• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.6B
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• pp.651-660
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• 2006

Although a harbor may be constructed with calmness in harbor in mind, which satisfies the design standard, it is frequently reported that the motion of moored ships disrupt the cargo handling. This is because of current design standard, which only deals with the wave height in the decision making process of cargo handling, and, now, a new kind of estimation method of operating ratio for calmness based on the motion of moored ship is in need. In this research, a computational method that analyses the harbor operation rate in harbor was put forward by considering the relation of allowable quantity of motion for cargo handling and the computation of the motion of moored ship at wharf by using moored ship motion analysis model. Here, a new estimetion method was applied at Onsan harbor, and it was compared with the current estimation method, and, then, the difference between the two methods was showed. The harbor operating ratio gained by a new method was dropped by 2~11% at ENE and NE directions when it was compared with the operating ratio based on the current design standard. However, when a harbor structure layout is to be designed, a harbor operating ratio test according to the wave height and a harbor operation rate test, which considers the motion of moored ship, are to be run side by side at a harbor designing process.

• Journal of the Korean Society of Marine Environment & Safety
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• v.26 no.5
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• pp.445-453
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• 2020

The use of tugboats for the safe berthing/unberthing of ships is the most crucial factor in the safe and efficient operation of the harbor. However, the adequate number and size of tugboats that should be held based on the characteristics of the port have not been investigated in detail, which causes disputes between involved parties. Therefore, the suitable number of tugboats and the ratio of the tugboat horsepower were determined in this study using simulation techniques, with focus on Ulsan Port. First, the ship and tugboat-operating models were designed for simulation application. Next, the input variables defined in the model design were standardized in an inputtable form using ARENA software. In addition, the arrival and division process of the ship was designed and simulated as an ARENA model. Finally, the simulation results for six scenarios showed that an effective tugboat operation could be achieved when 42 tugboats were held at Ulsan Port.