Conventional ground fighting vehicles can be transported by landing craft like the Landing Craft Utility and Landing Craft Air Cushion, but amphibious landing ships are able to carry many times more amtracs than they can other landing craft or hovercraft carrying vehicles. LCACs can move to a beach faster, but cannot travel inland and are not able to take enemy fire. Moving vehicles with few LCACs would require multiple trips, taking up time and leaving the hovercraft vulnerable for longer. Shortly after the Marine Corps submitted their FY 2015 budget request in February 2014, General Amos decided to postpone development of the ACV and return funding to the Marine Personnel Carrier program. Originally, the Marines planned to buy both the ACV and MPC to replace outdated vehicles to complement each other for different missions. During an amphibious assault, a limited number of ACVs would carry the initial landing force from ship to shore and further inland. After the beach was secured, a larger number of MPCs would be landed by landing craft to reinforce the first wave. When budgets tightened, the ACV was taken as the priority and funding was removed from the MPC, with the service figuring they could buy an off-the-shelf wheeled troop transport later when money was available. Technical challenges to the proposed ACV continued to mount as funds kept getting constrained, so the decision was made that wheeled APC advancements where significant enough to address needs quicker. Marines still want a high-speed fully amphibious vehicle to move troops from the ocean to a beach with enough armor, mobility, and firepower to fight while on land, which was proposed as ACV Phase 2. The Marine Corps plan to modernize its amphibious invasion force has three parts: upgrade 390 AAVs; buy 600 troop transports as part of ACV Phase 1; and do research for an ACV 2.0 "high-water-speed" option. Upgrades to the AAV will be added to around 392 vehicles (carrying one Marine brigade) out of the fleet of 1,062, including "limited survivability upgrades" of blast-resistant seats, additional armor, and a new transmission. Having AAVs self-deploy directly from ships is quicker than loading vehicles onto a connector, but long-range anti-ship missiles will force future amphibious invasion forces to stay between from shore. A high-speed connector can make that trip in 1–3 hours, while an AAV on water would take 15 hours to travel that distance. The Phase 1 ACV will be 200 modified versions of an existing U.S. or foreign armored vehicle to enter service around 2020.