• Journal of Advanced Research in Ocean Engineering
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• v.3 no.3
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• pp.102-111
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• 2017

This study considered the effects on the seabed of a harbor and quay wall from ship maneuvers in relation to the thruster jet flow and initial velocity. This study also included the engine capacity, RPM, and diameter and pitch of a ship's thruster for a required speed. The impact of a scour hole on the environment of a quay wall was investigated. Based on these results, a risk based analysis was conducted to evaluate different strategies and their consequences. There has been an increase in the loads on the bottom of a harbor during ship maneuvering. This increase is caused by the propeller loads of mooring and unmooring vessels. This indicates a greater number of arrivals and departures of vessels with larger drafts, larger thruster diameters, and larger available thruster power capacities. Another important cause could be an increase in the maneuverability of vessels from the use of bow thrusters. The increasing loads, which cause a higher jet flow above the bottom, can lead to undesirable scour holes.

• Journal of Navigation and Port Research
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• v.46 no.2
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• pp.82-91
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• 2022

When a ship moves in the proximity of the lateral bank, bank suction forces are generated due to bank effects. Thus, hydrodynamic forces can significantly impact the ship's maneuverability and navigation safety. In this study, model tests were performed to investigate the hydrodynamic forces exerted on a ship, especially suction forces caused by bank effects, using captive model and bank effect tests. A low-speed condition was selected in this study, because of the perilous situation as the ship moves close to the bank. The accuracy of the hydrodynamic forces exerted on the hull was verified, by comparing the results of the static drift test with the results obtained from other institutes at design speed. The straight simulation caused by bank effects was then implemented using estimated hydrodynamic coefficients.

• Journal of the Korean Society of Marine Environment & Safety
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• v.19 no.2
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• pp.193-199
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• 2013

Course keeping ability of ships under wave are analyzed with wave. The simulation with three degrees of freedom is developed and 3-D source distribution method is applied to get wave force for the simulation. The simulation is conducted with the restriction of maximum rudder angle and time delay of control and regular wave and irregular wave are considered as the source of external forces. Simulations with ships which have different maneuverability with tuned hydrodynamic coefficients are developed to assess the variation of the course keeping ability depending on the ship's maneuvering characteristics. The course Keeping ability is evaluated by comparison of distance while the ships are simulated with autopilot control.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.29 no.1
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• pp.35-40
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• 2005

Maneuverability of ships has been receiving a great deal of attention both concerning navigation safety and the prediction of ship maneuvering characteristics, to improve it. high-lift device could be applied to design of rudder at design stage. Now, we carried out the flow visualization and investigation of flow field around a flap rudder(trailing-edge flap). Flow visualization results of flap defection shown as the flow around a NACA0020 Flap Rudder will be conducted in a Circulating Water Channel. The purpose of this investigation will be to investigate the development of the separation region on the flap rudder with the variation of the angle of attack and determine the angle of attack at which the flow separates and reattaches.

• Journal of the Society of Naval Architects of Korea
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• v.36 no.2
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• pp.72-76
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• 1999

To predict the maneuverabiliy of a ship, it is most reliable to carry out the model tests for the ship. But, at the initial design stage of ships, scene other methods of predicting the overall maneuverabiliy of ships with confined data, like principal dimensions and propeller and rudder characteristics, are required. In this paper, the authors suggested new formulas for the linear derivatives of the sway force and yaw moment, based on the captive model test carried out by the Japanese researchers. These formulas can account the effects of stern frame line shape and stern profile, when assessing the maneuverability of ships. The usefulness of the formulas are discussed by comparing the simulations with the model tests.

• Journal of Navigation and Port Research
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• v.33 no.9
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• pp.609-614
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• 2009

The traffic of tug/barges which are carrying construction materials, large plants for harbor development, or offshore structures has recently increased in the coast of Korea. The west and south coast of Korea are always congested due to a lot of islands and traffic concentration. Specially tug/barges have higher probability of marine accidents due to their bad maneuverability than others. Considering the operational circumstance and maneuverability, this study was to develop a wide-area monitoring and control system for tug/barges in the coastal area of Korea. The system was made in the form of three program modules i.e. navigation analysis program module, monitoring and control program module, database module. And seven functions were programmed to monitor and control the tug/barges efficiently. These are ship information search, tug/barge information and track management, designated area and safe navigation zone management, fairway management, accident data management, warning of danger, safety information management.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.29 no.1
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• pp.77-83
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• 2005

In collision avoidance problem of a ship, collision risk model is usually set up using the interview results fron experts who sit on a simulator by varying parameters, in which DCPA and TCPA are commonly used. This method, however, has the weakness in that not only it is expensive but also it shows different results depending on the inerviewees and other navigational parameters. In this study, a fuzzy inference system is designed based on own ship's maneuverability verified fron simulation instead of interviewing navigators. The time and distance corresponding to the collision risk value on which avoidance maneuver should be started are set to the minimum marginal time at which own ship starts maneuvering and the minimum marginal distance suggested by marine traffic rules respectively. This system can be recorfigured as a nonlinearity-strengthened one by increasing the number of fuzzy membership functions.

• Journal of the Korean Institute of Navigation
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• v.16 no.3
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• pp.19-31
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• 1992

The Navigational System is the Fundamental System of Port Transportation System and comprises 3 Subsystems, say, the Waterway System, the Shiphandling System and the Support System. The Waterway System of Navigational System is the important and fundamental System for Traffic Safety inside the Port like a Car Road System on Land. This study aims to make a Guideline for the Optimal Waterway System of Port Development and Safety. The Conclusion of this Paper are drawn : 1) The complicated Shiphandling Operations should be avoided for the period of Physical night Time for eliminating the Human Errors. 2) For the Maneuverability and all-weather Combined Piloting the Inside Turn Point Buoy and Begin the-turn Buoy should be mounted with Racon(T) and Radar Reflector for foggy and bad weathers. 3) The Seabuoy located in the Approaching Area for Pilot Station and making Landfall should be mounted with Racon(G) and Morese A Light for giving a Hint of Pilot Station to the Captain on the Bridge, and these Equipments of Racon and Light should be operated normally and effectively even in a Heavy and stormy weathers. 4) A Basic Practical Expression, 1/2 L sin D, for calculating the Extra Width of Cutoff Turn Regions was derived Originally from the Viewpoint of Turn Maneuvers and Maneuverability of the Ship.

• Journal of the Society of Naval Architects of Korea
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• v.53 no.1
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• pp.76-83
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• 2016

The various model tests are carried out to estimate and verify a ship performance in the design stage. But in view of the cost, the model test should be applied to every project vessel is very inefficient. Therefore, other methods of predicting the maneuverability with confined data are required at the initial design stage. The purpose of this study is to estimate the hydrodynamic derivatives by using the multiple regression analysis and PMM test data. The characteristics of the stern shape which has an important effect on the maneuverability are applied to the regression analysis in this study. The correlation analysis is performed to select the proper hull form coefficients and stern shape factors used as the variables in the regression analysis. The comparative analysis of estimate results and model test results is conducted on two ships to investigate the effectiveness of the maneuvering hydrodynamic derivatives estimation applied the stern shape. Through the present study, it is verified that the estimation using the stern shape factors as the variables are valid when the stern shape factors are located in the center of the database.

• Journal of Korean Port Research
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• v.5 no.2
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• pp.39-63
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• 1991

A PC-based ship maneuvering simulator was developed which was configured in a high performance IBM PC compatible i486 and i286 computer with a TMS 340 graphic signal processor and 10 MBPS Ethernet Cards. A real-time ship maneuvering simulation program was developed which includes computer generated imagery (CGI) for bird's eye view type and perspective view type. The simulator H/W was designed and manufactured and S/W for interface of various navigation equipments was made Especially, programs for output, analysis, and assessment of simulations results were developed. Communications between PC's are made by using Ethernet bus type LAN system. Simulations could be performed under various environments (current, wind, wave etc.) using data base of harbors and ships. This system can be used for various purposes such as crew's training, harbor and waterway design, and assessment of ship maneuverability in harbor.