CONCLUSIONS 



Based on motion amplitude results obtained for five heterogeneous models in regular 

 head seas, it appears that, for fixed values of tuning factor and Froude number, the heave 

 parameter 2^/r associated with a particular hull form is related to the mean beam-draft 

 ratio given by C^B/C^H. The pitch parameter ^„,/0j^ is related to a hull parameter given by 

 L/Vl/3_ -jj^g above statements imply that empirical curves of motion parameters versus the 

 suggested hull parameters can be used to estimate, with good accuracy, the motion amplitudes 

 of any form whose characteristics are similar to those of the five models used in the present 

 investigation. 



The tuning factors used in this report were calculated using a formula proposed by 

 Kreitner for the natural heaving period. The use of other calculation methods, or the use of 

 experimental measurements, can be expected to produce differences in final results which are 

 perhaps minor for heave, but more serious for pitch. The Kreitner formula can perhaps be best 

 considered as a "natural period factor" rather than as a quantitative indication of the actual 

 pitching periods. 



REFERENCES 



1. Pournaras, U.A., "A Study of the Sea Behavior of a Mariner Class Ship Equipped with 

 Anti-Pitching Bow Fins," David Taylor Model Basin Report 1084 (in preparation). 



2. Bledsoe, M.D., "A Study of the Seaworthiness of the CA-68, CB-1, and DLG-9 Classes 

 of Ships." David Taylor Model Basin Report 1163 (in preparation). 



3. Todd, F.H., "Resistance Tests and Motion Cbservatioiis on Models in a Seaway," 

 David Taylor Model Basin Report 931 (Nov 1954). 



4. Szebehely, V.G. and Stefun, G.P., "Scale Effects on Ship Motions," Transactions, 

 American Towing Tank Conference, Vol. 1, David Taylor Model Basin Report 1099 (Sep 1957). 



5. Sibul, O.J., "The Effect of Method of Towing on Ship Model Motions," Transactions, 

 American Towing Tank Conference, Vol. 1, David Taylor Model Basin Report 1099 (Sep 1957). 



6. Vedeler, G., "Seagoing Qualities of Ships" Report to the Seventh International 

 Conference on Ship Hydrodynamics, Scandinavia (Aug 1954). 



7. Kreitner, H., "Heave, Pitch, and Resistance of Ships in a Seaway," Institution of Naval 

 Architecture, Transactions Vol. 81 (1939). 



8. Weinblum, G. and St. Denis, M., "On the Motions of Ships at Sea," Transactions, Society 

 of Naval Architects and Marine Engineers, Vol. 58 (1950). 



9. Korvin-Kroukovsky, B.V., and Jacobs, W.R., "Pitching and Heaving Motions of a Ship 

 in Regular Waves," Transactions, Society of Naval Architects and Marine Engineers, Vol. 65 

 (1957). 



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