Editing Amphibious vehicle (section)

== General technical notes ==
[[File:French VAB propeller dsc06844.jpg|thumb|Pod Water Jet on a French [[Véhicule de l'Avant Blindé|VAB]]]]

Two main categories of amphibious vehicles are those that travel on an air cushion ([[Hovercraft]]) and those that do not. Among the latter, many extend the off-road capabilities of land vehicles to all kinds of terrain, including ice, snow, mud, [[marsh]], [[swamp]] etc. This explains why many designs use [[Tracked vehicle|tracks]] in addition to or instead of wheels, and in some cases have [[Articulated vehicle|articulated]] body configurations or other unconventional designs such as [[screw-propelled vehicle]]s which use auger-like barrels which propel a vehicle through muddy terrain with a twisting motion.{{citation needed|date=January 2020}}

Most land vehicles – even lightly armoured ones – can be made amphibious simply by providing them with a [[waterproof]] [[Hull (watercraft)|hull]] and perhaps a propeller. This is possible as a vehicle's [[displacement (ship)|displacement]] is usually greater than its weight, and thus it will float. Heavily armoured vehicles however sometimes have a [[density]] greater than water (their weight in kilograms exceeds their volume in [[litre]]s) and will need additional [[buoyancy]], in the form of inflatable floatation devices, much like the sides of a rubber dinghy, or a waterproof fabric skirt raised from the top perimeter of the vehicle, to increase its displacement.

For propulsion in or on the water some vehicles simply spin their wheels or tracks,<ref>{{cite web |url=http://www.gizmag.com/go/6906/ |title=Killer amphibious vehicle - 39 mph on water and 55 mph on land |last=Hanlon |first=Mike |date=28 February 2007 |website=Gizmag |access-date=13 May 2018}}</ref><ref>{{cite web  |url=http://dsc.discovery.com/videos/howe-and-howe-tech-meet-the-assault-lander.html |title=Howe and Howe Tech: Meet The Assault Lander  |date=2 February 2010 |website=[[Discovery Communications]] |access-date=13 May 2018 |url-status=dead |archive-url=https://web.archive.org/web/20100901192851/http://dsc.discovery.com/videos/howe-and-howe-tech-meet-the-assault-lander.html |archive-date=1 September 2010}}</ref> while others use [[screw propeller]](s) or [[Pump-jet|water jet(s)]]. Most amphibians will work only as a [[displacement hull]] when in the water – few can [[Planing (sailing)|hydroplane]], skimming over the water like [[motorboat|speedboats]].