Force Pulse Testing of Ship Models 

 REFERENCES 



1. Cummins, W. E., "The Impulse Response Function and Ship Motions," Pre- 

 sented at Symposium on Ship Theory at Institut fiir Schiffbau der Universitat 

 Hamburg, 25-27 Jan. 1962, Schiffstechnik H. 47 B. 9 (June 1962). 



2. Fuchs, R. A. and MacCamy, R. C, "Linear Theory of Ship Motion in Irreg- 

 ular Waves," Institute of Engineering Research, Wave Research Laboratory 

 T.R. Series 61, Issue 2, University of California, Berkeley, California 

 (July 1953). 



3. Dalzell, J. F., "Cross-Spectral Analysis of Ship- Model Motions: A De- 

 stroyer Model in Irregular Long-Crested Head Seas," Davidson Laboratory, 

 Stevens Institute of Technology, Report 810 (Apr. 1962). 



4. Davis, M. C, Cdr. USN and Zarnick, E. E., "Testing Ship Models in Tran- 

 sient Waves," To be presented at the Fifth Symposium on Naval Hydrody- 

 namics, 10-12 Sept. 1964. 



5. Gerritsma, J., "Shipmotions in Longitudinal Waves," International Shipbuild- 

 ing Progress, Vol. 7 (1960). 



6. Hamming, R. W., "Numerical Methods for Scientists and Engineers," 

 McGraw-Hill, New York (1962). 



DISCUSSION OF FOUR PAPERS 



Leo Joseph Tick 



New York University 

 University Heights, Bronx, New York 



Since the papers by Smith and Cummins; Breslin, Savitsky and Tsakonas; 

 and Davis and Zarnick, concern themselves with testing, I will first combine my 

 comments to these papers.* These papers and the oral discussion which fol- 

 lowed devoted some time to the pros and cons of various methods for determin- 

 ing the defining properties of systems (mostly linear). Unfortunately, the lack 

 of a careful description of the logic of test procedures has served to add consid- 

 erable confusion. With a hope (?) of providing some clarification, I start with 

 brief discussions of "test functions." The test situation consists, as I see it, of 

 some system, device, etc., whose input-output characteristics one wishes to 

 determine. A test procedure is to be used to make the determination as distinct 

 from an analytical one. 



To make the discussion simpler, suppose we restrict ourselves to linear 

 systems. In this case the system is usually characterized by the transfer 



*pp. 439, 461, 507. 



457 



