• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.51 no.1
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• pp.71-78
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• 2015

In order to deduce an objective evaluation method of motion seasickness incidence (MSI) by ship motions during underway in irregular waves and to present the fundamental data of passenger comfort on the yacht and the passenger ship according to the result, the MSI of the trainees by the questionnaires was analysed and compared with the rate of variation of salivary ${\alpha}$-amylase activity (VSAA) on the training ship "A-ra ho" of Jeju national university. Relationship between rate of variation (x) by salivary ${\alpha}$-amylase activity and motion seasickness incidence (y) was described by the equation, MSI(%) = 0.6073 x + 12.189 including the correlation coefficient ($R^2=0.9853$). The result obtained through the rate of variation of salivary ${\alpha}$-amylase activity which was the quantitative evaluation method for ship motions causing seasickness was most affected by z-vertical acceleration and occurred within the frequency range 0.1 to 0.3Hz centered on 0.2Hz, and the simulation result based on this finding showed the motion seasickness rate at approximately 4% lower than the rate obtained through the survey.

• Journal of Power System Engineering
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• v.18 no.4
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• pp.112-116
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• 2014

Roll and pitching motions of a vessel can seriously degrade the performance of mechanical systems and the effectiveness of personnel. Many studies on roll stabilization and trimming control system design have focused on stabilizing the vessel through the use of fins, tanks, rudders and flaps. However the ultimate objective of such approaches must be to improve boarding sensitivity. This paper presents an anti-seasickness bed that consists of a rotator and bearing system that does not make use of electric power. The advantages of this system are its simple construction, usefulness, and safe operation. In this study, the rotation angles of the upper plate of a bed according to change weight of the rotator have been calculated to determine the stability. As a result, it can be concluded that proposed stabilizing bed can be of practical use in the field.

• Journal of Power System Engineering
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• v.10 no.1
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• pp.96-101
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• 2006

In ship operation the consequence of roll and pitchingmotion can seriously degrade the performance of mechanical and personnel effectiveness. So many studies for the roll stabilization and trimming control system design have been performed and good results have been achieved where the stabilizing fins, tanks, rudders and flaps are used. However the ultimate objective of such approach should be focused on improving the boarding sensitivity. But there may exist many unsolved problems, for examples, ship control performance degradation and increasing of system complexity. So, the achieved control performance could not give us enough comfortable boarding sensitivity where the residual rolling and pitching motion are main drawbacks. To get rid of these disadvantages, the main hull control systems design approach has been considered using semiactive absorber. In this system, dampers, spring, dynamic dampers and control system with sensors are incorporated. In our system considered in this study, just two motors and control system with sensors are used for the bed. And the control system can be installed on each bed. So, we can control every bed on the specified control objective respectively. Above all, the good advantages of this system are the facts followed from simple idea and usefulness. Of course the structural modifications are needed. Considering disturbances, we design control system and verify the usefulness of developed system from the experimental study.

• Journal of the Korean Society of Marine Environment & Safety
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• v.20 no.1
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• pp.42-48
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• 2014

Seasickness not only makes persons on board vessels to vomit but also causes vertigo, headache, sleepiness, fatigue, lethargy and other discomforts. This ailment leads to disturbance of biorhythm and decline of perception which would eventually cause reduction of situational awareness among ship's operators that leads to marine accident. This study is about the sensitivity of people onboard ships to seasickness and focused on deck or navigation officer cadets(apprentice officers) and engine officer cadets(apprentice engineers) who have no previous experiences on board. It is conducted by using motion sensor that can measure ship's X, Y, Z-axis motions and through the questionnaire survey, and evaluated each students' degree of seasickness symptoms. Through this study, in same circumstance, we have known that there are different degrees of motion sickness for wheel house worker and engine room worker, It also confirmed that seasickness have high relationship with degree of hull motion and also, with cycle of hull motion. In addition, we have confirmed that Z-axis hull movement has higher relationship with seasickness than X-axis and Y-axis hull movements. This study aims to initiate additional researches about X-axis and Y-axis of the ship's motion which it expects to greatly enhance safety of wheelhouse and engine room personnel, ship's livability and comfortable sailing.

• Journal of Fisheries and Marine Sciences Education
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• v.28 no.1
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• pp.14-21
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• 2016

Research on ship motion and seasickness is recognized as the important research area to ensure the pleasant operative environment in addition to the research of operation safety of ship. In this paper, the motion performance in waves for the training ship Kaya of Pukyong National University is obtained by using the computer program based on Strip Method. To guarantee the pleasant seafaring in ocean, the vertical acceleration of ship motion is calculated according to the habitation division location in the ship. The results of calculation by changes of location of habitation division are compared with the guideline of MSI(Motion Sickness Incidence). The degree of motion sickness is shown and discussed through the comparison between calculated vertical acceleration spectrum and MSI guideline. To improve the safety of ship in motion and the pleasant seafaring in waves, the downtrend of seasickness ratio is needed by the decrease on vertical acceleration of the ship. Through the results in this paper, the relocation of both bridge and accommodation toward the aftship reduced the vertical acceleration and MSI.

• Journal of Navigation and Port Research
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• v.32 no.5
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• pp.333-339
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• 2008

When a vessel is underway in a heavy weather, passengers and crew suffer from seasickness caused by ship motions such as pitch, heave or roll, or all combined Sickness induces drowsiness, dizziness, headache, stomachache etc, in extreme conditions, they are met with a serious trouble which is physiologically unrecoverable. It results in weakening of spiritual activities or making errors from decrease of motivation, dropping off skills, poor recognition and poor judgement. In this paper, it was examined the international standards concerning the occurrence of sickness and the execution of works, also evaluated the boarding comfort by conducting several times of questionnaire on cadets boarding on the training ship HANBADA As a result, it was confirmed that the main factor of occurring the sickness was the vertical acceleration and the level was more than 0.2g. Also, it was presented the way how to reduce the sickness by changing the speed and/or course in relation to the encounter period.

• Journal of Fisheries and Marine Sciences Education
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• v.26 no.4
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• pp.686-694
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• 2014

Research on ship motion and seasickness is recognized as the important research area to ensure the pleasant operative environment in addition to the research of operation safety of ship. In this paper, The motion performance in waves for the training ship Kaya of Pukyong National University is obtained by using the computer program based on Strip method. To guarantee the pleasant seafaring in ocean, the vertical acceleration of ship motion is calculated according to the hull form modification. The results of calculation by changes of hull form are compared with the guideline of MSI(Motion Sickness Incidence). The degree of motion sickness is shown and discussed through the comparison between calculated vertical acceleration spectrum and MSI guideline.