Ships' cost could sink plans for floating military bases.

The success of the U.S. Navy and Marine Corps forward-looking concept of deploying bases at sea relies heavily on the development of a new class of cargo ships. But as the Navy juggles ship acquisition programs in a tight budget environment, lawmakers and contractors wonder how the service will pay for these floating warehouses, which are called Maritime Pre-positioning Force Future ships, or in short MPF-F.

Sea basing envisions future landings of Marine Corps units conducted, supported and sustained from ships at sea. Although the entire fleet would play a role in the sea base, the most important platforms would be amphibious ships and future maritime pre-positioning vessels, according to the Congressional Budget Office.

Amphibious ships would continue to carry the first wave of troops in any expeditionary operation. The MPF-F ships would contain most of the material needed to sustain that force in the first 20 days of operations. They would also hold all of the equipment for the follow-on assault units that would be transported to the war zone by aircraft or high-speed vessels.

"The MPF-Fs are the linchpin of the sea base," said a CBO report entitled, 'The Future of the Navy's Amphibious and Maritime Pre-positioning Forces.' "Without them, the Navy and Marine Corps would not be able to implement that new approach to amphibious warfare or forcible-entry operations."

The MPF-F ships are intended to replace the current fleet of approximately 16 pre-positioning vessels, but the Navy and the Marine Corps have not settled yet on a design.

The Navy's program office for support ships, boats, craft, sealift and special mission ships has laid out an experimentation plan for MPF-F technologies, said program manager Capt. Pat Sudol.

But of the approximately $90 million the Navy requested for MPF-F research, Congress released $28 million, said Sudol.

"We are working hard to pull together money to invest into research and development," she said at a recent expeditionary warfare conference that was organized by the National Defense Industrial Association. "We intend to make some investments as money is released by Congress."

Some of the key technologies include integrated landing platforms, as well as mobile landing platforms, for heavy-lift helicopters, so-called skin-to-skin technologies to connect ships during cargo transfers and automated cargo handling, said Sudol.

Probably the most important feature is the selective cargo offload that would allow Marines to have immediate access to their equipment and supplies as necessary, said retired Vice Adm. Doug Katz.

Complementing the MPF-F ships are air and sea connectors. To put troops ashore and sustain them requires shipping troops from the continental United States to a theater of operations. The Navy and Marine Corps still are studying the best way to do that. One option would be to develop fast sealift ships capable of ferrying troops from the U.S. directly to the sea base at high speeds.

Another alternative for getting troops to the sea base would be to fly them to an advanced base some 200 to 2,000 nautical miles away from the theater of operations and then ferry them to the sea base using shorter-range, high-speed vessels. Ships of that type do exist, and the Navy, Marine Corps and Army have been experimenting with commercial off-the-shelf variants.

The Marine Corps said that it would need to replace its large CH-53 helicopters to provide the heavy lift necessary to support troops operating from a sea base. Pentagon officials are considering an even larger heavy-lift aircraft than the CH-53's replacement, such as a quad-tilt rotor capable of carrying 20 tons as far as 110 nautical miles.

Meanwhile, as part of its sea-basing concept, the Navy intends to replace most of its current amphibious and maritime pre-positioning ships during the next 30 years. The Navy plans to buy 12 amphibious transport docks of the LPD-17 San Antonio class, 10 amphibious assault ships of a new class, designated the LHA (R), which would have the ability to carry and support more aircraft that the existing LHD class, 12 dock-landing ships of a new class, called LSD (X), and up to 21 new MPF-F ships.

As far as the MPF-F design is concerned, options could range from a ship comparable to the current Bob Hope class of sealift vessels, to a much larger ship, or a family of dissimilar ships, explained Navy sources.

"We can't [tell] you exactly what MPF-F is going to look like," said Adm. Vernon Clark, the chief of naval operations and one of the staunchest supporters of sea basing.

As a temporary stopgap, the Navy may consider leasing or purchasing modified commercial S-Class container ships made by Maersk Line Ltd. The vessel could be reconfigured for military use by adding a flight deck and accommodations for 1,000 troops at a cost of approximately $300 million per ship, said industry sources. By comparison, a new MPF-F ship class could run in the billion-dollar range.

CBO estimated that the Navy's plan would require spending an average of $2.4 billion a year on ship construction between 2005 and 2035, more than twice the Navy's average annual spending to build amphibious and maritime pre-positioning ships between 1980 and 2004.

Clark said he promised Gem Michael Hagee, commandant of the Marine Corps, to fully support the new ship in future budget negotiations.

Hagee views the MPF-F as one piece of the larger picture of naval expeditionary forces. "MPF-F has to be looked at as a system of systems," Hagee said at the conference. "You can be tricked and will develop the wrong platform if you look at it in isolation." MPF-F ships should be built in such fashion that they allow the Marine Corps to perform arrival and assembly at sea and selective offload. At the same time, these ships should be able to sustain the joint force, said Hagee.

In order to free up shipbuilding funds, Clark is considering reducing the number of Navy expeditionary carrier strike groups from 12 to 10 or eight, and make up for the shortfall in forward presence by employing a form of crew rotation known as "sea swap." The Navy has experimented with sea swap on several types of surface combatants. Instead of having one crew deploy and return home with the same ship, the ship remains forward deployed while crews rotate in and out every six months. In between their deployments, the crews train on ships that remain in the United States.

Sea swap may be more difficult to apply to amphibious ships than to surface combatants, however, because of the logistical challenges of coordinating pre-deployment training between the Navy crews and the Marines who serve on board an amphibious ship, said the CBO report. Nevertheless, Clark has ordered Navy analysts to study the issue, and some experimentation is likely to follow.

Meanwhile, CBO outlined four plans for the future of amphibious and maritime pre-positioning forces that would lessen the Navy's funding challenge. All of the possible plans would result in a smaller amphibious force than exists today, and some would result in a smaller pre-positioning force as well.

The first option would be buying fewer, more-capable ships within the historical spending level for construction of those vessels. This approach would gradually reduce the number of expeditionary strike groups by half and the number of maritime pre-positioning squadrons from three to two. To compensate somewhat for those cuts, one of the maritime pre-positioning squadrons would be given sea-basing capabilities. Under this option, the Navy would buy four of the new LHA(R) amphibious assault ships through 2035, instead of 10 as under the Navy's plan; five rather than 12 new LSD(X)s that would be larger than today's dock landing ships; and one squadron of eight MPF-F ships instead of 16. This option would also involve the purchase of seven LPD-17 dock-landing ships, rather than 12, and a squadron of five conventional cargo ships.

The second option is buying more, less-capable ships within the historical spending level. The number of expeditionary strike groups would gradually be cut from 12 to nine. The number of maritime prepositioning ships would be reduced with just over half a squadron rather than by a whole squadron. Amphibious assault ships would be replaced with ships similar in size and capabilities to existing classes, and maritime pre-positioning ships would be replaced with modern cargo ships that lacked sea-basing capabilities.

The third option entails the creation of a more survivable sea-basing force. To address that issue, this option would build MPF-Fs that were closer, though not equal, in survivability to L-class amphibious ships. Because a more survivable ship would be more expensive, this option allows for buying only eight, or one squadron's worth. In all, this approach would cost approximately $1.5 billion a year on ship construction between 2005 and 2035, compared to $2.4 billion a year under the Navy's plan.

The last option focuses on de-emphasizing sea basing in favor of forward presence, which basically means forgoing the sea basing concept. This approach would end the LPD-17 program at 10 ships instead of 12. It would delay the start of the LHA(R) program from 2007 until 2013 and buy eight ships rather than 10 through 2035. The LSD(X) program would be delayed by two years from 2020 until 2022, and only 10 ships would be purchased instead of 12. The MPF-F program would consist of three full squadrons worth of ships, but they would not have sea-basing capabilities. With those changes, building amphibious and maritime pre-positioning ships would cost the Navy an average of $1.5 billion a year between 2005 and 2035.