Ship automation
Due to the ship automation introduced at the beginning of 1980 and the watch-free ship engine operation made possible by it, the number of crew members on the merchant ships has almost halved compared to the 1960s, despite considerable increases in the carrying capacity of the ships. Although automatic systems in shore facilities were already known and used, significantly higher requirements were placed on automation systems on ships due to the increased demands caused by the rough ship operation and the fast passage through different climate zones.
Automation
Ship automation is understood to mean the use of a higher-level technical device for monitoring, controlling , regulating , alerting and documenting various ship-related processes. Today's ships are equipped with it in all technical areas. On the bridge (bridge automation) in the machine room (main machine automation, electrical generation automation) and also with demanding loads, such as B. refrigerated cargo in the holds (cargo refrigeration systems automation) as well as in refrigerated container ships (power cable transmission, PCT), to name just the most important. An automation today consists of software and hardware , in which sensors, controls and regulators are integrated. In addition, suitable input and output options, displays, alarms and logs are required for documentation.
Sensors
The sensors are used to measure the physical parameters of the processes to be controlled and to inform the controller of the respective actual values. Often it is temperatures , pressures, forces, speeds and torques, current, voltage, power and frequency in the electrical systems as well as volume flows through lines, filling levels of tanks, but also the speed of the ship, humidity, salt content in the production of drinking water from sea water, oil content in ppm -Area with oil separators, air particles with smoke detectors and, as shown below, the oxygen and carbon dioxide content in the room air. All of these variables are measured using different methods and converted directly in the sensor or downstream converters into easily transferable and comparable electrical variables.
Controls and regulations
The open system is characteristic of the controls, since the change in the variable to be controlled caused by the control has no effect on the control. Controls are often influenced by time. A simple example is the elevator in a passenger ship. A passenger presses the call button, which then lights up and triggers a current pulse. The current impulse controls the drive motor of the elevator via a relay and contactor , which starts moving.
In contrast to control, there is a closed system with regulation, ie the change in the variable to be regulated (e.g. temperature) by switching on a tank heater for heavy fuel has a negative effect on the rising temperature. The temperature as a controlled variable is continuously recorded by the temperature sensor and compared with the setpoint . If the set temperature setpoint is reached, the temperature controller switches the tank heating off again via the actuating variable switch . The temperature, which then drops again, causes the heating to be switched on again through constant measurement and comparison when the temperature falls below the lower temperature limit.
Development of ship automation
The first propulsion systems for merchant ships such as the “Polarlicht” and the “Polarstern” ( Blohm + Voss shipyard ) were equipped with automation systems in Germany around 1965, and valuable experience was gained with these systems over the next ten years. At that time there were only a few shipping companies that commissioned these innovative ships for guard-free machine operation. These automation systems were also new territory for the classifications . The number of measuring points for monitoring the systems, the standards and definitions of the control terms as well as the redundancies for important systems were determined jointly by the manufacturers, the shipyards and the shipping companies in coordination with the classifications.
They were ships for German shipowners that were powered both with diesel engines (“Polarlicht”, “Polarstern”, Blohm + Voss shipyard) and with steam turbines. For American accounts, the North Sea Works in Emden also built fast merchant ships ( Euroliner type for Seatrain Lines ) that were equipped with automated gas turbine drives. Although automatic systems in shore systems were known, significantly higher requirements were made for automation systems on ships due to the increased requirements of ship operation and the fast passage through different climate zones.
Initially, the required electronic controls and regulations were built up from discrete components (transistors, diodes, resistors and capacitors) and combined on plug-in cards (1st generation). Integrated circuits were introduced in the late 1960s (2nd generation), which increased space requirements and, more importantly, increased reliability due to reduced solder joints . The use of highly integrated circuits and memories led to the 3rd generation, small computers (microprocessors) that could be used on plug-in cards for various tasks. Thus, depending on the programming, different tasks could be performed with the same standardized modules and plug-in cards. This took the step from hard-wired control to freely programmable control, which was also used in ship technology from the late 1970s. Now the setpoints, limit values, queries, processes and decisions were stored in programs that were called "software" in contrast to the sensors and actuators ("hardware").
Ship of the future
Experience with these systems led to improved automation systems, which, with advancing technology, especially in the area of computers , microcomputers and microprocessors, led from the central to the autonomous decentralized automation systems. These technologies and results were compiled in the important research project called the “ ship of the future ” by various companies, taking into account the experience of the technical on-board personnel, and were extensively tested on the Norasia Samantha . The redundancy of important systems then led to a considerably increased fault tolerance. In the period that followed, improvements were made particularly in the areas of speed, troubleshooting and optimizations in energy consumption and safety. Systems for diagnosis and trend monitoring in ship propulsion systems and auxiliary systems were developed and tested. They prevailed in the following years and with today's communication systems for worldwide data transmission and communication, in addition to the shipping company inspections, engine manufacturers and other suppliers can also be informed directly or indirectly. With all these measures and advances, the ship's crew could be halved from 1965 to 2000, despite the enormous growth in ship sizes and increased propulsion power. The guard duty was limited to the bridge. In the machine area, the security service is only carried out in the area.
Effects on the crew structure
Since the machine operation is largely carried out on a guard- free basis, the engineers and engineering assistants are exempt from the need for a round-the-clock guard duty. This allows you to take care of the necessary service work as well as any maintenance, overhaul and repair work in the "day shift". Instead of the sailors (deck and bridge service) and greasers (machine service), more universally trained ship mechanics were used both in the engine room and on deck for maintenance, overhaul and conservation work. This integrated crew can be more effective on board for labor-intensive work, such as B. Use mooring and casting off maneuvers. Stations at the bow and stern must be manned at the same time.
literature
- Ship of the future. Results of the research and development project. Development of a new ship operating technology. Eckardt & Messtorff, Hamburg 1986, ISBN 3-7702-0513-8 .
- D. Aschpurwis, P. Hellwich: Automatic remote bridge control using microprocessors. In: Hansa. Issue 1, 1978, Schiffahrts-Verlag »Hansa«
- K. von Thienen: Control and regulation with microcomputers in ship technology. In: Yearbook of the Shipbuilding Society . Volume 72, 1978.
- R. Damaschke: System standardization of automation systems on ships. In: Yearbook of the Shipbuilding Society. Volume 78, 1984.
- G. Ackermann: Measurement, control and regulation technology. In: Handbuch Schiffsbetriebstechnik. Seehafen Verlag, Hamburg 2006, pp. 661–702.
- V. Behrens, K.-H. Hochhaus, Y. Wild: Ship ventilation and air conditioning systems. In: Handbook of the shipyards. Volume 25, Schiffahrts-Verlag "Hansa".
- K.-H. High-rise: automation on ships. In: Hansa. Issue 1, 2012, Schiffahrts-Verlag »Hansa«.