by Shawn Arnold, Cultural Resource Manager, Joint Region Marianas
The Landing Vehicle Tracked (LVT), also known as the amphibious tractor (Amtrac, Amphtrac), was essential to U.S. forces during World War II (WWII) in the Pacific Theater. The vessel possessed the ability to travel both in and out of the water and was one of the first true amphibious vehicles.
Many Pacific islands have very shallow reefs off shore that form vast lagoons sometimes thousands of feet wide. These reefs are known as fringing reefs. At low tide, some fringing reefs are exposed on the water’s surface. These reefs prevent traditional watercraft from approaching the beach. If it were not for the use of amphibious vessels during World War II, the invasion forces would have had to walk or swim to shore with no protection form enemy gunfire. The capability of being able to travel in and out of the water prevented many Marines and soldiers from being wounded before making it to the beach.
There are different versions of LVTs. Some have large guns on top, which causes them to appear similar to traditional tanks (Figure 1). Other versions possess an open compartment for carrying people and supplies (Figure 2). Upon reaching the beach, the tank versions acted as mobile cannons and provided support for the invasion forces as they advanced further inland. Once the cargo version LVTs delivered troops to the beach, they returned to the sea in order to ferry more troops and supplies to the beach. On these return trips, LVTs evacuated the wounded.
LVTs are constructed of steel and kept afloat by air contained in pontoons located on both sides of the vehicle. The LVT’s amphibious capability was achieved by a single engine propulsion system consisting of tracks mounted on the port and starboard sides. The vessel’s tracks contain cleats known as grousers that act as paddles in order to propel the vehicle through the water and provide traction while crossing reef flats and shoreline terrain.
The troops who operated the LVTs would often modify their vessels. Almost all Amtracs were modified in some way. These modifications include adding extra metal plates and sandbags in order to provide additional protection for the troops inside. It was also very common for the operators to add additional weapons. These modifications often appeared in the next production version of the LVT for subsequent invasions.
Archaeologists are able to identify and record these modifications in the material remains that are discovered. These discoveries allow researchers the ability to track the modifications completed by specific units as a direct influence on future LVT production. These influences can be observed on amphibious vehicles presently being used by the military.
The first wave of the assault at Peleliu was led by the LVTs of the Marine Corps 3rd Armored Division. As their name implies, this group was composed of armored Amtracs consisting of a mixture of LVT (A)-1 and LVT (A)-4. These vehicles are sometimes referred to as Amtanks. The LVT (A)-1 had a 37-millimeter (mm) gun mounted in a closed turret on top, which was designed to penetrate armor plating and two .30 caliber machine guns in the rear. The LVT (A)-4 had an open turret with a 75-mm cannon on top. The original LVT (A)-4 had a single .50 caliber machine gun mounted to the turret. The 75 mm cannon was designed to penetrate reinforced concrete bunkers. These Amtanks provided the heavy firepower necessary to ensure the troop-carrying LVTs had a chance to make it to shore under the intense bombardment of the Japanese troops attempting to maintain control of the island.
Behind the Amtanks followed 241 troop-carrying LVTs of the 1st, 6th, and 8th Amphibious Tractor Battalions. These Amtracs consisted of the older LVT-2 and the LVT-4.
Twenty-six LVTs are documented as having been destroyed during the invasion of Peleliu. However, the types of destroyed LVT are not documented. Divers report the wreckage of LVTs and tanks in the waters of Peleliu, but to date, there has been no formal underwater archaeology investigations conducted at these submerged sites.
Submerged archaeological sites, such as LVTs, tend to attract marine life. These sites may offer an opportunity for ecological investigations. Studying these sites archaeologically offers researches the opportunity to:
- Explore archaeological remains for individualized LVT modifications
- Refine predictive models, to better understand site formation processes
- Conduct corrosion studies which could lead to a better understanding of how to preserve submerged vessels
The opportunity to participate in expeditions of this nature furthers our knowledge of history and the effects of historic events on both the natural and cultural world.