The landing craft mechanized (LCM) is a military landing craft designed for carrying personnel and vehicles from ship to shore without requiring a pier or other shore-based structure. Multiple different models with varying size, capacity, and power plants were produced starting in 1920. They came to prominence during the Second World War when they were used to land troops and tanks during Allied amphibious assaults.
Variants There was no single design of LCM used, unlike the landing craft, vehicle, personnel (LCVP) or landing craft assault (LCA) landing craft made by the US and UK respectively. There were several different designs built by the UK and US and by different manufacturers. The British motor landing craft (MLC) was conceived and tested in the 1920s and was used from 1924 in exercises. Nine were in service at the start of the war. It was the first purpose-built tank landing craft. It was the progenitor of all subsequent LCM designs.
LCM (1)
The landing craft, mechanised Mark I, was an early British model. It was able to be slung under the davits of a liner or on a cargo ship boom with the result that it was limited to a 16-ton tank. The LCM Mark I was used during the Allied landings in Norway (one alongside the MLCs), and at Dieppe and some 600 were built.
Displacement: 35 tonnes Length: 13.6 m (44 ft 7 in) Width: 4.27 m (14 ft 0 in) Draught: 1.22 m (4 ft 0 in) Machinery: two Chrysler 100 hp petrol engines Speed: 7 knots Crew: 6 men Armament: two .303 in. Lewis guns Capacity: one medium tank, or 26.8 tons of cargo or 60 troops 100 men 54,500 lb (24.3 long tons) with 9 in (23 cm) of freeboard
LCM (2)
The first American LCM design, from the US Navy's Bureau of Construction and Repair. Approximately 150 were built by American Car & Foundry and Higgins Industries.
Displacement: 29 tons Length: 45 ft (14 m) Beam: 14 ft 1 in (4.29 m) Draft: 3 ft (0.91 m) Speed: 8.5 knots (15.7 km/h) Armament: two .50-cal M2 Browning machine guns Crew: 4 Capacity; 100 troops, or one 13.5 ton tank, or 15 tons of cargo
LCM (3)
There were two designs:
Bureau Capable of carrying 120,000 lb (54,000 kg) of cargo
Higgins In appearance very similar to the LCVP which Higgins Industries also constructed, with a 10-foot (3.0 m) wide load area at the front and a small armoured (1/4 inch steel) wheelhouse on the aft decking over the engine room. A vessel claiming to be a Higgins LCM-3 is on display at the Battleship Cove maritime museum in Fall River, Massachusetts, however this vessel has the superstructure and overall length of an LCM-6. Another Higgins LCM-3 is displayed at the Museo Storico Piana delle Orme in Province of Latina, Italy, 18 miles east of Anzio.
Displacement: 52 tons (loaded); 23 tons (empty) Length: 50 feet (15 m) Beam: 14 feet (4.3 m) Draft: 3 feet (0.91 m) (forward); 4 feet (1.2 m) (aft) Speed: 8 knots (9.2 mph) (loaded); 11 knots (13 mph) (empty) Armament: two .50-cal M2 Browning machine guns Crew: 4 Capacity: One 30-ton tank (e.g. M4 Sherman), 60 troops, or 60,000 lb (27,000 kg) of cargo
LCM (4) In 1943 and 1944, seventy-seven LCM(4)s were built. Externally, the LCM(4) resembled a late model LCM(1) but inside the pontoon special bilge pumps and ballast tanks allowed the LCM(4) to alter trim to increase stability when partially loaded.
LCM (5) British model of LCM
LCM (6) The LCM (6) was an LCM (3) extended by 6 feet (1.8 m) amidships.
Power plant: 2 Detroit 6-71 diesel engines; 348 hp (260 kW) sustained; twin shaft; or 2 Detroit 8V-71 diesel engines; 460 hp (340 kW) sustained; twin shaft Length: 56 feet (17 m) Beam: 14 feet (4.3 m) Displacement: 64 tons (65 tonnes) full load Speed: 9 knots (10 mph; 17 km/h) Range: 130 miles (210 km) at 9 knots (17 km/h) Military lift: 34 tons (34.6 tonnes) or 80 troops Crew: 5 Many LCM-6s were later adapted for the Mobile Riverine Force in the Vietnam War. Some were modified as armored troop carriers (ATCs or "Tangos"), others became "monitors" with 105 mm guns, "Zippos" with flamethrowers or "Charlie" command variants. A few LCMs were converted to lay and repair hoses for tankers equipped with the offshore petroleum discharge system (OPDS).
LCM (7) British model of LCM
LCM (8)
General characteristics, LCM 8 Type
Power plant: four 6-71 six-cylinder diesels, two hydraulic transmissions, two propeller shafts. (Lighterage Division, Naval Support Activity Danang 1969–1970) crew of 3: coxswain, bowhook, and engineer (a.k.a. "snipe") Power plant: 2 Detroit 12V-71 diesel engines; 680 hp (510 kW) sustained; twin shafts Length: 73.7 feet (22.5 m) Beam: 21 feet (6.4 m) Displacement: 105 tons (106.7 tonnes) full load Speed: 12 kn (14 mph; 22 km/h) Range: 190 nmi (350 km) at 9 knots (17 km/h) full load Capacity: 53.5 tons (54.4 tonnes) Military lift: one M48 or one M60 tank or 200 troops Crew: 5
Operators Turkey – Turkish Naval Forces United States – United States Navy, U.S. Army 7th Transportation Brigade Expeditionary Thailand – Royal Thai Navy Australia – Royal Australian Navy Australia – Australian Army Spain – Spanish Navy El Salvador – Navy of El Salvador New Zealand – Royal New Zealand Navy Egypt – Egyptian Navy Saudi Arabia – Royal Saudi Navy Pakistan - Pakistan Navy Japan - Japan Maritime Self-Defense Force Vietnam - Vietnam People's Navy
Former operators Khmer Republic – Khmer National Navy South Vietnam – Republic of Vietnam Navy
See also Motor landing craft Landing craft, tank LCVP (United States) LCM2000 LCM 25 ton type - Japanese version of LCM-6
Notes
References Gordon L. Rottman & Tony Bryan, Landing Ship, Tank (LST) 1942–2002, New Vanguard series 115, Osprey Publishing Ltd, Oxford 2005. ISBN 9781841769233 Gordon L. Rottman & Hugh Johnson, Vietnam Riverine Craft 1962–75, New Vanguard series 128, Osprey Publishing Ltd, Oxford 2006. ISBN 9781841769318 Gordon L. Rottman & Peter Bull, Landing Craft, Infantry and Fire Support, New Vanguard series 157, Osprey Publishing Ltd, Oxford 2009. ISBN 9781846034350 Maund, LEH Assault From the Sea, Methuen & Co. Ltd., London 1949.
External links Skill in the Surf: A Landing Boat Manual LCM-6 principal characteristics History of "Logistics over The Shore" operations LCM & LCU fact file LCM information USS Rankin (AKA-103): LCM LCM-6 Xj3D/VRML model LCM-6 surface textures required for Xj3D/VRML model LCM 6 Project. French west coast association. https://www.facebook.com/profile.php?id=100086543887103