The above pics are of a 1970's/early 1980's effort by Bell Corporation to give the Marine Corps an AAV with high water speed. It reminds a bit of what the Koreans are doing today with their K-21 Infantry Fighting Vehicle. But unlike the K-21 which relied on inflating pontoons to aid in buoyancy, the Bell Landing Vehicle Air Cushion sought to combine the features of the LCAC with those of the AAV.
Which really brings us back to the issue at hand. We have been lusting for a vehicle that is high speed in the water and yet capable of fighting as well as an IFV that doesn't have a requirement to be amphibious.
Is that really the way to go? We had that with the EFV and it was considered too expensive. WHAT HAS CHANGED SINCE THEN? The answer is quite simple. Nothing.
We're looking for a technological answer when we might be facing a tactical problem.
The Navy and Marines have tested deploying an LCAC with AAVs aboard from over the horizon, the LCACs making the majority of the run to the beach and then the AAVs launching from the LCACs to complete the final leg of the amphibious assault on their own power.
Whether you're talking about an ACV, AAV Upgrade OR a Marine Personnel Carrier, that concept should be explored further. An LCAC that is doing 30 knots with 3 MPC's a piece on them and then allowing those vehicles to make the last dash would be more comfortable for the Marines inside the vehicles, would lower the water requirement and would give us more robust vehicles for land warfare.
THINK TACTICS. STOP WISHING FOR TECHNOLOGY TO FINALLY CATCH UP WITH MARINE CORPS DREAMS!
