April 25, 2016: The U.S. Marine Corps has finally selected the two finalists (out of five competing vehicles) in its search for a suitable ACV 1.1 (Amphibious Combat Vehicle). This comes after work on ACV 1.0 and the even earlier MPC (Marine Personnel Carrier) program. The finalists are the Terrex 2 (from Singapore) and SuperAV 8x8 (from a British-Italian consortium). ACV is needed to replace elderly (1970s) AAV7.

The ACV 1.1 competition is the aftereffect of a failed, decade long, effort to get the high-tech AAV7 replacement (the EFV or Expeditionary Fighting Vehicle) to work. Back in 2011 the marines gave up on high-speed (sea skimming) amphibious assault vehicles like EFV. The marines then decided that a simpler ACV design would do to replace the AAV7s. DARPA (the Defense Advanced Research Projects Agency) was called in to help design the new vehicle. This may sound either very innovative or very desperate, and in reality it was both. In part because the marines had spent three billion dollars on the EFV and that disaster made it clear that some original thinking was required for the ACV. In the end the $12 million ACV was the EFV without most of the expensive stuff that didn't work. In effect, the ACV was be a 21st century version of the AAV7, optimized to pass all its development tests and get into service as quickly as possible. DARPA quickly did its job but the resulting ACV was still more expensive ($12 million) than the shrinking marine budget could handle all at once.

The cold war era AAV7, used by the US Marines and militaries of many other countries, weights 29.1 tons and thanks to its large hull carries 25 marines and 4 crew members. The Singaporean Terrex 2 is a variant of Terrex, which is already used by Singaporean Armed Forces, modified to fulfill the requirements of the ACV program. Terrex 2 weights 32.5 tons and can carry 11 troops in addition to 3 crew. These numbers can change with turrets and other factors that affect internal space arrangement.

SuperAV 8x8 weights 31.5 tons and the variant offered to the Marines also carries 11 passengers plus 3 crew. A modified version of SuperAV’s 6x6 variant is in use by the Brazilian Army, designated VBTP-MR Guarani.

Both of the vehicles have similar reserve buoyancy; 23 percent for Terrex 2 and 21 percent for SuperAV 8x8. Both of them have the same speed in water, 11 kilometers an hour, and fulfill the requirement to be capable of crossing at least 36 kilometers of open water at sea state 3. On roads, Terrex is the slower of the two vehicles, reaching only 89 kilometers an hour in comparison to its competitor’s 105 kilometers for SuperAV. For comparison, the AAV7 has 30 percent reserve buoyancy, can cross 36 kilometers at sea state 5, reaching 12.5 kilometers an hour in water, and 72 on roads.

However, the sacrifices in passenger capacity and amphibious capabilities were not made for nothing, as both of the new vehicles have protective features vastly superior to those of the AAV7, which was shown to be extremely vulnerable to IED (Improvised Explosive Device) attacks during the Iraq war.

Instead of steel armor of their predecessor, the two ACV contenders use modular composite armor including ceramics, and have features that make them equal, if not better at resisting mine and IED explosions than MRAP (Mine Resistant Ambush Protected) vehicles, like advanced V shaped hull designs with additional blast protection features for their floors, and seats attached to the troop compartment’s ceiling instead of the bottom of the vehicle’s hull.

The lower passenger capacity per vehicle itself can also be considered a protective feature, as it limits the possible number of casualties when one vehicle gets destroyed, and allows the occupants to evacuate faster.

Sixteen of each vehicle has been ordered for extensive testing, at the price of $103.8 million for the SuperAV and $121.5 million for the Terrex vehicles. The winner of an over $1 billion, 204 vehicle contract will be chosen in 2018. --Adam Szczepanik