Standardized rectangular boxes for the transport of marine cargo. Since 1960, the ocean transportation of general cargo or freight has undergone a revolutionary technological change. The innovation was containerization—the development of standard marine cargo containers for consolidating packages into units of interchange between ships, docks, trucks, and railcars, and the development of special ships and handling systems to transport these containers at sea. This innovation brought economies of scale to marine cargo-handling operations, introduced capital-intensive processes to the labor-oriented stevedoring tasks, reduced cargo theft and damage, reduced the time a ship spent in port, and provided the means for efficient intermodal transport of cargoes.
Basic to the change to containerization was a new approach to loading and unloading cargoes. Instead of using nets or slings to lift individual bales, boxes, sacks, or pallets of cargo in and out of the ship's holds, the new systems employ standard cargo containers and special handling equipment to place the containers aboard (see illustration). The containers are loaded or stuffed at an inland factory or terminal and usually are never opened until they reach their ultimate destination. The ship carrying these containers becomes an extension of a truckline or a railroad.
Container crane and straddle carrier.
Intermodability, moving containerized cargo by more than one mode of transport without the need for intermediate reloading, is the essence of this technology. The containers can be moved to the ship via regular highway trailers or trailer chassis, or by flatbed railcar or rail piggyback. Once at the marine terminal, they can be lifted or rolled on the ships. Upon arrival at the discharge port, all land and water modes are again available to move them, with cargo undisturbed, to the consignee.
