Types of Ships
Ships can be classified according to the type of cargo they carry: dry cargo ships, tanker ships containerships, general cargo vessels, other specialized vessels, and miscellaneous ships. Dry cargo vessels are designed to carry dry cargo and can be subdivided into bulk carriers, multipurpose carriers (MPPs), container vessels, and Ro/Ro ships.
Bulk carriers are primarily designed for the carriage of bulk cargoes, such as ores, grains, coal and fertilizers. They range to size from the small Handysize (10 to 40,000 DWT) up to the large Capesize (100 to 170,000 DWT). Multipurpose vends are designed to be able to take bulk cargo, bagged cargo, containers, and general cargo with equal ease and, if necessary, at the same time. Container vessels are designed to take containers only, and they range In size from the small feeder up to the large and fast Ultra Large Container Vessel (ULCC). The size of the vessel can be expressed by the number of TEUs that the ship can carry. Ro/Ro (Roll on/Roll off) vessels are designed only for cargo that can be driven on and off the ship, such as cars, cargo on trailers, and so on. The size of a Ro/Ro is measured in lane meters, which indicate the total length of the marked parking lanes available on board. Tankers are merchant ships designed to transport liquid in bulk. In general, there are three categories of tanker vessels:
• Oil tankers
• Gas tankers
• Chemical tankers
Tankers range in size from ULCC (Ultra Large Crude Carrier) oil tanker of 350 to 500,000 DWT down to the smallest coastal tanker barge. Gas tankers such as LPG (Liquefied Petroleum Gas carrier) and LNG (Liquefied Natural Gas carrier) are capable of carrying gas in liquefied form under low temperature and/or high pressure. Chemical tankers have the capability of taking a large number of different products at one time. Because of their dangerous nature, such cargoes must be carried in specialized vessels and must be handled with particular care. The construction and operation of such ships as well as cargo handling operations are heavily regulated.
Containerships are vessels carrying general cargo in containers. The capacity of a containership is measured in twenty-foot equivalent units (TEUs).
There are six categories of containerships:
• Ultra Large Container Vessels (ULCV), e.g., the Triple E.
• New Panamax
• Post Panamax
• Small Feeder
Triple E (or EEE) ships are capable of loading up to eighteen thousand TEUs and are designed to achieve energy efficiency, environmental performance, and economies of scale. Miscellaneous vessels include the following:
• Tugs (salvage tugs, towing, and harbor tugs)
• Oil rigs (drilling and production platforms)
• Off-shore Vessels (built specifically to service oil rigs)
• Cruise/passenger liners
• Ferries (designed to travel between two ports as quickly as possible)
• Laker (capable of trading into the Canadian/United States Great Lakes)