Gone are the days of deploying a large contingent across a beach, moving them from ship to shore in a major assault.
"We're fighting in a more dispersed and distributed fashion now, and we're not necessarily going to mass Marines across small amounts of terrain," said Col. Chris Woodbridge, deputy director, Capabilities Development Directorate, Combat Development and Integration.
The Corps' plans for an Amphibious Combat Vehicle (ACV) program are part of that strategy, Woodbridge said. Its modernized amphibious assault vehicles (AAVs) would be part of the initial assault before the ACV arrives in a subsequent wave.
There is a tradeoff. In order to move a company-sized unit, the Marines will have to increase their fleet size by one-quarter to one-third. The ACV will hold just 13 Marines — the vehicle it is replacing holds 20. Three in each vehicle are crew members.
Also, the ACVwould rely on Navy connectors to transit them near to shore, and joint assets would be employed to blind an enemy's intelligence, surveillance and reconnaissance systems, to create gaps in which to land.
In April, the Corps released EF 21, which lays out the particulars for how the service sees its role in the coming years. It reinforces the Corps' traditional role as a globally responsive, quick-reaction force while doubling down on the crisis-response element.
"Part of Expeditionary Force 21 is the expeditionary mindset, getting back to working with the Navy after 15 years of working on shore primarily," Woodbridge said. "It's getting Marines used to what a lot of us geezers grew up with, and that's preparing for a wide range of crisis responses, working in austere environments, doing what we can with what we have."
The Marine Corps, in a series of war games and planning efforts, is exploring how it might quickly build combat power from different distances off shore and with the various vehicles involved.
"We're working our way through that, but it's nothing more than a new amphibious planning problem," Woodbridge said. "It's not a radical change from the way we sequence advance force operations."
A full-on Marine expeditionary brigade operation could require 400 AAVs and 700 ACVs distributed through a series of naval connectors and over a series of phases, according to Manny Pacheco, spokesman for the service's Program Executive Officer Land Systems office.
"The ACV is not the weapon, the Marine is still the weapon," Pacheco said. "This is the mobility piece."
Another approach to the growing challenge of anti-access, area-denial strategies employed by some nations could be landing ACVs by ship in a friendly country and then rolling into the hostile country, Woodbridge said.
"The fact that we're going to be reliant on connectors doesn't limit us, and in a lot of ways, it's expanding the battlespace for us, giving the combatant commander or joint commander greater options," Woodbridge said.
In its continuing effort to replace the amphibious Expeditionary Fighting Vehicle (EFV) program, which was scuttled in 2011, the Corps plans to gradually modernize one third of its fleet of tracked AAVs while buying several hundred wheeled ACVs by 2020. The Corps is also slated to begin buying about 5,500 joint light tactical vehicles starting in 2015.
As a bridge to the new ACV, about 400 of the AAVs are due for an upgrade to give it a level of protection similar to that of a mine-resistant, ambush-protected vehicle. This will include beefed up underbelly armor, seating, fueling systems and fire protection. In May, BAE Systems and SAIC were each awarded development contracts to begin work on the improvements. An award to one of these vendors is expected in February with the first upgraded AAVs to be delivered in 2019.
In its phased approach to ACV acquisitions, the Corps plans to receive its first tranche of ACV 1.1 test vehicles in 2016, which it will use to generate requirements for the next phase, the ACV 1.2.
The Marines plan to issue a request for proposals for ACV 1.1 this spring, Pacheco said.
A group of vendors that includes BAE Systems, General Dynamics, Lockheed Martin,SAIC and a fifth unnamed company have offerings, from which there will be a downselect to two in 2018, after testing is complete. The Marines will buy 16 from each of the two.
Several are foreign-made wheeled combat vehicles offered to the now-defunct Marine Personnel Carrier program, and several vendors are said to be exploring how to build the prototypes in the US. SAIC has the Terrex infantry carrier vehicle, Lockheed has the Patria armored modular vehicle, BAE the Iveco SuperAV and General Dynamics the light armored vehicle III, which is based on the Swiss Piranha.
(A BAE representative said its offering was US-built, as would be all subsequent vehicles.)
"They're not creating from whole cloth, but taking existing systems, and doing some engineering modifications on them to meet our requirements," Woodbridge said of the offerings. "Because this is a streamlined process, we are compressing things and partnering within the limits of the regulations."
The Marines will use the test vehicles, which are essentially modified production variants, to determine how they meet the requirements, some salvaged and modified from the MPC program, halted over costs in 2013.
"That's going to be occurring near simultaneously with us generating the capability development document for ACV 1.2," Woodbridge said. "It's really pulling us and industry along together. Based on that performance, then we will up the bar for the 1.2."
Probable mission variants for the 1.2 include a a command-and-control vehicle and a personnel carrier, Pacheco said.
"What we get in 1.2 is growth potential, whether it's growth potential to carry a couple more packs, or to travel at a higher speed," Pacheco said.
The next generation, ACV 2, considered a planning construct, could be a high speed, independently deploying vehicle, but it could also be two vehicles, a wheeled or tracked vehicle, and the high-speed naval connectorit relies upon.
If the Marines decide the ACV 2 is infeasible, the fallback plan is an ACV 1.3, with a 600-vehicle buy to replace the AAV fleet, Pacheco said.
The EFV, which came to an inglorious end after consuming $2 billion to develop, was a self-deploying tractor that could move 22 knots and have a range of 12 nautical miles.
"We may learn in the next 10 years there are technologies for a self-deploying tractor or wheeled vehicle that can perform from those ranges in-land," Woodbridge said. "If it's got to come from 100 miles, and its max speed is 10 knots, that's still five hours in the water. It's not a lot of fun."
Paul McLeary contributed to this report.
Joe Gould is the senior Pentagon reporter for Defense News, covering the intersection of national security policy, politics and the defense industry. He served previously as Congress reporter.