The existing amphibious vehicle of the U.S. Marines entered service back in 1970s, and they are now slated to be replaced as the Marine Corps announced it has selected the contractors who will build the new prototypes that will carry the American armed forces on land and at sea.

BAE Systems and SAIC were chosen to build the next generation Amphibious Combat Vehicle (ACV) prototypes. The pair beat three other defense contractors, securing $103.8 million and $121.5 million contracts, respectively. For the next two years, they will each develop 16 eight-wheeled amphibious crafts according to stated requirements. Based from the output, the Marine Corps will choose which company will manufacture 204 ACVs to be delivered by 2020, Defense News reported.

Aside from the consideration of the mission and vision of the Marine Corps, there are several new requirements for BAE Systems and SAIC. These include the increase of up to 16 times in the vehicle's speed. In order to achieve this, the Corps is willing to trim the passenger capacity of the new vehicle. Also, the ACV will also have wheels instead of tracks and will be outfitted with technologies and shields that will make it immune to landmines and other explosives, according to Popular Science.

"ACV 1.1 is the first phase of eventually replacing the (assault amphibious vehicle) with a truly amphibious, armor-protected personnel carrier to support the infantry ashore," Col. John B. Atkinson, director of the Marines' Fires and Maneuver Integration Division, told CNN.

Aside from the age of the existing amphibious assault vehicles (AAV) and the emergence of new combat threats, the current fleet has also become too costly to maintain, hence the upgrade. The parts of the vehicles are becoming harder to find, making their repair and upgrade costly and time consuming.