Container ships are cargo ships that carry all of their load in truck-size containers, in a technique called containerization. They form a common means of commercial intermodal freight transport.
Construction Container ships are designed in such a manner that no space is wasted. Their capacity is measured in TEUs (Twenty-foot equivalent units). This is the number of 20-foot containers that a vessel can carry. The majority of containers used today are 40 feet in length. Above a certain size, container ships do not carry their own loading gear. Hence loading and unloading can only be done at ports with the necessary cranes. However, smaller ships with capacities up to 2,900 TEUs are often equipped with their own cranes.
Informally known as "box boats," they carry the majority of the world's dry cargo, meaning manufactured goods. Cargoes like metal ores or coal or wheat are carried in bulk carriers. There are large main line vessels that ply the deep sea routes, then many small "feeder" ships that supply the large ships at centralized hub ports. Most container ships are propelled by diesel engines, and have crews of between 20 and 40 people. They generally have a large accommodation block at the stern, directly above the engine room. Container ships now carry up to 15,000 containers on a voyage.
Cargo too big to carry in containers can be handled using flat racks, open top containers and platforms. There are also container ships called roll-on/roll-off (RORO), which utilize shore-based ramp systems for loading and unloading. ROROs are usually associated with shorter trade routes, as they are unable to carry the volume of crane-based container vessels. However, due to their flexibility and high speed, ROROs are frequently used in today's container markets. Moreover due to the growth of the containers transit, companies must manage container ship risks.
History of container ships The earliest container ships were converted tankers, built up from surplus tanker T-2's after World War II. The first container ship was the Ideal-X, a converted T-2 tanker, owned by Malcom McLean, which carried 58 metal containers between Newark, New Jersey and Houston, Texas on its first voyage, in April 1956. Now container ships are all purpose-built and as a class are second only to crude oil tankers as the biggest cargo ships on the oceans.