Throughout the Second World War, LCAs were used for landing Allied forces in almost every Commando operation, major and minor, in the European theatre. They also saw service in North Africa and the Indian Ocean.
The first four LCAs used in an opposed landing disembarked 120 French Foreign Legionnaires of the 13th Demi-Brigade (13e DBLE) on the beach at Bjerkvik, 8 miles (13 km) above Narvik, on 13 May during the Norwegian Campaign, perhaps the last operational use of LCAs by the Royal Navy was in 1967 when boats from HMS Albion supported operations in Aden; an LCA being the last craft to carry British personnel away from Aden.
Landing Craft Assault (LCA) was a landing craft used extensively in World War II. Its primary purpose was to ferry troops from transport ships to attack enemy-held shores. The craft derived from a prototype designed by John I. Thornycroft Ltd. of Woolston, Hampshire, UK. During the war it was manufactured throughout the United Kingdom in places as various as small boatyards and furniture manufacturers.
When a new amphibious assualt craft was envisaged a maritime architect Mr. Fleming of Liverpool was proposed by the Board of Trade to vivst the Inter-Service Training and Development Centre (ISTDC) at Fort Cumberland and the design of the first LCA began, the concept was for the vessel to be built of Birmabright, an aluminium alloy.
A meeting with the Director of Naval Construction (DNC) was convened to discuss the results and due to some reservations DNC asked ISTDC to give their specifications to three other firms so that they could also submit designs.
Two of the firms were unable to tender, the third, Messrs Thornycroft, had a proposal on the drawing board in forty-eight hours and ISTDC and the DNC agreed that construction of a prototype should be paid for. The craft might be constructed for experimental purposes on the understanding that the DNC held no responsibility.
Two craft were brought down to Langstone Harbour for competitive trials. On its trials on a misty morning, the noise from the two 120 hp Chryslers in the Birmabright alloy hull scared some mothers who hurried their children away from the Isle of Wight beaches as the craft came inshore.
A platoon of Royal Marines disembarked from the Fleming craft in a quarter of the time taken by the platoon in the Thornycroft, the silhouette of the Fleming craft was less, it created less disturbance when steaming, and it beached better. But, and this was later the deciding factor, the Birmabright craft was so noisy that it meant sacrificing tactical surprise, while it was impossible to mount armour on its sides.
The failings of the Thornycroft craft on the other hand could all be overcome. A second prototype from Thornycroft had a double-diagonal mahogany hull with twin engines and those features — low silhouette, quiet engines, little bow wave — which appealed to the Centre's staff in their search for a craft that could make surprise landings. The craft beached satisfactorily, a quality retained in all LCA designs, but the troops took too long to disembark across this prototype's narrow ramp.
Armour could easily take the place of the outer mahogany planking, the exit could be lowered, the silhouette could be cut down and the engines could be so silenced that they would not be heard at twenty-five yards. So although the Fleming boat won at the trial, it was the Thornycroft design, duly altered, that became the assault landing craft.
In the 42 months prior to the end of 1944 Britain was able to produce an additional 1,694 LCAs, by the time production was in full tilt in preparation for Operation Overlord production rose to sixty LCAs a month.
The LCA's crew of four included a Sternsheetsman, whose action station was at the stern to assist in lowering and raising the boat at the davits of the Landing Ship Infantry (LSI), a Bowman-gunner, whose action station was at the front of the boat to open and close the armoured doors, raise and lower the ramp, and operate the one or two Lewis guns in the armoured gun shelter opposite the steering position, a stoker-mechanic responsible for the engine compartment, and a Coxswain who sat in the armoured steering shelter forward on the starboard side. Though in control of the rudders, the coxswain did not have direct control of the engines and gave instructions to the stoker through voicepipe and telegraph.
In July 1943 Royal Marines from the Mobile Naval Bases Defence Organization and other shore units were drafted into the pool to crew the expanding numbers of landing craft being gathered in England for the Normandy invasion. By 1944, 500 Royal Marine officers and 12,500 Marines had become landing craft crew. By 1945, personnel priorities had changed once more. Marines of landing craft flotillas were formed into two infantry brigades to address the manpower shortage in ending the war in Germany.
A junior naval or Royal Marine officer commanded three LCAs and was carried aboard one of the craft. The officer relayed signals and orders to the other two craft in the group by signal flags in the earlier part of the war, but by 1944 many of the boats had been fitted with two-way radios. On the wave leader's boat the Sternsheetsman was normally employed as the Signalman but flags, Aldis lamps, and loudhailers were sometimes more reliable than 1940s radio equipment.
Normally, a flotilla comprised 12 boats at full complement, though this number was not rigid. The flotilla's size could alter to fit operational requirements or the hoisting capacity of a particular LSI. An infantry company would be carried in six LCAs.
A flotilla was normally assigned to an LSI. These varied in capacity with smaller ones, such as the 3,975+ ton HMCS Prince David able to hoist 6 LCAs, and larger ones, such as the nearly 16,000 ton HMS Glengyle with room for 13 LCAs.
Throughout World War II, LCAs travelled under their own power, towed by larger craft, or on the davits of LSIs or Landing Ship, Tank (LSTs).
In larger operations such as Jubilee, Torch, Husky, and Overlord, LCAs were carried to invasion areas by Landing Ship Infantry (LSI). The location chosen for the LSI to stop and lower the LCA was a designated point inside the 'Transport Area' when the LSI was operating with a US Navy Task Force, or the 'Lowering Position' when with a Royal Navy Task Force. The transport area or lowering position was approximately 6–11 miles off shore (11 miles was amphibious doctrine for the USN by mid-war, while the RN tended to accept the risks associated with drawing nearer shore).
The LCAs were swung down to the level of the loading decks and the crews climbed aboard. At this time the troops were assembled by platoons ready to cross gangways. When the
coxswain gave the platoon commander the word, he took his men over and into the stern of the LCA and they filed forward. The platoon divided into three lines, one for each section of the platoon, the outboard two sections sitting under the protection of the troop well's armoured decks, the centre section crouched on the low seating bench down the middle. Despite the wires holding the craft to a fender, the LCA rolled with the motion of the ship. The coxswain would then call, 'Boat manned,' to the telephone operator at the loading station, who, in turn, reported to the 'LC' Control Room.
The coxswain would then warn the troops to mind the pulleys at the ends of falls fore and aft, which could wave freely about when the craft had been set in the water. The task of hooking on and casting off from the ship required skill and seamanship from the coxswain, bowman, and sternsheetsman. The snatch blocks used were heavy steel and difficult to handle.
The bowman and sternsheetsman stood by his respective block, as the craft was lowered into the water. At a time when there was sufficient slack in the falls both had to cast off at the same instant, and the blocks had to be released while there was slack in the falls. If the boat was not freed at both ends at once the rise and fall of the sea could cause the boat to tip, swamp, and perhaps capsize with loss of life. Casting-off was done in all sorts of sea conditions, and the sea might be rising and falling a metre or more (6' swells were not uncommon on D-Day).
A combination of skill and luck could redeem a failure to cast-off, nevertheless. On D-Day, an LCA of Royal Marine 535 Flotilla, LSI Glenearn, released all but its after falls, which were jammed, and the craft tilted alarmingly to 45 degrees. The coxswain kept his head, calming the passengers, while seamen worked to free the falls. Once free, the coxswain needed to get the LCA away to prevent colliding with the towering side of the LSI as it rose and fell with the swells.
Commonly, the LCAs of a flotilla would form line-ahead behind a motor launch or Motor Torpedo Boat (MTB) that would guide them to their designated beach (it was not normal for LCAs to circle the landing ship as was USN and US Coast Guard practice). As the LCA approached the beach they would form line abreast for the final run-in to the beach. When the front of the LCA came to ground on the beach it was called the 'touch down.'
Throughout the Second World War, LCAs were used for landing Allied forces in almost every Commando operation, major and minor, in the European theatre. They also saw service in North Africa and the Indian Ocean, and also saw some service in the Pacific close to the end of the war.