Underwater Security addresses the protection of land facilities and valuable
assets that are vulnerable to attack from the waterside. Attacks may take the form
of armed combat divers or the use of explosives against target vessels or facilities.
A complete Underwater Security program also includes examining ships for contraband
containers fixed to the hull.
Techniques commonly used are underwater video cameras and acoustics (sonar).
In most harbors underwater vision is extremely limited. Sonar, however, is not limited
by optical conditions.
Scanning sonar can be used to sweep or "clear" areas to ensure they are clear
of foreign objects such as mines, Improvised Explosive Device - IEDs, or contraband.
Multibeam sonar can be used to detect the presence of divers, whether in a secure
area within a defined perimeter or an underwater area under surveillance for law
enforcement purposes. Sonar altimeters may be used to create an "acoustic fence",
providing an alert for further investigation.
Kongsberg Mesotech Ltd. is a leader in the development of scanning and multibeam
sonar and its application to all facets of underwater security. Applications for
sonar can be classified into these categories:
Diver Detection or Underwater Surveillance, as it is also known, is a complex
and challenging task due to limitations placed on various technologies by the subsea
environment. A white paper prepared by Kongsberg Mesotech explores the different
approaches and their effectiveness.
Effective ranges for diver detection are from 400 meters to greater than 800
meters, depending on a variety of factors. Underwater Intruder systems will operate
on a range scale of 800 meters in order to provide the longest possible alert time,
thereby enabling an effective response. Due to the detection range involved, divers
are represented by icons on the display. The capability to view a sonar image for
confirmation can be provided through "zoom" capability on the sonar system, or through
a mobile sonar or underwater video system deployed using a boat or ROV.
The above video has been reduced to be playable on web. To view the video at full
resolution use the link below - file size about 27MB.
At ranges less than 200 metres, a higher frequency sonar can be employed that will
also enable confirmation at close ranges. This example demonstrates detection of
The above video has been reduced to be playable on web. To view the video at
full resolution use the link below - file size about 105MB.
Ship hulls are scanned to determine if explosives or contraband (usually narcotics)
have been attached. Magnetic mines may be attached anywhere to a steel hull below
the waterline. Containers for smuggling narcotics are often secured to bow thrusters
or rudder structures. Clearance divers are typically used to search the hull for
mines or containers, a time consuming and difficult process, particularly in limited
visibility. High Resolution Scanning Sonar can examine a ship's hull in a short
period of time and is able to resolve raised objects on the hull only a few centimetres
high. When properly deployed, details as fine as weld seams are visible as shown
in this scan.
Scanning sonar is positioned most easily by using an ROV with sufficient power to
hold against currents and to press the structure of the ROV against the hull. This
provides a steady platform for the high resolution scanning sonar and enables high
quality scans that readily define features such as this small container attached
to a ships hull.
The KONGSBERG MS1000 scanning sonar is an ideal solution for vessel hull inspection.
This high resolution sonar is capable of rendering complete vessel hull imagery
that can detect foreign objects down to several centimetres. The sonar is lightweight,
hand portable, and provides imagery on a laptop computer. It can easily be used
by a single person to perform a complete bow – to stern vessel hull inspection and
present data as a single (mosaicked) image that provides a complete view of the
submerged portion of any vessel. Vessel inspections can be completed in far less
time than diver searches with little or no risk. Merging the scans together using
a KONGSBERG software package can provide a complete picture of the ship’s hull,
verifying the areas scanned are clear, and documenting that areas have not been
Bow to stern vessel hull inspection.
High Resolution Scanning Sonar can examine a ship’s berth in the greatest level
of detail to determine if a berth is clear of objects that could represent a threat
to a visiting warship, cruise liner or other high value asset. Berth inspections
can be conducted in real time and comparisons made to previous scans in post processing
using commercial software packages or KONGSBERG 's KeyPoint TM image
Sonar imagery is obtained in real time using a portable laptop computer equipped
with the MS1000 software. A single person can easily provide a complete security
inspection of a vessel pier and the surrounding underwater terrain by performing
an interlocked series of scans. The sonar head can be oriented to provide horizontal
coverage (for the seafloor near the pier) and may be vertically oriented to provide
vertical coverage for inspection of pier walls.