An ocean liner is a ship designed to transport people from one seaport to another along regular long-distance maritime routes according to a schedule. Liners may also carry cargo or mail, and may sometimes be used for other purposes (e.g., for pleasure cruises or as hospital ships).
Cargo vessels running to a schedule are sometimes called liners. The category does not include ferries or other vessels engaged in short-sea trading, nor dedicated cruise ships where the voyage itself, and not transportation, is the prime purpose of the trip. Nor does it include tramp steamers, even those equipped to handle limited numbers of passengers. Some shipping companies refer to themselves as "lines" and their container ships, which often operate over set routes according to established schedules, as "liners".
Ocean liners are usually strongly built with a high freeboard to withstand rough seas and adverse conditions encountered in the open ocean. Additionally, they are often designed with thicker hull plating than is found on cruise ships, and have large capacities for fuel, food and other consumables on long voyages.
As of 2012, the Queen Mary 2 is the only ocean liner in active service in the world. In April 2012, the Australian mining magnate, Clive Palmer, announced his plans for building an ocean liner meant to be a replica of the RMS Titanic for trans-atlantic voyages.
Ocean liners were the primary mode of intercontinental travel for over a century, from the mid-19th century until they began to be supplanted by airliners in the late 1960s. In addition to passengers, liners carried mail and cargo. Ships contracted to carry British Royal Mail used the designation RMS. Liners were also the preferred way to move gold and other high-value cargoes.
The busiest route for liners was on the North Atlantic with ships travelling between Europe and North America. It was on this route that the fastest, largest and most advanced liners travelled. But while in contemporary popular imagination the term "ocean liners" evokes these transatlantic superliners, most ocean liners historically were mid-sized vessels which served as the common carriers of passengers and freight between nations and among mother countries and their colonies and dependencies in the pre-jet age. Such routes included Europe to African and Asian colonies, Europe to South America, and migrant traffic from Europe to North America in the 19th and first two decades of the 20th centuries, and to Canada and Australia after the Second World War.
Shipping lines are companies engaged in shipping passengers and cargo, often on established routes and schedules. Regular scheduled voyages on a set route are called "line voyages" and vessels (passenger or cargo) trading on these routes to a timetable are called liners. The alternative to liner trade is "tramping" whereby vessels are notified on an ad-hoc basis as to the availability of a cargo to be transported. (In older usage, "liner" also referred to ships of the line, that is, line-of-battle ships, but that usage is now rare.) The term "ocean liner" has come to be used interchangeably with "passenger liner", although it can refer to a cargo liner or cargo-passenger liner.
Beginning at the advent of the Jet Age where transoceanic ship service declined a gradual transition from passenger ships as mean of transportation to nowadays cruise ships started. In order for ocean liners to remain profitable, cruise lines have modified some of them to operate on cruise routes, such as Queen Elizabeth 2 and SS France. Certain characteristics of older ocean liners made them unsuitable for cruising, such as high fuel consumption, deep draught preventing them from entering shallow ports, and cabins (often windowless) designed to maximize passenger numbers rather than comfort. The Italian Line's Michelangelo and Raffaello, the last ocean liners to be built primarily for crossing the North Atlantic, could not be converted economically and had short careers.
The 19th century 
In 1818, the Black Ball Line, with a fleet of sailing ships, offered the first regular passenger service with emphasis on passenger comfort, from England to the United States. From the early 19th century, steam engines began to appear in ships, but initially they were inefficient and offered little advantage over sailing ships.
The clipper domination was challenged when the Great Western, designed by railway engineer Isambard Kingdom Brunel, began its first Atlantic service in 1837. It took 15 days to cross the Atlantic, as compared with two months by sail-powered ships. Unlike the clippers, steamers offered a consistent speed and the ability to keep to a schedule. The early steamships still had sails as well, though, as engines at this time had very inefficient consumption of fuel. Having sails enabled vessels like the Great Western to take advantage of favourable weather conditions and minimise fuel consumption.
In 1840 Cunard Line’s Britannia began its first regular passenger and cargo service by a steamship, sailing from Liverpool to Boston. Despite some advantages offered by the steamships, clippers remained dominant. In 1847, the Great Britain became the first iron-hulled screw-driven ship to cross the Atlantic. More efficient propellers began to replace the paddle wheels used by earlier ocean liners. In 1870, the White Star Line’s Oceanic set a new standard for ocean travel by having its first-class cabins amidships, with the added amenity of large portholes, electricity and running water. The size of ocean liners increased from 1880 to meet the needs of immigration to the United States and Australia.
The Umbria and her sister ship the Etruria were the last two liners of the period to be fitted with auxiliary sails. Umbria was built by John Elder & Co of Glasgow, Scotland in 1884. Umbria and Etruria were record breakers by the standards of the time. They were the largest liners then in service and they plied the Liverpool to New York route.
The Ophir was a 6814-ton steamship owned by the Orient Steamship Co, fitted with refrigeration equipment, which plied the Suez Canal route from England to Australia during the 1890s and the years leading to World War I, when she was converted to an armed merchant cruiser.
The 20th century 
The period between the end of the 19th century and World War II is considered the "golden age" of ocean liners. Driven by strong demand created by European emigration to the Americas, international competition between passenger lines and a new emphasis on comfort, shipping companies built increasingly larger and faster ships.
Canadian Pacific Railway became one of the largest transportation systems in the world combining with ships and railways operating from Canada. In 1891 CPR shipping division began its first Pacific operation. In 1903, CPR began its first Atlantic service because of rising migration of Europeans to western Canada as the result of free land offered by the Canadian government.
Since the 1830s, passenger liners had unofficially been competing for the honour of making the fastest North Atlantic crossing. This honour came to be known as the Blue Riband; in 1897 Germany took the award with a series of new ocean liners, starting with the Kaiser Wilhelm der Große. In 1905, the British Cunard Line fitted its liner Carmania with steam turbines with which it outperformed its near-identical sister Caronia, powered by triple-expansion steam engines. At the time, these were the largest ships in the Cunard fleet, and the use of the different propulsion methods in otherwise similar ships allowed the company to evaluate the merits of both. The engines in Carmania were successful and, consequently, in 1907 Cunard introduced the much larger Lusitania and Mauretania, both powered by steam turbines. The Mauretania won the Blue Riband and held it for an astonishing 20 years.
Cunard's dominance of the Blue Riband did not keep other lines from competing in terms of size and luxury. In 1910 White Star launched the Olympic, the first of a trio of 45,000 plus gross ton liners with the Titanic and Britannic. These ships were almost 15,000 tonnes larger and 100 feet (30 m) longer than the Lusitania and Mauretania. Like most other White Star Liners, these three ships were born of a special effort by the White Star Line to attract more immigrants by treating them with respect and making their crossings pleasurable.
Hamburg-America Line also ordered three giant ships, the Imperator, Vaterland and Bismarck, all over 51,500 gross tons. Imperator was launched in 1912. Bismarck would be the largest ship in the world until 1935. These ships did little or no service with Hamburg-America before World War I. After the war, they were awarded as war reparations and given to British and American lines. The surge in ocean liner size outpaced the shipping regulations. In 1912, the Titanic sank after hitting an iceberg, with more than 1,500 fatalities. A factor contributing to the high loss of life was that there were not enough lifeboats for everyone. After the Titanic disaster, the regulation was revised to require all ocean liners to carry enough lifeboats for all passengers and crew. In addition, the International Ice Patrol was established to monitor the busy north-Atlantic shipping lanes for icebergs.
Until the 1920s, most shipping lines relied heavily on emigration for passengers and they were hard hit when the US Congress introduced a bill to limit immigration into the United States. As a result, many ships took on cruising, and the least expensive cabins were reconfigured from third-class to tourist-class. To make matters worse, the Great Depression put many shipping lines into bankruptcy.
Despite the harsh economic conditions, a number of companies continued to build larger and faster ships. In 1929 the German ships Bremen and Europa beat the crossing record set by the Mauretania 20 years earlier with an average speed of almost 28 knots (52 km/h). The ships used bulbous bows and steam turbines to reach these high speeds while maintaining economical operating costs. In 1933 the Italian 51,100-ton ocean liner Rex, with a time of four days and thirteen hours, captured the westbound Blue Riband, which she held for two years. In 1935 the French liner Normandie used a revolutionary new hull design and powerful turbo-electric propulsion to take the Blue Riband from the Rex. Due to the poor economic conditions, the British government amalgamated Cunard Line and White Star Lines. The newly merged company countered with its liners Queen Mary and Queen Elizabeth. The Queen Mary was to hold the Blue Riband in 1936-37 and from 1938-52.
During the Second World War, many liners were used as troop ships. Notable ocean liners such as the RMS Queen Mary, RMS Aquitania, SS Cap Arcona, RMS Laconia, Queen Elizabeth, and the SS Orontes all helped transport troops. While some Ocean liners survived the war many others would be lost.
The post-WWII era was a brief but busy period. Notable ships included the fastest transatlantic liner ever built, the United States, which in 1952 bested the records set by the Queen Mary to become the holder of the Blue Riband, a designation it retains to this day. Also significant was the 1961-built France (later renamed Norway) which held the record for the longest passenger ship from when she entered service in 1961 until the launch of Queen Mary 2 in 2003. Australian government-sponsored immigration resulted in a busy trade between Europe and Australia, producing such notable ships as the Oriana and Canberra. These two, operating on the P&O-Orient Line service, were the largest, fastest and last liners built for the Australian route.
Decline of long-distance line voyages 
Before World War II, competition from passenger aircraft had not been a large threat to ocean liners. World War II accelerated the development of large, long-distance aircraft. Four-engined bombers such as the Avro Lancaster and Boeing B-29, with their long range and massive carrying capacity, were a natural prototype for a next-generation airliner. Jet aircraft technology also accelerated after the development of jet aircraft for military use in World War II. In 1953, the De Havilland Comet became the first commercial jet airliner; the Sud Aviation Caravelle, Boeing 707 and Douglas DC-8 followed, and much long-distance travel was done by air.
The Michelangelo and Raffaello, built in 1962 and 1963 for the Italian Line, were two of the last ocean liners to be built primarily for liner service across the North Atlantic. Cunard's transatlantic liner Queen Elizabeth 2 was also used as a cruise ship. By the early 1970s, many passenger ships continued their service in cruising. By the first decade of the 21st century, only a few former ocean liners were still sailing, while others, like Queen Mary, were preserved as museums or floating hotels. After the retirement of Queen Elizabeth 2 in 2008, the only ocean liner in service was Queen Mary 2, used for both point-to-point line voyages and for cruising.
The 21st century 
In 2012, Australian businessman, Clive Palmer, announced his plans to construct a modern-day replica of the famous RMS Titanic.  To be named Titanic II, Palmer's vision is to create a trans-Atlantic ocean liner that closely mimics her namesake. Palmer, through his new venture, Blue Star Line, and with the help of the Finnish marine engineering firm, Deltamarin, have commenced the process of designing the ocean liner. 
At war 
Ocean liners played a major role in World War I. Large ocean liners such as the Mauretania and Olympic were used as troopships and hospital ships while smaller ocean liners were converted to armed merchant cruisers. The Britannic, sister to the Titanic and Olympic, never served on the liner trade for which she was built, instead entering war service as a hospital ship as soon as she was completed—she lasted a year before being sunk by a mine. Some other liners were converted to innocent-looking armed Q-ships to entrap submarines.
In 1915 the Lusitania, still in service as a civilian passenger vessel, was torpedoed by a German U-boat with many casualties. Ocean liners were also used in World War II as troopships. The Normandie caught fire, capsized and sank in New York in 1942 while being converted for troop duty. The majority of the superliners of the 'twenties and 'thirties were victims of U-boats, mines or enemy aircraft. The Empress of Britain was attacked by German planes, then torpedoed by a U-boat when tugs tried to tow her to safety. She was the largest British ocean liner to sink during World War II. Germany's speed queen the Bremen in 1941 fell victim to an arsonist, believed to be a disgruntled crew member, and became a total loss. Italy's giants, the Rex and the Conte di Savoia were respectively destroyed by the British RAF and the retreating German forces. The United States lost the American President Lines vessel the President Coolidge when she steamed into an Allied mine in the South Pacific. No shipping line was untouched by World War II.
More recently, during the Falklands War, three ships that were either active or former liners were requisitioned for war service by the British Government. The liners QE2 and Canberra were requisitioned from Cunard and P&O to serve as troopships, carrying British Army personnel to Ascension Island and the Falkland Islands to recover the Falklands from the invading Argentine forces. The P&O educational cruise ship and former British India Steam Navigation Company liner Uganda was requisitioned as a hospital ship and, after the war, served as a troopship until an airport was built at Stanley that could handle trooping flights.
Safety and reliability 
Many ocean liners have been lost through the decades in various circumstances. The Titanic sank on her maiden voyage from Britain to the United States in 1912 after hitting an iceberg, with the loss of 1,523 lives; her name has entered the language as an archetypical catastrophe. Her larger sister ship Britannic, which had been converted into a hospital ship in 1915, sank in the Aegean Sea in 1916 after hitting a mine and remains the largest ocean liner on the sea bed.
In 1914 the Empress of Ireland sank in the Saint Lawrence River with 1,012 lives lost. The Lusitania was lost in 1915 to a German U-Boat during World War I while on passage from the United States to Britain. The Morro Castle burned off the coast of New Jersey in 1934. The worst disasters were the loss of the Cunarder Lancastria in 1940 off Saint-Nazaire to German bombing while attempting to evacuate troops of the British Expeditionary Force from France, with the loss of more than 3,000 lives; the sinking of the Wilhelm Gustloff with more than 9,000 lives lost, and the sinking of the Cap Arcona with more than 7,000 lives lost in the Baltic Sea in 1945.
Contrary wise, many ships with their reliability, comfort and decades of service, became particularly popular with passengers of that time. Cunard Line's Mauretania and Aquitania were considered the finest liners of their time, while the superliners like Normandie and Queen Mary became symbols of national pride and important part of western civilization with influences in design, technology, popular culture and standards of international travel.
- Note: This does not include the RMS Queen Mary 2
Of the pre-war Ocean Liners, two survive today. The RMS Queen Mary was preserved after her retirement in 1967 as a hotel and museum in Long Beach, California. The other is the Japanese ocean liner Hikawa Maru, preserved in Japan as a museum ship in 1961. Remaining modern (post-war) ocean liners that were preserved are: The United States, currently laid up in Philadelphia, the Queen Elizabeth 2, which is currently laid up in Port Rashid, the Rotterdam now moored in Rotterdam as a museum/hotel, and the Veronica, (former S.S Kungsholm) which was converted into a floating hotel in Duqm Oman. Two former ocean liners remain in active service today: The MS Marco Polo (former MS Alexandr Pushkin), and the MS Athena (former MS Stockholm which was built in 1948 and is notable for colliding with the SS Andrea Doria) both which are currently used for cruising.
See also 
- List of cruise ships
- List of cruise lines
- List of ocean liners
- Transatlantic crossing
- Superliner (passenger ship)
- Packet ship
- E.g., Craig R. Steam tramps and cargo liners, 1850-1950
- Pickford, Nigel Lost Treasure Ships of the Twentieth Century, National Geographic Society, 1999 ISBN 0-7922-7472-5
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- "Clive Palmer Launches Titanic II". Blue Star Line.
- "Global Ship Design Firm Commissioned to Titanic II Project". Blue Star Line.
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- "Queen Elizabeth 2 1969 - Present Day". The great ocean liners.
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- "Welcome to Oman's First Floating Hotel - Veronica Duqm". www.veronicaduqm.com. Retrieved 2012-08-11.
|Wikimedia Commons has media related to: Ocean liners|
- The Great Ocean Liners
- Cruise Line History: The Cruise Ship, Ocean Liner, Travel and Social History website
- Encyclopedia Titanica (includes Ocean liner and Titanic discussions)
- Gare Maritime : A Journey into the Golden Age of Travel
- 20th Century Ships
- Cruise Vacations
- Transatlantic Ocean Liners and Nationalism
- Monsters of the Sea: The Great Ocean Liners of Time
- Martin Cox and Peter Knego's "Maritime Matters"
- The Last Ocean Liners 1950s-1960s
- Kevin Tam's "Ships of State:The Great Atlantic Liners"
- "The Ocean Liner Virtual Museum"