Throughout
history, the development of newer and better ship
technology has always been an indication of progress.
The first boats were undoubtedly simple rafts and
canoes used to travel on rivers and to hug the
shores of lakes and oceans. The single-sail ships
of the Egyptians, Greeks, and Romans eventually
gave rise to much more sophisticated ocean-going
ships, such as those used by the legendary Chinese
Admiral Zheng He and the Italian Christopher Columbus.
In fact, it's interesting to compare the voyages
of these two great seamen. Zheng He, who sailed
70-some years before Columbus, led a fleet of 62
ships—some as long as 120 meters—and
almost 28,000 sailors on seven voyages to the West.
However,
the emperor of China destroyed Zheng He's ships
and burned official records of his voyages in an
attempt to isolate China from the rest of the world.
Christopher Columbus's initial voyage across the
Atlantic was made with three leaky ships—about
one fifth the length of Zheng He's ships—and
fewer than 100 sailors, but his voyage had a very
dramatic impact on the history of Europe and the
Americas. In more recent times, the steamboat freed
man from relying solely on the currents and wind
for power, and made it possible to build much larger
ocean going vessels for transporting passengers
and cargo.
The revolution in ship technology of the 20 th Century progressed steadily with each passing decade. In recent years, in-ship communication has received a boost from the trend of using Ethernet networks to integrate the operation of distributed communication systems on ships. Using Ethernet to integrate in-ship communication systems is a breakthrough that provides centralization of information and an easing of management tasks. In the following sections, we discuss the traditional control systems that are responsible for a variety of operations on a ship, and the trends to integrate most control systems for ships into one network.
Primary Control Systems on Ships
The major control systems on a ship can be divided into four primary systems based on the different operating principles used by the systems. The four categories are low-pressure air control systems, hydraulic systems, electrical control systems, and automatic control systems.
Low-pressure Air Control
Systems
Low-pressure air control systems are used to control pneumatic tools. Such tools are used for many purposes, such as driving small machines and instruments, the engine system, and electric power generators.
Hydraulic Systems
Hydraulic systems control large-scale machines, pump systems, and davits. In addition, hydraulics are often used to manage storage systems on a ship.
Electrical Control Systems
Electrical control systems control electrical
systems, communication equipment, and electrical
tools. The electric power generated by a ship
is used mostly for these systems, which require
a lot of energy to operate.
Automatic Control Systems
Automatic control systems play a role with
most systems operating on a ship. Such systems
are usually combined with small-scale motors and
gears to control mechanical equipment.
Challenges of Managing Traditional Control Systems
In modern shipbuilding, the hydraulic systems, electrical control systems, and automatic control systems play important roles in different facets of ship operation, whereas low-pressure air control systems have been gradually phased out. The existing primary control systems are distributed around the ship to control different operating functions, such as the electrical system, water cooling system, air-conditioner system, damage control system, fuel system, cargo loading system, propulsion system, auxiliary equipment, radar system, sonar system, radio system, guidance system, emergency system, warning system, and weapons system (for warships). Each control system is required to be connected with an independent HMI or SCADA for control and monitoring. Distributed systems on ships are inherently highly complex, involve different operating standards, and require a lot of manual labor to operate and maintain. Each system calls for people with varied technical knowledge for daily operation and monitoring, with a large crew spread around the ship in different cabins. The crew uses in-ship phones as the only communication medium between systems operators and the control center on the ship. In general, a larger ship require a bigger crew, and consequently the high cost of recruiting well-trained crews to manage the different systems on the ship is one of the biggest challenges for today's ship management. Is there any solution to reduce the workload and crew requirements while maintaining mission readiness and safety? The main problems of traditional in-ship operation and communication are that distributed system control and monitoring leads to a big crew size and complicated workload requirements. The only way to solve this kind of problem is to incorporate an integrated network that coordinates the transmission of automatic control and monitoring information from ship's main systems to the control center.
Industrial Ethernet Solution for in-Ship Communication
These days, automation control equipment and devices have taken the place of many conventional systems that used to be applied on the ship. An increasing number of automation control manufacturers, such as PLC and field I/O manufacturers, now produce products that come with a built-in Ethernet interface. In fact, Ethernet has become the solution of choice to network a ship's automation systems. The automation control systems work together with the Ethernet communication network to reduce the workload and crew size on the ship by automatically transmitting distributed operation and control information to the control center. Overall, Industrial Ethernet benefits automation on ships in six primary ways:
| • Centralized Control and Management |
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Since Ethernet is based on an open standard, all the automation devices that support Ethernet standards can be connected to the network, so that control information can be transmitted to the control center in real time for synchronous monitoring. |
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| • Lower Management Cost |
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Traditionally, large crews could be a nightmare for ship owner because of the sophisticated systems and specific HMI/SCADA requirements. Control networks integrated by Ethernet not only reduce the workload, but also the number of crew members required to maintain the ship's distributed systems. For example, a 100,000-ton merchant ship can be operated with a crew of only 20 well-trained sailors, reducing hiring costs dramatically. |
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| • Easy to Maintain and Manage |
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Ethernet is a standard communications protocol that has been in use for about 30 years. With such a well developed technical foundation, it is easier and more convenient to manage information over the Ethernet with readily available tools, and experts in Ethernet technology are relatively easy to find. |
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| • Affordable Bandwidth |
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With all control systems integrated into a single network, the amount of complex data transmitted over the network can quickly become a "data monster" that requires higher bandwidth for successful transmission. Ethernet provides an affordable network bandwidth for use on ships. Currently, industrial Ethernet switches used to form the network come mainly with 10/100M ports, providing a much higher bandwidth than traditional serial communication networks. Some Ethernet switches can even support a backbone network up to 1 Gigabit for higher bandwidth demands. |
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| • High Flexibility |
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A variety of Ethernet switches have different port density and intelligent management functions, and some Ethernet switches come equipped with fiber optic ports to meet long haul transmission requirements on ships. A ship's system integrator can select the most appropriate switches according to their network requirements. Some switches also provide built-in management functions, such as redundancy, VLAN, QoS, IGMP snooping, and Port trunking to provide added value for network planning and management. |
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| • Expandable and Upgrade-able |
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Automation control manufacturers now provide control devices with an Ethernet interface, and more and more applications, such as video surveillance and RFID also support Ethernet, making Ethernet a top choice for communication systems that incorporate data from a number of different sources.
An integrated industrial automation network based on Ethernet can be an efficient and cost-effective solution for the management of large merchant ships, ocean liners, cargo vessels, tankers, and shipyards. Compared to merchant ships, warships are much more sophisticated and require integrating control and monitoring. Ethernet is already becoming a trend for integrating in-ship communication for a variety of large ships. |
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