Whilst the size of almost all other merchant ships is normally described in tons (or the metric counterpart – tonnes), the capacity of container ships is usually expressed in terms of the number of containers it is designed to carry. As the standard container sizes are traditionally either 20 feet or 40 feet long, you will encounter the expression TEU meaning ‘twenty-foot equivalent units’. Vessel sizes can range from about one hundred TEU to over 8000. The latter size vessels exceed Panamax dimensions and are referred to as ‘post panamax’. Plans exist for ships capable of carrying between 10 and 15,000 TUEs but whether these will ever be built remains to be seen. They were being considered as feasible during 2001 but a subsequent downturn in world trade and a glut of newbuildings in the 6,000 – 8,000 TEU range has meant that there is a current surplus of expensive new tonnage in this sector already. TEU is used to provide an approximate indication of the vessel’s container carrying capacity, each container space being called a slot. However when trading a vessel will carry a mixture of 20 foot and 40 foot containers, some of the stowage positions may only be suitable for the smaller size, so that a more specific description of the vessel will indicate the number of 20 foot slots available (TEU) as well as the number of 40 foot slots (FEU); because the vessels deadweight cargo capacity is also relevant the maximum average weight of the containers will also be stated. The smaller container vessels are used as ‘feeder‘ ships, feeding the hinterland around major container terminals with loaded containers inbound from abroad, before feeding containers for export back to the container terminal on the return journey. Because these vessels serve less sophisticated container ports they may well be geared – probably with gantry cranes – enabling them to load and to discharge containers with their own shipboard equipment.