Modular Causeway Systems

The MCS is a theater opening asset. It will provide a critical link between the offshore arrivals of combat power loaded aboard strategic sealift ships and placing that power ashore in a ready to fight configuration. The wartime commitment requires deployment with the pre-position assets of the Army Heavy Brigade Afloat. The MCS is expected to operate continuously for 90-days to cover force opening and surge assets. If there is a second near simultaneous Major Regional Conflict, the MCS will be redeployed to the new area. It must be restored to full mission capability in transit to that location. The MCS is a part of the UNAAF special response force support and may be deployed to Operations Other Than War (OOTW) to include policing actions and humanitarian efforts.

A diverse package of Army Watercraft provides a foundation of theater opening and reception of Army and joint forces committed to Regional Commander in Chief?s (CINCs) under Unified Action, Armed Forces (UNAAF). The Modular Causeway System is an integral part of the total Joint Logistics over the Shore (JLOTS) mission. LOTS missions are the unloading of ships without the benefit of fixed port facilities in either friendly or undefended territory and, in time of war, during phases of theater development. LOTS operations are conducted over unimproved shoreline, through fixed ports not accessible to deep draft shipping, and through fixed ports that are inadequate without the use of LOTS capabilities.

The Army has a mission to rapidly offload cargo and war fighting materiel from strategic sealift and commercial vessels upon their arrival in a theater of operations. The offload mission is best accomplished in a fixed, deep draft port facility. However, when such ports are unavailable, denied, damaged or lack required capacity, or when called out in strategic planning, Logistics-Over-The-Shore (LOTS) or Joint LOTS (JLOTS) operations are used to carry out the mission. The MCS is a critical element of LOTS/JLOTS operations.

The MCS is an assemblage of interoperable and interchangeable components which constitute the Army's primary means of augmenting existing port facilities, or conducting logistics over-the-shore (LOTS) operations where no port is available due to shallow water or low-sloping beach gradients prevent access by deep draft vessels, or because ports are otherwise inaccessible or denied to deep draft shipping.

The MCS is comprised of powered and non-powered floating platforms and will have the following sub-systems: Roll-On/Roll-Off Discharge Facility (RRDF), Causeway Ferries (CF), Floating Causeways (FC) and the Warping Tug (WT). Each subsystem will be made up of the same modular sections arranged in different configurations. This will allow commanders greater flexibility in determining the best method of discharge based on the operational situation. This appendix will use the notional scenario for a mild sloping beach area as used in the Theater Opening model for the Army Strategic Mobility Program (ASMP). The same assumptions have been validated with the Joint Tactics, Techniques, and Procedures for Joint Logistics over the Shore, Joint Publication 4-01.6 dtd 22 August 1991. The Joint Mission Area (JMA) Assessment for Maritime Support of Land Forces, December 1995 and more recent arrival of the Large Medium Speed Roll On/Roll-Off (LMSR) ship have lead to a more robust RRDF platform.

The MCS sections are made up of several modules with further subdivision into watertight compartments. These modules are interconnected with multiple pins and connection devices. This redundancy in system construction is built in to preclude catastrophic failure. The RRDF and FC platforms are designed for the 90-day continuous operation without repair. Some temporary patches may be applied to the outer layer of modules if needed. Support Equipment will require routine service and repairs throughout the operation.

The MCS consists of the following subsystems composed of modular sections in various combinations:

• Roll-On/Roll-Off Discharge Facility (RRDF). This floating platform provides an interface between a RO/RO ship ramp and watercraft lighters. The Roll-On/Roll-Off Discharge Facility provides interface platform between a RO/RO ship ramp system and watercraft lighters, as well as, mooring positions and loading platform for other vessels. This system may be configured as a Force Opening platform of six sections to as great as seventeen sections with two lane drive-through capacity.
• Causeway Ferry (CF). This ferry accepts Lift-on/Lift-off and/or RO/RO cargo from commercial and strategic sealift ships anchored in-stream. It is capable of conducting unassisted beaching and retracting, drive-through of rolling stock, and offload of cargo using material handling equipment (MHE). The Causeway Ferry is a ferry, powered by a modular warping tug with a frame, winch and stern anchor removed to allow for drive-through capability. Its primary purpose is to transfer 20 ft. containers from containerships directly to the beach for offload by Rough Terrain Container Handlers. This system may be used to haul rolling stock (wheeled and tracked vehicles) directly to the shore in mild and flat beach gradients. This, however, is envisioned to be less than 10% of its mission performance. Normally once the Floating Causeway is constructed, the highest productivity for the CF is achieved with containers direct to the beach.
• Floating Causeway (FC). This anchored platform provides a floating pierhead at the shore for simultaneous discharge of more than one lighter, drive-off of rolling stock, and offload of cargo using MHE. The Floating Causeway provides a docking pier head for simultaneous discharge of more than one lighter. This subsystem allows unassisted offloading and back loading at beach interface for rolling stock and cargo using Material Handling Equipment. The system can bridge up to 1500 feet from shore. Fifteen (15) feet of water depth is required at pier head to accept lighters. Gentle slope beach gradients may only require as little as four eighty foot sections to be installed.
• Warping Tug (WT). This tug is used as a tendering vessel to assemble, push, pull, restrain and maneuver the RRDF and FC, and to emplace and retrieve anchors. The Warping Tug is a self-propelled craft utilized for pushing, pulling, restraining and maneuvering each fully assembled, fully loaded sub-system. The warping tug shall be used to also emplace and retrieve anchors. The tug Table will reflect times for installation and recovery of the FC, movement of the RRDF to ship ramp discharge sites, and tendering common to both.

In the mid-1980's, the Navy and Army, recognizing the trend in the commercial sector towards the use of ISO freight containers, investigated the feasibility of using container-sized pontoons as a replacement for the NL causeway system. Since the transport of 21-ft wide by 90-ft long NL causeway sections requires specialized lift assets, a significant improvement in transportability was expected by shifting to container-sized causeway assets. The modularity of the system would also provide the users with the ability to assemble platforms of various sizes and configurations to meet their changing needs at the forward logistics site.

After completing a preliminary investigation of modular pontoon concepts, the Naval Civil Engineering Laboratory (NCEL) conducted a demonstration of two commercial modular barge systems in December 1983. Based upon the results of this effort, a contract was awarded to design and fabricate a version of Robishaw Engineering's Flexifloat(tm) modular barge system that was modified to meet ISO requirements. This 24- by 120-ft prototype causeway section was subsequently tested during JLOTS II in Sep/Oct 1984. Following the JLOTS II test, the prototype causeway was outfitted with a flush-mounted, waterjet propulsion unit. With the successful testing of this system, NCEL was able to prove the feasibility of a container size pontoon system.

The Army adopted the prototype design and purchased 35 non-powered Modular Causeway Sections (MCS), and later awarded a contract for powered causeway ferry assets.

The Navy decided not to replace their floating pontoon assets with the demonstrated system, but to focus on replacing the ELCAS with a modular equivalent. A contract was awarded for the design, fabrication, and testing of a Modular Elevated Causeway (ELCAS(M)) facility. The ELCAS(M) pontoons differ from the Army's MCS system, using a pontoon connector based on the British Army's Mexeflote system. An ISO 20-ft version of this pontoon had previously been procured by NCEL to serve as a Navy diver support platform. The Contractor's Demonstration of ELCAS(M) was successfully completed in April 1995 in Little Creek, Virginia. The user, Amphibious Construction Battalion Two, had also demonstrated their capability to install the system.

Through two contracts with different manufacturers, the Army acquired sufficient MCS sections to configure two RRDFs, six CFs, two FCs, and four WTs. It is this MCS fleet with which the new MCS procurement must be interchangeable at the modular level. The system is configured of International Standardization Organization (ISO) compatible modules for efficient and effective transportability.

The US Army Tank Automotive and Armaments Command procured the Modular Causeway System (MCS) on a competitive Small Business Set-Aside basis utilizing Best Value Source Selection methods. The contract was a firm fixed priced five year requirements-type contract. The major subsystems to be procured are as follows (with estimated quantities over the 5 year period): Roll-On/Roll-Off Discharge Facility (RORO DF), 5 ea; Causeway Ferry (CF), 11 ea; Floating Causeway (FC), 4 ea; and the Warping Tug, 18 ea.

The three modular sections composed of modular strings in various combinations that compose these subsystems are referred to as:

• Powered
• Intermediate
• Combination Beach and Sea End (CBSE)

A fourth modular section, the CF Beach End (CFBE), does not currently exist in the fleet but will result when the contractor designs and builds the CFBE module. Three modular strings compose a section. A string is either a center or powered module and two rake end modules, or a center module and one end rake module and a beach ramp module or beach end module. Strings are not separately labeled in the purchase description. The modules use an integral connector system which is proprietary but for which the Government had a licensing agreement in place. The Government assumed liability for any patent infringement with regard to the integral connector system.

As more and more materials began to be delivered worldwide using ISO compatible containers, it became evident that pontoons and pontoon structures needed to address this size question. The Naval Civil Engineering Laboratory (NCEL), Port Hueneme, California, in conjunction with United States Army personnel, began investigations into the feasibility of using container size pontoons in 1984. Comparison tests were conducted of large commercial pontoons and one system was selected for prototype development. The first, ISO compatible pontoon structure was fielded and tested in 1985. This unit was used successfully as a replacement for a NL causeway section in the Joint Logistics Over the Shore (JLOTS) II tests. The prototype ISO compatible pontoon system did not replace the Navy's NL system; however, it was adopted by the US Army and serves as the Modular Causeway Section (MCS) system.

The MCS is composed of nine modules which connect with lock pins. Unlike the NL section, the MCS section can be disassembled for more convenient transport and storage. The modules are joined to one another with reversible, locking male/female connectors. The assembly process can be accomplished on land or in calm waters, but not at higher sea states. Under favorable conditions, assembly takes approximately three hours. To begin the assembly process, two end-rake modules are connected to the ends of a Quadrafloat module to form a "string" 80 feet long and 8 feet wide. Next, a second string is constructed and connected to the side of the first string. To complete the section, a third string is constructed and connected to the side of the first two.