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REPORT DOCUMENTATION PAGE 



READ INSTRUCTIONS 

 BEFORE COMPLETING FORM 



1, REPORT NUMBER 



DTNSRDC-81/039 



2. GOVT ACCESSION NO 



3. RECIPIENT'S CATALOG NUMBER 



4. TITLE (and Subtitle) 



PREDICTION OF MOTIONS OF SWATH SHIPS IN 

 FOLLOWING SEAS 



5. TYPE OF REPORT & PERIOD COVERED 



Final 



6. PERFORMING ORG. REPORT NUMBER 



7. AUTHORfsJ 



Young S . Hong 



8. CONTRACT OR GRANT NUMBERfsJ 



PERFORMING ORGANIZATION NAME AND ADDRESS 



David W. Taylor Naval Ship Research 

 and Development Center 

 Bethesda, Maryland 20084 



10. PROGRAM ELEMENT. PROJECT. TASK 

 AREA a WORK UNIT NUMBERS 



Program Element 61153N 

 Task Area SR 0230101 

 Work Unit 1572-031 



11. CONTROLLING OFFICE NAME AND ADDRESS 



Naval Sea Systems Command 

 Washington, B.C. 20362 



12. REPORT DATE 



November 1981 



13. NUMBER OF PAGES 



87 



U. MONITORING AGENCY NAME a ADDRESSf// diflerent from Controlling Olllce) 



15. SECURITY CLASS, (ot this report) 



UNCLASSIFIED 



16. DISTRIBUTION ST ATEMEN T fo/ Ih/s Repor/J 



APPROVED FOR PUBLIC RELEASE: DISTRIBUTION UNLIMITED 



17. DISTRIBUTION STATEMENT (of the abstract entered In Block 20, It different from Report) 



18. SUPPLEMENTARY NOTES 



19. KEY WORDS (Continue 



side If necessary and identify by block number) 



Small-Waterplane-Area, Twin Hull (SWATH) Ship 

 Heave and Pitch Motions in Following Seas 

 Unified Slender-Body Theory 



20. ABSTRACT (Continu 



sary and identify by block i 



To predict motions of SWATH ships in following seas, especially when 

 the encounter frequency is small, unified slender-body theory has been 

 applied. The longitudinal interaction term is computed and added to the 

 results of the strip theory as a correction term. The added mass co- 

 efficients are computed to be much larger than those from strip theory, 



(Continued on reverse side) 



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