DARPA releases video of floating tank-like CAAT vehicle


August 22, 2012

DARPA's one-fifth scale prototype of the Captive Air Amphibious Transporter - walks on land, marsh, and water (Photo: DARPA)

DARPA's one-fifth scale prototype of the Captive Air Amphibious Transporter - walks on land, marsh, and water (Photo: DARPA)

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So the year is 2015, and you're in a serious disaster – one that requires the immediate provision of food, water, medical care, and shelter for a hundred thousand people. In other words, not something that a few airlifts will handle. If there is navigable water anywhere nearby, you could be saved by a future version of one of DARPA's new toys: the Captive Air Amphibious Transporter (CAAT).

Part of DARPA's Tactically Expandable Maritime Platform (TEMP) program, CAAT is a tool for enabling rapidly organized and executed ship-to-shore operations. In essence, the concept is to load standard shipping containers on a vehicle that operates close to shore which is equipped with an amphibious drive. CAAT is designed to provide a flexible and modular capability for solving supply problems cropping up during unconventional warfare scenarios, and also to assist during humanitarian disasters.

DARPA program manager Scott Littlefield said, "to allow military ships and aircraft to focus on unique military missions they alone can fulfill, it makes sense to develop technologies to leverage standard commercial container ships."

DARPA's CATT prototype swimming through the ocean (Photo: DARPA)

CAAT is essentially a tank with air-filled treads that supply buoyancy and amphibious propulsion to a cargo of multiple shipping containers. This enables CAAT to roll over water and debris in the water while also being able to drive on land. These vehicles are intended both to carry cargo and, when conditions allow, to tow much larger cargo-laden rafts to the shore.

There are certain tasks which must be dealt with to properly react to a major disaster. You have to know what the situation is, how much damage has been caused, where survivors are located, and the condition of the sustaining infrastructure. Another crucial task is quickly finding the material and equipment needed to supply and/or evacuate survivors and preparing it for transport. But once these tasks are underway, you have to transport an enormous quantity of supplies to the right places in the disaster area. Transportation is often the most difficult part of disaster relief and recovery.

The best way to quickly move huge quantities of supplies and equipment from one point to another is by water. A single mid-size container vessel can carry five thousand 20-foot cargo containers, or about 100,000 tons of cargo. The draft (depth of the hull) is rather small in container ships, so many are also able to deliver supplies inland to sites along navigable rivers and lakes. In addition, many container ships carry their own loading cranes, so that remote unloading can be accomplished in a timely manner.

Still, disasters have a way of rendering harbors temporarily non-navigable. Consider Katrina or Fukushima – in the aftermath the seaport facilities were damaged and flooded, and an enormous amount of flotsam and debris clogged the coastal waters for days or weeks. DARPA perceived a need for a rugged amphibious transport that could transfer supplies from a container ship a safe distance from shore to onshore locations where the supplies were needed.

The video below shows how a one-fifth scale prototype performs in the sort of conditions described above. Note that this prototype is not a remote control toy – it is over ten meters (33 ft) in length and weighs four tons. A full-scale CAAT will be half the length of a football field but weighs only 450 tons, leaving plenty of capacity for hundreds of tons of cargo in shipping containers. The CAAT is also equipped with a snorkel so that it can run in the roughest of seas and storms if necessary. It is safe to say that CAAT would be a valuable addition to the disaster relief toolbox.

Source: DARPA via PopSci

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Brian Dodson From an early age Brian wanted to become a scientist. He did, earning a Ph.D. in physics and embarking on an R&D career which has recently broken the 40th anniversary. What he didn't expect was that along the way he would become a patent agent, a rocket scientist, a gourmet cook, a biotech entrepreneur, an opera tenor and a science writer. All articles by Brian Dodson

The money would have been better spent buying LCACs.


This is MEGA-cool! I WANT one! I love the design of those "treads" - beautifully thought-out and implemented! I am convinced that a small version of this thing would be REALLY popular with civvies. Look at how popular the Humvee is with civilians! This thing would be the next "big thing" with the 4WD crowd. Awesome!


A fine idea, and one of these, you just have to say: "-Why didn't anybody thought of that, before?"

Edgar Castelo

This is an awesome design and the performance is impressive. However, I hope this NEVER gets into the hands of civies. On land, those treads would beotch slap and pulverize everthing in their path. On water though, you could really splash up a good time.


"Only" weighs 450 tons - like that is not going to present any problems with deploying it or having it use roads and bridges to deliver the containers to where they are needed. A supposed disaster relief operation is not going to involve simply dumping containers on an accessible beach and then unloading them by hand and transporting the items inside on bicycles.

Shows how limited the military mindset is in dealing with situations and why most of the casualties in Afghanistan and Iraq are not with front line troops but with men and women driving the supply trucks through areas controlled by warlords and freedom fighters.


The overall reference here is to Logistics Over The Shore operations, LOTS. While this seems to One good approach it should not be the only One good tool. A Twenty Foot Equivalent, TEU, container holds a lot of stuff and this vehicle apparently is intended to be 450 tons big, they did not say how many containers per trip but I would guess at 50. This seems to be a the large end of the scale. I would think at least one more vehicle probably near the size of this working model would also be appropriate, if not more so. In constricted inland waterways moving 2 to 10 containers per trip may be the ONLY choice and not 100 containers. Think of how constricted the New Orleans area was and for how long! Moving 100 to 1000 containers may be an objective but getting them there or wherever in increments of 2 to 10 per trip is what can be achieved. The whole area in Indonesia hit by the tsunami required thousands of tons of material but along the whole coast there were very few ports and workable roads. Therefor, a LOTS operation a few containers at a time across the length of the coast damaged would have faster, better and ultimately cheaper for everyone in contrast to one big depot with hundreds to thousands of containers coming in.


this is sweet. and for some reason, it seems way better than a hovercraft, probably because it doesn't have to sound like a hurricane when the engine is running.

1) amphibious landings provide a great stealth option, but hovercraft sort of eliminate the stealth of amphibious landing.

2) if you scale this thing up, it would be a great landing pad for vtol aircraft when loitering silently. the thing looks like a giant flotation device. the bigger, the floatier.

----how many hovercraft are designed as vtol landing stripps?

basically this thing could be a moving amphibious vtol aircraft platform .which would be sweet. hover craft are not going to do that , not by a long shot. ----their steering is horrible. this thing turns on a dime. in the water or on the beach.


Hovercraft, including the LCAC, don't do well on land because their skirts can be damaged by rocks. The air chambers on the treads of the CAAT will function like tires. A Humvee is just an ordinary SUV with different sheet metal, it's not a civilian version of the military HMMWV. If a small version of the CAAT is made for the recreational market, it will probably be too expensive for most if not the great majority of 4X4 owners.


I agree with Pikeman, why not just use a hovercraft? If they want to develop a vehicle with the military in mind, why not develop an armored hovercraft?....


That thing is just begging to throw a track. Every bit of dirt and debris that gets between the floats puts extra strain on the hinges, and the extra thickness that the floats add to the tracks makes maneuvering on them like trying to play soccer (futbol?) wearing platform shoes. Also tracked vehicles require almost as much maintenance as helicopters.

LCACs and where terrain permits HETs or HEMTTs


Actually someone did! Back in the late 50's or early 60's they invented a vehicle called a 'Rolligon' that had giant inflated sausages that rolled along. Because they were so big they floated and also their ground pressure was so small they were able to go on marsh and snow and anything soft. I remember it from probably Mechanix Illustrated at the time.


An average 3.2 billion dollar budget says wikipedia and when I see all these devices I see a waste of money. Fun toys maybe but a giant waste of our money.

The Hoff

The concern over narrow access for a large CAAT vehicle is valid.

A road train design for CAAT can be considered with a main CAAT vehicle to house the main internal combustion power plant, pulling several other CAAT wagons. Serial hybrid design with independent electric motors in each cargo wagon for independently controlling track speeds. This would be a requirement for ascending awkward structures that require the tracks to rotate at different speeds. Articulated steering between wagons. I believe Gizmag hosted some articles on electric robot snakes that had amazing abilities to scale virtually any structure because of the ability of the independent track sections to work together.

Also from a civilian version, why design a dedicated CAAT vehicle when this design can be made into a platform a 4WD can drive on to. With fittings that can screw directly into the 4WD rims to provide the drive. For steering, have a mechanism that progressively decouples one track or another, controlled by a remote control in the hand of the user sitting in his car. The user would simply need to control which gear (in low range) to pick, acceleration, and use the hand held remote control for steering. No different to operating an electric vehicle winch. The design would need fold out wheels so it could be towable behind a 4WD. Realistically about $20-30,000, in the ballpark for purchase of a small hover or boat for recreational hunters/fisherman.


Just give me some inflatable ones that stow in the boot of my 4x4, which can be inflated and attached when I need it - thanks.


Wow! I JUST landed on this page RIGHT after watching the two best documentaries onhurricane Katrina, ever made, and also a top rate NBC report on it as wel (what went wrong, NBC, from Miami to New Orleans Independent, and Refuge-of-Last-Resort-The-true-Hurricane-Katrina-Story)

And to land here, after, is cosmic. I really hope that this gets used, SOON

Doc Rock

This is one of those devices that need to be built to see if they work first, however what use is it if it is in Calfornia and it needs to be in West Africa in 2 days. The HAV airlander 200 is rated for an 80 tonne payload vertically lifted meaning your cargo ships containers could be deployed directly off deck by a hybrid airship, which with refueling has an infinite range.


re; L1ma

Airships are far more dependent on low wind speed conditions than hovercraft.


re Pikeman; And the loading of a 40 foot container onto a floating tank at sea will not be affected by sea state ?.


re; L1ma

Funny thing about ships they can create small areas of relatively calm water. This fact was used before the development of practical helicopters to create a suitable place for the catapult launched water landing spotter planes used to direct over the horizon artillery fire.


Just came across the ZIL-PKU, an airbag -track amphibeous vehicle created by the soviets in 1965. (video:

Maybe other variants along similar lines were tried by the USA...

Of course a problem with airbags is that they wear out and puncture.. BUT the airbags also rotated (like a rolling log/roller bearing) as the track progressed, which would be self cleaning unlike this version with opening and closing gaps collecting crud.


"The CAAT is also equipped with a snorkel so that it can run in the roughest of seas and storms if necessary. It is safe to say that CAAT would be a valuable addition to the disaster relief toolbox."

Really? A SNORKEL determines all-weather usefulness?

Whoever wrote that needs to spend more time in REAL weather conditions....

Nothing is running cargo by choice in the ROUGHEST seas&storms...

NOT safe to say anything based on such statements.

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