One of the great uses for submersibles and
remotely operated vehicles is their ability to go
where humans can’t, and for long periods of
time. This is why they are incredibly useful as
search and rescue devices. In the past, the 1966
Woods Hole Oceanographic Institution’s DSV
(Deep Submergence Vehicle) Alvin was tasked
with locating a missing hydrogen bomb, lost in a
plane crash in the Mediterranean Sea. Alvin
searched for two months before recovering the
bomb, complete with attached parachute, under
762m (2,500ft) of water.
A more recent example of submersible search
and rescue is the use of autonomous underwater
vehicle (AUV) Bluefi n-21 in the search for missing
plane MH370. On 8 March 2014 a Malaysia
Airlines fl ight from Kuala Lumpur to Beijing
disappeared from radar and was presumed to
have crashed into the southern Indian Ocean.
With such a huge search area to cover in order to
fi nd the missing plane, Bluefi n-21 was drafted in
to help the effort.
The AUV is equipped with side-scan sonar –
acoustic technology that creates pictures of the
seabed using refl ected sound waves instead of
light. Bluefi n-21 can be programmed to search a
particular area, sweeping and scanning 50m
(164ft) above the seabed for 24 hours, after
which the data can be downloaded and analysed.
This creates a 3D map of the area and highlights
any wreckage that could potentially be linked to
the missing plane.
Unfortunately, despite having scanned over
850km^2 (328mi^2 ) of the vast search area, at the
time of writing Bluefi n-21 has yet to locate the
missing aircraft.Search and
rescue subs
Side-scan sonar
This maps the sea fl oor
to show if any fuselage
has come to rest on the
ocean fl oor.Vital stats
Bluefi n 21 can dive to a
depth of 4,500m
(14,763ft), reach a speed
of 8.3km/h (5.2mph) and
weighs 750kg (1,653lb).Navigation system
Accelerometers and
gyroscopes on board help
this AUV to track its
location from a known
starting point.Advanced
hydrophone
TPL-25 uses a powerful
hydrophone to listen for
pings from the plane’s
black box, able to detect
signals from up to 1.6km
(1mi) away.TPL-25
Also used in the
search for MH370
was the Towed
Pinger Locator 25,
towed behind a
research vessel.Distance searched
The TPL-25 system can
search an area of over
260km^2 (100mi^2 ) per day.Multi-beam
echo sounder
This technology
onboard Bluefi n-21
detects the depth of
the water that the
sub is surveying.Images showing ship hulls
lying at the bottom of an
ocean fl oorThe design of Bluefi n-21 is
reminiscent of a torpedo
© NRL; Peters & Zabransk y; Bluef in RoboticsDID YOU KNOW? Russian submersibles MIR I and MIR II can take tourists to the depths for a hefty price of £205,200 ($350,000)