Water has long been considered a formidable defense, whether a moat surrounding a castle or the oceans surrounding a nation. Of course, through the ages, considerable effort has been expended to counter this defensive strategy.
Within the U.S. Army, considerable emphasis was, and continues to be, placed on bridging, with armored launched bridge layers, ponton, and truss bridges--all capable of being quickly positioned--being at the forefront. However, such measures only successfully span narrow water crossings--and even the fastest of these consume valuable time for preparation and emplacement.
It is not surprising, then, that attention turned to developing amphibious vehicles that would be capable of operating both in water and on land. During WWII, designers, for whom amphibians were a priority, made considerable advancements in the development of these vehicles.
During the Cold War era, strategists believed that the ability to achieve water crossings en masse was critical to defending against the Soviet military. Therefore, deep fording capabilities were mandatory for virtually all U.S. wheeled and tracked vehicle. This led to some vehicles integrating full amphibious abilities.
The following photographic survey chronicles the development and deployment of amphibious vehicles in the U.S. arsenal.
The Jeep--the seemingly universal conveyance of the GI--was a natural for adaptation to an amphibian. Famed yacht designer Roderick Stephens, working with Marmon-Herrington, refined the concept. It was then mass produced by Patton Museum, Fort Knox, Kentucky Ford as the "GPA." The most successful amphibious vehicle ever fielded by the military was another Roderick-Stephens design--the Military History Institute GMC-produced DUKW. Sparkman and Stephens, his firm, designed the hull--which, not surprisingly, resembles an enlarged GPA--to wrap around the chassis of a GMC 6x6 cargo truck. Later versions of the Patton Museum, Fort Knox, Kentucky Studebaker Weasel, designated M29C, were made amphibious by the addition of flotation tanks at the front and rear. When in the water, rudders guided the track-propelled vehicle. Photographic evidence exists of M29Cs in U.S. military service well into the Vietnam-era. Patton Museum, Fort Knox, Kentucky The Alligator series of vehicles were instrumental to the success of landings in the Pacific, as well as river crossings in Europe. Though track-laying, these vehicles lacked the armor and firepower of tanks, sorely needed during landings. To counter the Alligator's lack of armor and firepower, Studebaker was contracted to adapt a Stuart light tank for amphibious operations. This was achieved through the use of folding canvas floatation screens and outboard motors. Though the floating Stuarts were only test vehicles, the Fort Knox, Kentucky Sherman DD ("Duplex Drive") tanks were used by U.S., Canadian and British armored units, most notably during the Normandy landings. Sadly, many of these were swamped, and their crews drowned. Patton Museum, The Pontiac-built M76 Otter was envisioned as a replacement for the famed Studebaker Weasel. The aluminum-bodied vehicle was driven in the water by a propeller. Not well-received by the Army, the vehicles were none-the-less used by Marines in Vietnam, where this photo was taken near Da Nang in 1968. National Archives Also employed by the Marines in Vietnam was the Blaw-Knox built M116 Husky, seen in the foreground, and the Pacific Car and Foundry built armored Husky, following. Both seen here in Vietnam in service of the 11th Motor Transport Battalion in March 1970. National Archives Seen here in prototype form, the Patton Museum, Fort Knox, Kentucky M561 Gama Goat was an attempt at an amphibious transport vehicle. Perhaps overly complex, the articulated vehicle was known to be very loud. Unfortunately, many collectors speak ill of the vehicle, equating it to merely a truck--rather than realizing it is an amphibian--with the additional maintenance tasks inherent with the dual functions. When the Patton Museum, Fort Knox, Kentucky M551 Sheridan entered production in the mid-1960s, it had flotation capability. The flotation screens have a clear lineage back to the Studebaker-modified Stuarts. Though less maintenance intensive than the Gama Goat, the big Ford M656 8x8, was still known to require more maintenance than a conventional cargo truck. The truck, which had an aluminum body with inflatable door seals, was deemed too expensive for Army-wide use, and was found primarily in Pershing missile batteries. U.S. Army Tank-Automotive Command With development begun in 1951, the Rock Island Arsenal Museum LVTP5 was an oversized replacement for the WWII-era LVT series of vehicles. FMC, Pacific Car and Foundry, Baldwin-Lima-Hamilton and St. Louis Car Company built 1,123 of these vehicles. It was developed by Ingersoll Products Division of Borg-Warner. Not surprisingly, given their traditional mission, the Marine Corps was the largest user of these vehicles. As originally developed, the aluminum-armored Patton Museum, Fort Knox, Kentucky M113 family of armored personnel carriers were amphibious, as shown by this example with surf-shield extended. Combined with other vehicles such as the M551 Sheridan and M548 carrier, a fully-amphibious armored unit could be deployed. Changing missions and changing threats have resulted in the latest versions of this venerable carrier losing their floatation capability. Propulsion of the Rock Island Arsenal Museum M548 on both land and water was provided by the tracks. With a high horsepower to weight ratio, and a smooth, flat bottom, the M548 was well-suited for operation in marshy areas often found surrounding rivers, lakes and streams. "Better" often equates to "bigger" for the military. The thirty-five foot lon National Archives g LARC V is a prime example of this. Designed for ship to shore transport, the LARC's (Lighter, Amphibious, Resupply, Cargo) twin 300-hp Cummins V-8 diesels moved the ten-foot wide vehicle through the water at 10 MPH, or overland at three times that speed. If bigger is better, then huge must be ideal. This is the LARC LX, also known as the BARC (Barge, Amphibious, Resupply, Cargo). This sixty-ton capacity monster is just over 26 feet wide and 62 feet long. Amazingly, it could attain a speed of 15 MPH on land, and half that in water. The vehicle, powered by four diesel engines, was considered by the Army Materiel Systems Analysis Activity its "most versatile lighteraqe vessel." National Archives Although the M571 (as the Ordnance Museum, Aberdeen Proving Ground. Hagglunds BV-206 is known to the U.S. Army) is generally thought of as a snow vehicle, it is also fully amphibious. Many variants of the M571 SUSV (Small Unit Support Vehicle) have been produced, and some are now being surplused. Known as the Mobile Assault Bridge or the Mobile Floating Assault Bridge/Ferry unit, this 12-foot wide, 43-foot long vehicle was self-propelled both aground and afloat. Multiple vehicles could be lashed together to form a bridge, or fewer, to form a ferry. Capacity of such a six-bay unit is two class 60 tanks. Powered by a Detroit Diesel 8V71 engine, the vehicles had a top land speed of 35 mph. Marine drive was through an outboard propeller. USMC The AAVP7, originally designated LVTP7 came into being in 1967. It continues to be the primary amphibious armored assault vehicle of the Marines, and has seen extensive use in Iraq. The most recent versions are powered by a Cummins VT400 diesel engine, and are armed with a .50 caliber machine gun and a 40-mm grenade launcher. The Landing Craft Air Cushioned (LCAC) is not what one would think of as a traditional amphibious vehicle. Rather than wheels or tracks, the vehicle rides ashore on a cushion of air. Moving at 40 knots, the gas turbine powered vehicle can quickly put huge amounts of personnel and materiel ashore. USMC