Jeff18-The AAV7-A1 amphibian vehicle series Part I: The Origins

Thanks to the following sources:

http://en.wikipedia.org

http://www.Marines.com

http://www.globalsecurity.org

http://ww2drawings.jexiste.fr

http://araeld.deviantart.com

1-Purpose of the AAV7

"From ship to shore to objective, no equipment better defines the distinction and purpose of Marine Corps expeditionary capabilities than the AAV-7 Amphibious Assault Vehicle. Designed to assault any shoreline from the well decks of Navy assault ships, AAVs are highly mobile, tracked armored amphibious vehicles that transport Marines and cargo to and through hostile territory."

2-Short History :

"The Assault Amphibious Vehicle (AAV) official designation AAV-7A1 (formerly known as Landing Vehicle, Tracked, Personnel-7 abbr. LVTP-7) is a fully tracked amphibious landing vehicle manufactured by U.S. Combat Systems (previously by United Defense, a former division of Food Machinery Corporation - FMC).
The AAV-7A1 is the current amphibious troop transport of the United States Marine Corps. It is used by USMC Assault Amphibian Battalions to land the surface assault elements of the landing force and their equipment in a single lift from assault shipping during amphibious operations to inland objectives and to conduct mechanized operations and related combat support in subsequent mechanized operations ashore. It is also operated by other forces. Marines call them "amtracks," a shortening of their original designation.

Altaya/IXO 1/72 model - AAVP7 A1 "USMC 53445 - D30", 1st USMC Division, Kuweit 1991.

The LVTP-7 was first introduced in 1972 as a replacement for the LVTP-5.

-In 1982, FMC was contracted to conduct the LVTP-7 Service Life Extension Program, which converted the LVT-7 vehicles to the improved AAV-7A1 vehicle by adding an improved engine, transmission, and weapons system and improving the overall maintainability of the vehicle.

-The Cummins VT400 diesel engine replaced the GM 8V53T, and this was driven through FMC's HS-400-3A1 transmission.

-The hydraulic traverse and elevation of the weapon station was replaced by electric motors, which eliminated the danger from hydraulic fluid fires.

-The suspension and shock absorbers were strengthened as well.

-The fuel tank was made safer, and a fuel-burning smoke generator system was added.

-Eight smoke grenade launchers were also placed around the armament station.

The headlight clusters were housed in a square recess instead of the earlier round type.

-The driver was provided with an improved instrument panel and a night vision device, and a new ventilation system was installed.

These upgraded vehicles were originally called LVT-7A1, but the Marine Corps renamed the LVTP-7A1 to AAV-7A1 in 1984."

3-Origins: The Alligator

Florida and Hurricanes are indissolubly linked.

In 1935, after such one more catastrophic event which led drowned a lot of people and flooded vast territories, the lack of rescue adapted vehicles appeared clearly.

"John Roebling, whose father built the Brooklyn Bridge, called upon his son, Donald, to design a vehicle that had amphibious capabilities for rescue missions.

By 1936, Donald Roebling, a wealthy young inventor living in Clearwater, Florida, had already completed his first design for an amphibian and built the first model. It was a light vehicle that featured horizontal paddle-like cleats that gave the vehicle a water speed of 2.3 miles per hour and featured a 92-horsepower Chrysler engine.

The "Alligator," as Roebling called his creation, was a track-laying vehicle which derived its propulsion afloat from flanges fixed to the tracks, essentially the principle of early paddle-wheel steamships. The first "Gators" were a disappointment, in that the water speed was slow, and the land speed was 25 mph. Originally intended as a vehicle of mercy, for rescue work in the Everglades, the "Alligator" was destined for fame as an instrument of war.

Here is a link to a video relating to the Alligator:

http://www.youtube.com/watch?feature=player_embedded&v=FRBaOeiNwF8

By 1937, Roebling had attracted considerable attention, and on October 4, 1937, his "Alligator" was exposed to the public eye in Life magazine."
On the other hand, the US Navy had for long (1918-1940) sensed the need of an amphibian Fleet Marine Force for Pacific operations.
The Marine Corps first took notice of the Alligator when Rear Admiral Edward C. Kalbfus, Commander, Battleships, Battle Force, United States Fleet, knew of the Marine Corps' need for a unique amphibian vehicle. He immediately grasped its potentialities and sent the picture and accompanying article to the Commandant. Without hesitation, the article was pushed up the chain of command and ended up on the desk of the Marine Corps Equipment Board."

After that, Marine and Roebling improved together the Alligator model so that it complies with desired military characteristics. Through design changes, and by using larger engines, the water speed of the Alligator was increased to 8.6 mph by 1939.

4-The real 1st LVT: the LVT-1

In January 1940, Roebling had completed the new design. The new model which was designated the CROCODILE. The Crocodile had a land speed of 25 mph and a water speed of 9.4 mph, was unsinkable even flooded and abilities to climb a 55° slope.

Further improvements, as passing from aluminum to steel, and the approach of the war for USA, decided authorities to order a prebatch of 200 vehicles to Roebling. In July 1941 the first vehicle, now designated LVT(1) (Landing Vehicle Tracked), came off the assembly line at the FMC plant in Lakeland, Florida. To achieve maximum output, the design of LVT(1) was "frozen" shortly after Pearl Harbor and the vehicle put into mass production."

5-Characteristics of the LVT-1

Engine Hercules
No. Cylinders 6
Speed (land) 12 mph
Speed (water) 6 mph
H.P. 150
Cruising Range (land) 150 miles
Cruising Range (water) 60 miles
Fuel Capacity 80 gal
Gear Configuration 3 fwd - 1 rev
Weight (empty) 17,300 lbs
Weight (loaded) 21,800 lbs
Length 21' 6"
Width 9' 10"
Height 8' 2"
Hull Thickness 3/16 max
Track Shoes 79
Track Adjustment By Idler
Bogie Wheels 316
Suspension Rigid
Armor N/A
Armament Machine Guns, 30 cal.
Crew 2 - 3
Ramp No
Mfg Donald Roebling, Clearwater, Fla.
Food Machinery Corp., Lakeland, Fla.
Food Machinery Corp., Riverside, Ca.
Graham-Paige Motor Corp., Detroit, MI.
Ingersoll Steel & Disc Division -
Borg-Warner Corp., Kalamazoo, MI.
St. Louis Car Co., St. Louis, Mo.
Total Mfg 1,225

6-MAJOR CAMPAIGNS THAT THE LVT-1 PARTICIPATED IN:
GUADALCANAL

D-Day 07 August 1942
Units Involved:
1st Amphibian Tractor Bn comprised of (100) LVT-1s
2nd Amphibian Tractor Bn comprised of (30) LVT-1s

BOUGAINVILLE
D-Day 01 November 1943
Unit Involved:
3rd Amphibian Tractor Bn comprised of (124) LVT-1s

TARAWA
D-Day 20 November 1943
Unit Involved:
2nd Amphibian Tractor Bn comprised of (75) LVT-1s

CAPE GLOUCESTER
D-Day 26 December 1943
Unit Involved:
1st Amphibian Tractor Bn comprised of (100) LVT-1s

7-WWII LVT subsequent models & variants

LVT-1 exhibited by manufacturer (FMC) in 1941 parade, Lakeland, FL.

LVT-1 (1941)
The first military model. Traveling at a respectable six knots in the water and twelve mph on land, it could deliver 24 fully equipped assault troops to the beach, and supply supporting fire from two .30 cal. machine guns. Many vehicles were refitted prior to the Tarawa landing to hold two .50 cal Browning machine guns forward, with the .30 cal guns aft. The vehicle was not armored and its thin steel hull offered virtually no protection, although prior to Tarawa some vehicles received 9 mm armor to the cab. Tracks performed well on sand, but not on tough surfaces. Proper maintenance of the new machine was often an issue, as few Marines were trained to work on it, and early models suffered frequent breakdowns. 1,225 units produced.

LVT1s

LVT-2 Water Buffalo, British designation Buffalo II (1942)
Featured new powertrain (taken from the M3A1 light tank) and torsilastic suspension. Hard terrain performance was much better compared to the LVT-1. 2,962 units produced.

HM 1/72 model - LVT-2, unknown unit, Saipan (Marianas Islands), June 1944.

The LVT-2 Water Buffalo loaded with Marines bound for the beaches of Tinian Island. 1944.

LVT(A)-1 (1942)
Based on the LVT-2, A standing for armored, this fire support version had an armored (6 to 12 mm) hull. It was fitted with a turret nearly identical to that of the Light Tank M3, with a 37 mm Gun M6 in an M44 mount, and also carried two rear-mounted machine guns. 510 units produced.

Altaya/IXO 1/72 model - LVT(A)-1 708th US Army Tank Battalion, Blue Beach, Saipan (Marianas Islands), June 1944.

HM 1/72 model - LVT(A)-1, Pacific Theatre, 1944-45.

Altaya/IXO 1/72 model diorama - LVT(A)-1, USMC, Peleliu (Palau Islands), 1944.

Photos of the LVT(A for Armored)-1.

LVT(A)-2 Water Buffalo (1943)
Armored version of the LVT-2. Capacity 18 troops. 450 units produced.

LVT(A)-2.

LVT-4 Water Buffalo, British designation Buffalo IV (1943)
The engine was moved forward and a large ramp door was added to the rear, allowing troops to exit from the rear of the vehicle. This innovation also greatly facilitated the loading and unloading of cargo. Some vehicles received armor kits. It was by far the most numerous version of the LVT, with 8,351 units delivered. Many of the British LVT versions were armed with a Polsten 20 mm cannon and 2 × .30 cal Browning machine guns.

LVT4s.

And here is a U-Tube link:

http://www.youtube.com/watch?v=NugZHgqdax0

and another one (look out for some crual war scenes):

http://www.youtube.com/watch?v=sfGdoJq8wZY

Sea Serpent
The Sea Serpent was designed by the 79th Armoured Division for use by the British in the Far East. Its armament was two "Wasp" flamethrowers and a machine gun. These would have been used by the "flame battery" of the 34th Amphibian Support Regiment, Royal Marines in any assault on the Japanese mainland but the war ended before they were used.

LVT(A)-3
Armored version of the LVT-4, never approved for production.

LVT-3 Bushmaster (1944)
Developed by the Borg Warner Corporation, this vehicle had engines moved to sponsons and a ramp installed in the rear similarly to the LVT-4. Some received armor kits. First used in Okinawa in April 1945. 2,964 units produced.

LVT(A)-4 (1944)

Another fire support version, with 75 mm Howitzer Motor Carriage M8 turret armed with a 75 mm howitzer, in some cases replaced with the Canadian Ronson flamethrower. A single .50 cal machine gun was installed on the ring mount above the turret rear. In the late production vehicles the heavy machine gun was replaced with two M1919A4 .30 MGs on pintle mounts and one more in the bow mount. 1,890 units produced. The Chinese PLA captured several from Nationalist forces during the Civil War and placed them in service, eventually modifying some with the 37 mm M6 tank gun (?) in place of the 75 mm howitzer and others with the ZiS-2 57 mm anti-tank gun, complete with shield, the conversion necessitating the removal of the original mantlet as well.

HM 1/72 model - LVT(A)-4, USMC, 2nd Armoured Amphibian Battalion, Red Beach, IWO JIMA 1945.

LVT(A)-4s

LVT(A)-4 Specifications

Weight 18.1 tonnes
Length 7.95 m
Width 3.25 m
Height 3.1 m
Crew 6 (commander, gunner, loader, driver, assistant driver, AA machine gunner)
Armor 6 to 38 mm
Main
armament 1 × 75 mm M2/M3 Howitzer
Secondary
armament 3 × .30-06 Browning M1919A4 MGs
Engine Continental W-670-9A; 7 cylinder, 4 cycle, radial gasoline
250 hp
Power/weight 13.9 hp/t
Suspension torsilastic
Operational
range 200 km (road), 120 km (water)
Speed 40 km/h, in water 11 km/h

LVT(A)-5 (1945)
LVT(A)-4 with powered turret and a gyrostabilizer for the howitzer. Some were upgraded in late 1940s by changing armor configuration. 269 units produced.

LVT-3C (1949)
Modified LVT-3. Armored roof was fitted and the bow was extended to improve buoyancy. Armament included .30 MG in a turret and .30 bow MG in ball mount. 1200 LVT3s were converted.

LVT3C

Amphibian, tracked, 4-ton General Service (1944/45)
A British vehicle based on the LVT-4 and known as the Neptune. Only a handful of the 2,000 ordered were completed.

The Sealion was a recovery version, and the Turtle a workshop version.