Seakeeping Constderattons tn a Total Destgn Methodology 
because wave added resistance is overpredicted. Since preliminary 
ship design decisions are primarily based on ship speed it is recom- 
mended that research effort bedirected to improving the prediction of 
wave added resistance. Research should also be directed in the area 
of propeller operation in the seaway in order to permit a better pre- 
diction of the propulsive efficiency as it also affects our ability to 
predict correctly the ship's speed. Finally the establishment of some 
ship motion criteria that are widely accepted is also recommended, 
As a continuation of the present work the author suggests 
computerization of the mathematical model described in the previous 
section in order to permit a complete investigation of the effect of 
seakeeping in preliminary ship design. In addition such a model will 
help to direct seakeeping research by examining the importance of 
its contribution in ship design. It is suggested that the computer pro- 
gram recommended for development employ a more detailed descrip- 
tion for the environment that the one used in the present analysis. It 
is also suggested to extend the model to include ballast condition con- 
siderations. Finally it is recommended to extend the coverage of the 
Seakeeping Tables of Reference 3 to include transom stern ships as 
these types of ships are extensively used in certain trades such as 
container transportation. 
III - SECOND AND THIRD ITERATION 
III. 1. Second Iteration 
The model recommended for the second iteration of the pro- 
posed design methodology for the prediction of the seakeeping qualitie 
of the different alternatives under investigation, is in the form of 
detailed seakeeping computer programs. The description of typical 
examples of such computer programs can be found in References 12, 
PS, .and.:16 ; 
n 
With the aid of these computer programs it is possible to 
analyse the effect of variations in the value of LCB-LCF separation, 
for example, for which average values were assumed in the first 
iteration, However unless the designer is willing to investigate large 
changes in these parameters the effect in the seakeeping qualities of 
the ship is not expected to be appreciable. 
Recently the Classification Societies, e.g. Lloyds, ABS, 
etc., started to recommend the use of seakeeping theory for the pre- 
diction of wave bending moment, For the application of such inform- 
ation in ship design the reader is directed to Reference 17 
1609 
