Amphibious warfare ship Informations

An amphibious warfare ship (or amphib) is an amphibious vehicle warship employed to land and support ground forces, such as marines, on enemy territory during an amphibious assault. The largest fleet of these types is operated by the United States Navy.

Specialized shipping can be divided into two types, most crudely described as ships and craft. In general, the ships carry the troops from the port of embarkation to the drop point for the assault and the craft carry the troops from the ship to the shore. Amphibious assaults taking place over short distances can also involve the shore-to-shore technique, where landing craft go directly from the port of embarkation to the assault point. Some tank landing ships may also be able to land troops and equipment directly onto shore after travelling long distances, such as the Ivan Rogov-class landing ship.

In the days of sail, ships boats were used as landing craft. These rowing boats were sufficient, if inefficient, in an era when marines were effectively light infantry, participating mostly in small-scale campaigns in far-flung colonies against less well-equipped indigenous opponents.

In order to support amphibious operations during the landing in Pisagua by carrying significant quantities of cargo, and landing troops directly onto an unimproved shore, the Government of Chile built flat-bottomed landing craft, called chalanas. They transported 1,200 men in the first landing and took onboard 600 men in less than 2 hours for the second landing.:40

During World War I, the mass mobilization of troops equipped with rapid-fire weapons quickly rendered such boats obsolete. Initial landings during the Gallipoli campaign took place in unmodified rowing boats that were extremely vulnerable to attack from the Ottoman shore defences.

In February 1915, orders were placed for the design of purpose built landing craft. A design was created in four days resulting in an order for 200 X lighters with a spoon-shaped bow to take shelving beaches and a drop down frontal ramp.

The first use took place after they had been towed to the Aegean and performed successfully in the 6 August landing at Suvla Bay of IX Corps, commanded by Commander Edward Unwin.

X lighters, known to the soldiers as beetles, carried about 500 men, displaced 135 tons and were based on London barges being 105 feet 6 inches (32.2 m) long, 21 feet (6.4 m) wide, and 7 feet 6 inches (2.3 m) deep. The engines mainly ran on heavy oil and ran at a speed of approximately 5 knots (9.3 km/h; 5.8 mph). The sides of the ships were bullet proof, and was designed with a ramp on the bow for disembarkation. A plan was devised to land British heavy tanks from pontoons in support of the Third Battle of Ypres, but this was abandoned.

During the inter-war period, the combination of the negative experience at Gallipoli and economic stringency contributed to the delay in procuring equipment and adopting a universal doctrine for amphibious operations in the Royal Navy.

Despite this outlook, the British produced the Motor Landing Craft in 1920, based on their experience with the early beetle armoured transport. The craft could put a medium tank directly onto a beach. From 1924, it was used with landing boats in annual exercises in amphibious landings. A prototype motor landing craft, designed by J. Samuel White of Cowes, was built and first sailed in 1926.

It weighed 16 tons and had a box-like appearance, having a square bow and stern. To prevent fouling of the propellers in a craft destined to spend time in surf and possibly be beached, a crude waterjet propulsion system was devised by Whites designers. A Hotchkiss petrol engine drove a centrifugal pump which produced a jet of water, pushing the craft ahead or astern, and steering it, according to how the jet was directed. Speed was 5 to 6 knots (9.3 to 11.1 km/h; 5.8 to 6.9 mph) and its beaching capacity was good. By 1930, three MLC were operated by the Royal Navy.

The United States revived and experimented in their approach to amphibious warfare between 1913 and the mid-1930s, when the United States Navy and United States Marine Corps became interested in setting up advanced bases in opposing countries during wartime; the prototype advanced base force officially evolved into the Fleet Marine Force (FMF) in 1933.

In 1939, during the annual Fleet Landing Exercises, the FMF became interested in the military potential of Andrew Higginss design of a powered, shallow-draught boat. These LCPL, dubbed the Higgins Boats, were reviewed and passed by the U.S. Naval Bureau of Construction and Repair. Soon, the Higgins boats were developed to a final design with a ramp - the LCVP, and were produced in large numbers. The boat was a more flexible variant of the LCPR with a wider ramp. It could carry 36 troops, a small vehicle such as a jeep, or a corresponding amount of cargo.

In the run up to WWII, many specialized landing craft, both for infantry and vehicles, were developed. In November 1938, the British Inter-Service Training and Development Centre proposed a new type of landing craft. Its specifications were to weigh less than ten long tons, to be able to carry the thirty-one men of a British Army platoon and five assault engineers or signallers, and to be so shallow drafted as to be able to land them, wet only up to their knees, in eighteen inches of water. All of these specifications made the Landing Craft Assault; a separate set of requirements were laid down for a vehicle and supplies carrier, although previously the two roles had been combined in the Motor Landing Craft.

J. S. White of Cowes built a prototype to the Fleming design. Eight weeks later the craft was doing trials on the River Clyde. All landing craft designs must find a compromise between two divergent priorities; the qualities that make a good sea boat are opposite those that make a craft suitable for beaching. The craft had a hull built of double-diagonal mahogany planking. The sides were plated with "10lb. DIHT" armour, a heat treated steel based on D1 steel, in this case Hadfield’s Resista ¼".

The Landing Craft Assault remained the most common British and Commonwealth landing craft of World War II, and the humblest vessel admitted to the books of the Royal Navy on D-Day. Prior to July 1942, these craft were referred to as "Assault Landing Craft" (ALC), but "Landing Craft; Assault" (LCA) was used thereafter to conform with the joint US-UK nomenclature system.

The Landing Craft Infantry was a stepped up amphibious assault ship, developed in response to a British request for a vessel capable of carrying and landing substantially more troops than the 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. 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. This was changed shortly after initial use of these ships, when it was discovered that many missions would require overnight accommodations.

The first LCI(L)s entered service in 1943 chiefly with the Royal Navy and United States Navy. Some 923 LCI were built in ten American shipyards and 211 provided under lend-lease to the Royal Navy.

Following the successful development of the infantry carrying LCA by the Inter-Service Training and Development Centre (ISTDC), attention turned to the means of efficiently delivering a tank to a beach in 1938. Inquires were made of the army as to the heaviest tank that might be employed in a landing operation. The army wanted to be able to land a 12-ton tank, but the ISTDC, anticipating weight increases in future tank models specified 16 tons burthen for mechanised landing craft designs. Another limit on any design was the need to land tanks and other vehicles in less than approximately 2½ feet of water.

Complete article available at this page.