Passenger ship

There are several types of passenger ships:

1. Ocean liners: Ocean liners typically are passenger or passenger-cargo vessels transporting passengers and often cargo on longer line voyages. An ocean liner is the traditional form of passenger ship. Once such liners operated on scheduled line voyages to all inhabited parts of the world. With the advent of airliners transporting passengers and specialized cargo vessels hauling freight, line voyages have almost died out. But with their decline came an increase in sea trips for pleasure and fun, and in the latter part of the 20th century ocean liners gave way to cruise ships as the predominant form of large passenger ship containing from hundreds to thousands of people, with the main area of activity changing from the North Atlantic Ocean to the Caribbean Sea.
2. Ferries: Ferries are vessels for day to day or overnight short-sea trips moving passengers and vehicles (whether road or rail). Many modern ferries, such as Stena Germanica, employ a RoRo (Roll-On-Roll-Off) system to transport these vehicles. There also exist cruise ferries, designed for longer routes, lasting from one to a couple of days. They are named such because they tend to include amenities common on cruise ships, such as pools, discos, and spas.
3. Cruise ships: Cruise ships mainly transport passengers on round-trips, in which the trip itself and the attractions of the ship and ports visited are the principal draw. For a long time, cruise ships were smaller than the old ocean liners had been, but in the 1980s, this changed when Knut Kloster, the director of Norwegian Caribbean Lines, bought one of the biggest surviving ocean liners, the SS France, and transformed her into a huge cruise ship, which he renamed the SS Norway. Her success demonstrated that there was a market for large cruise ships. Successive classes of ever-larger ships were ordered, until the Cunard liner Queen Elizabeth was finally dethroned from her 56-year reign as the largest passenger ship ever built (a dethronement that led to numerous further dethronements from the same position).

Although some ships have characteristics of both types, the design priorities of the two forms are different: ocean liners value speed and traditional luxury while cruise ships value amenities (swimming pools, theaters, ball rooms, casinos, sports facilities, etc.) rather than speed. These priorities produce different designs. In addition, ocean liners typically were built to cross the Atlantic Ocean between Europe and the United States or travel even further to South America or Asia while cruise ships typically serve shorter routes with more stops along coastlines or among various islands.

Tanto el Queen Elizabeth 2 ( QE2 ) (1969) como su sucesor como buque insignia de Cunard, el RMS Queen Mary 2  ( QM2 ), que entró en servicio en 2004, son de construcción híbrida. Al igual que los transatlánticos , son barcos rápidos y robustos, construidos para soportar las inclemencias del Atlántico Norte en viajes regulares, ^{[ 2 ]} pero ambos barcos también están diseñados para operar como cruceros, con las comodidades propias de ese sector. El QM2 fue superado por el Freedom of the Seas de la línea Royal Caribbean como el mayor barco de pasajeros jamás construido; sin embargo, el QM2 aún ostenta el récord del transatlántico más grande. El Freedom of the Seas fue superado por el Oasis of the Seas en octubre de 2009. ^{[ 3 ]}

Because of changes in historic measurement systems, it is difficult to make meaningful and accurate comparisons of ship sizes. Historically, gross register tonnage (GRT) was a measure of the internal volume of certain enclosed areas of a ship divided into "tons" equivalent to 100 cubic feet (2.8 m³) of space. Gross tonnage (GT) is a comparatively new measurement, adopted in 1982 to replace GRT. It is calculated based on "the moulded volume of all enclosed spaces of the ship", and is used to determine things such as a ship's manning regulations, safety rules, registration fees, and port dues. It is produced by a mathematical formula, and does not distinguish between mechanical and passenger spaces, and thus is not directly comparable to historic GRT measurements. Displacement, a measure of mass, is not commonly used for passenger vessels. While a high displacement can indicate better sea keeping abilities,^[4] gross tonnage is promoted as the most important measure of size for passenger vessels, as the ratio of gross tonnage per passenger – the Passenger/Space Ratio – gives a sense of the spaciousness of a ship, an important consideration in cruise liners where the onboard amenities are of high importance.^[5][6]

Historically, a ship's GRT and displacement were somewhat similar in number. For example, Titanic, put in service in 1912, had a GRT of 46,328 and a displacement reported at over 52,000 tons.^[7] Similarly, Cunard Line's mid-1930s RMS Queen Mary and RMS Queen Elizabeth were of approximately 81,000 – 83,000 GRT and had displacements of over 80,000 tons.^[8]

Today, due to changes in construction, engineering, function, architecture, and, crucially, measurement system – which measures functionally all of a ship's internal volume, not just part of it – modern passenger ships' GT values are much higher than their displacements. The Cunard Queens' current successor, the 148,528 GT Queen Mary 2,^[9][10] has been estimated to only displace approximately 76,000 tons.^[11] With the completion in 2009 of the first of the over 225,000 GT Oasis-class cruise ships, Oasis of the Seas, passenger ships' displacements rose to 100,000 tons,^[12] well less than half their GT.

Esta nueva clase es característica de un crecimiento explosivo en el tonelaje bruto, que se ha duplicado con creces desde los cruceros más grandes de finales de la década de 1990. Esto refleja el peso relativo mucho menor del espacio cerrado en la superestructura relativamente ligera de un barco en comparación con su casco, fuertemente reforzado y cargado de maquinaria, ya que los cruceros han aumentado su anchura verticalmente desde su manga máxima para dar cabida a más pasajeros dentro de un tamaño de casco determinado.

Los pasajeros en buques sin generadores de reserva sufren graves inconvenientes debido a la falta de agua, refrigeración y sistemas de alcantarillado en caso de pérdida de los motores o generadores principales por incendio u otra emergencia. La tripulación tampoco dispone de energía para operar los mecanismos eléctricos. La falta de un sistema de reserva adecuado para propulsar el buque puede, en mares agitados, dejarlo a la deriva y provocar su pérdida. ^{[ 15 ]} Las Normas de Seguridad para Buques de Pasajeros Revisadas de 2006 abordan estos y otros problemas, exigiendo que los buques encargados después de julio de 2010 cumplan con las normas de retorno seguro a puerto; sin embargo, a partir de 2013, muchos buques siguen en servicio sin esta capacidad. ^{[ 16 ]}

Después del 1 de octubre de 2010, el Convenio Internacional para la Seguridad de la Vida Humana en el Mar (SOLAS) exige que los buques de pasajeros que operan en aguas internacionales se construyan o modernicen para excluir materiales combustibles. Se cree que algunos propietarios y operadores de buques construidos antes de 1980, que están obligados a modernizar o retirar sus embarcaciones, no podrán cumplir con las regulaciones. ^{[ 16 ]} El Black Prince de Fred. Olsen Cruise Line , construido en 1966, era uno de esos buques, pero se informó que se dirigía a prestar servicio entre islas en aguas venezolanas. ^{[ 17 ]}

La Patrulla Internacional de Hielo se formó en 1914 después del hundimiento del Titanic para abordar el problema pendiente desde hace mucho tiempo de las colisiones con icebergs . ^{[ 18 ]}

Los pasajeros y su equipaje en el mar están cubiertos por el Convenio de Atenas . ^{[ 19 ]}