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In oceanography the major objective, of course, 
is the greater understanding of the environment to 
enhance our capabilities in all forms of warfare. 
One example, and perhaps the one which most 
directly benefits from oceanography, is Anti-Sub- 
marine Warfare. Here, the sophistication and 
effectiveness of major improvements which have 
been made in weapons systems have been due not 
only to increased knowledge of the environ- 
ment, but largely to advances in other areas of 
science and technology. Signal processing is a 
good example. The effective utilization of these 
systems, however, requires a broader and more 
detailed understanding of the environment, its 
properties and processes. Such understanding 
will, in addition, lead to new concepts of opera- 
tions as well as new systems. It is for this main 
purpose that the Navy has undertaken a major 
oceanographic effort. 
Let us briefly examine some of the properties 
of the environment and manner in which they 
influence naval planning. Sound is the only form 
of energy which propagates to any distance in the 
sea so that this work centers on audihility prob- 
lems. A submarine’s audibility -to underwater 
listening gear in various operating areas during 
the different seasons of the year depends not 
only on sound transmission conditions, which are 
affected by the temperature, salinity structure, 
depth, and reflectivity characteristics of the bot- 
tom, but also by the screening effect of noise cre- 
ated by breaking waves at the surface, the engines 
of other marine traffic, and the creaks, groans, 
snappings, and whistles emitted by a variety of sea 
creatures. 
This is as true, of course, for enemy submarines 
as it is for our own. Everything we learn about 
how to hide our Polaris boats from enemy detec- 
tion contributes, therefore, to our knowledge of 
how best to go about finding his. 
When it is realized that sound not only travels 
five times as fast in water as it does in air but for a 
given source intensity produces pressures which 
are some 60 times as great, it is not surprising 
that such ordinary sounds as the singing of rotat- 
ing propellers and the swish of bubbles and eddies 
in the passage of a hull through the sea, all of 
which seem of comparatively short range to a lis- 
tener on land, suddenly assume tremendous sig- 
nificance when the sound source is in water and 
the listener has “underwater ears.” 
NATIONAL OCEANOGRAPHIC PROGRAM—1965 
Furthermore, the ocean is layered to an extent 
seldom realized in the atmosphere and the trans- 
mission of sound by “channels” in a fashion 
somewhat like the production of mirages in the 
air is acommon occurrence in the sea. Submarines 
tens and even hundreds of miles away can some- 
times be heard by listening equipment exploiting 
these sound conduits. Some layers, the most per- 
sistent, are very deep and can be utilized only by 
hydrophone arrays lowered down the sloping 
edges of islands or on the edges of the continental 
shelves to catch the deep sound transmission. 
Certain frequencies in the sound spectrum are 
more favored than others under some conditions. 
In general, the high frequencies are more easily 
attenuated and it is the very low frequencies which 
travel farthest. Since ‘the size of the underwater 
ear must match the size of the wavelength being 
listened to, there is a complex design problem 
involved in fitting equipment to specific opera- 
tional missions. That is, there is an important dif- 
ference in systems optimally suited to an acoustic 
environment where treble notes with wavelengths 
of a few inches dominate as compared to systems 
best suited to one where the bass notes which have 
wavelengths of many feet are most important. 
The essential point is that increasing the range 
of detection of hostile submarines and the accuracy 
of target classification depends critically on ocea- 
nographic research. The Navy’s Oceanographic 
Office, the Bureau of Ships, and the Office of 
Naval Research conduct or support research on 
various aspects of this problem, including the pre- 
diction of the key features of the “anti-submarine 
warfare environment” and how to exploit it opera- 
tionally. 
Almost every other Navy mission depends on 
similarly complex and critical relations between 
operations, technology, and environment. One 
reason aircraft carriers must be so large, for 
example, is to be sufficiently stable in a seaway that 
high-performance aircraft need not be exposed 
to dangerously large excursions of the flight deck 
as they approach the stern for a landing. Even 
high-speed destroyers and frigates have to slow 
down if waves are too high, and faster transits to 
distant operating areas can often be made by 
taking “the long way around” and avoiding the 
worst sea conditions enroute. Where timely arrival 
on the scene is important, such routing could 
spell the difference between failure and success. 
Weapons technology is also pressing against 
