UPDATED 1:35 pm Wednesday with more details from Lt. Gen. Glueck

WASHINGTON: The Marines are about to move out sharply with their once-stalled Amphibious Combat Vehicle, the smallest service’s biggest program. After years of uncertainty and a last-minute change of course that came too late to make it into the administration’s budget request for 2015, the Marines will soon announce their new strategy for something they’re calling an ACV. It will be much more modest than the revolutionary vehicle the Corps once envisioned.

“We are doing well with the ACV,” Marine Commandant Gen. James Amos said at the Atlantic Council Tuesday afternoon. “We are about to go public with the way forward on it. It’s affordable, ladies and gentlemen, it’s doable, and we can have our cake and eat it too here. So we’re pretty excited about it.”

Amos was short on details at the event and slipped into the elevator a step ahead of pursuing journalists afterwards. But his staff referred me to Manny Pacheco, spokesman for the Marine Corps’s Program Executive Office (PEO) Land Systems. Then, on Wednesday morning, I and two other reporters cornered the Marines’ deputy commandant for “combat development & integration,” Lt. Gen. Kenneth Glueck, after he testified before the Senate Armed Forces subcommittee on seapower, where the general provided additional details.

Between them, they laid out the not-quite-final plan:

Buy 200 to 600 armored troop transports as a Phase 1 ACV, which would enter service around 2020 (its “Initial Operational Capability” date or IOC). These will be modified versions of an existing US or foreign design, not an all-new vehicle. They’ll also have only limited amphibious capability: enough to cross a river or coastal inlet, but not necessarily enough to move from a ship at sea to the beach on their own power. They will probably have to be carried on some kind of landing craft, at least to within a few miles of a beach. ACV 1 is essentially a re-envisioned and resurrected Marine Personnel Carrier (MPC), a program which was effectively canceled just last year

which would enter service around 2020 (its “Initial Operational Capability” date or IOC). These will be modified versions of an existing US or foreign design, not an all-new vehicle. They’ll also have only limited amphibious capability: enough to cross a river or coastal inlet, but not necessarily enough to move from a ship at sea to the beach on their own power. They will probably have to be carried on some kind of landing craft, at least to within a few miles of a beach. ACV 1 is essentially a re-envisioned and resurrected Marine Personnel Carrier (MPC), a program which was effectively canceled just last year Upgrade about 390 of the current AAV-7 Amphibious Assault Vehicles . These 1970s-vintage vehicles, descendants of the World War II amtrac, can move from ship to shore on their own power but have proven dangerously vulnerable to roadside bombs. (The MPC prototypes were up to 2.8 times as well-protected as the current AAV-7, according to Marine Corps tests). A contract for the first set of “limited survivability upgrades” will be announced in the next 30 to 60 days, Pacheco told me.

. These 1970s-vintage vehicles, descendants of the World War II amtrac, move from ship to shore on their own power but have proven dangerously vulnerable to roadside bombs. (The MPC prototypes were up to 2.8 times as well-protected as the current AAV-7, according to Marine Corps tests). A contract for the first set of “limited survivability upgrades” will be announced in the next 30 to 60 days, Pacheco told me. Research a future “high water speed” option, an “ACV 2.0,” which may be an all-new and fully amphibious vehicle, a very fast landing craft to carry the ACV 1 — Glueck suggested the current Joint High Speed Vessel as a model — or something entirely different. Said Pacheco, “that’s not a procurement, it’s more in the R&D realm.”

“We were talking to some [congressional] staffers last week and things were changing just as we were talking,” Pacheco told me in a Tuesday evening phone call, “but I’d venture to say we’re pretty close to making some announcement.”

What Pacheco laid out and Glueck elaborated on was the most refined and detailed form I’ve seen so far of the Marines’ new multi-phase, multi-vehicle approach.

The first step has to be making the existing AAV-7 more robust, Pacheco said. That means those “limited survivability upgrades,” such as blast-resistant seats and additional armor, which may require a new transmission to handle the extra weight. But of the 1,062 AAV-7s in service, only about 392 will get the upgrades: That’s enough to carry four Marine infantry battalions, a full brigade, in a single assault wave, Glueck told the Senators. There is no current plan for a fleet-wide overhaul or a service-life extension program (SLEP) for the aging vehicles.

The next step is what the Marines are calling “ACV 1.1.” This will not be an all-new vehicle but rather a “non-developmental item,” that is a modification of an existing US or foreign design. It also probably won’t be able to swim from ship to shore under its own power, instead requiring some kind of landing craft, what Marines prefer to call a “connector.”

“It won’t go from the ship to the shore on its own — at least at this point right now,” Pacheco told me. “I know at least one vendor who claims they’ve deployed their vehicle from the back of an amphib, [but] we have not tested that.”

However, while the four prototypes tested for the MPC program may not be able to launch themselves into the water from an amphibious warship and swim directly ashore, Glueck said they could be loaded about a “connector” vessel that would carry them towards the coast but then drop them off up to five miles offshore to swim the rest of the way by themselves.

“The MPC or ACV 1.1 that we’re talking about here, it has a robust swim capability,” Glueck told reporters after the Wednesday morning hearing. “From all the video that I’ve seen of the different versions, I feel very confident that you could drive it into the water probably in sea state three [i.e modest winds and two-foot-high waves], and it would go ahead and go to the beach.”

What’s more, he said, the five-mile, one-hour swim the ACV 1 could make is about the same distance and duration that the current AAV-7 can handle. The limiting factor is less the technology than what the human passengers can endure before they’re too seasick to fight. “Y’know,” Glueck said, “you lose the John Wayne factor there once you’ve been riding in one of those things with the smell of diesel fumes and everything else after about an hour, rocking and rolling.”

But doesn’t the AAV-7 have the advantage that it can launch directly from the amphibious ship, without the time-consuming bottleneck of loading onto a connector vessel? That makes a difference in current operations, Glueck acknowledged, but the proliferation of long-range anti-ship missiles will force the amphibious ships to stay further out to sea: not five miles from shore, but 25, 50, or even 75 miles — which would take one to three hours for even a high-water-speed vehicle to cross, or an utterly impractical five to 15 hours for the current AAV-7.

In such circumstances, regardless of what kind of amphibious vehicle the Marines are riding in, “that connector is going to become all important,” Glueck said. “Even if you had a self-deployer” — i.e. an amphibious vehicle that can launch straight from the ship like the current AAV-7 — “you’re still going to have to use a connector to get that vehicle closer to the shore.”

Glueck said his staff has finished 90 percent of the detailed requirements for the ACV 1.1. They’ll probably require a higher standard of swimming capability than the MPC did, but he’s confident all four of the MPC contenders will be able to meet it — but performance in open water will be a big part of the ACV competition.

Glueck expects to get the major decisions made within six months. In budgetary terms, he said, “you’re looking for about ’17 [seventeen] when you’d actually have to put money on the table to make a selection to have the ability to have a vehicle by 2020.”

If a company can offer an ACV 1 that can swim from ship to shore without a landing craft, that capability would “absolutely” be a major plus, Pacheco said — but it’s not going to be a requirement. That, in turn, is why it’s crucial to keep the AAV-7s viable, since those can self-deploy from the ship, which means they can all head shorewards in a single wave rather than wait to load aboard a limited number of landing craft.

That ACV 1.1 competition would be for about 200 basic troop transports. If that goes well, the Marines will expand the program to an ACV 1.2, buying up to an additional 400 vehicles in multiple variants: not just personnel carriers but also, say, a mobile command post or a fire support vehicle that trades passenger capacity for bigger weapons. Those 600 ACVs of various types would be able to transport six Marine rifle battalions in a single wave.

Meanwhile, research and development will continue on faster means of crossing the water. “That would be ACV 2.0,” said Pacheco. “There’s some things out there that the Marine Corps wants to keep pursuing…. to see what’s in the realm of the possible… to get us to an affordable high-water-speed ACV.” But right now such a vehicle, whatever it might be, looks like an idea for the indefinitely distant future.

Some critics of the Marine Corps have questioned why the service needs this kind of capability at all. The last opposed landing by amphibious armored vehicles came during the Korean War, they argue, and in an era of increasingly long-range anti-ship and anti-tank missiles, even a high-water-speed landing force is unlikely to reach the beach alive. But the Marines see the ability to move from ship to shore and on inland as central to their mission — and not just in major wars.

When 6,000 Marines aboard seven Navy amphibious ships responded to the Haiti earthquake of 2010, Gen. Amos said Tuesday, “there wasn’t one ounce of combat involved.” But the Navy ships couldn’t enter Haiti’s damaged ports — which had been in bad shape even before the quake — and tie up at the pier. Nor could helicopters carry the sheer volume of relief supplies required. Instead, the operation relied on AAV-7s, he said: “all those amphibious tractors that swam ashore and swam back every day and carried fuel, water, medical supplies, people back out to the ships,” Amos said.

In fact, “I think the bulk of [the] forces in my service are what we call general purpose, applicable across the range of military operations” from humanitarian aid to major war, Amos went on. A Navy-Marine amphibious task force is “the Swiss Army Knife of the Department of Defense,” he said, using one of his favorite phrases. (And, by the way, “our United States Navy needs more money for ships,” he added). “If you want to hand out humanitarian supplies or food or rescue people, you bring in an amphibious ship full of marines and sailors,” he said. ” They can also make a forcible entry landing some place [with] the exact same force.”

“The standard-issue United States Marine… is trained as a rifleman first and can hand out water, can hand out diapers,” Amos said, citing recent relief efforts in the Philippines after Typhoon Haiyan last fall and in Japan after the 2011 earthquake.

Amos’s problem is paying for enough Marines with enough training and enough modern equipment to handle this wide range of missions. “Yes, we can do the same with less, but there’s a price to be paid for that,” he said. For example, the Marines have been raiding equipment and base maintenance funds to pay for training, fuel, spare parts, and other immediate operational needs.

The automatic budget cuts known as sequestration are “forcing us to sacrifice our long-term health for near-term readiness,” Amos said. “I can’t continue to do this for forever.” Around 2017, he said, the next Commandant will probably have to cut back readiness to keep alive programs like the Amphibious Combat Vehicle.