Footprint of the future: Offshore sea bases
Aug. 15, 2019 — Typhoon Kaibutsu ravages a foreign country. Hundreds of thousands are left homeless and hungry.
The nation desperately needs humanitarian supplies and services, but a tense political situation rules out a large U.S. military base of operations on shore.
The storm obliterated the ports, making traditional supply offloading impossible.
Forty miles out in the ocean, the U.S. military sets up a floating base with 14 ships and thousands of troops.
Amphibious landing craft and helicopters deliver food, water, trucks and more — all of it pre-sorted at sea.
A few weeks later, the mission is complete and the base simply sails away.
This imagined humanitarian scenario might one day be possible if the U.S. Navy completes its plans to establish futuristic floating bases at sea.
Today’s ships can get thousands of troops and supplies to shore for war pre-positioning and humanitarian aid efforts, but not without creating a giant footprint that could serve as a magnet for local opposition to the United States.
The solution heralded by the top brass at the Navy and Marine Corps — and even among a few in the Army — is to place most of that footprint in the ocean with “sea bases.”
“When you have less boots on ground for logistic forces, you have less resentment for American forces,” said Robert Button, a Rand Corporation senior analyst, who has explored seabasing capabilities in Defense Department-backed studies.
Seabasing isn’t a new idea. Aircraft carriers function like floating bases, and cargo ships have long positioned themselves offshore to support land operations.
However, the Navy’s seabasing concept is on a grander yet more efficient scale, and the service says it’s critical to its 21st-century vision.
The self-contained sea base squadron, a concept known as the Maritime Prepositioning Force (Future), could carry several dozen helicopters, thousands of trucks and all the armored vehicles found in a Marine or Army brigade.
It also would carry millions of square feet in supplies and berthing for thousands of troops.
The ships could then seamlessly transfer troops and supplies to amphibious landing craft, or send them to shore on helicopters.
Most importantly, if less glamorous, the sea base’s ships could use recently developed technology to sort through tons of supplies at sea and deliver custom supply packages to shore in a fraction of the time it takes now.
Officials say the full vision won’t be realized until at least sometime during the next decade, and some technological challenges remain.
In the meantime, some of the required pieces are rolling off assembly lines and entering the fleet right now.
Putting the pieces together
A future sea base squadron and its 14-odd ships — including flight decks, cargo holds and amphibious landing craft — would set up 30 to 125 miles offshore and then deploy and sustain thousands of Marine expeditionary brigade troops, complete with heavy-armored vehicles and rotary aircraft.
In its top-shelf version, Button said, it would include three amphibious assault ships that function as helicopter carriers.
They would carry about 40 helicopters and 48 tilt-rotor Osprey aircraft.
The assault ships also can produce 200,000 gallons of water per day and store double that amount to sustain troops.
Cargo ships play the next crucial role, one type of which represents the biggest technological leap available today.
The Lewis and Clark-class T-AKE ship, several of which have been delivered already to the Navy’s Military Sealift Command, has eased the logistical nightmare of sorting through tons of cargo.
Most Navy ships are “dense-packed,” meaning cargo is stuffed as tightly as possible. It can be unloaded only in the reverse order it was packed. If troops need that first crate, they might have to wait a few weeks for all of the crates to be offloaded at a port.
The T-AKE can eliminate that wait by using automated crate selection, said Jim Strock, director of the seabasing integration division at the Marine Corps Combat Development Command, at Quantico, Va.
The T-AKE can hold more than a million gallons of oil and has about 900,000 cubic feet of cargo capacity.
The future sea base squadron would include three of these ships. It would also include two older cargo ships capable of rolling cargo off ramps to smaller ships. The older ships would be retrofitted to carry roughly 202,000 tons of cargo and berthing for 850 troops each, according to a 2007 study by the Rand National Defense Research Institute.
However, they would also need a new system to allow them to select crates like the newer ships, and one Florida-based engineering contractor wants to install such a system.
BEC Industries already has sea-tested its GRID system, which uses multiple, computer-controlled bridge cranes that work in concert to collect and drop containers.
Brian Pfeifer, the company’s director of engineering, points to an episode during the first Gulf War as an example of the value of selective offloading.
When a cargo ship couldn’t dock in port during the war, it had to sort out 500 crates among the 2,500 it had dense-packed at sea. It took them 30 days to sort the right crates, Pfeifer said.
“This system could do it in about a day,” he said.
The challenges ahead
One of the reasons why the future sea base squadron isn’t sailing today is that one of its most important ships hasn’t had a single piece of metal cut yet.
The Mobile Landing Platform ship will act as the bridge between the behemoth cargo ships remaining at sea and the ships and landing craft bringing troops and supplies to shore. The ship’s design contract was awarded through the Naval Sea Systems Command in February.
“The Mobile Landing Platform is the game-changer in the ability to get gear off,” said Strock, a retired Marine colonel.
As theorized, the ship would have a long, flat platform with ramps running to the cargo ships. Cargo could be dropped by crane or transported across the ramps.
The Mobile Landing Platform would also include berthing for troops and landing space for helicopters. And the platform ship would be able to deploy Marine Corps air-cushion landing craft, which are hovercraft capable of beach landings. Depending on the final design, it might be able to accommodate a new high-speed troop carrier that the Army and Navy are jointly developing for shore landings.
The Mobile Landing Platform is expected to have an advanced counter-ballasting system that shifts the boat’s weight in reaction to wind and waves, Button said.
However, different ships react differently to rough seas, and even if the ships coordinate perfectly, rough seas will probably rule out seabasing in some parts of the world.
Nevertheless, sea base supporters say the potential advantages outweigh the challenges — challenges they believe technology will minimize.
“When we did Desert Storm, we spent months building up supplies on the shore, and we couldn’t do anything until we were done offloading the supplies and equipment,” Button said. “With a capable seabasing force, you dispose of the iron-mountain pileup, and you’re ready to go immediately.”
When the advantage of speed is considered alongside the current geopolitical environment — when the U.S. must sometimes argue over base use, as it did in Kyrgyzstan — a base over the horizon that can leave without a trace is needed, experts contend.
“First and foremost,” Strock said, “we want to be able step lightly when it comes to our allies and partners.”
Study envisions Army brigades using sea base
If the Army wants to be a part of the future sea base sometime in the next decade, it should be thinking about compatibility issues now, experts say.
At the Defense Department’s request, Rand Corporation senior analyst Robert Button and four others were commissioned in 2007 to study whether a sea base could sustain an Army brigade.
An Army Stryker or heavy brigade, carrying 15,000 to 20,000 tons of supplies and equipment, could be deployed in two to six days from a sea base under the right conditions, Button said.
However, several impediments to Army participation remain.
Army helicopters don’t have the braking systems and collapsible blades needed for landing on decks crowded with Navy and Marine aircraft, nor are they built to land on metal decks repeatedly.
Army pilots would need to learn to land on ships, and its drivers would need training on driving around sea-based ramps.
Another is that a jointly conceived high-speed amphibious vessel comparable to the Navy-Marine hovercraft hasn’t been built yet and would have to fit the landing platform ships.
“I’ve met some Army officers who think this is a terrific idea,” Button said. “Others in the Army think other problems have a far greater urgency.”
— Erik Slavin