#protection of coastal facilities, #perimeter alarm
The most famous objects of this category are ports.
But in fact, similar problems arise when protecting many industrial enterprises.
Power plants (nuclear and thermal) usually have reservoirs to supply the cooling circuit.
Many factories have their own water intakes and water treatment facilities and are therefore located near water bodies.
Finally, in addition to industrial facilities, many specially protected recreation areas are located on the banks of water bodies.
All of these facilities have one feature and, accordingly, the main headache for designers and installers — solving the problem of protection from the water side of the perimeter or, in other words, protecting the water area of the facility.
This is truly a constant headache.
The ground section of the perimeter can be fenced off and equipped with hundreds of different, well-developed detection devices.
These include vibration, capacitive, magnetometric, seismic, radio beam, infrared, passive, single-position and dual-position, etc., etc. – even a simple listing of all available technologies would take up an unacceptably large amount of magazine space.
Moreover, all of these products have been manufactured by dozens of manufacturers for decades.
As for the water section of the perimeter, the headache begins already when trying to fence it. In shallow areas, this can be a lattice fence, in deeper areas — only boom (floating) barriers, possibly with an underwater net.
Do you think this is easy?
This is quite simple in the southern seas. And in our latitudes, most reservoirs freeze at least partially in winter. Or at least during floods, ice drifts from the upper reaches of the rivers pass through them.
Have you ever seen in the news what ice drift does to insufficiently reinforced bridges and dams?
Can you guess what it does to the floats on the ropes?
Now imagine that on the eve of ice drift (at sub-zero temperatures) you have to temporarily dismantle the moored barriers and quickly reassemble them after the last ice floe has passed. And then watch to see if another ten ice floes weighing a hundred tons have lingered somewhere.
In addition, the fence itself will not stop anyone, it is only a means capable of delaying an intruder for some time. The fence (underwater barrier) must be guarded.
Install intrusion detection sensors on it and ensure their maintenance and response to alarm signals. That is, the security service of the facility must include floating craft and a diving service. This is not the same as hiring a guard with a Berdan rifle.
And the detection devices for water boundaries are not as simple as those used on the land surface. The barriers themselves are protected by disposable explosive detection devices.
Simply put, the net is braided with wire, and the control device detects a break or change in the resistance of this wire. Any damage from a floating snag or strong waves — and you have to get into the water and restore the wire.
The main means of protecting the water borders of an object are active sonar systems.
The border service and the Navy also use the classic ship-based passive acoustic surveillance service, but at civilian facilities, ensuring the constant duty of highly qualified «listeners» is, firstly, very expensive, and secondly, in the coastal zone, their use is not nearly as effective as on a submarine in the depths of the Atlantic Ocean.
Near the shore, the surf and especially human activity create so much noise that it is impossible to hear the splash of enemy oars against their background.
Active hydroacoustic means are, in fact, an echo sounder, like the one used for fishing.
Of course, for stationary use, this is a rather large device, with a directional system of emitters (like a phased array) and connected to a fairly powerful computer for signal processing.
However, the result of its work is similar to the picture that a fisherman sees on his small echo sounder. And in the same way, in order to confidently distinguish a swimmer from a school of fish or from warm currents, it is desirable to have a very trained eye.
Of course, specialized systems are capable of operating in a mode similar to a video motion detector, when all moving targets that disrupt the usual distribution of signals are detected and an alarm is triggered.
However, the quality of such systems (the ability to distinguish false alarms from real ones) is significantly inferior even to commercial video detectors. And their quality of operation is familiar to many.
In Russia, such devices are produced by only 3-4 companies, and in single quantities, I have only seen them in trial operation at Minatom and Defense Ministry facilities.
I don't want to advertise them or denigrate them — these are complex, interesting developments, which have not reached the reliability of mass products.
If you want to install such a device to protect your dacha from the pond side, get your wallet ready and don't be surprised if the device only works normally in the presence of its developer.
In addition, do not forget that it is again advisable to have divers to service echo sounders. And for some reason, damage occurs in winter.
Well, and to respond to the alarm signal, again, you either need to send out a group of divers, or (if the fisheries protection service allows it) do as the army manuals recommend – just in case (preventively) throw ordinary grenades into the water area.
In addition, echo sounders have a significant drawback. They are quite bad at detecting targets at the edge of the water – in the bottom layer and near the surface.
In addition to active sonars, magnetometric sensors are also used. Mines that trigger when a thousand-ton ship approaches were already known to be made at the beginning of the last century.
However, such sensors hardly react to plastic and rubber boats or to an individual swimmer — a modern saboteur does not have much magnetic material: an engine in a boat and a machine gun in his bosom.
Nevertheless, magnetometric devices with a detection range of 2-3 m are also produced, they are sometimes used on land and they are also used in shallow water to prevent combat swimmers from getting close enough for an aimed shot.
After all, it is difficult to shoot from the water, and when you try to go ashore or at least into shallow water and stand with your feet on the bottom, such a sensor will work.
Finally, above the water surface, conventional navigation radar stations are used (again, they are practically powerless against individual swimmers) and optical surveillance: thermal imagers, video cameras. For reliable protection of a water area of one square kilometer, a dozen trained operators on duty at all times are enough (it is not so important, with binoculars in their hands or behind the video system monitors), capable of detecting a scuba diver swimming just under the surface of the water among the whitecaps and debris on the waves.
So, as you already understood, at civilian facilities it is necessary to protect mainly land structures. The water area and the coastal strip are practically uncontrolled.
However, even on the shore, everything is not so simple.
First, salt spray. One of the most terrible tests for any equipment is a test in a salt spray chamber.
Three-layer paint coating, galvanized steel — most materials can withstand such a test only for a short time. But security equipment must serve for years, and continuously.
At the same time, security equipment is not just a steel case, it is complex electronics that must be carefully sealed (precisely sealed, IP67 protection is completely insufficient, and even explosion-proof equipment, as a rule, is not sealed at all).
The most reliable method of protection is the use of pre-inflated cases with excess pressure inside. This ensures that sea salt will not get inside the case, on the delicate electronics of video cameras, sensors, spotlights.
In addition, a pressure sensor will help to quickly detect a leak and take measures to restore the tightness of the casing.
In addition to the casing itself, special attention must be paid to auxiliary materials.
Connectors, junction boxes, and finally, just bolts for fastening the equipment must be very well protected from corrosion, otherwise, even if, say, the video camera itself is in a casing pre-inflated with dry nitrogen and is safe and sound, the power cable leading to it may lose contact.
Or the entire casing will turn downwards when icing, and you won’t be able to fix it because of the rusted mounting bolts and will have to unscrew them at a height of 10 m using an oxyacetylene torch.
And two more facts – one bad and one good.
Bad: dense fogs are common at coastal sites, in which visibility (the range of video surveillance) is measured in units of meters.
Good:popular infrared illumination devices can increase visibility by a factor of two because infrared radiation is less scattered by fog.
In general, despite the pessimistic tone of the article, I would like to note that many organizations, including those with my participation, have managed to equip coastal facilities with a fairly high-quality system of technical security equipment.
The basis of the security system is the same in any case — equally strong multi-line protection of the objects or persons that need to be protected.
It is imperative to take into account the briefly mentioned features — fog, corrosion hazard.
And if possible (if the customer has enough money), new, still rare special underwater security devices should be used.
It is precisely because of their low prevalence that a potential intruder, as a rule, does not expect to encounter them, and therefore their use can be very effective, despite all the listed disadvantages.