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Landing Ship, Tank (LST)

British developmental experiments with seagoing landing ships furnished the United States with an insight to solving the problem of getting amphibious forces and all of their combat gear ashore in as complete a package as possible. The most important of the larger landing vessels developed in the war was the Landing Ship, Tank (LST), which quickly attained a reputation for being the workhorse of the amphibious fleet.

Winston S. Churchill developed the concept of a "tank-landing lighter" that could put tanks directly ashore in World War I. However, it was not until World War II that he recalled the need for an ocean going ship to move tanks to beaches. In origin, the LST was a British-designed vessel, like virtually all the landing ships and craft used in World War II. A few LST's of special design were constructed in Britain early in the war. Under wartime agreements, the United States constructed most of the merchant and amphibious shipping used by both countries, thus enabling Britain, with limited building capacity, to concentrate on expanding its Navy.

While the LCT - the basic vehicle-carrying landing craft of World War II - was being perfected, the British also began experimenting with a much larger ocean-going ship capable of discharging vehicles directly across the beach. As an interim measure, three medium-sized tankers were selected for conversion because of their shallow draft, built to pass over the restrictive bars of Lake Maracaibo, Venezuela. Built by Furness Shipbuilding Company Ltd., Haverton Hill-on-Tees in 1937, the Bachaquero (LST F.110) and Misoa LST F.117) were sister ships. They were 379.4 feet in length and 64.2 feet breadth, with a displacement of 4,193 tons. Built in 1938 by Furness Shipbuilding, the slower Tasajera [not Tusajera] (LST F.125) was slightly smaller, 365 feet in length and 60 feet breadth, with a displacement of 3,952 tons.

Bachaquero and Misoa were requisitioned by December 1940 and sent to Belfast for conversion, while Tasajera was requisitioned in late February 1941. They were converted to prototypes of the LST (Landing Ship, Tank) by cutting off the bows, installing bow ramps, and scooping out the insides to accommodate vehicles. The first two ships emerged from their conversion in August 1941, and the third by December 1941. After conversion the three ex-Maracaibo tankers were capable of carrying two LCMs (Mark 1). Alternatively, vehicle carrying capacity was either 22 X 25-ton or 18 X 30-ton tanks or 33 X 3-ton vehicles. There was also accommodation for 210 troops. Trials with Bachaquero and Misoa soon demonstrated that this type of landing ship would ran into some difficulties if the beach angle was not suffifiently steep.

The most serious problem confronting planners on both sides of the Atlantic continued to be the scarcity of assault shipping. The Navy's original estimate of fourteen weeks as the time required to convert conventional ships to assault vessels, train crews, rehearse troops in embarkation and debarkation, load troops and cargo, and sail from ports of embarkation in the United States and the United Kingdom to destination remained unchanged. This meant that 07 November 1942, the date given in the original estimate, would be the earliest possible day for the assault to begin. The Navy might also have pointed to the shortage of landing craft for transporting tanks and other assault vehicles as an argument against an early D Day. LST's were under construction at the time but none were expected to be available before October or November 1942.

No LST's actually became available in time for the initial landings, but three LST Mk 1 "Maracaibo" Class Landing Ships of the Royal Navy, were. Operation TORCH brought United States and British troops ashore in French Morocco and Algeria on 07 November 1942. Two Maracaibo tank carriers, Misoa and Tasajera, arrived at the beach near Oran at 4 AM, and put out pontoon bridges to enable their loads of M3 Stuart light tanks to roll ashore, a process which took four hours. Once the tanks and their 4,772 men were ashore, they seized the La Senia and Tafaroui airfields, and support the parachute assault on them. The main punch, 20 M3 Stuart tanks, arrives on the Maracaibo tank ship Bachaquero, at 4 AM. The converted tanker ran aground about 120 yards from the beach, and engineers spent three hours rigging a pontoon bridge shallow enough to allow the tanks to land. By 7 AM, the little tanks were ashore. These "Maracaibos," forerunners of the LSTs, 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. Though designed with shallow draft, neither the converted Maracaibo [nor the first model LST] proved satisfactory.

The British evacuation from Dunkirk in 1940 had 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. At their first meeting at the Argentia Conference in August 1941, President Roosevelt and Prime Minister 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 LST's 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 LST's for the Royal Navy under the terms of lend-lease.

One major design obstacle was how to reconcile the deep draft needed for stable ocean travel with the shallow draft needed for beaching. The Navy solved this problem by designing an exceptionally large ballast system that could be filled with sea water for stability in ocean passage and then be pumped out for beaching operations. For ocean travel the vessel was capable of a draft of 14 feet and when beaching a minimum draft of only 3 feet 9 inches.

Improvements were gradually worked out through experimentation and study by both British and American designers. The U.S. Navy took the lead in designing the LST. The final result was the LST (2) or LST MkII, an ocean-going ship capable of grounding and discharging vehicles on the shallow-gradient beaches of France. The United States undertook the entire production of the LST (2) for both British and American use. Its unique characteristics included a reduced forward draft of less than four feet for successful beaching. It also had bow doors and ramp, nine-knot speed, and a flat bottom. After seven months the keel for the first LST was laid.

The preliminary plans initially called for an LST 280 feet in length; but, in January 1942, the Bureau of Ships discarded these d rawings 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 and called for a 50-foot beam and minimum draft of three feet 9 1/2 inches. 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 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 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 maind eck 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, DC.

The first LST was commissioned Oct. 27, 1942. Nicknamed "Large Slow Targets," LSTs saw action in every theater of World War II and performed multiple missions. From their combat debut in the Solomons in June 1943 until the end of the hostilities in August 1945, the LST's 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.

Although hydrographic conditions in the Central Pacific often prevented LSTs from reaching the shore to load or unload their cargoes, these vessels were ideally suited as sea-going transports for DUKWs and amtracs, which could easily offload into the water from the huge LST bow ramp. At the staging are a for the Marianas invasions, assault troops and amphibian vehicles were carried to the target on LSTs for the first time in the Central Pacific. This procedure became commonplace in later World War II amphibious assaults in this area. Throughout the war, LST's 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 LST's 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 LST's 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 LST's were transferred to Great 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.

LST Variants

The LST proved to be a remarkably versatile ship. This mission flexibility remains a hallmark of amphibious ships today. Depending on how and for what purpose they had been modified, LSTs were employed as offshore radar stations, repair ships, and hospital ships. 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.

Other LST's, 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 LST's to go simultaneously alongside an anchored battleship or cruiser to accomplish replenishment more rapidly than standard ammunition ships. Some served as motor torpedo boat tenders, battle damage repair ships, or aircraft engine repair ships. The LST-H provided immediate medical care facilities, evacuating over 40,000 casualties from Normandy alone.

Specially equipped LST's were scheduled to move assembled railway cars to France after the Normandy landing. Rails were laid on the lower deck, and the ramp was modified. The cars were loaded and unloaded over track laid on improvised shore-side ramps that could be raised or lowered with the tide. The LST was made fast to the tracked ramp, and the cars were pulled on or off as required. Such ramps were constructed first at Southampton and later in Cherbourg, the principal terminals for cross-Channel railway traffic. By 6 June 1944 some 15 LST's had been converted to ferry rolling stock. Actual ferrying to the Continent was begun in the following month. Larger rolling stock, such as locomotives and tank, refrigerator, and passenger cars were lifted on British sea ferries, on the two American seatrains - the Texas and the Lakehurst - and aboard a number of large car floats that had been towed to the theater from New York. The seatrains operated mainly between Cardiff and Cherbourg, while the ferries shuttled between Southampton and Cherbourg. A Transportation Corps officer, Colonel Bingham, was in charge of the entire ferrying program.

In the latter stages of World War II, some LST's were even fitted with flight decks from which small observation planes were sent up during amphibious operations. These LSTs were converted to mini-aircraft carriers and actually launched fixed wing reconnaissance aircraft from their modified decks. They were used as floating platforms from which small spotter planes were launched and recovered by Brodie Gear, which may very roughly be compared to a giant slingshot.

Many missions that required liaison aircraft were not possible, even with the excellent short field takeoff and landing ability of the L-4, without taking some extraordinary measures. To provide artillery observation during amphibious assaults, the Army employed two unorthodox methods. The first was to convert a Landing Ship Tank (LST), into a mini-aircraft carrier with a plywood runway approximately 60 meters (197 ft) long and 5 meters (16 ft 5 in) wide, which could support no more than ten light planes. These vessels saw extensive service supporting amphibious landings in the Mediterranean and the invasion of the Philippines. However, the conversion of the LSTs into a liaison plane carrier took considerable time and effort and the large scale of amphibious operations frequently required the use of all available LSTs. Thus, a more exotic, but simpler system came into use.

Navy Lieutenant James Brodie, on assignment to the Office of Strategic Services (OSS), forerunner of the Central Intelligence Agency (CIA), developed a system in which an L-4 or an L-5, with a hook mounted above the cockpit, could catch a trapeze bar suspended off the side of an LST or Liberty ship. The trapeze rolled along a wire suspended between two gantries that hung over the sides of the ship, and allowed the aircraft to come to a smooth stop. A similar rig allowed the aircraft to launch by reaching flying speed while suspended and then disengaging the hook. The advantage of this system was that it did not preclude the use of the ship for standard operations. The Brodie system only saw operational service during the invasion of Okinawa. Brodie also developed a land-based version for use in the Far Eastern theaters in situations where there was insufficient time or capability to construct a suitable airstrip, but the opportunity never arose to use this system.

In September 1957, LST 32 Alameda County, was converted and redesignated an Advance Aviation Base ship, AVB 1. First of her class, the new ship was designed to provide fuel, spare parts, technicians and facilities necessary to establish and operate an airstrip for patrol and carrier aircraft in locations where there were no base facilities.

LST 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 LST's in the immediate post-war years was modest. LST- 1153 and LST-115I, commissioned respectively in 1947 and 1949, were the only steam-driven LST's 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 LST's 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 LST's of what were later to be known as the Terrebonne Parish-class were constructed in the early 1950's. These new LST's 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 LST's, which previously had borne only a letter-number hull designation.

In the late 1950's, seven additional LST's of the De Soto County-class were constructed. These were an improved version over earlier LST's, 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 LST's. She was the first of a new class of 20 LST's 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 ramp operated over the bow and supported by twin derrick arms. A stern gate to the tank deck permits unloading of amphibious tractors into t he 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 LHA's, LPD's, and LSD's, the Newport-class LST can transport tanks, othe r heavy vehicles, and engineer equipment which cannot readily be landed by helicopters or landing craft.

Sixty years and nearly 1,100 LSTs later, the need to land vehicles directly on a beach from a ship has been replaced by over-the-horizon assaults and ship to objective maneuver. Twenty-first century expeditionary warfare no longer focuses on direct beach landings and assaults that characterized the value of the LST. The World War II naval historian, Samuel Eliot Morison, described the LST as the "most useful all-around craft invented by the Navy." Frederick's decommissioning not only culminates the successful career of this fine ship, but also marks the end of the LST ship class. The LST will remain as part of the transition.

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Page last modified: 12-02-2012 18:52:28 ZULU