Ship science

Ships (boats and ships), a general term for all kinds of ships. Ships are vehicles that can sail or be berthed in waters for transportation or operations, and have different technical performance, equipment and structural types according to different usage requirements.

A ship is a man-made vehicle that operates primarily in geographic water. In addition, civilian ships are generally called ships, military ships are called ships, and small ships are called boats or boats, which are collectively called ships or boats. The interior mainly includes accommodation space, support structure and drainage structure, and has a propulsion system that utilizes external or self-contained energy. The shape is generally a streamlined envelope that is conducive to overcoming fluid resistance. The materials are constantly updated with the advancement of science and technology. In the early days, natural materials such as wood, bamboo, and hemp were used. In modern times, they are mostly steel, aluminum, glass fiber, acrylic, and various composite materials.

Ships started from prehistoric wooden boats and went through the era of canoes and planks. After the world's first steel ship came out in 1879, the era of steel ships began. The propulsion of ships also developed from relying on manpower, animal power and wind power (ie, poles, paddles, oars, pulling fibers and sails) in the 19th century to the use of machine drives.

In 1807, Fulton in the United States built the first steam engine ship "Clermont" with paddle wheel propulsion, with a speed of about 8 kilometers per hour; in 1839, the first steam engine ship equipped with propeller propulsion " "Archimedes" came out, the main engine power is 58.8 kilowatts. This kind of thruster has fully demonstrated its superiority, so it was quickly promoted.

In 1868, China's first steam engine ship "Hui Ji" with a load of 600 tons and a power of 288 kilowatts was successfully built. In 1894, British Parsons used the reactionary steam turbine he invented as the main engine, installed it on the speedboat "Turbonia", and successfully tested it on the Thames, with a speed of more than 60 kilometers.

The steam turbine and the propeller of the early steam turbine ship were rotating at the same speed. Later, in about 191 [2] 0, gear reduction, electric transmission reduction and hydraulic transmission reduction devices appeared. After that, marine steam turbines all began to adopt the reduction transmission method.

From 1902 to 1903, a diesel strait boat was built in France; in 1903, the Russian-built diesel ship "Wanda" was launched. In the middle of the 20th century, diesel engine power plant became the main power plant for transport ships.

In 1947, the United Kingdom first modified the gas turbine for aviation, and then installed it on the coastal speedboat "Gatlick" to replace the original gasoline engine. The box and shafting drive the propeller. The unit weight of this unit is only 2.08 kg/kW, which is far lighter than other units. In the 1960s, large and medium-sized surface warships with combined power plants of gas turbines and steam turbines appeared.

In countries with strong navies in the modern era, in the large and medium-sized ships, in addition to the use of steam turbine power plants with high power, almost all of them use gas turbine power plants. In civil ships, gas turbines are rarely used due to their lower efficiency than diesel engines.

The discovery and utilization of atomic energy has opened up a new way for ship power. In 1954, the nuclear submarine "Nautilus" built by the United States was launched with a power of 11,025 kilowatts and a speed of 33 kilometers; in 1959, the former Soviet Union built the nuclear-powered icebreaker "Lenin" with a power of 32,340 kilowatts; The Savannah was launched with a power of 14,700 kilowatts.

Existing nuclear power plants all use pressurized water nuclear reactor steam turbines, which are mainly used in submarines and aircraft carriers, while in civilian ships, they have not been developed due to economic reasons. The emergence of nuclear batteries has solved these problems, which means that ships powered by nuclear batteries can be manufactured in batches. In the 1970s and 1980s, in order to save energy, some countries absorbed the advantages of sailboats and developed a kind of ship that was mainly driven by machines and assisted by sails. Joint control with electronic computer, Japan-built "Shin Aide Maru" is the representative of this energy-saving ship.