Text 5 Passenger Liners

The great age of the ocean liner came in the early 1900s. It reached its height in the 1930’s with the launching of three of the most luxurious ships ever built. They were the Normandie of France and the Queen Mary and Queen Elizabeth of Britain. These giants, each almost 1,000 feet (300 meters) long, crossed the Atlantic Ocean in just over four days. In 1942, a fire destroyed the Normandie as it lay in New York Harbor.

In designing the hull of the ocean liners the dimensions of fashion and luxury sometimes dominated over sea worthiness. Huge surface volume in bow part of the liner hull caused navigation with free yaw on a course, which did not admit by bulb. The wide aft deck essentially limited opportunities of a storm rate choice. As a whole the storm safety depended mainly on reliability of engines and experience of helm’s watch.

Today, the only luxury liner to make transatlantic crossings is Britain’s Queen Elizabeth 2, which was launched in 1967. It crosses the Atlantic from April until December and it carries passengers on a cruise around the world during the winter months. Most liners today are used as cruise ships to the Mediterranean, the Caribbean, and other vacation areas. Norway’s Sovereign of the Seas, a cruise ship that began service in the Caribbean in 1988 can carry more passengers than any other ship. The Sovereign can carry almost 2,700 passengers and 750 crewmembers.

Text 6

Submarine is a ship which can operate completely submerged in the water. The term formerly applied to any ship capable of operating completely underwater, but now usually describes a ship built for military purposes. The term “submersible” usually is applied to small, underwater vehicles that are built for research, rescue, commercial work, or pleasure.

By the end of World War II, antisubmarine warfare had progressed significantly by exploiting the limited underwater endurance and speed of the diesel-electric designs of that era. The application of nuclear power to submarines after World War II reestablished the near-invulnerability of the submarine to antisubmarine warfare from surface ships and aircraft. Nuclear power depends on nuclear fission rather than the oxidation of fossil fuels and thus requires no oxygen source as do diesel engines, allowing the submarine to operate submerged for very long periods. However, advances in submarine technology and nonnuclear propulsion cause the nonnuclear submarine to remain highly attractive to the navies of many nations.

Submarines can be classified by their primary military missions. Attack submarines are fast, long-range ships equipped with torpedo tubes or cruise missile launch tubes. They carry sensitive underwater sound receivers and transmitters (sonar) used to detect enemy submarines. They may be armed with torpedoes of various kinds, cruise missiles, mines, and equipment for deployment of small units of clandestine troops.

Ballistic-missile submarines carry long-range missiles fitted with nuclear warheads that can be launched while submerged. The submarine can remain submerged and undetected for many days and, on command, launch missiles on any target within range. The missiles are stowed in and launched from vertical tubes.

Experimental submarines are occasionally built to test new designs of hull shape, deeper depth capability, power plants, or controls.

Submersibles are usually small, deep-diving vehicles. Their use is for exploration and study of the ocean depths, development of equipment, rescue, or commercial work. Some designs take advantage of the forces of gravity and buoyancy for vertical motion. Other designs use vertically oriented propellers to propel the craft up and down. Movement is restricted to short distances and slow speed because of small size and small battery capacity.

Compared with surface ships, the submarine has features that enable it to submerge and resist great sea pressure. Submarines have a pressure hull and a nonpressure hull. The pressure hull is the watertight, pressure-proof envelope in which equipment operates and the officers and crew live. In certain areas of the submarine there is a nonpressure hull of lighter structure, forming the main ballast tanks. A nonwatertight superstructure provides a smooth, fair envelope to cover pipes, valves, and fittings on top of the hull. Above the superstructure the fairwater similarly encloses the bridge, the periscope, and multiple mast supports.

The principal means of detecting the presence of a submerged submarine is to listen for sounds which may have been generated on board or by its movement through the water. Very small amounts of acoustic energy can be detected by sophisticated sonars. Therefore, modern submarines are designed with multiple features to greatly reduce the amount of noise they generate.