208
The Last Resource
have been suggested as the culprits, but no one is really sure about
what causes the deep scattering layers.
Navy scientists and engineers have to investigate every possible
source to interference with sonar. The Royal Navy, for example,
recently led a three—year investigation of the North Atlantic from
10°N to beyond the Arctic Circle. Called Operation Navado (North
Atlantic Vidal and Dalrymple Oceanography), the study included
observation of the deep scattering layers and investigation of the
ocean’s acoustic properties during 17 transits—in all, the survey
ships, among them H.M.S. Vidal and H.M.S. Dahymple, travelled
over 60,000 miles. Apart from widespread oceanic effects on sonar,
the noise created by the ship’s passage through the water, cavitation
noise and that coming from the engines and other machinery present
further possible sources of ‘contamination’. If left completely
unsuppressed, such ‘self noise’ would obscure any similar types of
noise radiated from an enemy submarine as well as give warning of
the pursuit ship’s approach.
By persistent attacks on the types of disturbance described above,
and by improving the detection gear itself, the average range of the
rst contact with an enemy submarine has increased probably ten—
fold or more since the Second World War; some potential aids to
sonar such as the existence of deep—sound channels in the ocean are
still being explored. These channels can conduct sound over con—
siderable distance with remarkably little loss: one of the longest
recorded paths of sound is 12,000 miles—from Bermuda to the
Indian Ocean—in experiments by scientists of the Lamont Geo—
logical Laboratory. Nevertheless, with all the ocean to play with,
the nuclear submarine commander still has the advantage over a
surface pursuer, and enjoys the security of a needle in a haystack.
‘Spin—o’‘om navy research
Commentators have grown accustomed to justifying at least part
of the expenditure on space research in terms of its scientic and
technical ‘spin—off’ which industry can protably exploit. Because
navy research is concerned with national defence, the benets of
similar benecial ‘spin—off’ tends to be forgotten even though in
quantity it is vastly superior to that from space. Recent research in
Admiralty laboratories, for example, has produced acoustic cladding
for reducing engine noise, new welding techniques, crack detection
equipment, new materials covering many applications from the
The Last Resource
have been suggested as the culprits, but no one is really sure about
what causes the deep scattering layers.
Navy scientists and engineers have to investigate every possible
source to interference with sonar. The Royal Navy, for example,
recently led a three—year investigation of the North Atlantic from
10°N to beyond the Arctic Circle. Called Operation Navado (North
Atlantic Vidal and Dalrymple Oceanography), the study included
observation of the deep scattering layers and investigation of the
ocean’s acoustic properties during 17 transits—in all, the survey
ships, among them H.M.S. Vidal and H.M.S. Dahymple, travelled
over 60,000 miles. Apart from widespread oceanic effects on sonar,
the noise created by the ship’s passage through the water, cavitation
noise and that coming from the engines and other machinery present
further possible sources of ‘contamination’. If left completely
unsuppressed, such ‘self noise’ would obscure any similar types of
noise radiated from an enemy submarine as well as give warning of
the pursuit ship’s approach.
By persistent attacks on the types of disturbance described above,
and by improving the detection gear itself, the average range of the
rst contact with an enemy submarine has increased probably ten—
fold or more since the Second World War; some potential aids to
sonar such as the existence of deep—sound channels in the ocean are
still being explored. These channels can conduct sound over con—
siderable distance with remarkably little loss: one of the longest
recorded paths of sound is 12,000 miles—from Bermuda to the
Indian Ocean—in experiments by scientists of the Lamont Geo—
logical Laboratory. Nevertheless, with all the ocean to play with,
the nuclear submarine commander still has the advantage over a
surface pursuer, and enjoys the security of a needle in a haystack.
‘Spin—o’‘om navy research
Commentators have grown accustomed to justifying at least part
of the expenditure on space research in terms of its scientic and
technical ‘spin—off’ which industry can protably exploit. Because
navy research is concerned with national defence, the benets of
similar benecial ‘spin—off’ tends to be forgotten even though in
quantity it is vastly superior to that from space. Recent research in
Admiralty laboratories, for example, has produced acoustic cladding
for reducing engine noise, new welding techniques, crack detection
equipment, new materials covering many applications from the