CSP Causeway Section Powered
SLWT Side Loadable Warping Tug

The main building block for the MCS is the modular causeway section. These sections are 24' x 80' platforms configured from ISO compatible floating pontoons. The sections can be disassembled and shipped via military/commercial assets capable of handling 40 foot containers. Causeway sections are assembled to configure three sub-systems: Floating Causeway (CF), Roll On/ Roll Off Discharge Facility (RRDF), and Causeway Ferry (CF).

The mission of the MCS is to provide a rapid means of transporting rolling stock, containerized and breakbulk cargo from ship to shore during Logistics Over the Shore Operations (LOTS). MCS will be used in areas with undeveloped port facilities or where established ports are denied, unavailable or inadequate. The FC consists of standard causeway strings that are attached end to end to form a bridge/ramp from the shore, seaward. This system will be used to overcome a shallow gradient or reef barrier. An RRDF is also composed of standard causeway sections and provides the interface between Roll On/Roll Off (RO/RO) vessels and the lighters that will move rolling stock to shore. The Causeway Ferry (CF) is composed of one powered section and three causeway sections. This system is used to carry rolling stock and containers from ship to shore.

The causeway is essentially a floating pier that stretches outward from a beach, allowing ships that can't actually get to the beach itself to load or unload vehicles and cargo offshore. At the causeway's seaward end is a wide area onto which vehicles and equipment can be unloaded and then driven directly to shore. The causeway is especially valuable if existing port facilities are unusable because of damage or enemy action. The basic causeway pieces are a 40-foot-long by 8-foot-wide by 4-foot-deep rectangular center section and two 20-foot-long by 8-foot-wide by 4-foot-deep end sections. When joined, the three sections form an 80-foot-long unit. Three completed units, joined along their long sides, form an 80-foot-by-24-foot segment called a "section." Multiple sections are then joined together to form the causeway, which can extend up to 1,500 feet offshore.

A key element in the causeway assembly process is the side-loadable warping tug, or SLWT, the craft used to move the causeway sections and tend the completed structure. Though the barge-like SLWT is ungainly looking -- it's 85 feet long, rectangular, low to the water and has a small pilothouse set off to one side -- it's actually well suited to the job. The swiveling heads on its two water-jet propulsion units make it more maneuverable than it looks, and in favorable seas a good coxswain can move the floating causeway sections around with relative ease.

Using a huge roll-on/roll-off stern ramp pierside, a ship can discharge all its cargo in three days. If no port facilities are available, the ship can use its in-stream off-load capabilities to discharge all cargo within five days. The in-stream off-load equipment includes several small water craft, causeway sections and a side-loadable warping tug. The ships can pump cargo fuel or water to troops from up to two miles from shore and can launch amphibious assault vehicles directly from the stern ramp into the sea.

The SLWT, the workhorse of the COTS system, is used to install, tend, and maintain other causeway system components. The Navy SLWT is 85 feet long (5 feet shorter than other Navy standard causeways) to keep it within the parameters for side loading on the Navy's landing ship, tank (LST) class ships. The Army SLWT is composed of a 40-foot section and two 20-foot raked ends which are configured into 80' x 24' sections. The SLWTs install floating causeways and RRDF. The SLWT is propelled by two Waterjet Propulsion Assemblies. The SLWTs install ELCAS and perform a wide variety of other functions such as powering causeway ferries, emplacing anchors, installing ship-toshore bulk fuel transfer systems, and performing surf salvage.

The Barge/Ferry Pilot/Coxswain Training System provides familiarization, operational and mission rehearsal training for Side Loadable Warping Tug, (SLWT) pilots and coxswains. It includes Instructor/Operator Station, Coxswain Cab and Visual System.

Even one month after the deadly tsunami on Dec. 26, 2004, ships of the Military Sealift Command were delivering much needed supplies to victims in the Republic of the Maldives. A total of 107 Sailors and Marines from five different commands were embarked in Colombo, Sri Lanka, for this mission. During the seven-day operation, supplies were delivered to six different islands in the Laamu Atoll. Two LCM (mechanized landing craft), two LARC (lighter, amphibious resupply, cargos), and one SLWT (side loadable warping tug) were used to deliver more than 1 million pounds of life sustaining supplies including 101,699 gallons of fresh water, 15 pallets of food, and thousands of dollars worth of medical supplies.

Causeway Section, Powered (CSP)

The Navy CSP is the normal power unit for causeway ferries. Its propulsion system is identical to that of the SLWT; however, the Naval CSP is 5 feet longer than the Navy SLWT, while the modular CSP is the same size as the modular warping tug. The CSP hull is 5 feet longer and it does not have a winch, A-frame, or stern anchor installed.

The Causeway Section Powered (CSP) consists of three modules assembled into one integral unit; the powered-section, the non-powered subsection and the waterjet propulsion plant subsection. When attached to three or four other standard causeway sections the unit becomes a Self-Powered Causeway (SPC). The SPC is used to transport containers from the ship to shoreline. Steering in any direction can be accomplished by rotating the waterjet nozzles. Speed of the CSP is ten knots. The CSP can be converted into a Side Loadable Warping Tug (SLWT) by adding an A-frame and winch. The SLWT is used to perform boat functions similar to a tug.

Provisional approval for use was achieved in FY-82 and approval for limited production was received in FY-83. By 1985 plans were to procure 181 units by FY-89. During JLOTS tests in December 1984, the CSPs moved an average of 26 containers per lift. CSPs demonstrated superior maneuverability over old LCM-6 tender boats and warping tugs.