• 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.23 no.2
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• pp.139-145
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• 2017

Recently, gusts, typhoon and tsunamis have been occurring more frequently around the world. In such an emergency situation, a moored vessel can be used to predict and analyze other vessel behavior, but if the mooring system is destroyed, marine casualties can occur. Therefore, it is necessary to determine quantitatively whether a vessel should be kept in the harbour or evacuate. In this study, moored ship safety in an exclusive wharf according to swell effects on motion and mooring load have been investigated using numerical simulations. The maximum tension exerted on mooring lines exceeded the Safety Working Load for intervals 12 and 15 seconds. The maximum bollard force also exceeded 35 tons (allowable force) in all evaluation cases. The surge motion criteria result for safe working conditions exceeded 3 meters more than the wave period 12 seconds with a wind speed of 25 knots. As a result, a risk rating matrix (risk category- very high risk, high risk and moderate risk) was developed with reference to major external forces such as wind force, wave height and wave periods to provide criteria for determining the control of capabilities of mooring systems to prevent accidents.