Observations on 1, 000m3 experimental LNG carrier at sea (1st report)

Observations on a ship at sea carried out to verify the usefulness of a method of analysis developed for the safety assessment of LNG carriers.The ship is 60 m in length between perpendiculars and has two LNG tanks (spherical and prismatic).In the observations, various kinds of dynamic responses such as ship motions, pressures on tanks, stresses on tanks and their supports etc. totaling about 60 channels are measured simultaneously. Besides them, wave is measured using a wave buoy with a pressure transducer.For the first report of the observations, this paper deals with measurments and analyses of wave data, and evaluation of wave spectra dfrom measured ship responses.The wave spectra evaluated from measured ship responses show better agreement with measured ones in head seas than in following seas. The errors of the evaluated wave heights and wave periods are within 20% mostly.