Abstract: A transportable modular flotation system with sections incorporating a decked supporting structure that is buoyed by heavy duty flotation tubes. The sections are coupled together with pre-tensioned ropes, straps or cables of High Modulus Fiber. The system is suitable for off-loading items from cargo ships in small harbors and onto remote beaches. One embodiment is a heavy-duty lightweight modular causeway system (LMCS™) that is rapidly deployable and recoverable from a Joint High Speed Vessel (JHSV). Other embodiments of the present invention may be deployable floating piers or docks; modular commercial causeways, and expedient means to cross environmentally sensitive areas such as marshes or wetlands without employing major earthmoving equipment. Embodiments may also be used for wet-gap crossings, such as currently served by modular bridges, such as the Army Dry Support Bridge (DSB).