Pimp My SBCT Round 3 - The Amphibious Assault Brigade Combat Team (AABCT)

The USMC is moving away from large-scale amphibious assaults towards smaller, battalion-and-below formations and EABO.  However, the US Military may still find itself in need of performing such an assault as part of a broader forcible-entry operation. What’s needed is a “relatively” inexpensive way to land a large, mobile, armored force in short order.  

So how about give the large-scale amphibious assault mission to the Army?  Switch three IBCTs (roughly a division) over to an Amphibious Assault Brigade Combat Team (AABCT), an organization mirroring the SBCT, but replacing the ~300 Strykers with the USMC ACV.

USMC ACV with 30mm Remote Turret

SBCT Organization (CBO)

SBCT Organization Pg 2

In this way, existing, land-based SBCT doctrine and training could remain the same.  The AABCT can be used in more or less the same ways and same situations as an SBCT.  ACVs are somewhat heavier and larger than Strykers so the logistics elements in the SBCT will need a bit of a bump.

Outfitting the AABCT

The Army has selected the Rafael Sampson 30mm remote turret to arm its Stryker brigades.  This may include integration of Javelin missiles with the Sampson turret.  Rafael offers a Sampson variant that includes the TROPHY Active Protection System.  A full-capability Sampson turret with TROPHY and Javelin is ideal for AABCT infantry ACVs.  

Sampson turret on a Stryker

Perhaps do away with the goofy overhead 105mm MGS for a proper turret.

CMI 3015 MPF 105mm Turret (CMI Defense)

Also consider replacing some or all of the M777 155mms with a turreted howitzer on the ACV that can swim ashore with the rest of the AABCT.  

Denel/GDLS 105mm T7 Turret on a Stryker (Army Recognition)

GDLS 105mm LAV III Artillery Weapon System (NDIA)

Lastly, the Army is looking to replace its current Stryker mortar variants with a turreted system.  This may even more important for an AABCT, potentially allowing indirect and direct fire while swimming.  One obvious option, which has already been trialed on boats, is the Nemo mortar turret.

Patria Nemo

Moving the AABCT

Unlike current USMC doctrine that relies heavily on rotary wing lift and landing craft to move forces ashore, the AABCT's main combat element of 300+ ACVs would wade ashore on their own, in a single wave, ready to fight immediately and move off the beach at vehicle speeds.  This hearkens back to the huge waves of LVTs in the Pacific in WWII.

LVTs waves coming ashore at Iwo Jima (Pinterest)

Obviously the AABCT would need a way to get from its home to the line of departure.  The Navy is investigating modifications to the stern ramp of the JHSV/EPF to support launch and recovery of ACVs.

Expeditionary Fast Transport (EPF)

Around twelve to fourteen EPFs would be required to carry all of the AABCT's ACVs.  Given that the Navy only plans to buy 14 EPFs total, a larger buy would be required.  Perhaps some could be bought using Army funds and manned by soldiers, much as the Besson-class LSV is today.

Another option instead of the JHSV would be to re-introduce the humble LST.  Stay away from the faster, more complex Newport class LST, in favor of something like the older, simpler, 17-18kt De Soto County class.  

A modern version should be relatively inexpensive to build, perhaps even less than the EPF, if sticking to a modest combination of commercial and naval design practices.  Damen Shipbuilding has a line of LST designs that might be a good starting point.

However, ACVs still only constitute around a third of the AABCT's total rolling stock of around 1,000 vehicles.  These other vehicles would have to be carried by other vessels and landed by regular landing craft, lifted ashore by heavy lift helicopters, or make use of a port or pier to offload.  Additional LSTs or EPFs could be purchased for this, but I propose re-introducing Amphibious Cargo Ship (LKA).  A larger LKA could carry more with fewer ships.  

We already have a suitable starting point with the M/V Craigside conversion to the SOCOM MV Ocean Trader.

MV Ocean Trader 

A similar design was considered for the Royal Navy Littoral Strike Ship.

Prevail MSV (Save the Royal Navy)

And the Canadian Maritime Support Ship (Irving Shipbuilding).

Maritime Support Ship (ThinkDefence)

The LKA could offload vehicles and logistics via its rear ramp to its own lighterage, to LSTs, or to other Navy or Army lighterage.

Both the LST and LKA could be built by second or third tier yards, which don't normally build Navy warships, and are more accustomed to building commercial vessels.  

A combination of fourteen LST/EPFs and four or five LKAs could carry the entire AABCT, likely with room to spare.  

Perhaps some or all of these ships could be bought or leased by the Military Sealift Command and crewed with a mix of civilian mariners and Navy sailors.   

Obviously there is a cost to buying 19 or so additional large ships per AABCT and introducing the ACV to the Army.  However, LKAs and LSTs should be an order of magnitude cheaper than existing Navy amphibious ships, like the LHD/A and LPD, especially if they’re limited to amphibious transport and eschew the Sea Base and warship roles of current Navy amphibious ships.  Removing the requirement to spend months at sea supporting open-ended ARG/ESG tasking, in favor of point to point troop movements should greatly simplify their design. 

For the LST, the Army’s smaller and slower, but conceptually similar, 83m Besson-class LSV costs a mere $32 million each.

Besson class LSV (The Drive)

Shoot for a unit cost in the neighborhood of $200-300M per LST.  At around $180M each, the EPF is less expensive than this.

Assuming a unit cost of $200M per LST and $300M per LKA, the 19 ships needed to transport a single AABCT would cost $4.3 billion.  Three AABCTs-worth would need $12.9 billion.  

Certainly not pocket change, but consider a single, battalion-sized ARG requires three ships that cost close to $8 billion.  The LST/LKA combo lifts an entire brigade for a bit more than half the price.  

Not a bad deal, IMHO.

Ground Combat Power	MEU GCE	AABCT
Troops	1200	3600
LAVs	7 to 16	0
ACVs Total	15	>300
ACV 105mm gun systems	0	27 (original SBCT)
155mm howitzer: M777	6	18
120mm/81mm mortar	8	24
TOW missile launchers	8	9
Javelin missile launchers	8	81