24 WAVE RESISTANCE THEORY AND APPLICATION 
This inadequate survey of wave-resistance 
theory and its applications may be concluded by 
indicating briefly some directions in which further 
work would be specially useful. Even with the 
theory as it stands at present, much could be done 
to extend its range of application: for instance, 
by a systematic study of methods of approxima- 
mation and by the computation of necessary 
tables of functions, so that numerical calculations 
could be carried out more readily. But the two 
main problems, broadly speaking, are those of 
the ship of finite beam and of the effects of vis- 
cosity. It may well be that in both cases it may 
only prove possible to advance by successive 
stages of approximation to a solution: but the 
former problem, leaving viscosity out of account, 
is essentially a mathematical one for which a new 
approach is much to be desired. On the other 
hand, our knowledge of boundary-layer condi- 
tions is insufficient and the latter problem is pre- 
eminently one for combined theoretical and ex- 
perimental investigation. Indeed the whole sub- 
ject calls for a close association between mathe- 
matical and experimental work, especially if we 
keep in view its practical application to ship 
problems. 
Note: 
sources: 
Figs. 2 and 3: T. H. Havelock, Proceedings 
of the Royal Society, (A), Volume 201, page 297 
(1950). 
Fig. 4: T. H. Havelock, Quarterly Journal of 
Mechanics and Applied Mathematics, Volume 2, 
page 419 (1949). 
Figs. 6 and 7: W. C. S. Wigley and‘J. K. 
Lunde, 7vansactions of the Institution of Naval 
Architects, Volume 90, page 92 (1948). 
Fig. 8: W.C.S. Wigley, Bulletin, L’ Associa- 
tion Technique Maritime et Aéronautique, Vol- 
ume, 48, page 533 (1949). 
Fig. 9: R. S. Guilloton, Transactions of the 
Institution of Naval Architects, Volume 90, page 
48 (1949). 
Fig. 10: T. H. Havelock, Transactions of the 
North East Coast Institution of Engineers and 
Shipbuilders, Volume 60, page 47 (1943). 
Fig. 11: J. K. Lunde, Transactions of the 
Institution of Naval Architects, Volume 91, page 
182 (1949). 
Figs. 12 and 13: T. H. Havelock, Transactions 
of the Institution of Naval Architects, Volume 
90, page 259 (1948). 
The illustrations are from the following 
574 
