would not have to bid against one another. Through vigorous follow-up action on materials ordered, the agency made possible the completion of construction schedules in record time.
The need for LSTs was urgent, and the program enjoyed a high priority throughout the war. Since most shipbuilding activities were located in coastal yards and were largely used for construction of large, deep-draft ships, new construction facilities were established along inland waterways. In some instances, heavy-industry plants such as steel fabrication yards were converted for LST construction. This posed the problem of getting the completed ships from the inland building yards to deep water. The chief obstacles were bridges. The Navy successfully undertook the modification of bridges and, through a "Ferry Command" of Navy crews, transported the newly constructed ships to coastal ports for fitting out. The success of these "cornfield" shipyards of the Middle West was a revelation to the long-established shipbuilders on the coasts. Their contribution to the LST building program was enormous. Of the 1,051 LSTs built during World War II, 670 were constructed by five major inland builders.
By 1943, the construction time for an LST had been reduced to four months; and, by the end of the war, it had been cut to two months. Considerable effort was expended to hold the ship's design constant; but, by mid-1943, operating experience led to the incorporation of certain changes in the new ships. These modifications included: the replacing of the elevator by a ramp from the main deck to the tank deck, an increase in armament, and the addition of a distilling plant to make potable water. The main deck was strengthened to accommodate a fully-equipped landing craft tank (LCT).
Service in World War II
From their combat debut in the Solomon Islands in June 1943 until the end of the hostilities in August 1945, the LSTs performed a vital service in World War II. They participated in the invasions of Sicily, Italy, Normandy, and southern France in the European Theater and were an essential element in the island-hopping campaigns in the Pacific which culminated in the liberation of the Philippines and the capture of Iwo Jima and Okinawa.
The LST proved to be a remarkably versatile ship. A number of them were converted to become landing craft repair ships (ARL). In this design, the bow ramp and doors were removed, and the bow was sealed. Derricks, booms, and winches were added to haul damaged landing craft on board for repairs, and blacksmith, machine, and electrical workshops were provided on the main deck and tank deck.
Another successful conversion was the LST "Mother Ship". This version of the standard LST hull had two Quonset huts erected on the main deck to accommodate 40 officers. Bunks on the tank deck berthed an additional 196 men. A bake shop and 16 refrigeration boxes for fresh provisions augmented the facilities normally provided the crew. Four extra distilling units were added, and the ballast tanks were converted for storage of fresh water.
Thirty-eight LSTs were converted to serve as small hospital ships. They supplemented the many standard LSTs which removed casualties from the beach following the landing of their cargo of tanks and vehicles. For example, on D-Day, LSTs brought 41,035 wounded men back across the English Channel from the Normandy beaches. Other LSTs, provided with extra cranes and handling gear, were used exclusively for replenishing ammunition. They possessed a special advantage in this role, as their size permitted two or three LSTs to go simultaneously alongside an anchored battleship or cruiser to accomplish replenishment more rapidly than standard ammunition ships. In the latter stages of World War II, some LSTs were even fitted with flight decks from which small observation planes were sent up during amphibious operations.
Throughout the war, LSTs demonstrated a remarkable capacity to absorb punishment and survive. Despite the sobriquet, "Large Slow Target", which was applied to them by irreverent crew members, the LSTs suffered few losses in proportion to their number and the scope of their operations. Their brilliantly conceived structural arrangement provided unusual strength and buoyancy. Although the LST was considered a valuable target by the enemy, only 26 were lost due to enemy action, and a mere 13 were the victims of weather, reef, or accident. A total of 1,152 LSTs were contracted for in the great naval building program of World War II, but 101 were cancelled in the fall of 1942 because of shifting construction priorities. 0f 1,051 actually constructed, 113 LSTs were transferred to Britain under the terms of Lend-Lease, and four more were turned over to the Greek Navy. Conversions to other ship types with different hull designations accounted for 116.
Post war developments
The end of World War II left the Navy with a huge inventory of amphibious ships. Hundreds of these were scrapped or sunk, and most of the remaining ships were put in "mothballs" to be preserved for the future. Consequently, construction of LSTs in the immediate post-war years was modest. LST-1153 and LST-1154, commissioned respectively in 1947 and 1949, were the only steam-driven LSTs ever built by the Navy. They provided improved berthing arrangements and a greater cargo capacity than their predecessors.
The success of the amphibious assault at Inchon during the Korean War pointed up the utility of LSTs once again. This was in contrast with the earlier opinion expressed by many military authorities that the advent of the atomic bomb had relegated amphibious landings to a thing of the past. As a consequence, 15 LSTs of what were later to be known as the Terrebonne Parish-class were constructed in the early 1950s. These new LSTs were 56 feet longer and were equipped with four, rather than two, diesel engines, which increased their speed to 15 knots. Three-inch 50-caliber twin mounts replaced the old twin 40-millimeter guns, and controllable pitch propellers improved the ship's backing power. On 1 July 1955, county or parish names (Louisiana counties are called "parishes") were assigned to LSTs, which up to then had borne only a letter-number hull designation.
In the late 1950's, seven additional LSTs of the De Soto County-class were constructed. These were an improved version over earlier LSTs, with a high degree of habitability for the crew and embarked troops. Considered the "ultimate" design attainable with the traditional LST bow door configuration, they were capable of 17.5 knots.
The commissioning of Newport (LST-1179) in 1969 marked the introduction of an entirely new concept in the design of LSTs. She was the first of a new class of 20 LSTs capable of steaming at a sustained speed of 20 knots. To obtain that speed, the traditional blunt bow doors of the LST were replaced by a pointed ship bow. Unloading is accomplished through the use of a 112-foot (34 m) ramp operated over the bow and supported by twin derrick arms. A stern gate to the tank deck permits unloading of amphibious tractors into the water or the unloading of other vehicles into a landing craft, utility (LCU) or onto a pier. Capable of operating with today's high speed amphibious squadrons consisting of LHAs, LPDs, and LSDs, the Newport-class LST can transport tanks, other heavy vehicles, and engineer equipment which cannot readily be landed by helicopters or landing craft. Thus, the utility of the LST seems to be assured far into the future.
LST-1 Class Specifications:
- unloaded: 1,780 t (1,600 t),
- fully loaded: 3,880 t (3,500 t)
- Length: 328 ft (100 m)
- Beam: 50 ft (15 m)
- Draft unloaded: bow 2 ft 4 in (0.7 m); stern 7 ft 6 in (2.3 m)
- loaded: bow 8 ft 2 in (2.5 m); stern 14 ft 1 in (4.3 m)
- Speed: 12 knots (22 km/h)
- Complement: 8 to 10 officers, 100 to 115 enlisted;
- Troop Capacity: approx. 140 officers and enlisted;
- Boats: 2-6 LCVP;
- Armament: 1 x 3 in (76 mm) gun
- 6 x 40 mm gun
- 6 x 20 mm gun
- 2 x .50 cal (12.7 mm) machine guns,
- 4 x .30 cal (7.62 mm) machine guns;
- Propulsion: two General Motors 12-567 diesel engines, two shafts, twin rudders.