II. LONG-RANGE OBJECTIVES 



The Long-Range Objectives of the HS-2-1 Program is frequently referred to as the Ra- 

 tional Approach to the design of vibration-free ships. The principal aspects of the program 

 include: 



1. The development of the relationships between hydrodynamic forces and structural re- 

 sponse. This work naturally includes the hydrodynamic studies carried out under the H-8 

 Panel. 



2. The development of conversion techniques for design purposes. This aspect of the 

 program includes the prediction of the exciting forces and the structural response of the ship 

 to these forces. 



3. The publication of design guides, through SNAME. In a manner similar to that employ- 

 ed in the TMB Program, it is planned to develop an analytical procedure which would permit 

 the review of the vibration characteristics of a proposed design while still in the preliminary 

 design stage. 



Significant areas which still require development include: 



1. Virtual Mass 



2. Damping 



3. Propeller Forces (Hydrodynamic and Mechanical) 



4. Vibration Reference Levels (Based on the "Norm" Program) 



The virtual mass and damping studies will naturally be restricted to those individual 

 cases in which vibration generator tests and detailed analyses can be carried out. The bulk 

 of this work will have to be borne by the Navy Department and the Maritime Administration, 

 as is presently being done in the studies of NS SAVANNAH and in the past on SS GOPHER 

 MARINER. 



As a supplement, however, damping data may be obtained from the anchor drop test re- 

 quested in conjunction with the tests called for by the "Code for Shipboard Vibration Measure- 

 ments." The oscillograph records will be turned over to the HS-2-1 Task Group for processing. 



At the present time a cooperative effort, sponsored by the HS-2-1 Task Group and the 

 H-8 Panel, will be carried out in 1964 on a commercial tanker, through the cooperation of the 

 Humble Oil Co. This study is aimed at the determination of the forces which enter the hull 

 through the water and through the shaft bearings. The cost of instrumentation and testing 

 will be borne largely by the Navy but hopefully, this limited program will start a program of 

 cooperation between The Society of Naval Architects and Marine Engineers and the Maritime 

 Industry in the U. S. 



The vibration reference levels which would be used in assessing the adequacy of a 

 proposed design will be based on the "Norm" Program which has been fully described in the 

 previous section. This program is well underway. What remains at this writing, however, is 

 the development of a method of treatment of the data collected to compute the "Norms." Ef- 

 forts are underway at this time. However, suggestions from the committee members would be 

 gratefully received. 20 



