Средства на воде и принцип его действия

Прочитайте текст. Назовите особенности современного спасательного

За счет чего можно устранить недостатки в существующих погружаемых

аппаратах?

Now most submersibles are connected with a support ship on

the surface. This connection is an armoured cable measuring an

inch or two in diameter and weighing up to 10 tons and it transmits

power and navigational commands to the submersible, as well as

sends sensor data and television images back to the support ship.

Cables allow submersibles to transmit data at a great speed, but

they limit the range of territory studied and have many disadvantages

in operation.

Autonomous underwater submersibles can move freely. Controlled

by on-board microprocessors or by acoustic signals transmitted

by a ship on the surface, battery-operated submersibles can

cover much greater areas. They can operate under ice and in very

deep water. Such three-ton unmanned crafts can submerge to the

depth of almost 20,000 feet and stay there for up to seven hours.

High quality images of the ocean bottom can be transmitted to the

support ship in three to four seconds (because of the slow speed —

about 5,000 feet per second through water — acoustic data transmission

is much less quick than signals sent via cable which travel

at the speed of light).

But even these most advanced submersibles have definite disadvantages:

batteries are heavy, data transmission is slow and computer

programs are primitive. Future submersibles may overcome

those difficulties. Some may be propelled by nuclear power or by

fuel cells (топливные элементы) that use oxygen from the sea

water. Many of them will rely on signal-compression techniques

to speed up acoustic data links. Computerized systems will enable

some submersibles to repair damaged telephone cables or oil platforms.

If research work in this field continues to expand at its

present rate, the number of radically different kind of more efficient

crafts will appear very soon.

Text 9C

Lifeboats

Even though we now have ships of a kind unknown in earlier

centuries, we are still very far from mastering the sea. The Greek

sailor who was shipwrecked (терпеть кораблекрушение) on his

way home from Troy and the sailor of tomorrow whose nuclearpowered

cargo ship might be on fire both face the same dangers.

They may drown (тонуть), and so they need to keep afloat. They

may die, and so they need to keep themselves covered and dry.

Rescuers (спасатель) may never find them, and so they need to

send signals.

The Greek sailor at the time of the Trojan war had only a small

chance of survival (спасение). The sailor of tomorrow has a greater

chance, especially if the ship has one of the new rescue crafts on

board.

One such lifeboat looks more like a flying saucer (тарелка)

than a boat. Sailors on board a ship which is in trouble can get into

the capsule, close the water-tight doors and operate the controls

which drop the capsule automatically into the sea. Made of glass

fibre (стекловолокно) the capsule will float on the sea and will not

be dragged down by the sinking ship. It will protect the men inside

from explosions, fire and extreme cold. It has a thirty-kilowatt

diesel engine and so can carry survivors to the coast. To help rescue

ship and aircraft to find it, the upper part of the capsule is covered

with a special orange paint which can be detected by radar. Each

capsule is large enough for twenty eight men.

Text 9D

Дата добавления: 2014-12-27