Editing Amphibious vehicle (section)

==Tracked==
===Unarmored===
==== M29 Weasel ====
The [[M29 Weasel]] (Studebaker Weasel), whilst originally designed as a snow vehicle, operated successfully in an amphibious role by the addition of front and rear floats. The basic vehicle will float but its bow is square so the additional floats add stability and load carrying capacity.

=== Armored ===
[[File:AAV-australia.jpg|thumb|right|Two U.S. Marine Corps [[Assault Amphibious Vehicle|AAV-7s]] emerge from the Aberdeen.]]
[[File:acrossthescheldt.jpg|thumb|[[Landing Vehicle Tracked|LVT]] 'Buffalos' taking Canadian troops across the [[Battle of the Scheldt|Scheldt in 1944]]]]
<!--
[[File:DA-SC-85-11316.JPG|thumb|[[M2 Bradley]] infantry fighting vehicle exiting the water (1983)]]
-->

Tracked armored vehicles with amphibious capabilities include those that are intended for use in [[amphibious assault]]. The United States started developing a long line of LVT ([[Landing Vehicle Tracked]]) designs from around 1940.

Many tracked armored vehicles that are primarily intended for land-use, such as [[armoured fighting vehicle]]s and [[armoured personnel carrier]]s nevertheless also have amphibious ability, tactically useful inland, reducing dependence on destroyable and easily targeted bridges. To provide motive power, they use their [[caterpillar track|tracks]], sometimes with an added propeller or water jets. As long as the opposite bank has a shallow enough slope for the vehicle to climb out within a few miles, they can cross rivers and water obstacles. An American example is the [[M113 Armored Personnel Carrier]]. Soviet examples are the [[PT-76]] amphibious tank, and the [[BTR-50]] and [[MT-LB]] APCs based on its chassis.

Some heavier tanks have an amphibious mode in which a fabric skirt is needed to add [[buoyancy]]. The [[M4 Sherman|Sherman]] [[DD tank]] used in the [[Normandy landings|D-Day invasion]] had this setup. When in water the waterproof float screen was raised and propellers deployed. The M2 and M3 Bradleys also need such a skirt.

==== Tanks ====
At the end of World War I a [[Mark IX tank]] had drums attached to the side and front and was tested as an amphibious vehicle launched into [[Hendon Reservoir]].<ref>{{cite book |title=The Vickers Tanks: From Landships to Challenger |last1=Foss |first1=Christopher F. |last2=McKenzie |first2=Peter |year=1988 |publisher=Patrick Stephens Limited |isbn=1-85260-141-8 |page=28}}</ref> A modified [[Medium Mark D]] successfully swam in a river near Christchurch.<ref>Fletcher, David (2001). ''The British Tanks 1915-1919''. Crowood Press. pp. 178, 185</ref>

By the early 1930s, Vickers had developed an amphibious tank. By using very thin armour, flotation could be achieved without external buoyancy aids. The British Army trialled the [[Vickers-Carden-Loyd Light Amphibious Tank]] but did not adopt it for service use. An order was placed with Vickers by the USSR for a small number of tanks. After negotiations to purchase the Vickers tank by Poland failed, they developed their own design the [[PZInż 130]] but dropped the idea of amphibious tanks as obsolete. A pontoon based tank, the [[L1E3 Tank|L1E3]], was produced by Vickers in 1939.<ref name=Fletcher5 /> It was tested but further work was halted during WW2.<ref name=Fletcher5 /> It was tested again at the end of the war.<ref name=Fletcher5>{{cite book |last=Fletcher |first=David  |author-link=David Fletcher (military historian) |date=2017 |title=British Battle Tanks British-made Tanks of World War II  |publisher=Osprey Publishing |page=5 |isbn=9781472820037}}</ref>

In World War II the British further developed amphibious tanks. The [[Crusader tank|Crusader]] was trialled with two pontoons that could be attached or removed, the tracks driving the tank in the water. The "Medium Tank A/T 1" was a tank with inbuilt buoyancy some {{convert|24|ft|m|abbr=on}} long and {{convert|11|ft|m|abbr=on}} tall. The Valentine, then the [[Sherman tank|M4 Sherman]] medium tank were made amphibious with the addition of a rubberized canvas screen to provide additional [[buoyancy]] and propellers driven by the main engine to give propulsion. These were [[DD tank]]s (from "Duplex Drive") and the Sherman DD was used on [[D-Day]] to provide close fire support on the beaches during the initial landings. The Sherman DD could not fire when afloat as the buoyancy screen was higher than the gun. A number swamped and sank in the operation, due to rough weather in the [[English Channel]] (with some tanks having been launched too far out), and to turning in the current to converge on a specific point on the battlefield, which allowed waves to breach over the screens. Those making it ashore, however, provided essential fire support in the first critical hours.

Before World War II, The Soviets produced light amphibious tanks called the  [[T-37A tank|T-37A]] and [[T-38 tank|T-38]]. A third serial model, the [[T-40]], started production after the beginning of the war. A 14-ton tank, the PT-1, was created but was not mass-produced. In addition, an attempt was made to attach pontoons to the [[T-26]]. While successful, the project was closed due to the high vulnerability and unwieldiness of the construction.

Some [[light tank]]s such as the [[PT-76]] are amphibious, typically being propelled in the water by [[hydrojet]]s or by their tracks. In 1969, the U.S. Army rushed the new [[M551 Sheridan]] to Vietnam. This 17-ton light tank was built with an aluminium hull, steel turret, and the 152&nbsp;mm "gun-launcher" (which could fire the [[MGM-51 Shillelagh]] missile), and could swim across bodies of water. The M551 upon arrival in Vietnam began replacing the [[M48 tank|M48A3 Patton]] in all cavalry squadrons, leaving only the M48A3 in the U.S. Army's three armored battalions in Vietnam, the 1/77th, 1/69th, and the [[34th Armor Regiment (United States)|2/34th Armor]]. The Sheridan needed no modifications for river crossings: crewmen simply raised the cloth sides that were tucked inside rubber tubes along the hull's upper edges, raised the driver's front shield which had an [[acrylic glass]] window, the driver turned on his bilge pumps, shifted his transmission lever to water operations and the Sheridan entered the water. For newly arrived Sheridans, this might work as engineered. For "war-weary" M551s, the driver's window was often "yellowed" or cracked as to obscure his vision, and the rubber tubes that contained the rolled up side sleeves were often cracked or frozen into place. The Sheridan could still cross a body of water, but like its swimming cousin, the [[M113 armored personnel carrier|M113 armoured personnel carrier]], also built of aluminium, the river had to be narrow, less than {{convert|100|yd|m|-2}}. In all cases, the bilge pumps had to be working properly, and even then by the time the Sheridan or the APC reached the other side, water would often fill the insides up to their armoured roofs, spilling through the hatches' cracks and emptying onto the earth once safely ashore. Often a fold-down trim vane is erected to stop water washing over the bow of the tank and thus reducing the risk of the vehicle being swamped via the driver's hatch.

During the [[Cold War]], the Swedish [[Stridsvagn 103]] main battle tank carried flotation gear all the time and was, therefore, theoretically, always amphibious.

<gallery widths="200px" heights="145px">
File:Vickers Light Amphibious Tank.jpg|Vickers Carden Loyd amphibious tank
File:DD-Tank.jpg|1944 Sherman DD (Duplex Drive) amphibious tank with float screens lowered
File:PT 76 7 DOW TBiU 12.jpg|A Polish PT-76 amphibious light tank coming out of the water during an amphibious exercise
</gallery>

=== Multi-unit ===
[[File:US 5055th Range Squadron M973 SUSV.jpg|thumb|right|Hagglunds Bv206 in US military service as M-973 SUSV (small unit support vehicle)]]

According to a 1999 article in ''Military Parade'' magazine,<ref>{{cite magazine |url=http://milparade.udm.ru/security/31/052x.htm |title=Vityaz Transporters From Ishumbai |first=Vladimir |last=Shangin |issue=31 |date=February 1999 |magazine=Military Parade |access-date=15 April 2007 |url-status=dead |archive-url=https://web.archive.org/web/20120216091705/http://milparade.udm.ru/security/31/052x.htm |archive-date=16 February 2012 }}</ref> multi-unit, all-terrain transport vehicles were first proposed by the British in 1913, and by the 1950s, over 40 types of articulated tracked vehicles (ATV) were in production. The articulated tracked concept is chosen primarily for its combination of high maneuverability, cross-country abilities, and load-carrying capacity. In some cases the design is made amphibious, giving them all-terrain capability in the truest sense. Usually, the front unit houses at least the engine, gearboxes, fuel tank(s) and the driver's compartment, and perhaps there is some space left for cargo or passengers, whereas the rear unit is the primary load carrier.

Examples of this concept are the Russian [[Vityaz (ATV)|Vityaz]], Swedish Volvo [[Bandvagn 202|Bv202]] and Hagglunds [[Bandvagn 206|Bv206]] designs, and the [[Bronco All Terrain Tracked Carrier]] of Singapore.

A highly specialised development is the ARKTOS Craft, that uses a linkage with two joints to connect the two units and each unit having independent drive systems, giving enhanced mobility and redundancy. They are capable of climbing large ice steps from open water.<ref>{{cite web |url=http://www.arktoscraft.com |title=ARKTOS Craft }}</ref>