If I were free, I should help you. Were I free, I should help you. If he had known about the lecture, he would have come. Had he known about the lecture, he would have come.

1. If it were possible, we should begin this work at once. 2. If he had had all the necessary books, he would have made his report in time. 3. If the books had been available in our library, we could have done this work much earlier. 4. If there were no computers, space flights would be impossible. 5. If drivers were more attentive while driving, there would be less accidents on the road.

В. Переведите бессоюзные условные придаточные предложения.

1. Had he used new materials, the device would have been more reliable. 2. Were electric motors used, cars would not pollute the air, would be practically noiseless and very easy to control. 3. Had they applied the new method, the result would have been much better. 4. Were the design of cars improved, the fuel consumption would be greatly reduced. 5. Had a less explosive gas been used in dirigibles at the beginning of the century, they would have been in operation since that time. 6. Were it possible to learn how birds find their way, people would use the principle to develop a naviga­tion system for aviation.

Упражнение З. Переведите предложения и запомните значения глагола to provide и союза provided.

1. The experiments conducted provided very good results. 2. Rus­sian technological achievements that provided the launching of rockets are known all over the world. 3. A tire pressure display pro-

vides informatioii for front and back pairs of tires. 4. Provided new composite materials are used, it will be possible to reduce overall aircraft weight. 5^ Provided with a new vacuum-controlled carbure­tor this car model has several important advantages. 6. Superliners could develop a higher speed provided some special cooling mea­sures were used. 7. An aircraft pilot can get all the information he needs provided he contacts a radio navigation station. 8. The work done provided us with new data. 9. Having measured the distance between two points, it is possible to calculate the time during which a car can cover it provided we know the car's average speed. 10. Our laboratory has been provided with the latest equipment.

Упражнение 4. А. Дайте степени сравнения для прилагательных.

great, easy, good, far, many, difficult, possible.

B. Поставьте much перед прилагательным в сравнительной степени (го­
раздо, намного), переведите.

late, simple, important, valuable, quick, reliable, useful, com­plex.

C. Переведите словосочетания.

гораздо (намного) раньше, гораздо (намного) длиннее, на­много (гораздо) труднее, намного эффективнее, намного легче.

Упражнение 5. А. Найдите русские эквиваленты для словосочетаний.

as old as seagoing, a round container, the Swiss National Fair, as primitive as marine life, so-called, to take people deep into the lake, underwater tasks, around the ocean floor, wrist of the manipu­lator, to lift 120 pounds, marine life, the world's deepest vehicle, underwater helicopter.

швейцарская национальная ярмарка; подводные работы; опускать людей на большую глубину озера; по морскому дну; подводный вертолет; запястье манипулятора; морской живот­ный и растительный мир; самый глубоководный в мире аппа­рат; такая же примитивная, как и морская среда (жизнь); так же стары, как мореплавание; так называемый; круглый кон­тейнер; поднимать 120 фунтов.

В. Переведите словосочетания.

round glass container, marine life people watch around them, centuries before, to take people deeper than before, difficult under­water tasks, mounted on a metal platform, it looks like an underwa-

ter helicopter, move like a sport car, video cameras provide vision, to lift up to 120 pounds, work for up to nine hours.

СЛОВООБРАЗОВАНИЕ

Упражнение 6. Переведите следующие производные слова согласно об­разцу:

прилагательное + th = существительное, deep — глубокий -» depth — глубина length, width, strength;

прилагательное + en = глагол light — легкий -» to lighten — облегчить deepen, brighten, lessen;

префиксы sub- (суб-_у под-, до-), under- (под-, ниже, недо-) submerge — погружать(ся) -» submersible — подводный,

погружаемый estimate — оценивать -» underestimate — недооценивать subsystem, subsonic, subcommittee, subdivision, subsurface, submarine, undersea, underground, undercooling, underproduc­tion, underdeveloped;

префикс поп- (не-) non-conductor — непроводник; non-military — невоенный non-effective, non-essential, non-standard, non-metal, non-stop.

Упражнение 7. Прочитайте и переведите интернациональные слова.

ocean ['eujen], container, apparatus [,aepe'reites], machine [me'Ji:n], spherical ['sfenkel], plastic, metal platform, helicopter ['helikopte], manoeuvre [me'nu:ve], sport, mechanical [mi'kaenikel], manipulator [me'nipjuleite], system, miniature ['minjetj'e], microphone ['maikrefeun], to lift, minerals, battery, stereo ['stierieu], construct, cultivate, videocamera, titanium [tai'teinjem].

Упражнение 8. Прочитайте и запомните произношение слов.

descend [di'send], legend ['ledjend], submerge [seb'meids], submersible [seb'me:sibl], da Vinci [Vintfi], national ['пае Jen I], Geneva [d3i'ni:ve], Japanese [,c|3aepe'ni:z], technician [tek'nijen], extreme [iks'tri:m], precision [pn'si3en], essentially [i/senjeli],

cycloid ['saikloid], particular [pa'tikjula], wrist [rist], provide [pra'vaid], sample ['sa:mpl], image ['iimcfe], scale [skeil], join [cfeoin], politician! [,poli'tiJan].

СЛОВА И СЛОВОСОЧЕТАНИЯ ДЛЯ ЗАПОМИНАНИЯ

accurate a — точный almost adv — почти advanced p.p. — новейший, пере­довой

collect v — собирать construct v — строить, сооружать crew n — экипаж depth n — глубина descend v — спускаться, опус­каться

due to prp — благодаря, из-за explore v — исследовать find out v — выяснить, узнать image n — изображение instead of adv — вместо join v — соединять, объединять lift v — поднимать(ся) mankind n — человечество operate v — работать, действовать

particular a — данный, особенный, отдельный penetrate v — проникать precision n — точность promise v — обещать provided cj — при условии что; в том случае, если realize v — осуществлять, реализовывать resist v — сопротивляться, выдерживать sample n — образец submerge v — погружаться, опускаться вглубь test v — проверять, под­вергать испытанию transparent a — прозрач­ный

try v — пытаться, пробо­вать

battery-operated p.p. — работающий на батареях

Text 9A

Прочитайте и переведите текст. Ответьте на следующие вопросы:

В каких странах ведутся работы по созданию погружаемых аппаратов?

Каковы особенности погружаемых аппаратов нового типа?

Descending to New Ocean Depths

We know little about the ocean yet. The dream of exploring un­der the waves is almost as old as seagoing. Legend says that Alexan­der the Great submerged himself in a round glass container, and Leonardo da Vinci designed a submersible vehicle in his notebooks centuries before Jules Verne wrote «Twenty Thousand Leagues Un-

der the Sea». If their dreams had been realized ai|d such a craft had been constructed, mankind would have known about the secrets of Ocean much earlier. However, already during tjhe Swiss National Fair in 1964 a submersible vehicle took thousands of people deep

into Lake Geneva.

i

Not long ago, the crafts that penetrated the' ocean depths were almost as primitive as the marine life they watched around them. However, non-military deep sea ships, so-cklled submersibles, were progressing rapidly. Russian, French, Japanese and American scientists are developing crafts that can submerge deeper, stay lon­ger and find out more than earlier apparatuses.

Soon, one of the most advanced crafts, a one passenger sub­merging ship, will be tested. It may be able to take explorers and technicians deeper than ever before (up to 3,300 feet) and perform difficult underwater tasks with extreme precision.

This new submersible is essentially a spherical transparent plastic hull¹ mounted on a metal platform. It looks like an underwater heli­copter and can manoeuvre itself in its water environment with some of the versatility² of a helicopter due to the use of a cycloid rotor³ instead of conventional marine-propeller screws⁴. It is expected that this apparatus will move around the ocean like a sports car.

However, the breakthrough⁵ that will make this particular craft quite different from other manned submersibles is a mechanical hand called the sensory manipulator system⁶. Miniature video cameras on the «wrist» of the manipulator provide it with vision and microphones enable the submersible to «hear». This manipula­tor system is designed to lift up to 120 pounds and will also be able to perform such accurate scientific work as collecting samples of ocean-floor minerals and marine life. When demonstrated, it lifted crystal glasses, drew pictures and wrote with a pen.

Some scientists are trying to develop the world's deepest manned submersible. When completed, it will be capable of sub­merging to the depths of 21,000 feet. Its crew will be in a pres­sure-resistant titanium-alloy cabin. This craft will be driven by a battery-operated electric motor and will work for up to nine hours. It will record images with colour television and stereo cameras and will collect samples by manipulating two robotic arms.

If such crafts are constructed on a large scale, we shall be able not only to spend our holidays enjoying the underwater life, but also grow and cultivate sea plants, fish and pearls. It will be possible provided scientists, designers and politicians from all over the world join their efforts and solve the most important problems in this field.

Notes to the Text

1. transparent plastic hull — прозрачный пластмассовый корпус

2. versatility — свобода передвижения

3. cycloid rotor — несущий винт циклоидного типа

4. marine-propeller screw — судовой гребной винт

5. breakthrough — радикальное решение

6. sensory manipulator system — сенсорная система манипу­лятора

УПРАЖНЕНИЯ

Упражнение 9. Просмотрите текст 9А и ответьте на вопросы.

1. What is the text about? 2. What is a submersible? 3. Who was the first to think of a submersible vehicle? 4.What writer wrote about a submersible? 5. What special systems will be used on a new submersible? 6. What are the characteristics of the manipulator system? 7. What kind of submersible is being designed at present? 8. What do you think of the future of such vehicles? 9. What is the name of the famous French scientist, an explorer of the ocean? 10. Have you seen his film? Have you read his books?

Упражнение 10. Укажите, какие утверждения соответствуют содержанию текста 9А. Исправьте неправильные.

1. We know very little about the ocean yet. 2. The dream of ex­ploring the underwater life is very old. 3. It was Jules Verne who was the first to write about a submersible vehicle. 4. Only Japanese scientists are developing deep water submersible crafts. 5. A new submersible craft looks and moves like an underwater helicopter. 6. A new submersible is provided with a manipulator that is de­signed to lift 120 tons. 7. When demonstrated, it lifted crystal glass and drew pictures. 8. When completed, the world's deepest manned submersible will be capable of submerging to the depth of 21,000 feet. 9. This craft will be driven by a battery-operated elec­tric motor.

Упражнение 11. Найдите в тексте 9А условные придаточные предложе­ния; сделайте, где возможно, их бессоюзными.

Упражнение 12. Найдите условные придаточные предложения, выра­жающие нереальные действия. Переведите.

1. If a scientific research is closely linked with practice, the re­sults are always good. 2. If you looked at the equipment of 1946,

you would notice the difference with that available at present. 3. If there is a pressure change in the tires, a transmitter signals to adjust the pressure. 4. If we were to make a journey in a plane to the nearest star, we should have to travel for several thousand centuries. 5. Were traffic controlled by computers, cars could travel with safety and speed. 6. Had submersibles been developed since the time of Alex­ander the Great, mankind would have used natural resources from the ocean floor and cultivated plants and fish there. 7. Had all sub­mersibles had autonomous principle of operation, they would have become much more useful. 8. If fire-arms had not been invented, the secret of Damascus steel would not have been lost. 9. If we could make a non-stop flight around the sun in an airplane at a speed about 300 km per hour, it would require 565 days to encircle it at the equator. 10. If the satellite speed is less than necessary, it will go down from the orbit and enter the atmosphere.

Упражнение 13. Переведите предложения, обращая внимание на различ­ные значения слов provide, if (whether).

1. Specialists reported that a miniature video camera provided the latest submersible with vision. 2. The speed of a satellite would be less provided it moved at a greater distance from the Earth. 3. Drivers don't know yet whether radars will be mounted on the next car models. 4. If the weather is too bad for flying, passenger airplanes don't leave airports. 5. It was very important to find out if electricity could be used for long distance communication. 6. Dur­ing the entire flight, the pilot is provided with all the necessary in­formation about weather conditions. 7. Modern submersibles can remain at the depth of 20,000 feet for eight hours or, if needed, as long as two or three days. 8. A new system for motor cars can be provided with infrared sensors that can detect a human figure at night. 9. If underwater tourism continued to develop at the present rate, the number of passengers could grow up to millions in only a few years.

Упражнение 14. Переведите предложения с союзом unless и запомните особенности его перевода.

1. Isaac Newton stated that a body would continue moving un­less some force was applied to stop it. 2. Space flights would be im­possible unless special materials for space vehicles were produced. 3. We should have no radio, telephone, television or computers un­less there were electricity. 4. The earth temperature would increase indefinitely unless heat were radiated. 5. Unless the temperature rises, the speed of the molecules will not increase. 6. It would have

been impossible to send satellites into orbit unless Newton's laws of motion had been studied. 7. With heat generated by friction of the air on aircraft surface, the temperature inside the cabin would in­crease to almost 1,000 °C unless it were cooled by mechanical means.

УПРАЖНЕНИЯ ДЛЯ САМОСТОЯТЕЛЬНОЙ РАБОТЫ

Упражнение 15. Образуйте от следующих слов:

а) глаголы

usage, subdivision, indication, complication, difference, large, systematisation, appearance, changeable, measurable;

б) существительные

noiseless, powerful, deep, dangerous, perform, realise, lighten.

Упражнение 16. Образуйте производные от следующих слов:

manipulate, compress, move.

Упражнение 17. Найдите русскому слову соответствующее английское.

исследовать — exploration, explorer, to explore; точно — exactness, exactly, exact, exaction; погруженный — submergence, submerge, submerged, sub­mersion;

направлять — navigate, navigable, navigation; стойкий — resistance, to resist, resistant, resistor; ширина — wide, width, widely, widen.

Упражнение 18. Найдите:

а) синонимы

to finish, to submerge, to work, craft, to build, to descend, ve­hicle, to operate, rapid, fast, to construct, to complete;

б) антонимы

to lift, difficult, to complete, after, to descend, before, easy, to start.

Упражнение 19. Определите, какой частью речи являются выделенные слова; переведите предложения.

1. In a new apparatus rotors mounted on the fuselage provide lift acting as wings when the craft is moving at high velocity. 2. The aerostatic apparatuses of the latest design can vary its lift force. 3. The man can't lift this weight, it can be lifted only automati­cally. 4. When weight is lifted to a given level, it possesses potential

energy due to its position. 5. Russia possesses the world's heaviest helicopters MI-26 which lift and transport cargoes up to 20 tons.

Упражнение 20. Переведите предложения, обращая внимание на значе­ния слов before и after в функции предлога и союза.

1. There was no means of direct communication before the telephone was invented. 2. After World War 1 dirigibles gradually lost their significance as a means of transportation. 3. Before New­ton no one could explain why the planets moved around the sun. 4. After a French engineer invented the first self-propelled road vehicle in 1770, many car designers wanted to make a better auto­mobile. 5. Before each flight pilots must ask for the information about the weather expected during the planned route. 6. The «night vision» system enables drivers to see better after dark. 7. Before the industrial production of materials in space can be started, it is necessary to create special space stations. 8. Soon after Karl Marx's arrival in England he became a daily visitor of the Reading Room of the British Museum.

Упражнение 21. Выберите соответствующий глагол из приведенных в скобках.

1. A young physicist can (get, get up) a prize for his work.

2. Designers tested a new engine to (find, find out) whether the ce­ramics it was made of could withstand temperatures up to 1,000 °C.

3. It is difficult to (get, get up) early in winter. 4. Many specialists are working at the problem of developing a new kind of telephone which we (call, call for) «video phone». 5. The projects in Siberia (call, call for) the most effective means of transporting various car­goes over long distances. 6. Specialists wanted to (find, find out) whether telephone communication was reliable or not. 7. Further development (call, call for) new specialists who are able to generate new technical ideas. 8. New generation materials which we (call, call for) composite materials will allow to lighten the aircraft. 9. To translate this text, we must (find, find out) some words in a dictionary.

Упражнение 22. Укажите предложения, где выделенное слово имеет сле­дующее значение:

— действуя

1. They should know in what direction this force is acting. 2. Acting upon the body the force changes. 3. They should find the force, acting upon the body.

— имеет дело, рассматривает

1. Thermodynamics is the branch of physics dealing with the transformation of heat into work. 2. The experience of France deal­ing with environmental problems is very important. 3. Now Russia is dealing very seriously with the problem of Baikal protection.

— используя

1. Using thermomagnetic alloys in the turbine rotor allows to develop a lot of various sensors. 2. By using thermomagnetic alloys it is possible to develop a lot of various sensors. 3. Many American companies began using submersibles for tourism.

— совершенствование

1. Construction specialists are working at improving the design of metro escalators. 2. While improving the design of metro escala­tors specialists developed a two speed escalator. 3. Our design bu­reau has developed spiral escalators improving the construction of public buildings.

— превышающий

1. A car exceeding its speed, the indicators show it on the dis­play. 2. Exceeding the speed limit the driver should be very atten­tive. 3. There are relatively few cargoes exceeding 400 tons.

Упражнение 23. А. Прочитайте текст без словаря.

Three Stonecutters

Three stonecutters (каменотес) were working hard. A man who was passing by watched them for a few minutes and then, turning to the first stonecutter, he asked: «What are you doing, my friend?» «I am working like a slave (раб). Look at my hands. Did you think I was playing?», he replied. The passer-by then looked at the second workman. «And what are you doing?», he asked. The stone-cutter answered quickly, «I am earning seven dollars and fifty cents a day. I hope to receive at least nine dollars a day in a very near future.» The visitor studied the face of the third stonecutter. Once more, he asked, «And what are you doing, my friend?» The stonecutter's face lighted up as he replied, «I am helping to erect a magnificent building. Look at the colour in this piece of marble. I was just thinking how beautiful it will be when it is thoroughly polished. This building will last for hundreds of years and its beauty will in­spire everyone who sees it.»

В. Составьте предложения в соответствии с содержанием текста А.

1. The first stonecutter was the 1. he saw beauty and joy in his unhappiest of the three because work.

2. The second one was happier 2. he thought that all work was than the first stonecutter because hard and dull.

3. The third stonecutter was the 3. he thought that honest work happiest of the three because brings advancement.

Упражнение 24. Дайте недостающие формы глаголов, запомните их. drawn, grew, feeling, wake up, drank, cutting, sink.

Упражнение 25. Прочитайте и переведите текст без словаря.

Deep Trouble

An experimental undersea telephone cable in the Canary Is­lands had to be lifted from the ocean floor three times because of breakage. Each time sharks' (акула) teeth were found in the dam­aged cable. Though the cable contains optical fibres transmitting signals in the form of light, it carries a very small amount of electri­cal wires. It is known that electricity attracts sharks. Therefore, or­dinary electric power cables are usually provided with some kind of protection to stop their being attacked by sharks. However, it was not expected that it was necessary to mount this expensive protec­tion on the new cable. But provided the designers had used this conventional protection on the new cable, the sharks would not have approached it.

CONVERSATION

Exercise 1. Answer the questions.

l.What apparatuses are used for exploring the ocean depths at present? (non-military submersibles) 2. What countries are de­veloping such submersibles? (Russia, the USA, France and Japan) 3. What kind of submersible is being designed? (an advanced manned submersible) 4. What is the depth it is capable to submerge to? (21,000 feet) 5. What motor is used in it? (a battery-operated electric motor) 6. What devices are provided for collecting samples from the ocean floor? (robotic manipulators) 7. What is the practi­cal application of the submersible? (cultivating sea plants, fish and pearls)

Exercise 2. Make a sentence out of the two parts.

1. an underwater helicopter. 2. to the depth of 3,300 feet. 3. this apparatus will move like a sports car. 4. its sensory manipulator with miniature video cameras and mi­crophones. 5. accurate scientific explorations. 6. due to the use of rotor instead of conventional propeller. 7. mounted on a metal platform.

1. A new one-passenger submer­sible is designed for performing

2. This submersible is a spherical transparent plastic apparatus

3. It looks like

4. It can move in water environ­ment

5. While exploring the ocean floor

6. The apparatus is capable to descend

7. A special feature of this man­ned submersible is

Exercise 3. Read and learn.

Hiking in the Mountains

Mike: My steps become lighter because I hear the music of running water. Let's stand and look at the stream.

Jane: Why only look? I'm thirsty (хочу пить) and nothing tastes so good as cool mountain water.

M.: But passing the same water through the pores of the skin does the body fifteen times as much good as it does when you drink it. Put your hands and arms into the deepest place and keep them for a while and you'll feel so wonderful.

J.: I can't stop drinking. Look at the clear, smooth surface of the stream. Water is beautiful.

M.: And perhaps, the most beautiful thing about it is its use. It helps all living things in one way or another.

J.: I know that my own body is eighty-five per cent water.

M.: Yes, and this water keeps you going in spite of the weather.

J.: How does it do this?

M.: By circulation it keeps your body at the same temperature all the time.

J.: I've read that water has the most interesting properties of all liquids. It is the slowest to cool and the slowest to heat.

M.: In winter the water in your body keeps you warm by circulat­ing evenly to all parts. In the heat of summer it passes off through the million of pores of your skin. This keeps you cool and takes away toxic material at the same time.

J.: I think the great supply of water in the body is one of the na­ture's great provisions.

M.: Sure, especially taking into consideration (принимать во внимание) that the human being can live only within the nar­row range (диапазон) in body temperature of a very few de­grees Fahrenheit. Have you had enough water?

J.: Yes, I have. Usually I drink at least six glassfuls of water daily.

Exercise 4. Speak about:

1. An advanced manned submersible.

2. Practical applications of manned submersibles.

Use exercises 1, 2 and the following words and word combinations for your topic: to realize a dream, underwater exploration, to penetrate, a submersible vehi­cle, to descend to a depth up to, to perform tasks, collecting samples of minerals and marine life, to work for nine hours, to join efforts.

Exercise 5. Comment on the following statement.

Scientists cannot afford (позволить себе) to be interested in things not connected with their subject.

One point of view: There is no alternative to narrow (узкий) specialization, ev­erybody has a limited amount of time, it is unrealistic to expect a scientist to be in­terested in other fields than his own, a person who is interested in many things is sure to become a dilettante.

A contrary point of view: It is impossible to understand a particular science in complete isolation, the scientist should not be treated as a machine for solving spe­cialized problems, a narrow specialist may tend to become a narrow -minded per­son, really great scientists have always had wide interests.

What do you think about it? Why?

Exercise 6. A. Read and say what you think about tea and what it does for you.

Tea

The English know how to make tea and what it does for you. Seven cups of it wake you up in the morning; nine cups will put you to sleep at night.

If you are hot, tea will cool you off, and if you are cold, it will warm you up.

If you take it in the middle of the morning, it will stimulate you for further work; if you drink it in the afternoon, it will relax you for further thought. Then, of course, you drink lots of it in off hours (свободное время).

The test of good tea is simple. If a spoon stands in it, then it is strong enough.

В. Use the following phrases.

1. If you ask me, tea...

2. If you want my opinion, tea...

3. I entirely / quite agree with the idea that...

4. That's exactly my opinion / that's exactly what I feel...

5. I don't like tea because...

Exercise 7. Read and smile.

A Fable from Aesop [T.sop]

While sitting together one time, a group of animals was discuss­ing the popularity of the elephant. They all agreed that the elephant was the most popular animal in the forest, but none of them could give a satisfactory explanation of this fact. Yet they all had certain comments to offer.

The giraffe [d3i'ra:f] said, «If the elephant had a long neck like mine, then it would be easy to understand his popularity. He would be the tallest animal in the forest».

The peacock (павлин) said, «If he possessed my beautiful tail, it would be easy to understand. He would be the most beautiful creature in the forest».

The rabbit said, «If he could run as fast as I, it would be easy to understand. He would be the fastest animal in the forest».

The bear said, «If he was as strong as I, it would be easy to un­derstand. He would be the strongest animal in the forest».

Suddenly the elephant himself appeared. He was larger and stronger than any of the other animals, and he was also superior in many ways. But he was always quiet and modest about his many accomplishments. This, after all, was the real explanation for his popularity.

An American lady got into a smoking carriage (вагон) where an Englishman was smoking a pipe.

She began doing everything to show him she objected to his smoking. At last, seeing that the man paid no attention, she said, «If you were a gentleman, you would stop smoking when a lady got into the carriage».

«If you were a lady», replied the Englishman, «you would not get into a smoking carriage».

«If you were my husband», said the American lady angrily, «I would give you poison (яд)».

«Well,» said the Englishman at last, «if I were your husband, I would take it».

Text 9B

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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.

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