Landing craft
Because of the need to run up onto a suitable beach, World War II landing craft were flat-bottomed, and many designs had a flat front, often with a lowerable ramp, rather than a normal bow.
These utility 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.
Initial landings during the Gallipoli campaign took place in unmodified ship's boats that were extremely vulnerable to attack from the Turkish shore defenses.
[2] The Imperial Russian Navy soon followed suit, building a series of similar landing motor barges of the so-called Bolinder class, named after the supplier of semi-diesel engines installed in them.
While the landings for which they were created never happened, the ships themselves turned out quite useful and had a long career, supporting the Caucasus Campaign and later as minesweepers, gunboats and utility transports.
[4] 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.
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 White's designers.
[8] In 1939, during the annual Fleet Landing Exercises, the FMF became interested in the military potential of Andrew Higgins's design of a powered, shallow-draught boat.
Victor Harold Krulak, a native of Denver, who joined the Marines after graduating from Annapolis in 1934, witnessed the Japanese use small vessels like the Daihatsu-class.
Krulak noted that the boats' droppable ramps enabled troops to quickly disembark from the bow, rather than having to clamber over the sides and splash into the surf.
Envisioning those ramps as answering the Marines' needs in a looming world war, Lieutenant Krulak showed the photographs to his superiors, who passed on his report to Washington.
[12] 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.
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 (28 km/h; 17 mph).
[7] Constructed of steel and selectively clad with armour plate, this shallow-draft, barge-like boat with a crew of 6, could ferry a tank of 16 long tons to shore at 7 knots (13 km/h).
Tank tests with models soon determined the characteristics of the craft, indicating that it would make 10 knots (19 km/h; 12 mph) on engines delivering about 700 hp (520 kW).
The Mark 4 was slightly shorter and lighter than the Mk.3, but had a much wider beam (38 ft 9 in (11.81 m)) and was intended for cross channel operations as opposed to seagoing use.
When tested in early assault operations, like the ill-fated Allied raid on Dieppe in 1942, the lack of manoeuvring ability led to the preference for a shorter overall length in future variants, most of which were built in the United States.
When the United States entered the war in December 1941, the U.S. Navy had no amphibious vessels at all, and found itself obliged to consider British designs already in existence.
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.
To carry 13 Churchill infantry tanks, 27 vehicles and nearly 200 men (in addition to the crew) at a speed of 18 knots, it could not have the shallow draught that would have made for easy unloading.
Lightly armored, they could steam cross the ocean with a full load on their own power, carrying infantry, tanks and supplies directly onto the beaches.
[23] The Landing Craft Control (LCC) were 56-foot (17 m) U.S. Navy vessels, carrying only the crew (Scouts and Raiders) and newly developed radar.
The crew then vanished below (apart from the commanding officer who retreated to a special cubby hole to control things) and the launch was then set off electrically.
[29] After Pearl Harbor, the U.S. Army and Navy began intense planning for the transport of millions of men into combat and the training for amphibious operations.
By June 1942, Amphibious Force, Atlantic Fleet (AFAF) established headquarters at Norfolk (Virginia) under the command of Admiral Henry Kent Hewitt.
[31] Clarke was given orders to "secure, organize, and train crews for approximately 1,800 landing craft" including LSTs and LCIs, which at that time were still in the design phase.
In creating training programs, Clarke studied blueprints for the new craft and "from these paper drawings he prepared ship's organizations for each type.
He set up a training facility at Solomons Island, and held exercises on the shores of the Chesapeake Bay around the clock, day and night.
[32] "Captain Clarke had less than two months, about one-third of what had been considered the minimum, to train these men to conduct night ship-to-shore landings," wrote Samuel Eliot Morison about the preparations for Operation Torch.
With a crew of 20 plus, they could carry food for 800 for a week and provide 1,600 hot and 800 cold meals a day, including freshly baked bread.
