ÐÓ°ÉÔ­´´

SEA WARFARE will never be the same again. Instead of titanic mid-ocean
struggles between the West and the Soviet Union, Western military tacticians
believe that future battles will be fought along coastlines against developing
countries or small regional powers. As most naval equipment and weaponry
is designed to work at sea, navies are developing a new generation of weapons
and equipment that can cope with coastal conditions. Foremost in the race
to adapt is the US.

The reason is simple. ‘Eighty-five per cent of all world cities and
strategic objectives are within 200 miles of the ocean,’ says John Dalton,
the US government’s Navy Secretary who is in charge of the force. To maintain
a worldwide military presence, the US believes its navy must be able to
operate effectively in the waters off these coasts. Consequently, it is
rushing to re-equip its navy for shallow water warfare.

Naval strategy now focuses on ‘the littoral’. The military definition
is deliberately vague but includes coastal waters from the surface to the
seafloor, the seafloor itself, the air above the water, and even territory
inland from the shore and the air above that. And in some cases the littoral
battlefield could stretch for many kilometres over land as well as out to
sea.

The littoral is a much more complicated environment for military manoeuvres
than those which navies tackled during the Cold War, says Eric Hartwig,
an associate director at the US Naval Research Laboratory in Washington.
One of the major problems is finding and tracking enemy submarines – a task
that is difficult enough even in deep water. In shallow water, the seabed
offers many hiding places in the form of reefs, crevices and even sunken
ships. One option is to use sonar: the vessel hunting the submarine broadcasts
sound waves and listens for the echo when they bounce off its prey. But
in shallow water, sound waves bounce repeatedly between the surface and
the seabed. Also, the speed of sound in water varies with its temperature,
and currents of warm and cool water in the littoral are more complex than
those in mid-ocean. If sounds from a submarine reach a sensor at different
times because of multiple reflections or because they travel at different
speeds, they may not be recognised as components of the same signal.

Another technique, known as passive acoustic detection, is to listen
for the noise made by pumps, propellers and engines that combine to produce
a ‘sound signature’ characteristic of a type of submarine. During the Cold
War US submariners claimed that they routinely shadowed Soviet submarines
in deep water and were even able to identify individual vessels using this
method. But the shallows are far more noisy than the open sea. Civilian
shipping and oil drilling, which tend to be concentrated in coastal zones,
the flow of rivers into the sea and even seismic activity beneath the seabed
all generate a complex cacophony which makes it almost impossible for human
operators to distinguish important sounds. So the US Navy is enlisting the
help of computers. Researchers at the Naval Research Laboratory are developing
computer software which will sift through the noise looking for patterns
that correspond to the signature of subs.

Even if researchers achieve their goal, they may not know exactly what
to listen for. Before the collapse of the USSR, the US Navy compiled a database
of signatures of Soviet subs, but it has not gathered similar information
on the wide variety of submarines from other nations, including vessels
built by North Korea, Algeria, Romania, China and Libya. It estimates that
potentially unfriendly powers operate more than 200 submarines and Thomas
Ryan, a rear admiral and director of the US Navy’s Submarine Warfare Division,
says that it cannot identify about 10 per cent of these. Building a new
database will take time. One way of gathering this information is with hidden
underwater microphones which record the sounds made by vessels as they leave
their base. Because they begin their journeys on the surface, submarines
can be identified by satellite and reconnaissance aircraft and matched to
their signatures.

Acoustic methods are not the only way of finding submerged objects.
The Navy has developed a helicopter-mounted laser known as the Magic Lantern,
for example, which illuminates objects underwater and measures the reflections.
The system uses blue-green laser light because it travels further underwater
than other colours. But the equipment must be used at low altitude and low-flying
aircraft can cover only a small area of water compared with high-flying
reconnaissance planes. Nevertheless, in 1997 the Navy plans to buy 15 of
the Magic Lantern systems.

Radar might also be useful. Regional powers are likely to operate diesel
subs which have a limited air supply and so must surface at regular intervals.
When they do, radar can spot periscopes and air ducts poking above the
surface.

The big advantage of non-acoustic sensors is that they are not affected
by acoustic noise. But they have other disadvantages. Radar provides very
limited information about the identity of a sub, for example, compared
to acoustic methods. And sediment and phytoplankton suspended in the water
absorb light which ruins the view for optical systems. The Navy hopes to
develop a computer model of sediment and phytoplankton movement in the sea.
Although this is theoretically possible, the Navy’s model will have to be
powerful enough to simulate conditions in real time so that sailors will
know exactly when conditions underwater are good enough for hunting submarines
with lasers.

The problems navies now face in the littoral were not a factor in the
past. The Cold War strategy centred on dominating the shipping lanes between
the US and its European allies. The Navy anticipated that such battles would
occur in the middle of the ocean where it is difficult to hide. But the
littoral is different. The difficulties are illustrated by the Swedish
Navy’s repeated failure in the past to track Soviet subs in its waters.
‘They found only one and that had beached itself on the rocks,’ says Ronald
O’Rourke, a defence analyst at the Congressional Research Service in Washington
DC. He is not optimistic that the US Navy will ever be able to do much better.

Deadly and buried

Hidden submarines are not the only peril; mines can be just as deadly.
In one form or another, mines have been part of warfare for more than 200
years. But during the Cold War the US Navy virtually ignored the threat
because the chances of ships running into minefields in the vast ocean expanses
were small.

In the littoral, however, mines can be an effective weapon. During the
Gulf War two US warships were damaged by Iraqi mines in a single 24-hour
period. The USS Tripoli, a helicopter carrier, was holed but was able to
remain in action. However, the USS Princeton, a guided missile cruiser and
one of the US Navy’s most sophisticated ships, suffered $20 million worth
of damage and had to be towed back to base.

Mines can be detonated in a variety of ways which makes it difficult
to protect ships against them. Some mines sense the change in the surrounding
magnetic field caused by the enormous metallic bulk of a passing ship. Others
are triggered by the change in water pressure when a vessel passes overhead.
Even the sound of propellers can be used to set them off. Once triggered
some mines wait for a second ship to pass, on the assumption that the first
is a small minesweeper leading a larger convoy. Modern mines might possess
two or three of these capabilities. The mine that damaged the Princeton
lay on the seabed but others are tethered a certain distance above the
ocean floor or float free. To counter amphibious assaults, some are buried
into the sand near a beach.

Because they are small and usually lie beneath the surface, mines are
difficult to spot. Once a mine has been found, the most common way of dealing
with it is simply to set it off. Minesweepers trigger mines by towing a
loudspeaker through the water broadcasting the sound of a ship’s propeller
or by producing a large magnetic field. They also tow devices which cut
anchored mines free. When they float to the surface they can be detonated
by gun fire.

Mines are cheap. The Italian MR-80 bottom mine, which damaged the Princeton,
cost an estimated $30 000 to $35 000 – very little in military terms.
At this price they can be sown in large numbers, making a minesweeper’s
task long and arduous. One mistake can cause enormous damage and in the
past navies have often avoided suspected minefields altogether. That is
changing. By 1997, the US Navy plans to have a minesweeping command ship
and 26 sweepers costing between $118 million and $125 million apiece.
A dozen of those will be the fibreglass hulled ships known as Osprey-class
minesweepers, which do not disrupt the Earth’s magnetic field and can better
absorb an underwater blast.

But the American Navy has an even more ambitious plan. It is developing
a remotely operated submersible called the Mine Neutralisation System (MNS)
which is designed to find mines using sonar and relay TV images of them
to a support ship. Once a mine is located on the seafloor, the MNS drops
an explosive charge to trigger it. The submersible can also cut tethered
mines loose. By 1996, the Navy hopes to have 26 of these machines in service
at a cost of about $2.5 million apiece. Eventually, each minesweeper will
be equipped with a pair of MNS vehicles.

Explosive solution

On top of this, the Navy is spending about $172 million this year on
developing ways to find, deactivate and remove mines or avoid them altogether.
The Buried Mine Detection System, for example, will find them by using sonar
and a magnetometer which can spot the telltale disruptions in the Earth’s
magnetic field that the metal parts of mines create.

Removing mines from the littoral clears the way for an amphibious assault.
But conventional minehunters and submersibles cannot operate in the very
shallow water a few metres from the beach. In future, minesweeping hovercraft
will look for mines in these areas and direct troop-carrying vehicles around
them. The Navy hopes to clear the beach of mines by launching a ‘net’ of
explosives to trigger them.

The Navy is also beginning research that could lead to a new generation
of mines. In particular, officials would like a powerful multipurpose sea
mine that could be sown from aircraft and submarines as well as from surface
ships. Such mines would not need to be sown as densely as less powerful
models and would be designed to work at a wide variety of depths.

In future, mines may not be used in war zones alone. In a report on
navies’ vulnerability to mines, Harry Jenkins, director of expeditionary
warfare for the Navy and a major general in the Marine Corps, argues that
they could also be used ‘to thwart seaborne drug movements’ or to blockade
an enemy nation during a crisis.

The US Navy’s highest priority, however, is to develop ways to watch
enemy minelayers at work using submarines. This saves lengthy and potentially
damaging searches for minefields later. The Navy’s next generation submarine,
the $1.3 billion New Attack Submarine, is being designed for just this
purpose. It will be equipped with a mine hunting and neutralising device
called the Submarine Offboard Mine Search System. Launched through torpedo
tubes, the SOMSS would be controlled via several kilometres of fibre optic
cable allowing the main sub to remain undetected. Since any mine neutralisation
is done underwater, the enemy might never know its fields had been cleared.
Lurking in enemy waters, the New Attack Submarine could monitor shipping
before a planned invasion and could even land troops in secret before the
main attack.

Yet another task for military chiefs waging littoral warfare is to distinguish
quickly and accurately between friends and foes, a job that is all the more
important given the amount of civilian activity in the littoral. The US
has already discovered how difficult this is. In 1988, the USS Vincennes
shot down an Iranian passenger airliner over the Persian Gulf after the
destroyer’s crew mistook it for an Iranian warplane on the attack. The mistake
cost the lives of 290 civilians.

The problem occurred because the ship’s computerised air defence system,
called Aegis, reassigned the number it used to identify the Airbus to another
plane landing at an airport nearby without the captain’s knowledge. As the
second plane descended, the captain believed the Airbus was diving towards
his ship when, in fact, it was continuing at high altitude. Acting on this
information he ordered the destruction of the Airbus. O’Rourke says the
Aegis system is designed to cope with a mid-ocean attack by Soviet warplanes,
not a complex littoral battle in which distinctions must be made between
enemies and bystanders. He believes it must be improved to cope with such
warfare.

More recently, two US F-15 warplanes mistakenly shot down two US military
helicopters over northern Iraq in April, killing the 26 people aboard. The
reason for the error has not been established but the helicopters were
fitted with transponders that should have identified the helicopter as friendly.

The Pentagon says such incidents could have been avoided had it been
possible to identify the aircraft without relying on transponders. But
identifying a distant plane with great accuracy is not easy. One option
is to look at radar signals reflected from the fan blades in the other
aircraft’s engines. Each engine produces a different signal which a computer
can recognise and use to identify the plane.

Hidden protection

Until now, missiles launched from ships could follow and hit aircraft
but were unable to destroy incoming missiles. Building such a system is
not simple. Any ship-based missile system must be built to cope with the
corrosive effects of salt and the continual battering from the elements.
US Navy chiefs believe they can upgrade the Navy’s air defence missile
known as the Standard with a homing device developed by scientists working
on the Star Wars project in the early 1990s. The device replaces the warhead
normally carried by the Standard. It uses a highly sensitive infrared sensor
to pick up the heat trail of an incoming missile, and gas thrusters that
manoeuvre the Standard into its path. The sheer force of the collision destroys
both projectiles.

Defending ships would be only part of this system’s role. Stationed
close to the shore, such a missile could provide a protective antimissile
umbrella over a port, for example. Two ships equipped with upgraded Standards,
stationed in the Sea of Japan, could protect both South Korea and Japan
from North Korean missiles, says Philip Coady, director of the Navy’s surface
warfare division. And this protection could be provided without the fuss
of airlifting land-based units, such as the Patriot missile system, onto
foreign territory. North Korea might not even realise the protection was
there.

A modified Aegis could also protect an invading army from missile attack.
To help coordinate invading troops, the Navy wants to use unmanned aerial
vehicles (UAVs) launched from aircraft carriers which fly over the coastline
relaying enemy positions to the invading forces without risking the lives
of pilots. Once identified, the Navy can bombard these positions. But for
the moment a destroyer’s 5-inch guns have a limited range of about 13 miles.
A US Navy project to develop rocket-assisted projectiles may increase this
range to about 50 miles.

The Standard and the Aegis computer systems that control it are already
in use on five $800 million Arleigh Burke type destroyers launched since
1991. Navy officials argue that fitting the Star Wars device and providing
an electronic communications link between ships to coordinate the system,
will be relatively cheap, costing perhaps another $4 billion. But given
the recent cuts in military funding, Navy chiefs concede that such missile-defence
ships may have to wait.

For the moment, military chiefs are enthusiastically discussing littoral
missions as their equipment is adapted. These missions are more complex
than ever. ‘We are in the midst of an era of revolutionary technological
and geopolitical change,’ says Dalton. Already, military crises in the former
Yugoslavia and Ukraine show that the collapse of the Soviet Union is making
naval warfare more complicated, not less.