2 O. H. Oakley 
outline broadly the possible solutions to these problems and then develop the most promis- 
ing. The high performance ships discussed in this paper are products of all three methods. 
At the risk of oversimplifying, we can state that there are three principal reasons for 
exploring unusual hull forms as they apply to naval craft: to increase speed, to minimize or 
control motions, and to improve stealthiness. The first two are neither new nor peculiar to 
naval ships; men have been concerned with speed since the first log canoe and with motions 
since the first case of mal-de-mer. The third feature, stealthiness, was concocted to cover 
the functions of detection, localization, and classification of the enemy ships while remain- 
ing immune to detection, localization, and classification by the enemy. One of the major 
components of stealthiness is hydrodynamic quietness. This is a relatively new goal in 
ship design and is, of course, important where sonar performance is concerned. 
The three qualities of speed, motion, and quietness are obviously not independent, so 
that changing one changes the other two. It appears, sometimes, to be a fundamental law of 
nature that maximizing one quality usually results in degrading others. In a few cases this 
did not occur; these are exceptions and like all good exceptions only go to prove the rule. 
The phenomenon of surface waves is one of the more interesting properties of water. In 
a sense it is the subject of this symposium, since it is by the avoidance or minimization of 
wave effects that we hope to maximize speed and seakeeping performance. The energy 
absorbed in the creation of surface waves to a large degree limits the speed of surface 
ships. Likewise, it is the energy imparted to the ship by surface waves that limits other 
aspects of ship performance. Quite naturally, therefore, exploratory studies have been 
directed primarily at avoiding or minimizing these surface wave effects. 
Fig. 1 illustrates a range of concepts and relates them to the free surface. In the top 
group, two methods of avoiding the free surface are indicated, in the middle group the avoid- 
ance is less complete, while in the bottom group, two surface ship hull forms are shown 
which are designed to cancel wave effects rather than avoid them. 
! / 
ae 
GROUND 
EFFECT 
SUBMARINE 
NEAR SURFACE 
HYDROFOIL 
ee 
SHARK FORM ESCORT RESEARCH 
Fig. 1. Various high performance ships 
