• Journal of the Society of Naval Architects of Korea
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• v.45 no.6
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• pp.710-718
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• 2008

This paper presents a simple and fast approach to plan the arrangement of supports and to do a ship docking analysis. The unpredicted structural damages often happen from a docking works as the size of ships are getting larger and larger. In docking a ship, excessive reaction forces from supports are primary causes of the structural damage. The grillage analysis method is employed to simply calculate only the reaction forces at supports. The grillage modeling strategies are proposed to improve the accuracy. In this paper, the results obtained by the proposed approach are compared with those of the current whole-ship FEA for typical types of ships. Comparison shows that the results from the present grillage approaches are reasonably in a good agreement with the 3-D full F.E one. Finally, an integrated program developed for the ship docking analysis is described.

• Bulletin of the Society of Naval Architects of Korea
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• v.17 no.2
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• pp.33-42
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• 1980

This paper compared the seakeeping quality of U, V type ships in infinite depth by using the finite element method. From the calculated results, it is found that heaving and pitching motions of V type are comparatively better than those of U type ship in the water of infinite depth and the reversed phenomenon occures in the water of finite depth. And the seakeeping quality of U type is better than V type ship in larger ranges than the nondimensional wave number 2.0.

• Journal of Fisheries and Marine Sciences Education
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• v.27 no.6
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• pp.1865-1871
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• 2015

Ship's trim is the one of the most important factor for safety at the sea. Turning circle test and Z-test were carried out to find the effect of ship's trim and draft changes. The results are as follows. 1. If the ship's draft and trim became large, turning circle would be wide. 2. If the ship's draft and trim became large, ship's drift angle would be small. Small drift angle made wide turning circle. 3. Trim by the head made slow ship's final speed when turning circle test. 4. By Z-test, the deeper draft and trim by the stern made small OSA. Small OSA means strong ship's stability. 5. Totally 2nd OSA is smaller than 1st OSA on Z-test. 6. There were small differences of 2nd OSA in trim by the stern, but there were large OSA in trim by the head. 7. The larger trim by the stern, the smaller OSW. The small OSW means better ship's stability and maneuverability.

• 한국기계연구소 소보
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• s.13
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• pp.123-141
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• 1984

The safety aspects of ship handing have become increasingly important recently, due to the changes in sea transportation. These are characterizes by larger units, increased traffic density on sea lane, sea transport of dangerous cargo, etc. In addition, as a economic aspect of ship handing, it has obtained an increased attention in connection with port development and consideration of allowable ship size for existing ports. One method for evaluation of maneuvering problems is simulation on a computer by means of a mathematical model of the ship maneuvering motion. The present report describes the elements of a mathematical model for ship maneuvering and gives some results of maneuvering predictions through the simulation.

• Journal of the Korea Society for Simulation
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• v.26 no.3
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• pp.47-54
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• 2017

This paper analyzed the motion characteristics of two ships according to the ship's dimension using Ship Handling Simulator. When the panamax container ship passes the smaller ship, peak point and patterns of interaction forces for the moored ship are noticeable. Accordingly, special attention should be paid to the movements of moored ship because surge force and yaw moment changes in the opposite direction before and after condition of ship's beam. However, when the container ship passes the larger moored ship in reverse, peak point stood out on the passing ship at the beginning of ship-to-ship interaction and attraction force on the passing ship occurred steadily during 1L(length overall of passing ship) interval at a point of beam. In addition, as the lateral distance between the hull of two ships decreases less than 2B(breadth of passing ship), interaction forces on the passing ship at the beginning are sharply increase.

• Journal of Power System Engineering
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• v.3 no.3
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• pp.97-103
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• 1999

As the noise of ship engine room is too loud, the engineer who works in a ship engine-room has the trouble of hearing. In this paper deals the investigation of the noise of ship engine room and cabins with the internationally allowable noise exposure level and noise exposure time. Recently, the problem of engine-room noise is more serious because of shipowner wants to make small number and larger size of cylinder. Therefore, engineers work in a ship engine-room for a long time have the trouble of hearing when they are exposed the high noise level. In this study, two kinds of vessels were used to investigate the noise of engine room, engine-control room, bridge, offices and cabins. As criteria of sound levels, A-weighted sound pressure level and octave band pressure level were used.

• Journal of the Korean Institute of Navigation
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• v.19 no.1
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• pp.1-8
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• 1995

The motion of a small boat in seas is affected in relatively higher degrees than the case of a larger ship by the specific characteristics of sea waves, i.e., the wave length and height. Ship's motion caused by sea waves is a matter of special importance to small fishing boats, because they carry out fishing job in rough seas frequently. This is an experimental study on the rolling and pitching motions of full scale ship. In the experiment, the ship's motions were measured for head, how, beam, quarter and following seas. The experiment were carried out on board the training ship Pusan 404(160 GT) in the adjacent waters off NAM HYENG JAE DO on Dec. 13th 1994. The sea condition during the measurements was that wave height 2.5m, no swell and the wind velocity of 12 m/sec. Some statistic considerations were given to the observed data by the series analysis methods and discussed in this paper.

• International Journal of Naval Architecture and Ocean Engineering
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• v.12 no.1
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• pp.856-867
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• 2020

This paper aims to provide the most useful method of determining an optimum LCB position and design direction of fore- and aft-body hull shape for a SLBV. It is known that the SLBV has a lower length-to-beam ratio, larger Cb and simpler stern shape designed for the installation of azimuth thrusters comparing to those of conventional LNG carriers. Due to these specific particulars of SLBV, the optimum LCB position was very different to that of conventional LNG carrier. And various approaches were applied to determine the optimum fore- and aft-body hull shape. The design direction for the optimum hull-form was evaluated as the minimization of the total resistance which includes the wave-making resistance and form-drag with numerical simulation.

• Journal of Navigation and Port Research
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• v.37 no.1
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• pp.63-69
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• 2013

Since most merchant vessels are mainly influenced by the added resistance in an actual sea, they could be navigated more efficiently if this added resistance could be precisely predicted and then effectively reduced. In this paper, we have computed the effective horsepower based on the resistance performance in still water and then calculated the added resistance in regular wave in order to estimate a ship's propulsion performance on a voyage. Firstly, we have performed experiments using a model of KCS in a circulating water channel to estimate the flow characteristics around a container ship and the ship's resistance in still water. Then we have calculated the motion response function in regular wave as well as the values for the increase in resistance, and evaluated the ship's motion performance in waves according to the calculated response function. It was found that the resistance in waves increased because the ship's motion response value became larger as the ship's speed increased in the case of head sea. The effect of the added resistance could be reduced by maneuvering the ship to the encounter angle of $120^{\circ}$ in areas of long wavelengths and to head sea in areas of short wavelengths.

• Bulletin of the Society of Naval Architects of Korea
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• v.12 no.1
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• pp.47-58
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• 1975

The effect of the bow shape on the ship motion response among longitudinal regular waves, is investigated employing the strip theory. The two dimensional hydrodynamic forces such as added mass and damping are calculated by the integral equation method for arbitrary sections. Nine ship models are selected for investigation. They are U, UV and V bow ship forms of different block coefficient of 0.6, 0.7 and 0.8 with constant after body. The heave amplitude of the V bow ship is smaller than that of the U bow ship in the whole range of wave length except extremely short wave as were stated by the earlier investigators. This results holds also in the case of bow vertical motions such as vertical relative displacement, velocity and acceralation. As to the pitch amplitudes, the V bow ship gives smaller value in long waves but larger value in short waves. However, heave and pitch phase angles are practically not influenced by the form of the fore body sections. In the bow motions, a little difference in phase angle is appeared in the vicinity of the wave which has same ship length. With respect to the wave exiting force and moment unfovourable effects could be expected in V bow ships. And these tendency hold also in the wave bending moment.