Understanding and Prediction of Ship Motions 



Pierson, W. J., and P. Holmes (1965): The force on a pile due to irregular 



waves. (Submitted for publication to ASCE, Journal Waterways and Harbor 

 Division.) 



Reid, R. O. (1958): Correlation of water level variations with wave forces on 

 a vertical pile for non-periodic waves. Proc. Sixth Conf. on Coastal Engi- 

 neering, Gainesville, Florida (1957) . 



St. Denis, M., and W. J. Pierson (1953): On the motions of ships in confused 

 seas. Trans. Soc. of Naval Architects and Marine Engineers , v. 61, pp. 

 280-357. 



Tick, L. T. (1958): Certain probabilities associated with bow submergence and 

 ship slamming in irregular seas. JSR SNAME , v. 2, no. 1, June (p. 30). 



Tick, L. J. (1959): A nonlinear random model of gravity waves. J. Math, and 

 Mech., VIII, 643-652. 



Tick, L. J. (1963): Nonlinear probability models of ocean waves. Ocean Wave 

 Spectra, Prentice-Hall, Inc. 



SOME REMARKS ON THE STATISTICAL ESTIMATION 

 OF RESPONSE FUNCTIONS OF A SHIP 



Yasufumi Yamanouchi 



Ship Research Institute 



Tokyo, Japan 



INTRODUCTION 



In connection with the papers by Dr. Ogilvie, Prof. Lewis, Mr. Smith and Dr. 

 Cummins, Drs. Breslin, Savitsky and Tsakonas, I would like to make several 

 comments on three problems concerning the statistical estimation of the re- 

 sponse functions of ship. The first problem concerns the statistical considera- 

 tions that occur in estimating the frequency response function, which no paper 

 has referred to in this symposium and which still has several difficulties to be 

 solved. The second problem is about the impulse response of ship motion which 

 has been one of the main topics in this symposium. The third problem is about 

 the effect of nonlinearity on the response of motion, on the computation of spec- 

 trum, and on the estimation of the frequency response itself. 



221-249 O - 66 - 8 97 



