 If ACV Phase 2 becomes infeasible, the Marine Corps fallback plan is the ACV 1.3, with a 600-vehicle buy to replace the AAV fleet.An RFP for ACV 1.1 was issued in November 2014.Even though the Marine Corps has spent $3.5 billion on four failed high-water speed amphibious vehicles over the past 25 years, such a vehicle is still a requirement for the Corps.