• Journal of the Society of Naval Architects of Korea
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• v.35 no.4
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• pp.87-97
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• 1998

One of good ways to make a ship perform well in rough seas is to reduce its waterplane area and accordingly is subject to a reduced wave exciting forties. However, a great reduction of the waterplane area may create a penalty in speed performance due to the increased ratio of the wetted area to the displacement volume. This paper suggests a new catamaran hull form which compromises the speed and seakeeping quality by increasing the waterplane area somehow compared with that of the conventional SWATH ship. A 350 passenger carrying SWATH ship with a cruising speed of 30 knots in sea state of 4 has been developed and its performance was validated by the model tests. The design concept resistance performance and seakeeping dualities of the design craft are presented together with its comparative performance comparison with other high speed crafts.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2010.04a
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• pp.413-414
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• 2010

For the purpose of technological analysis in the marine accidents and their prevention, IMO have made it obligatory to load VDR which is similar to the black box in aircraft. However, in case of body sinkage, capsizing, stranding and plunging which are almost 10% of marine accidents, it is difficult to take out the necessary data from the VDR in order to analyze the cause of them. Therefore, this paper apply the navigation dangerousness evaluation technology to the VDR to improve its performance. And we suggest that the vertical acceleration which is one of the factors for evaluating seakeeping performance of a ship is to be added in the existing VDR record data recommended by IMQ.

• Journal of the Korean Society of Marine Environment & Safety
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• v.4 no.2
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• pp.43-52
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• 1998

Generally, the navigational safety of a ship under various loading conditions is evaluated by a loading manual. However, the loading manual handles only statical factors such as weight and buoyancy of ship without including any wave conditions. Practically ship's safety is much concerned with the occurrences on the rough sea as propeller racing, rolling, deck wetness, vertical acceleration, lateral acceleration, slamming and so on. The purpose of this paper is to present a synthetic and practical evaluation method of navigational safety using the integrated seakeeping performance index(ISPI) under loading conditions of ship in seaways. The method is calculated by means of the ISPI by measuring only vertical acceleration. Judgement of dangerousness is carried out for four lading conditions : homogeneous full loaded, half loaded, heavy ballast loaded, and normal ballast loaded conditions. In developing the practical evaluation system of navigational safety, it is useful to solve the difficulties in measuring factors by sensors. And by applying the evaluation diagrames, navigators are able to avoid dangerousness by keeping away of the danger encountering angle of wave direction which the diagram shows.

• Proceedings of KOSOMES biannual meeting
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• 2017.11a
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• pp.16-16
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• 2017

• International Journal of Naval Architecture and Ocean Engineering
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• v.11 no.1
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• pp.1-10
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• 2019

Nowadays, the study on Floating Offshore Wind Turbines (FOWTs) is being performed globally. Dozens of numerical simulation tools have been developed for designing FOWTs and simulating their performances in combined wave and wind environments. On the other hand, model tests are still required to verify the results obtained from numerical simulation tools. To predict seakeeping performance of the OC3-Hywind platform, a OC3 spar model moored by a 3-leg catenary spread mooring system with a delta connection was built with a 1/128 scale ratio. The model tests were carried out for various sea states, including rotating rotor effect with wind in the Ocean Engineering Wide Tank, University Of Ulsan (UOU). The model test results are compared with the numerical simulations by UOU in-house code and FAST.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 1994.04a
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• pp.69-79
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• 1994

• International Journal of Naval Architecture and Ocean Engineering
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• v.8 no.5
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• pp.442-455
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• 2016

The resistance and seakeeping performance of a high-speed monohull vessel were investigated through a series of model tests in a towing tank. The hull had a slender wave-piercing bow, round bilge, and small deadrise angle on stern. Tests on the bare hull in calm water were first conducted and tests on spray rails followed. The spray rails were designed to control the flow direction and induce a hydrodynamic lift force on the hull bottom to reduce trim angle and increase rise of the hull. The maximum trim of the bare hull was $4.65^{\circ}$ at the designed speed, but the spray rails at optimum location reduced trim by $0.97^{\circ}$. The ship motion in head seas was examined after the calm water tests. Attaching the rails on the optimum location effectively reduced the pitch and heave motion responses. The vertical acceleration at the fore perpendicular reduced by 11.3%. The effective power in full scale was extrapolated from the model test results and it was revealed that the spray rails did not have any negative effects on the resistance performance of the hull, while they effectively stabilized the vessel in calm water and waves.

• Journal of Navigation and Port Research
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• v.32 no.10
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• pp.785-791
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• 2008

Because of increasement on the transportation of goods by ship and the operation of coastal ships for leisure, the interest of marine parts is growing up lately and then the safe navigation of ships are essential. In these circumstances, it is necessary that it should be examined the regulation of vessel traffic control in effect. Therefore, the wave height is analyzed on korean coast, and then the seakeeping performance with the wave height and the various hull types on operating on the coast is evaluated. These results will be helpful to the improvement of the regulation of vessel traffic control and safe navigation of coastal passenger ships.

• Journal of the Society of Naval Architects of Korea
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• v.36 no.4
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• pp.56-63
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• 1999

The seakeeping and resistance tests of a 47.7m class catamaran are conducted in a towing tank with the 1/21.5 scale model. The effect of the trim tab on the resistance is investigated with the trim tab angle variations and the resistance and trim angle of the catamaran with the trim tab are compared with those without the trim tab. The heave and pitch motions are measured at the three full scale speeds in sea state of 3.4 and 5 and the vertical accelerations at five points on the deck are also measured. The measured accelerations are compared with the criteria of ISO 2631/3 and it is shown that the seakeeping performance of the catamaran is good.

• Journal of the Korean Society of Marine Environment & Safety
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• v.27 no.7
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• pp.1031-1037
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• 2021

The frequency of marine accidents of vessels in Korea is steadily increasing and it is concentrated on small vessels with less than 10 tons of gross tonnage. Therefore, preventing capsizing accidents in small vessels is important to reduce the cost in terms of human and property damage due to such accidents. However, research on the seakeeping performance of small vessels has been insufficient, and there are no domestic and international regulations on seakeeping performance. Therefore, in this study, capsizing accidents caused by poor loading conditions were investigated by examining the adjudications of the small vessels in which the capsizing accidents occurred. Hydrostatic calculations and seakeeping performance analysis were performed for a representative vessel. A vessel generally performs a six-degree-of-freedom motion during operation. In this study, the response amplitude operator and response spectrum of a representative vessel were calculated to determine the roll motion. Moreover, a short-term statistical analysis of the vessel according to the loading conditions was performed for the wave stationary status for 3 h. From the results, it was estimated that, when the loading condition of a small vessel is poor, its roll motion increases, greatly reducing its stability.