put on a safer foundation. The importance of the recent model work aimed at the 

 determination of bending moments and shearing force cannot be overestimated from 

 a point of view of practice. 



More basic and revolutionary can be the contribution of ship theory when a 

 large increase in ship speed is postulated. It is difficult to predict how strong a pres- 

 sure will be exerted in this direction by navies, shipping and shipbuilding practice. It 

 is, however, the obligation of science to appraise the possibilities and to prepare the 

 necessary solutions. 



16. The future of the development of hydrofoil vessels depends upon their 

 seaworthiness. Much more work must be invested in this field. Beside its immediate 

 significance it may have a considerable stimulating effect on advanced design of dis- 

 placement ships especially with respect to fin action. 



Ill Future Research 

 1. Facilities 



When describing a new large wind tunnel Betz denounced some twenty years 

 ago the trend to increase the size of facilities as uninspiring, and asked (without suc- 

 cess) for suggestions to stop this race. The development did not bring any relief in 

 aerodynamics, and, generally speaking, in ship research. 



After Havelock had disclosed that wave effects are the principal source of 

 damping in heave and pitch the use of small models for seaway research, notable 

 after the war, appeared justified. Minimum size models become especially desirable 

 when arbitrary courses in a seaway are investigated. Unfortunately, the situation is 

 less simple with self-propelled models which obviously present definite advantages. 



It is the author's contention that the establishment of large wave tanks is 

 justified provided the number (and stature!) of scientists connected with such a tank 

 work corresponds to the size of these facilities. If only a limited amount of funds is 

 available it is preferable to invest the money in researchers rather than in facilities. 



Beside large tanks, however, there will be an increasing need for facilities 

 intended to tackle special problems. 



The scientific foundation of methods used in "General Wave Tank Work" will 

 require a large number of special investigations. 



From the synopsis presented it seems at first easy to make proposals for the 

 future research by analytical methods, model experiments and full scale investigations. 

 Certainly it is a more pleasant task to speculate about things which should be done by 

 others than to do the work oneself; nonetheless the task presents difficulties. 



Roughly speaking, research in our field is proceeding following two lines: 



1. Development of ship mechanics. 



2. "Rigorous" solution of the boundary problem. 



The first way leads to a program of research. Problems presented in such a 

 way can be solved experimentally as well as analytically, whereby more rigorous 

 methods become more and more popular. 



We enumerate now a list of concrete tasks which are being tackled or should 

 be attacked; they embrace surface and submerged displacement vessels as well as 

 hydrodynamic craft. 



1. The establishment of general equations of motion of displacement ships in 

 a seaway. 



1.1. Complete equations. 



1.2. Linearized equations. 



As mentioned above this work constitutes a necessary prerequisite for systematic 

 work in our field yielding a comprehensive program of research. Simplified problems 

 which can be treated with success can be derived from this general task. 



2. Determination of forces experienced by an oscillating body moving in calm 

 water as substitute for the actual seaway problem, one and several degress of freedom. 



93 



