Text 3. Water transport

1. One of the most important things about water transport is the small effort needed to move floating craft. A heavy boat or a barge weighing several tons can be moved through the water, slowly but steadily, by one man. An aeroplane of the same weight as the barge needs engines of 1,000 horsepower or more in order to fly.

2. The raft made of logs of wood is supposed to be the earliest type of boat.

Rafts seem to be clumsy vessels, although the Norwegian scientist Thor Heyerdahl and his five companions in 1947 made a voyage on the raft Kon-Tiki from Peru to Tuamotu Islands - a distance of 4,500 miles.

3. The water transport in ancient times developed most rapidly on great rivers. The ancient Romans used vessels to carry their armies and supplies to colonies. These ships, usually called galleys, continued to be used in the Mediterranean till 1750.

4. The introduction of the magnetic compass allowed long voyages to be made with much greater safety. At the end of the 15th century, sailing vessels are known to have carried men from Europe to America and round Africa to India.

The middle of the 19th century proved to be the highest point in the development of sailing ships.

5. Steam and Motor Ships. One of the earliest steamboats is known to have been tested at the end of the 18th century. The first steamship to cross the Atlantic was the Savannah, 98-foot ship built in New York, which made the crossing in 1819. Like all the early steamships, it had sails as well as paddles.' By the middle of the 19th century it became possible to build much larger ships for iron and steel began to replace timber.

6. The rapid increase in the size and power of ships was promoted by the industrial revolution.)The industrial countries produced great quantities of goods which were carried to all parts of the world by ships. On their return voyages, the ships brought either raw materials such as cotton, metals, timber for the factories, or grain and foodstuffs for the growing population.

During the same period, a great deal was done to improve ports, and that permitted larger ships to use them and to make loading and unloading faster.

7. Improvements introduced in the 20th century included the smoother and more efficient type of engines called steam turbines and the use of oil fuel instead of coal. Between 1910 and 1920 the diesel engine began to be introduced in ships. These diesel-engined ships are called motor ships. The largest ships, however, are still generally driven by steam turbines. In the late 1950s a few ships were being built which were equipped with nuclear reactors for producing steam.

8. In 1957 the world's first atomic ice-breaker was launched in Leningrad.

This atomic ice-breaker is equipped with an atomic engine owing to which her operating on negligible quantities of nuclear fuel is possible. In spite of the capacity of her engine being 44,000 h.p. it will need only a few grams of atomic fuel a week.

The atomic ice-breaker has three nuclear reactors. The operation of the nuclear reactor is accompanied by powerful radiation. Therefore, the ice­breaker is equipped with reliable means of protection. The ice-breaker is designed for operation in Arctic waters.

Date: 2015-12-13; view: 1213; Нарушение авторских прав