The U.S. Navy
has adapted surveillance balloons (aerostats) to operate from the rear
deck of a high-speed transport vessel. This increases the ability to
detect small drug smuggling boats from 8 kilometers to 80 kilometers and
provides the ability to spot the smugglers in all weather, day or
night. This is a big deal for naval reformers advocating the return of
untethered blimps. After over half a century of effort, blimps (helium
filled lighter-than-air aircraft, tethered or not) have returned to
favor on the battlefield. The last time blimps were widely used was
World War II, when hundreds roamed coastal waters looking for enemy
warships (mainly German submarines), and thousands of tethered ones
served to prevent low altitude bombing attacks. The U.S. continued to
use blimps for maritime patrol until the early 1960s, and advocates have
been trying to get blimps back into action
ever since. Now, combat commanders who have used can't get enough
tethered blimps. The key difference here is the tether, which allows the
“blimps” to stay in the air for weeks at a time because they don’t run
out of fuel and the “crew” is on the ground. It’s the same for aerostats
at sea, where sudden changes in weather have destroyed many blimps,
often with no survivors.
The high-speed ship that has been turned into an “aerostat
carrier” is the USS Swift (HSV 2), a twin hulled catamaran. This vessel
is 103 meters (320 feet) long and displaces 1,900 tons. It can carry up
to 800 tons of cargo and has airline style seating for 300 troops, although up to 600 can be carried. The cargo
can include vehicles of up to 70 tons each, including M-1 tanks.
Vehicles are driven on and off. There is a trade-off between tonnage
carried, and speed and range. The twin hull design is also slowed down quite a bit in rough seas. This is not the kind of
ship you can use much in the north Atlantic or Pacific. But in the
Caribbean or off the west coast of Central America the Swift can stay
out for a long time and, barring nasty weather, keep the aerostat in
action 24/7.
The U.S. Army has used over a hundred aerostats in Iraq,
Afghanistan and elsewhere. Originally designed to operate with vidcams,
in 2010 the army added the AN/ZPY-1 Starlite lightweight radar. The
Starlite radar weighs 29.5 kg (65 pounds), occupies 34 cc (1.2 cubic
feet), uses 750 watts of power and costs about $2.3 million each. The
Starlite was originally designed for use in the army's 1.5 ton MQ-1C Sky
Warrior UAV. Starlite can deliver photo quality black and white radar
images of what is down there, in any weather. The army has developed
software that enables the Starlite images to be transmitted to video
terminals and automatically appear on electronic versions of standard
maps. Starlite is used in combination with vidcams and heat sensors
(infrared or thermal) making it possible to see anything on the water
within 80 kilometers of the aerostat equipped ship no matter the
weather.
The army aerostats usually float at about 320 meters (a
thousand feet) up, tethered by a cable that provides power and
communications to the radar and day/night vidcams up there. The navy
uses a 640 meter (2,000 foot) cable because the aerostat tends to trail
behind the slow moving ship. During land operations the aerostats could
stay up for 30 days at a time, but if the enemy was shooting at them
some of them came down every few days to get patched up.
The USS Swift has a helicopter pad and space for two UH-60 or
CH-46 class choppers but when carrying an aerostat that is where the
aerostat sits. The basic crew of the Swift is only 20, but there are
crew quarters for 51 and the galley can feed up to 150. Additional
personnel would be onboard to operate the aerostat sensors round the
clock.
The important aspect of the HAV is speed. The Swift maintained
a speed of 83 kilometers an hour for four hours during sea trails. The
ship can cruise at 63 kilometers an hour for 2,000 kilometers, or 7,200
kilometers at 36 kilometers an hour before it has to be refueled. The
HSV has four water-jets, in addition to its normal engines, making it
very maneuverable. The Swift was going to be used mainly as a mine
warfare support ship, but additional HSVs will serve as high speed
transports.
Weapons can include manned 25mm automatic cannon and remote
controlled 12.7mm machine-gun or 40m grenade launchers.
The Swift can also carry high speed inflatable boats to carry
boarding parties to suspicious boats. But the main advantage of the
aerostat equipped Swift is to spot drug smuggler boats and alert other
navy and coast guard ships to intercept.
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