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LST-1 Landing Ship, Tank

The Tank Landing Ship or LST was the only ship designed and built for the Navy with thecapability to land on beaches, unload troops and supplies and then retract off the beach. The LST is a shallow drafted vessel with a flat bottom, bow doors and stem anchor with 900 feet of 1-5/8 cable. During landing operations, the anchor is dropped allowing the cable to unroll off a winch. After unloading, the winch is engaged and the LST is pulled from the beach. The anchor also helped stabilize the ship while it was on the beach.

The unloading took place through the bow doors. There was an elevator on the first LSTs but on later models, a ramp replaced the elevator. The ramp connects the main deck to the tank deck. Troops disembarked either through the bow doors or via cargo net on the side of the ship. LSTs were also equipped with a floating causeway which was used as an extension of the ship to the beach and facilitated unloading.

The LST was powered by two diesel engines. The diesel engine is an internal combustion power unit, in which the heat of the air being compressed is sufficient to ignite the diesel fuel as it is injected directly into the cylinder. Diesel engines differ from gasoline engines principally because they do not require an ignition system to sustain operation. The transfer of power from the V-12 diesel engine to the propeller shaft was through the use ofa reduction drive with a pneumatic clutch designed and constructed by the Falk Corporation. Its operation would permit reduction of the engine speed to the propeller shaft speed, provide for both a forward and reverse (astern) direction of rotation, and a means to connect and disconnect the engine from the drive unit.

The maximum speed was 11.5 knots. Six ballast tanks are in the bow and four are situated near the engine room. The tanks helped keep theship stable in open waters and during beach landings. Water from the ballast tanks next to the engine room was used to cool the engines during beach landings so as to avoid drawing in sand. LSTs were equipped with anti-aircraft guns, typically six-40 mm and four-20 mm guns. These guns were not designed for use against land targets but for defense against attacking enemy aircraft. By itself, a LST is an easy target [LST = Large Slow Target]. However, LSTs traveled in convoys of usually 15-30 in number. By doing this, their fire power was significantly enhanced which gave them a formidable defensive capability.

LSTs are equipped with a unique feature for a vessel design for open sea use: the bow is fitted with moving doors. The doors and internally-stowed ramp allowed LSTs to bring armored vehicles directly to the beach. The bow door is handled by two 3-horsepower bow door drive units, each consisting of a gear motor which drives a screw through open gearing. This screw is engaged by means of a taper and wedge to a rack traveling in a rackguide and mating with a segment made fast to the bow doors. Clearance is provided between the hub flanges of the screw gear, and the bedplate washers. This clearance is such that when the doors are almost closed, and the bow door limit switch has operated, the doors may be jacked together and locked by means of turn-buckles.

In three separate acts dated 6 February 1942, 26 May 1943, and 17 December 1943, Congress provided the authority for the construction of LST's 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 LST's that the keel of an aircraft carrier, previously laid in the dock, was hastily removed to make place for several LST's 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 LST's 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 c ompletion 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 LST's 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 LST's 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).

Only one category of supply - landing craft - threatened seriously to limit Allied strategy in 1944. At Cairo and Tehran, indeed, the apparent necessity of choosing between a postponement of OVERLORD and abandonment of planned or proposed amphibious operations elsewhere was dictated by the shortage of landing craft-more particularly, of one type of landing vessel, the Landing Ship, Tank (LST). The repercussions of landing craft decisions were to be felt all during 1943 and 1944 until Churchill at last complained with some bitterness that "the destinies of two great empires . . . seemed to be tied up in some god-dammed things called LST's whose engines themselves had to be tickled on by . . . LST engine experts of which there was a great shortage."

In September 1943 Donald Nelson, chairman of the U.S. War Production Board, went to London and talked to General Morgan and his staff about landing craft requirements. As a result of his conversations he cabled Charles E. Wilson his conviction that LST's and LCT's were the "most important single instrument of war from the point of view of the European Theater," and that the requirements for them had been "grossly understated."

Fewer than 300 LST's were in existence in November 1943, almost all built in the United States. Of these, 139 were in the Mediterranean - 67 of them allocated to the British under lend-lease - and, except for a small contingent, were all earmarked for transfer to the United Kingdom for OVERLORD as soon as the amphibious phases of the Italian campaign were completed. For OVERLORD, in addition, the United States had agreed the preceding spring to provide 62 more new LST's during the coming winter. The remaining new production of LST's was allocated to the war in the Pacific.

Production of LST's and other landing ships and craft in the United States had been late in getting under way, reaching large volume only in the winter of 1942-43 and then rapidly falling off. This first wave of production, aimed originally at the now discarded plan for a cross-Channel invasion in spring of 1943 (ROUNDUP), had proved generally adequate, together with the smaller output of British factories and yards, to meet the rather modest needs of Allied amphibious operations before mid-1943.4 Even the invasion of Sicily, in some respects the most massive amphibious operation of the entire war (eight divisions were landed simultaneously), was adequately mounted without drawing upon a substantial reserve of U.S. assault shipping in the Atlantic or interfering with planned deployments of craft to the Pacific.

From the Navy's point of view the whole landing craft production program had been undertaken at the worst possible time-when the Navy was straining to rebuild sea power destroyed or immobilized at Pearl Harbor and in later engagements, in order to gain supremacy in the Pacific, while at the same time trying to break the strangle-hold of enemy submarines upon the sea lanes in the Atlantic. The program competed with many other lines of war production for materials, above all for the steel, engines, and facilities needed to build other types of combatant vessels. A Navy official commented bitterly in April 1943 that the high rate of landing craft construction achieved late in 1942 had been obtained "only by cutting across every single combatant shipbuilding program and giving the amphibious program overriding priority in every navy yard and every major shipbuilding company. The derangement . . . will not be corrected for about six months." As landing craft schedules were terminated or cut back that winter and spring, the Navy pushed the building of escort vessels to meet the revived menace of the German U-boats in the Atlantic, which in March reaped a harvest of more than a million deadweight tons of Allied shipping. Navy officials candidly wanted no more emergency landing craft programs.

By August 1943, however, presures were building up to increase the output of landing craft, at a time when, as a result of the abatement of the submarine menace, the Navy was cutting back its escort and antisubmarine vessel programs. While the landings on Sicily had been successful, with losses lower than anticipated, the greater part of the entire amphibious fleet in the Mediterranean was tied up for weeks after the initial landings moving supplies over the beaches and performing other administrative tasks. Other amphibious undertakings were in prospect in the Mediterranean, in southeast Asia, and on the two main avenues of advance toward Japan across the Pacific. The biggest prospective deficit of amphibious shipping, however, loomed in the planned cross-Channel assault, then scheduled, as a result of decisions at the Washington Conference of May 1943.

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Page last modified: 18-05-2013 18:57:45 ZULU