A Survey of Ship Motion Stabilization 



The literature having to do with seasickness substantiates Commander Du- 

 Cane's statement as to the motion that is the principal cause. In addition to the 

 literature, personal experience leads to this conclusion. 



In regard to the specification of performance for fin stabilizers, it might 

 be possible to test the performance of the control system by pre-programming 

 the fins on one side of the ship to a certain time history of fin angle, and having 

 the control system and the fins on the other side stabilize. 



The authors' must apologize to Mr. Silverleaf for the apparent omission of 

 reference to Mr. Allan's work. This reference was inadvertently omitted in the 

 typing of the manuscript. An errata sheet was issued correcting this oversight 

 prior to the meeting but was not available in time for distribution. 



The authors' conclusions on the inventive approach to design of active anti- 

 roll fins was based on published literature. It is apparent from Mr. Silverleaf 's 

 remarks that a great deal of unpublished scientific work has been performed in 

 this area. The reference to additional model work in this design area was made 

 specifically with respect to activating ship model fins, that is to say model in- 

 vestigations of the entire control loop. To the authors' knowledge, little work 

 has been done in this area. 



The authors agree with Mr. Silverleaf's views on the design of passive 

 tanks. 



The authors are grateful for Mr. Numata's interesting observations and 

 supplemental comments. His proposal for inducing roll by a moveable weight 

 system is an interesting one and is quite parallel to the present scheme of forc- 

 ing roll with active fins and determining roll quenching ability. We would have 

 to determine the amount of weight required for such a system and the required 

 frequency responses of the control system before we could evaluate the practi- 

 cality of applying such a scheme to practice. 



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