Lewis 



Finally, progress in applying results of seakeeping research requires much 

 more complete information on criteria of seagoing performance for different 

 types of ships. What values of acceleration are acceptable? How much water 

 can be shipped over the bow before speed must be reduced? How severe can 

 slamming be in terms of hull stress or local pressures before remedial action 

 must be taken? For being able to predict ship performance at sea is not enough. 

 We must be able to determine at what speeds and in what seas any particular 

 design is satisfactory or unsatisfactory. 



In conclusion, it is felt that valuable tools are now available to determine 

 significant trends of ship behavior in realistic sea conditions. It is urged that 

 in planning research in the field of seakeeping vigorous efforts be applied to the 

 systematic accumulation of basic data on the sea, model series results in waves, 

 and criteria of seagoing performance. Then our future improved theories and 

 computation techniques can be verified and applied rather than set to gather dust 

 on library shelves. 



ACKNOWLEDGMENTS 



The assistance of various members of the Webb staff is gratefully acknowl- 

 edged, particularly Professor Robert B. Zubaly and Mr. Roger H. Compton. Mr. 

 Larry Liddle, Student Assistant, prepared the figures. The courtesy of Ameri- 

 can Bureau of Shipping and Panel H-7, SNAME, in permitting reproduction of 

 research results is appreciated. 



REFERENCES 



1. Korvin-Kroukovsky, B. V., "Investigation of Ship Motions in Regular Waves," 

 TRANSACTIONS OF SNAME, Vol. 63, 1955. 



2. St. Denis, M. and Pierson, W. J., "On the Motions of Ships in Confused 

 Seas," TRANSACTIONS OF SNAME, Vol. 61, 1953. 



3. Vossers, G., Swaan, W. A., and Rijken, J., "Experiments with Series 60 

 Models in Waves," TRANSACTIONS OF SNAME, Vol. 68, 1960. 



4. Vossers, G., Swaan, W. A., and Rijken, J., "Vertical and Lateral Bending 

 Moment Measurements on Series 60 Models," INTERNATIONAL SHIP- 

 BUILDING PROGRESS, Vol. 8, No. 83, July, 1961. 



5. Moskowitz, L., Pierson, W. J., and Mehr, E., "Wave Spectra Estimated 

 from Wave Records Obtained by the O. W. S. WEATHER EXPLORER and the 

 O. W. S. WEATHER REPORTER ," New York University Research Division 

 Report, Part I, November, 1962, and Part II, March, 1963. 



6. Lewis, E. V. and Bennet, Rutger, "Lecture Notes on Ship Motions in Irreg- 

 ular Seas," Webb Report, October, 1963. 



208 



