Abstract. 1 Introduction

Transcription

1 Designing ports with computer simulation methods J. Hajduk Institute of Navigation and Deep-sea Fishing, Szczecin Maritime University, Wafy Chrobrego 1/2, Szczecin, Poland Abstract Designing a new sea port or new elements of the existing port infrastructure is a complex task solved in several stages. One of the problems to be solved is planning waterway and quay arrangements with stress put on the safety of ship traffic. As quality requirements in this respect have grown, traditional methods applied so far are gradually neglected driven away by methods of computer simulation that support a difficult and responsible process of port designing. 1 Introduction The general notion of navigational safety is superior when ship movement is involved. What it means is that a vessel at any time should comply with safety criteria and should not, by her movement, potentially pose threat to property, life or the natural environment. Maintaining desired standards of shipping safety or raising them depends directly on naval architects, ship crews, designers of waterways and hydrotechnical facilities. Indirectly, the growth of shipping safety depends on activities of other institutions aiming at the implementation and enforcement of rules of law [10]. A large number of navigational accidents causing constant threat of ecological disasters particularly in restricted areas in the vicinity of land, makes it necessary to continuously seek new legal and organizational solutions. One such solution supposed to bring about complex increase in shipping safety standards is the International Safety Management Code. The

2 140 Marine Technology and Transportation ISM Code in connection with quality assurance standards ISO 9000 is to be implemented soon and be obligatory for shipowners and all other maritime companies engaged in the process of ship building and operation [8]. The sea port is principally built to provide a mooring place for ships for the time of cargo handling operations. To fulfill one of her basic functions i.e. transfer of cargo or passengers, the vessel has to safely approach and moor at an allocated berth. Undoubtedly, the port and its approach waterways should ensure assumed standards of navigational safety for ships being served. The construction or modernization of a port is not a short-term investment. Therefore, one should make all efforts possible to give priority to shipping safety while designing maritime projects. Conventional methods used so far in the process of designing a port comprise only certain variables. These variables define the ship, environment and additional facilities. Taking into account all variables which eventually affect shipping safety is ensured by applying methods of computer ship motion simulation [5 ]. The support of computer simulation methods applied in designing ports in view of shipping safety is to be seen as a qualitative improvement of the designing process. The methods used allow to choose appropriate parameters of the object, environment and additional facilities with safety criteria being fully considered. Assuming adequate objective functions, one can optimize the variables defining the object, environment and additional facilities. An extra advantage from developing computer simulation models is that they can be used for training future operators in safe handling of ships within the designed water area. 2 Problems Port design or modernization based on investor's guidelines require solving a number of complex problems. One group of problems is concerned with ensuring safe navigation. There are two independent issues connected with navigational safety - that of an individual vessel and that of the whole stream of vessels travelling in an area under examination. As these problems are separable, our attention will hereafter focus on movements of and ensuring safety to an individual vessel. Research problems solved by computer simulation methods which support the process of designing a port and decision making during its construction may be formulated as follows: - do natural or present conditions of the approach waterway ensure safety for designed vessels?; if not, how should it be rebuilt to provide safe shipping at an assumed level of significance and minimum costs? - how should quays be best arranged to ensure safe approach and mooring of vessels? - what mooring and fender equipment should quays be fitted with^ - is strengthening of the bottom required^; if yes, what are the parameters^

3 Marine Technology and Transportation what are the permissible hydrometeorological conditions at an assumed level of shipping safety? - what supporting equipment, such as coast marking and buoyage has to be installed^ - are other facilities and systems necessary^; if yes, which ones and what parameters should they have*? - to what extent the ship movement should be assisted by tugs'? - what is the probability of a navigational accident and what are its effects on the environment? Computer simulation methods allow to obtain answers at assumed levels of significance to all the above questions. A solution to each of the problems supports designing and decision making in the course of port construction or modernization. The results may be presented in a variety of ways - an additional advantage of this method. They can be directly utilized by the investor, designer or other decision makers in the process of port designing 3 Solution - methods Computer simulation methods for port designing applications were worked out and implemented at the Institute of Sea Navigation, Szczecin Maritime University, in early 1980's. New methods are based on ship movement simulation programs. Currently these programs are ship handling simulators of complexity arying and have research and teaching applications. An additional requirement to enable this kind of research is the conformity of simulated models with reality. In each case the requirement is verified by conformity tests. Apart from a classical simulation method there is a simulation method of waterway parameters optimization. The idea behind the classical simulation method comes down to determining waterway parameters and other port infrastructure elements on the basis of statistically elaborated simulation research results. The method is accurate and takes into account both the dynamics of ship movement in restricted areas and hydrometeorological and navigational conditions. One shortcoming of the method is that it investigates and compares specific solutions defined at the stage of designing an experimental arrangement, which confines this method to comparisons of models defined by the designer [4,5]. The use of the simulation method for waterway parameters optimization allows to avoid shortcomings of the classical simulation method and to determine waterway parameters for the desired optimal conditions. The method can be used to optimize selected elements of the waterway as well as harbours and port basins. The optimization of parameters for multi-purpose terminals requires the application of multi-criterion optimization methods [5]. Thanks to the results of both methods one can also simulate spillages of petrochemicals and forecast the spreading range of such ecological disasters. This method uses the results of ship movement simulation in the scope of

4 142 Marine Technology and Transportation statistic probability of a navigational accident It provides the basis for modelling spillage dynamics and a possible selection of equipment and systems to fight against the created threat. Currently, the weakest point in port designing by computer simulation methods is the necessity of performing single simulations in real time. These simulations are conducted by persons authorized to steer the examined vessels in an area being designed. This substantially delays the availability of research results and excludes the variability of certain parameters of the object, environment or additional facilities. The future of computer simulation methods supporting the process of port designing clearly belongs to large computer design systems. In such systems all problems concerning shipping safety will make up a sub-system. Individual simulations creating series of data processed with mathematical statistics apparatus will be executed without the man's participation in simulation time. First heralds of such capabilities are off-line simulators. It should be stressed, however, that achieving this objective would not be possible without the research and methods applied today Another obstacle in using the research results is the lack of standards for data processing and presentation of results. Such standards will probably be indispensable when powerful automated systems are implemented. 4 Examples of application The Ferry Terminal at Swinoujscie [6 This has been Poland's largest marine investment in recent years. Its designing commenced in the second half of the 1980's. Today the new terminal is in operation. The research conducted by computer simulation methods has determined: - ferry berths arrangement (Fig. 1), - distribution of energy released in the quays which helped to select appropriate fenders, - distribution of propeller streams which provided basis for preparing proper river bed strengthening, - operating conditions of the Terminal, including ice conditions, - verification of the effect of berth no 6 on channel ferry traffic. The present model developed on the ship handling simulator enables complete training of pilots covering the area previously investigated. The simulation model and training program have been approved by the maritime administration [7].

5 Marine Technology and Transportation 143 Figure 1: Ferry quay arrangement at the Sea Ferry Terminal at Swinoujscie. The Pomeranian Fuel Terminal [1] The idea of building a new port basin at the base of the eastern breakwater at Swinoujscie emerged a few years ago. The simulation research allowed to determine the optimal shape of the basin and operating conditions of the terminal (Fig.2). In operating conditions, on the basis of resultant ship's swept paths, kinetic energy of ship impact on the quay while berthing and the distribution of propeller race (streams), the following have been unequivocally defined: - maximum sizes of ships entering the basin, - limitations due to other vessels currently at berth, - permissible hydrometeorological conditions [1,5]. The Fuel Huta Szczecin Terminal [2 Simulation research in this case aimed at defining the shape and location of the quay and turning basin of the Liquid Fuel Terminal situated in the region of Huta Szczecin (steel mill)(fig. 3). The investigation was concerned with shipping safety and the time of occupying the fairway. Three locations of the quay and turning basin were considered. For each version manoeuvring areas and operating conditions were determined. In addition, kinetic energies released on the quay at the first tanker's contact during her berthing were determined.

6 144 Marine Technology and Transportation Figure 2: Example of a movement trajectory of a tanker mooring in a basin of the Pomeranian Fuel Terminal. Figure 3: Movement trajectories of ten mooring simulations for the examined version no 2. Wind E 10 m/s, outgoing current 0.8 m/s.

7 Marine Technology and Transportation 145 ThePortofYstad [11] This is a typical example of port modernization enforced after a new bigger vessel is put in operation. The conducted simulation studies aimed at determining shipping safety of the new ferry in the area of the port of Ystad in various hydrometeorological conditions. The conducted investigation resulted in the shortening of the internal eastern breakwater which could be dangerous particularly at strong easterly and southeasterly winds. Moreover, operating conditions and mooring tactics were determined. The simulation model created on the ship handling simulator with optical visualization enables complete pilot training [7]. 5 Summary It is a fact that port designing processes are carried out with computer simulation methods to ensure the safety of shipping of all vessels entering the port. This means that traditional methods used so far will one day be forgotten. This novel approach has been due to at least a few reasons. Firstly, nations have begun to show more care for the environment and prevention of ecological disasters. This is expressed by developing increasingly more perfect rules and systems. They are to ensure continuous quality growth in all units co-operating with the ship from the commencement of her construction through her operation to delivering her to a demolition yard Secondly, this increased care has been somehow enhanced by the growth of the global fleet, ship size, as well as kinds and quantities of transported cargoes. The present situation in this respect sometimes creates a great threat to both people and the environment. Thirdly, a dynamic development of computer technology has enabled this type of simulations and methods to be used in practice. Also, which is economically important, simulation research is really inexpensive as compared to overall costs of a project. The foregoing premises are well-grounded. The research following the outlined direction and systems for performing automatic studies in simulation time are likely to develop rapidly Additionally, it will become necessary to be able to forecast quickly the probability of a navigational accident which may result in oil product spillage. The use of data for modelling spillage spreading range and possibilities of its control and elimination is very important at present. The Institute of Sea Navigation, Szczecin Maritime University, has got longtime experience in solving the described problems. The Institute has carried out numerous studies whose results have been implemented. Those studies were performed while designing the construction or modernization of most Polish ports. Recently studies have been started for several foreign ports. The Institute's equipment comprising simulators of a variety of arrangements and facilities allows to smoothly combine research applications and simulator training. Both students and seafarers undergo the training. Global trends show that such training will be obligatory in the future.

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