Cargo ship

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A cargo ship or freighter is a merchant ship that carries cargo, goods, and materials from one port to another. Thousands of cargo carriers ply the world's seas and oceans each year, handling the bulk of international trade. Cargo ships are usually specially designed for the task, often being equipped with cranes and other mechanisms to load and unload, and come in all sizes. Today, they are almost always built by welded steel, and with some exceptions generally have a life expectancy of 25 to 30 years before being scrapped.[ citation needed ]



The Colombo Express, a container ship built in 2005 Colombo.Express.wmt.jpg
The Colombo Express , a container ship built in 2005
A container ship unloading at Zanzibar, Tanzania Container Ship.jpg
A container ship unloading at Zanzibar, Tanzania
A US cargo ship off McMurdo Station, Antarctica MV American Tern at McMurdo Sound.jpg
A US cargo ship off McMurdo Station, Antarctica
General cargo ship Namibia Namibia (2007).jpg
General cargo ship Namibia

The words cargo and freight have become interchangeable in casual usage. Technically, "cargo" refers to the goods carried aboard the ship for hire, while "freight" refers to the act of carrying of such cargo, but the terms have been used interchangeably for centuries.

Generally, the modern ocean shipping business is divided into two classes:

  1. Liner business: typically (but not exclusively) container vessels (wherein "general cargo" is carried in 20- or 40-foot containers), operating as "common carriers", calling at a regularly published schedule of ports. A common carrier refers to a regulated service where any member of the public may book cargo for shipment, according to long-established and internationally agreed rules.
  2. Tramp-tanker business: generally this is private business arranged between the shipper and receiver and facilitated by the vessel owners or operators, who offer their vessels for hire to carry bulk (dry or liquid) or break bulk (cargoes with individually handled pieces) to any suitable port(s) in the world, according to a specifically drawn contract, called a charter party.

Larger cargo ships are generally operated by shipping lines: companies that specialize in the handling of cargo in general. Smaller vessels, such as coasters, are often owned by their operators.


Cargo ships/freighters can be divided into seven groups, according to the type of cargo they carry. These groups are:

  1. Feeder ship
  2. General cargo vessels
  3. Container ships
  4. Tankers
  5. Dry bulk carriers
  6. Multi-purpose vessels
  7. Reefer ships
  8. Roll-on/roll-off vessels.

Rough synopses of cargo ship types

  1. General cargo vessels carry packaged items like chemicals, foods, furniture, machinery, motor- and military vehicles, footwear, garments, etc.
  2. Container ships (sometimes spelled containerships) are cargo ships that carry all of their load in truck-size intermodal containers, in a technique called containerization. They are a common means of commercial intermodal freight transport and now carry most seagoing non-bulk cargo. Container ship capacity is measured in twenty-foot equivalent units (TEU).
  3. Tankers carry petroleum products or other liquid cargo.
  4. Dry bulk carriers carry coal, grain, ore and other similar products in loose form.
  5. Multi-purpose vessels, as the name suggests, carry different classes of cargo – e.g. liquid and general cargo – at the same time.
  6. A Reefer, Reefer ships (or Refrigerated) ship is specifically designed [1] and used for shipping perishable commodities which require temperature-controlled, mostly fruits, meat, fish, vegetables, dairy products and other foodstuffs.
  7. Roll-on/roll-off (RORO or ro-ro) ships are designed to carry wheeled cargo, such as cars, trucks, semi-trailer trucks, trailers, and railroad cars, that are driven on and off the ship on their own wheels.

Specialized cargo ship types

Specialized types of cargo vessels include container ships and bulk carriers (technically tankers of all sizes are cargo ships, although they are routinely thought of as a separate category). Cargo ships fall into two further categories that reflect the services they offer to industry: liner and tramp services. Those on a fixed published schedule and fixed tariff rates are cargo liners. Tramp ships do not have fixed schedules. Users charter them to haul loads. Generally, the smaller shipping companies and private individuals operate tramp ships. Cargo liners run on fixed schedules published by the shipping companies. Each trip a liner takes is called a voyage. Liners mostly carry general cargo. However, some cargo liners may carry passengers also. A cargo liner that carries 12 or more passengers is called a combination or passenger-run-cargo line.

Size categories

Cargo ships are categorized partly by cargo capacity, partly by weight (deadweight tonnage DWT), and partly by dimensions. Maximum dimensions such as length and width (beam) limit the canal locks a ship can fit in, water depth (draft) is a limitation for canals, shallow straits or harbors and height is a limitation in order to pass under bridges. Common categories include:

Ship measurements comparison.svg

The TI-class supertanker is an Ultra Large Crude Carrier, with a draft that is deeper than Suezmax, Malaccamax and New Panamax. This causes Atlantic/Pacific routes to be very long, such as the long voyages south of Cape of Good Hope or south of Cape Horn to transit between Atlantic and Pacific oceans.

Lake freighters built for the Great Lakes in North America differ in design from sea water–going ships because of the difference in wave size and frequency in the lakes. A number of these ships are larger than Seawaymax and cannot leave the lakes and pass to the Atlantic Ocean, since they do not fit the locks on the Saint Lawrence Seaway.


A full-scale replica of a cog, a type of vessel commonly used for cargo in Northern Europe from the 10th to the 14th centuries Ubena von Bremen Kiel2007 2.jpg
A full-scale replica of a cog, a type of vessel commonly used for cargo in Northern Europe from the 10th to the 14th centuries

The earliest records of waterborne activity mention the carriage of items for trade; the evidence of history and archaeology shows the practice to be widespread by the beginning of the 1st millennium BC, and as early as the 14th and 15th centuries BC small Mediterranean cargo ships like those of the 50 foot long (15–16 metre) Uluburun ship were carrying 20 tons of exotic cargo; 11 tons of raw copper, jars, glass, ivory, gold, spices, and treasures from Canaan, Greece, Egypt, and Africa. The desire to operate trade routes over longer distances, and throughout more seasons of the year, motivated improvements in ship design during the Middle Ages.

Before the middle of the 19th century, the incidence of piracy resulted in most cargo ships being armed, sometimes quite heavily, as in the case of the Manila galleons and East Indiamen. They were also sometimes escorted by warships.


Piracy is still quite common in some waters, particularly in the Malacca Straits, a narrow channel between Indonesia and Singapore / Malaysia, and cargo ships are still commonly targeted. In 2004, the governments of those three nations agreed to provide better protection for the ships passing through the Straits. The waters off Somalia and Nigeria are also prone to piracy, while smaller vessels are also in danger along parts of the South American, Southeast Asian coasts and near the Caribbean Sea. [5] [6]

Vessel prefixes

A category designation appears before the vessel's name. A few examples of prefixes for naval ships are "USS" (United States Ship), "HMS" (Her/His Majesty's Ship), "HMCS" (Her/His Majesty's Canadian Ship) and "HTMS" (His Thai Majesty's Ship), while a few examples for prefixes for merchant ships are "RMS" (Royal Mail Ship, usually a passenger liner), "MV" (Motor Vessel, powered by diesel), "MT" (Motor Tanker, powered vessel carrying liquids only) "FV" Fishing Vessel and "SS" (Screw Steamer, driven by propellers or screws, often understood to stand for Steamship). "TS", sometimes found in first position before a merchant ship's prefix, denotes that it is a Turbine Steamer.

Famous cargo ships

Famous cargo ships include the Dynamics Logistics, partly based on a British design, Liberty ship. Liberty ship sections were prefabricated in locations across the United States and then assembled by shipbuilders in an average of six weeks, with the record being just over four days. These ships allowed the Allies in World War II to replace sunken cargo vessels at a rate greater than the Kriegsmarine's U-boats could sink them, and contributed significantly to the war effort, the delivery of supplies, and eventual victory over the Axis powers. Liberty ships were followed by the faster Victory ships. Canada built Park ships and Fort ships to meet the demand for the Allies shipping. The United Kingdom built Empire ships and used US Ocean ships. After the war many of the ships were sold to private companies. The EVER GIVEN is a ship that was lodged into the Suez Canal from March 25 to 28, 2021, which caused a halt on maritime trade. [7] [8] [9] [10]


Due to its low cost, most large cargo vessels are powered by bunker fuel also known as Heavy Fuel Oil which contains higher sulphur levels than diesel. [11] This level of pollution is increasing: [12] with bunker fuel consumption at 278 million tonnes per year in 2001, it is projected to be at 500 million tonnes per year in 2020. [13] International standards to dramatically reduce sulphur content in marine fuels and nitrogen oxide emissions have been put in place. Among some of the solutions offered is changing over the fuel intake to clean diesel or marine gas oil, while in restricted waters and Cold Ironing the ship while it is in port. The process of removing sulphur from the fuel impacts the viscosity and lubricity of the marine gas oil though, which could cause damage in the engine fuel pump. The fuel viscosity can be raised by cooling the fuel down. [14] If the various requirements are enforced, the International Maritime Organization's marine fuel requirement will mean a 90% reduction in sulphur oxide emissions; [15] whilst the European Union is planning stricter controls on emissions. [16]

See also

Related Research Articles

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Maritime transport The transport of people or goods via waterways

Maritime transport and fluvial transport, or more generally waterborne transport, is the transport of people (passengers) or goods (cargo) via waterways. Freight transport by sea has been widely used throughout recorded history. The advent of aviation has diminished the importance of sea travel for passengers, though it is still popular for short trips and pleasure cruises. Transport by water is cheaper than transport by air, despite fluctuating exchange rates and a fee placed on top of freighting charges for carrier companies known as the currency adjustment factor. Maritime transport accounts for roughly 80% of international trade, according to UNCTAD in 2020.

Container ship Type of cargo ship

A container ship is a cargo ship that carries all of its load in truck-size intermodal containers, in a technique called containerization. Container ships are a common means of commercial intermodal freight transport and now carry most seagoing non-bulk cargo.

Mitsui O.S.K. Lines Japanese shipping company

Mitsui O.S.K. Lines is a Japanese transport company headquartered in Toranomon, Minato, Tokyo, Japan. It is one of the largest shipping companies in the world.

Panamax Class of ships of the maximum size that can pass through the original locks of the Panama Canal

Panamax and New Panamax are terms for the size limits for ships travelling through the Panama Canal. The limits and requirements are published by the Panama Canal Authority (ACP) in a publication titled "Vessel Requirements". These requirements also describe topics like exceptional dry seasonal limits, propulsion, communications, and detailed ship design.

Merchant ship Civilian boat or ship that transports cargo or carries passengers for hire

A merchant ship, merchant vessel, trading vessel, or merchantman is a watercraft that transports cargo or carries passengers for hire. This is in contrast to pleasure craft, which are used for personal recreation, and naval ships, which are used for military purposes.

Tramp trade Cargo shipping without a fixed schedule

A boat or ship engaged in the tramp trade is one which does not have a fixed schedule or published ports of call. As opposed to freight liners, tramp ships trade on the spot market with no fixed schedule or itinerary/ports-of-call(s). A steamship engaged in the tramp trade is sometimes called a tramp steamer; the similar terms tramp freighter and tramper are also used. Chartering is done chiefly on London, New York, and Singapore shipbroking exchanges. The Baltic Exchange serves as a type of stock market index for the trade.

Bulk carrier Ship made to transport unpackaged bulk cargo

A bulk carrier,bulker is a merchant ship specially designed to transport unpackaged bulk cargo, such as grains, coal, ore, steel coils and cement, in its cargo holds. Since the first specialized bulk carrier was built in 1852, economic forces have led to continued development of these ships, resulting in increased size and sophistication. Today's bulk carriers are specially designed to maximize capacity, safety, efficiency, and durability.

Tanker (ship) Ship designed to transport liquids or gases in bulk

A tanker is a ship designed to transport or store liquids or gases in bulk. Major types of tankship include the oil tanker, the chemical tanker, and gas carrier. Tankers also carry commodities such as vegetable oils, molasses and wine. In the United States Navy and Military Sealift Command, a tanker used to refuel other ships is called an oiler but many other navies use the terms tanker and replenishment tanker.

Capesize Class of dry cargo ships too large to transit the Panama or Suez Canals

Capesize ships are the largest dry cargo ships. They are too large to transit the Suez Canal or Panama Canal, and so have to pass either the Cape Agulhas or Cape Horn to traverse between oceans.

Suezmax Ship size ceiling capable to pass through Suez Canal

"Suezmax" is a naval architecture term for the largest ship measurements capable of transiting the Suez Canal in a laden condition, and is almost exclusively used in reference to tankers. The limiting factors are beam, draft, height, and length.

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Ore-bulk-oil carrier type of bulk cargo ship

An ore-bulk-oil carrier, also known as combination carrier or OBO, is a ship designed to be capable of carrying wet or dry cargoes. The idea is to reduce the number of empty (ballast) voyages, in which large ships only carry a cargo one way and return empty for another. These are a feature of the larger bulk trades.

LNG carrier

An LNG carrier is a tank ship designed for transporting liquefied natural gas (LNG).

The A. P. Moller-Maersk Group is an international business conglomerate more commonly known simply as Maersk. This article focuses on the history of the company.

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An oil tanker, also known as a petroleum tanker, is a ship designed for the bulk transport of oil or its products. There are two basic types of oil tankers: crude tankers and product tankers. Crude tankers move large quantities of unrefined crude oil from its point of extraction to refineries. Product tankers, generally much smaller, are designed to move refined products from refineries to points near consuming markets.

History of the oil tanker

The history of the oil tanker is part of the evolution of the technology of oil transportation alongside the oil industry.

Chinamax Ship size class

Chinamax is a standard of ship measurements that allow conforming ships to use various harbours when fully laden, the maximum size of such a ship being 24 m (79 ft) draft, 65 m (213 ft) beam and 360 m (1,180 ft) length overall. An example of ships of this size is the Valemax bulk carriers.

<i>MSC Oliver</i>

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General references