Ship expansion
In 1960s, a ship with 65438+100000 dwt was called "10000 dwt ship". At the end of 2000, there were hundreds of VLCC ships in the world, including three ULCC tankers with a deadweight of 500,000 tons. At present, the largest bulk carrier is 360,000 dwt. In recent years, container ships have become bigger and bigger. Container ships with 5000TEU, 6000TEU, 7000TEU and 8000TEU have been put into use one after another, and container ships with 9000TEU and 10000TEU are under construction and development. In the second half of 1990s, European and American shipowners kept building large luxury oil tankers, from 1.998 to 2002, with an average of 1.3 ships per year, most of which were 1.4 million gross tonnage.
Ship specialization
In the past, marine transport vessels were mainly passenger ships, cargo ships and oil tankers. In recent 20 years, the number of special vessels such as container ships, ro-ro ships and liquefied gas ships has increased rapidly.
High-speed ship
In order to compete with highway and high-speed railway transportation, in recent 20 years, small high-speed hovercraft, hydrofoil craft, hydrodynamic craft and jet propulsion craft with a speed of more than 30 knots have developed rapidly and been put into use in large quantities. The speed of container ships is now 25-30 knots, which is about twice as fast as that of ordinary cargo ships in the past.
Ship automation
In 1970s, computers were widely used on ships. From the setting of engine room centralized control room to the appearance of unattended engine room and bridge for remote control and telemetry of main engine, the automation of ship engine room has become a trend. 1970, the completion of Japan's "Starlight Pill" opened a new era of integration of driving and aircraft, which was called "super automatic ship" at that time. Ship automation has halved the number of ships and reduced operating costs. All the new ships built in recent 10 years can basically be called automatic ships, and some of them with high degree of automation are called "high-tech ships". Ship automation has moved from engine room automation to driving automation.
Electronic navigation and positioning
At present, the traditional landmark positioning and astronomical positioning methods have become auxiliary means in special circumstances. The way of radio navigation and positioning has experienced radio direction finder (192 1), radar (1935), Roland A( 1943) and Deka (1944). The navigation satellite timing and ranging/global positioning system (GPS) developed by the United States can provide users with continuous and high-precision three-dimensional positioning, speed and time information on the sea, land, air and space around the world, which makes the navigation and positioning of ships, planes, cars and other vehicles undergo epoch-making changes. GPS technology combined with differential technology can improve the positioning accuracy to several meters. GPS has been widely installed on ships and has become the most important, commonly used, simplest and most accurate navigation and positioning means. In order to get rid of the dependence on American GPS, Russia has developed GLONASS global navigation system, China has developed Beidou satellite positioning system, and the European Union is developing Galileo satellite navigation and positioning system (China will participate in the cooperative development).
Collision avoidance automation
Marine radar plays an important role in collision avoidance when visibility is poor. However, when the marine radar was first used for collision avoidance at sea, the information provided by the radar was not properly interpreted and applied, which led to ship collision. The Automatic Radar Plotter (APPA) developed in 1970s solved this problem well. Therefore, the combination of APPA and radar is called automatic collision avoidance system. The system can automatically photograph and track the target and automatically display the position, course, speed, relative motion and collision danger data of the incoming ship, automatically display the motion vector line, possible collision point, predicted danger zone and other information of the encountering ship in the form of images, and also carry out collision avoidance test operation. The further development of collision avoidance automation is the development of Automatic Ship Identification System (AIS) at the end of the 20th century. It can continuously transmit its own data to other ships, and can continuously receive the data of other ships, such as ship name, ship type, ship size, loading, navigation status and navigation plan. This is beneficial to reduce the ship collision accidents caused by the wrong decision of ship identification and collision avoidance.
Electronic chart
Traditional paper charts with static and fixed navigation data can no longer meet the development requirements of ship automation and intelligent navigation. In recent ten years, Electronic Chart Display and Information System (ECDIS) has been successfully developed and continuously improved. The system can not only provide useful information for printing paper charts, but also replace the traditional manual chart operation, and integrate the information obtained by various modern navigation devices such as GPS, APPA and AIS into an integrated navigation information system. ECDIS has the functions of chart display, planned route design, route monitoring, dangerous event alarm, navigation record, chart automatic correction and so on. It greatly improves the safety and efficiency of navigation, and is called a technological revolution in the field of navigation.
Digitization of navigation data
All kinds of books and materials needed for navigation were originally paper. With the development of computer technology and internet technology, electronic and online tide meters and light meters for navigation notices have appeared. Seafarers can buy CDs or search and download them online, which is conducive to the rapid update of the contents of nautical books and materials, avoiding seafarers from manually modifying paper books and materials, and is more convenient to use.
Communication automation
The use of wireless telegraph, wireless telephone, telex and fax on board is a great progress compared with the use of hand flags and lights for communication. 1957 launched the first artificial satellite, which opened the prelude of satellite communication. Inmarsat was founded in 1979, and 1982 began to provide global maritime satellite communication services. Inmarsat developed the aviation satellite mobile communication service in 1985, and expanded the service from sea and air to land in 1987. Inmarsat can provide telephone, telex, fax, data, Internet and multimedia communication services for land, sea and air. Another important sign of ship communication automation is that ships use the Global Maritime Distress and Safety System (GMDSS), which uses two satellite communication systems, Inmarsat and COAPAS—SARSAT, so that ships can transmit information instantly in all directions and in all weather conditions. In the event of a maritime accident, the shore search and rescue authorities and the wrecked ship or the ships nearby can get an alarm quickly and participate in the coordinated search and rescue operation with minimum time delay. GMDSS can also provide emergency and safety communication services, broadcast maritime safety information and conduct daily communication. The use of GDMSS on ships makes the driving and communication integrated, and the traditional ship operator is cancelled.
Navigation record automation
In order to find out the causes of maritime accidents, learn from them and take targeted preventive measures, the voyage log and car clock record book, which were originally recorded manually by seafarers, are now replaced by Voyage Data Recorder (VDR), commonly known as the "black box" of ships. VDR system consists of host, sensor, data storage, special standby power supply and playback and reproduction system. With VDR on board, it helps to avoid the situation that accident data cannot be collected or the parties commit perjury.