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The Ship to Shore Connector: Building a Better LCAC

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The expanding use of amphibious ships for a wide range of missions has increased the importance of a Navy program to produce an upgraded replacement for its Landing Craft Air Cushion (LCAC), a high-speed hovercraft that supports amphibious operations in both combat and humanitarian situations. The replacement for the LCAC, called the Ship to Shore Connector (SSC), would bring new technology and increased performance to handle current and future missions, plus better fuel efficiency and reduced maintenance to meet the demand for lower total ownership cost.

The project to build the SSC has drawn proposals from two powerful contractor teams, both of which would bring considerable experience in hovercraft construction. A team combining aerospace giant Boeing, shipbuilder Marinette Marine, Griffon Hoverwork, and Oceaneering International will compete with a partnership of Textron Marine & Land Systems, which produced most of the LCACs; L-3 Communications; and Alcoa Defense.

The rival teams have aggressively touted their qualifications to produce the SSC because the contract to build 73 of the new air cushion craft could be worth $4 billion, a highly desirable prize in light of the expected tightening of defense budgets.

After months of delay, Naval Sea Systems Command released the formal request for proposals (RFP) on May 20, 2011. But the competing teams have been refining their concepts based on the information released since the program started in 2008 and a draft RFP issued in March.

The artists’ renderings of their proposals look nearly identical and the limited technical details they have revealed also are similar. But that is to be expected due to the fact that they are starting with the same set of requirements and because the SSC must be the same size and perform primarily the same missions as the LCACs.

LCACs are unique in that, as that name and the generic term hovercraft imply, they can hover above the surface on a cushion of air, which enables them to travel over dry land as well as water. That means as a landing craft, they can skim across the water at up to 50 knots and then ride up onto the beach to off-load their cargo. The air cushion also allows the LCAC to sail, or fly, as the craft crewmen prefer, up into the well deck of the amphibious ships that carry them.

Team SSC Ship to Shore Connector

An artist's rendering of the Ship to Shore Connector proposed by Team SSC (Boeing, Marinette Marine, Griffon Hoverwork, and Oceaneering International). Image courtesy of Team SSC

The Navy noted that the air cushion capability gives LCACs access to 70 percent of the world’s coastlines, compared to about 15 percent for conventional landing craft. Had they been available in 1943, LCACs could have saved a lot of Marines at Tarawa by flying over the reefs that stopped the Higgins boats hundreds of yards from the beach.

The first practical hovercraft were built in England in the late 1950s and began operating as ferries across the English Channel and among the British Islands in the late 1960s, while smaller craft were used for rescue and as personal watercraft. The British military adopted hovercraft for transport and even as small warships about the same time, and copies of the British craft, made by Bell Helicopter, were used by the U.S. Navy in Vietnam. The Bell design was chosen as the basis for the LCAC when the Navy tested two prototypes between 1977 and 1981.

The initial production, funded in the fiscal 1982-86 defense bills, was split between Textron Marine & Land Systems and Avondale Gulfport Marine, but Textron won a later contract for the remaining craft. The first LCAC was delivered to the Navy in 1984 and initial operational capability was achieved in 1986. A total of 91 were built, with the final LCAC delivered in 2001. Textron also produced six LCACs for Japan.The craft got their first operational use in a combat environment in 1991 when 11 deployed on amphibious ships into the Persian Gulf to support a possible amphibious assault into Kuwait during Operation Desert Storm.

The LCAC is powered by four turbojet engines that provide propulsion through large propellers mounted on the stern and create the air cushion by filling a flexible rubber “skirt” that lines the bottom of the hull.

At rest, the LCAC is 88 feet long and 47 feet wide. But that increases to 92 and 48 feet when the skirt is inflated. The craft has a normal carrying capacity of 60 tons – which does not support the M1A1 tank, but can haul 75 tons in limited overload conditions.

Although LCACs are used primarily to haul vehicles, other heavy equipment, and supplies, an enclosed personnel transport module can be loaded aboard that can hold 145 combat-equipped Marines or 108 casualty litters. They have an all-enlisted crew of five led by the craftmaster, usually a first class or chief petty officer. The unarmored LCACs are not considered assault vehicles and would be used in an amphibious attack after the beach had been secured. They have proven to be very useful in supporting non-hostile amphibious operations and were vital in delivering life-saving equipment, food, water, and medical supplies in humanitarian relief efforts after disastrous floods in Bangladesh, Indonesia, and Pakistan and the devastating earthquake in Haiti.

SSC Ship to Shore Connector

An artist's rendering of the Ship to Shore Connector proposed by SSC Team Textron (Textron Marine & Land Systems, L-3 Communications, and Alcoa Defense). Image courtesy of SSC Team Textron

The Navy currently is conducting a service life extension program (SLEP) to keep 72 LCACs in use until the SSCs can become operational, which is expected to start in 2019. The SLEP will sustain and enhance craft capability, replace obsolete electronics, and repair corrosion damage, according to Naval Sea Systems Command (NAVSEA) officials in the LCAC/SSC program office.

Improvements include boosting engine power from 16,000 horsepower to 19,000 and providing the improved “deep skirt,” which will enhance performance and reliability, NAVSEA officials said.

The deep skirt, which is a requirement for SSC, allows a greater cushion height for the craft, which provides an increase in safety in all sea conditions while allowing operations in a higher sea state and maintaining mission speed and payload, NAVSEA said. It also allows greater obstacle clearance capability, less wear on the skirt and craft equipment, and less maintenance due to reduced seawater spray.

“The result has been a better performing skirt, which requires less maintenance and has a longer service life,” the program office said.

As of the end of May, 29 craft had completed SLEP and 10 were undergoing the modifications. The program is expected to be completed by FY 18, at a projected cost of $1.6 billion. The need for a new and improved craft is founded on the fact that the Navy has no other platform to provide the high-speed, heavy-lift, ship-to-shore capability supplied by the LCAC, a Navy spokesman noted. But the LCACs need to be replaced because their basic technology is outdated, they are too expensive to maintain, and they do not meet current lift requirements.

“Given the age and limitations of the basic LCAC design, SLEP modernization efforts are at the limits of what can be economically achieved for LCAC,” NAVSEA officials said in written responses to questions. “LCACs were designed in the 1970s and built to lift U.S. Marine Corps expeditionary equipment of the 1980s,” they noted.

The current Marine equipment is heavier, partly due to the armor added to protect vehicles from the improvised explosive devices that are the primary cause of casualties in Iraq and Afghanistan.

“The increasing weight of expeditionary equipment and subsequent craft performance requirements exceeds LCAC SLEP capabilities and precludes the continuation of the aging LCAC,” NAVSEA said. And “technology has evolved to enable greater availability, performance and reliability for the SSC.”

The NAVSEA officials said release of the RFP was delayed “to allow for finalizing of the program acquisition approach by Navy and OSD leadership.”

Landing Craft Air Cushion (LCAC)

Marines assigned to the 13th Marine Expeditionary Unit (13th MEU) board a Landing Craft Air Cushion (LCAC) assigned to assault craft unit (ACU) 5 aboard the amphibious dock landing ship USS Comstock (LSD 45). U.S. Navy photo by Mass Communication Specialist 2nd Class Joseph M. Buliavac

Part of the delay may have resulted from the decision by Ashton Carter, the Pentagon’s top acquisition official, to make the SSC program an acquisition category 1 (ACAT 1) priority, which indicates how important it is considered. An ACAT 1 designation meant that the Secretary of Defense’s office was involved, not just the Navy.

An indirect benefit of the delay was refinement of various elements within the RFP’s Technical Data Package in response to questions about the draft RFP submitted by the prospective bidders, NAVSEA said.

NAVSEA said the SSC will provide many improvements over the LCAC, including command, control, communications, computers, and navigation systems that reflect the advances in technology since the LCACs were produced. The SSC also will incorporate material and systems improvements to address the LCAC’s top 25 high-maintenance drivers, including the use of more corrosion-resistant aluminum in the hull and carbon fiber composites in the propeller, the shroud assembly, and propeller shafts. Those material fixes will increase craft availability and lower life-cycle maintenance costs, the program office said.

With a load capacity of at least 74 tons, the SSC will carry heavier equipment, must be capable of speeds greater than 35 knots, and will have four more powerful and more fuel efficient jet engines. The SSC will have a simpler and more efficient power train design, with a reduction in gearboxes from the eight in LCAC to two, greatly reducing complexity and maintenance requirements. It also will use composites in the lift fans and bow thrusters, in place of the aluminum used on LCAC, which should increase service life and lower upkeep cost.

The new craft will have a 60-hertz electrical distribution system, which is common to ships, instead of the LCAC’s 400-hertz system that is more typical for aircraft. That would allow greater access to parts and lower component costs.

The SSC will have two gearbox-driven craft service generators, which will be more fuel efficient than the LCAC’s auxiliary power units. The SSC will also add windows to the port side cabin, which is closed in on the LCAC. That will provide better visibility and reduce fatigue for the loadmaster and deck engineer, who serve as lookouts when the craft is underway.

The craftmaster, engineer, and navigator operate in the larger starboard cabin, which on SSC will be equipped with dual controls to allow a pilot and co-pilot arrangement, rather than the single pilot setup in LCAC, and will have “state-of-the-practice flight and engineering control technology,” NAVSEA said.

The SSC’s two 11.75-foot diameter propellers will have six blades and seven stators encased in a protective shroud, all of which will be of composite material intended to reduce the excessive wear on the props that adds to the LCAC’s maintenance burden. The props are variable pitch and reversible, like an airplane, to improve efficiency and maneuverability, and will have anti-icing systems. The SSCs will have the same external dimensions as LCAC, which will make them compatible with all the existing and planned amphibious ships with well decks. That avoids expensive modifications of the gators.

The new craft are expected to function with essentially the same operating concepts as the LCACs. That means they will be used to transport larger weapon systems, equipment, cargo, and personnel of the assault elements of a Marine or Army brigade, “in a non-permissive environment,” but not the first wave, the Navy said.

For the Marines, who have been the primary users of LCACs, the high-speed craft are a key component in the ship-to-objective maneuver concept, which is aimed at avoiding heavily contested beach assaults by launching from farther off shore and landing where the enemy does not expect them.

The SSCs, however, will play a bigger role in another important Navy-Marine warfighting concept, using a “Sea Base” to conduct amphibious operations. Seabasing is intended to avoid the need to build up large quantities of supplies and equipment ashore, which would be vulnerable to attack by air, artillery, or missiles, by providing logistical support to the forces ashore from ships at sea.

LCAC

An LCAC approaches the multipurpose amphibious assault ship USS Iwo Jima (LHD 7) during Unit Level Training Assessment Sustainment (ULTRA-S) certifications. The SSC will have the same overall dimensions as the LCAC in order to fit on existing amphibious ships. U.S. Navy photo by Mass Communication Specialist 2nd Class Zane Ecklund

A key enabler of seabasing, the Mobile Landing Platform (MLP) ships are now being built and the first should be in service as the SSCs begin to reach the fleet. The MLP will not only carry supplies and troops to the assault area, but will serve as a transfer facility between the large pre-positioning force supply ships and craft that can take the material and men ashore, including SSCs.

In their printed and Web-based material and oral comments, the rival teams have been extolling their qualifications to produce the SSC.

Textron claims “55 years of combined and proved” air cushion vehicle construction and “the only facility that has produced 10 SSC-like vessels a year,” a reference to the LCACs. It says its 600,000-square-foot shipyard near New Orleans is “specifically designed to optimize the production of ACV materials based on years of experience and proprietary research that streamlines the construction process with a highly efficient assembly station configuration that cuts time and effort by consolidating production.”

Textron also cites the experience of the corporation’s subsidiary, Bell Helicopter, in rotary wing aircraft, which it says has relevance to air cushion operations.

The team’s website notes that its partner, L-3 Communication, “is a leader in command and control, guidance and navigation systems and secure communications,” and the other team member, Alcoa, is “a world leader in aluminum.” That means the team “has the technology and experience to reduce risk and successfully deliver the SSC to the Navy within budget, at weight and on schedule.”

The Boeing-led team proclaims itself “a powerful combination,” with Marinette Marine Corporation, “a worldwide leader in ship design and construction,” and Boeing, “a pioneer in advanced rotorcraft technology and systems integration.”

The team is strengthened by adding Oceaneering International, which is performing the LCAC SLEP, and Griffon Hoverwork, “a pioneer in the development of hovercraft technology.”

This team is prepared “to replace the current LCAC with a lower-cost, higher-availability, next-generation platform,” it said.

The production capabilities and records of the rival teams are likely to be key factors in who wins the contract because the requirements for SSC provide limited opportunity for significant technical innovation, while meeting cost, performance, and schedule are high priorities.

“Affordability will rival capability,” and keeping the program on schedule is essential to maintain the critical capabilities LCACs provide without further expensive life-extension efforts, the Navy has said.

The RFP also stresses weight management as a key requirement, because, like an aircraft, weight affects performance and fuel efficiency.

The competing teams also must be confident in their ability to execute their proposals, because the RFP said the contract will be a “Fixed Priced Incentive, Firm Fixed Price and Cost Plus Fixed Fee” agreement, which would require the winning contractor to bear much of the pain of cost overruns. But the RFP also offers cash awards for superior performance, including multimillion-dollar bonuses for completing software development and defect removal prior to acceptance trials and for early delivery of the test and training craft.

The contract will be awarded on the basis of the rivals’ detailed plans to meet the SSC’s technical and performance requirements, to produce the craft, and to meet both a standard and an accelerated delivery schedule.

“Selection will not be based on a full-scale prototype of the craft,” the program office said.

Although NAVSEA had planned to award the contract in the current fiscal year, the delay in releasing the RFP likely means a decision early in FY 12.

The initial contract apparently will cover a test and training SSC and three operational craft.

This article first appeared in Marine Corps Outlook: 2011-2012 Edition.

The post The Ship to Shore Connector: Building a Better LCAC appeared first on Defense Media Network.


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