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By Norman Friedman, Author, Naval Institute Guide to World Naval Weapons Systems
Navies Fight Smugglers and Pirates drain offshore oil fields from remote locations. Before the Gulf War,
® one of the main charges leveled by Iraq was that Kuwait was illegally
pumping from a disputed oil field, using slant-drilling techniques. Al- With the continued decline of the Cold War, many Western navies though this particular charge can hardly be dignified as a justification are showing interest in other national security tasks. European nations, for war, it provides an interesting pointer towardthe future. For an off- for example, which have substantial unemployment rates, seem in- shore field in relatively shallow water, exploitation from a platform fur- creasingly concerned by illegal immigrants entering through Mediter- ther offshore is surely not too difficult. Policing of offshore resources
ranean ports. thus becomes an important Navy or Coast Guard function.
The European nations have very generous welfare (including unem- All of this is quite aside from traditional naval policing roles. Piracy Ployment payment) systems, and their governments fear the burden of in the South China Sea has increased with the decline in the Royal Navy’s Providing for large numbers of additional recipients in generally stag- presence. Victims have included both commercial shipping and the Vietnam economies. This is not of course merely a naval issue; the coun- namese boat people. The U.S. Navy, though often equated with the Royal hies of the European Community fear mass immigration from the for- Navy of the past, has not explicitly adopted any similar role of ensur- mer Soviet Union and from Eastern Europe unless the economies of ing the free passage of shipping on a worldwide basis. One question, in- the East are restored quickly. The fear of mass migration, as an eco- deed, is whether such police activity might be a valuable U.S. post-Cold
nomic disaster, may well be at least as strong as the fear of right-wing revanchism as a motive for European Community aid to the East. For Western Europe, illegal immigration is likely to become a particularly difficult problem once national frontiers are weakened in the nm-up towards the unified market envisaged for 1992 and beyond. The Community already provides subsidies to its poorer governments to support seaborne policing; such grants financed most of the recent expan- S|0n of the Irish Navy, for example. The Community can argue easily that unless its sea frontiers are enforced to some uniform standard, im- tuigrants will flow through the weaker parts, particularly if the weakness is in an area of high pressure, such as the Mediterranean. It is also Possible that the immigration problem will stop the movement toward °Pen frontiers within the Community. It will almost certainly preclude any incorporation of the former communist states into the Community, smce their own populations would then be free to work throughout the Community. Similarly, navies are increasingly being drawn into the anti-drug camPaign. Governments have always resisted smuggling, including the drug haffic, but in recent years drugs have gained considerable prominence, not only in the United States. British efforts to combat arms traffic going mto Northern Ireland places an additional burden on the Royal Navy and its paramilitary brethren. In the Caribbean, the U.S. Coast Guard, assisted by several Latin ''merican navies, is running a large-scale interdiction campaign. Oper- atl°nally it is little different from a major military operation: very large numbers of ships and aircraft have to be identified and tracked, using urdware and software similar to that used by the Navy tactical data sys- m, for example. Participating ships and aircraft are provided with the Ult of such systems via Link 11. The U.S. government sponsored de- Vclopment of a simple receive-only version of Link 11, using software running on an IBM-clone personal computer, called Link America. The S°ftware was distributed to those navies operating with the U.S. forces against drug smugglers in the Caribbean. Link America was limited to reception because many of the partici- Pat|ng units had only limited navigational resources, and thus might well ahi^ entered misleading data, corrupting the overall data base. Presum- y wider availability of the global positioning satellite system will SOl';e this problem. ne pressure for positive control of the 200-mile exclusive eco- uuc zones provided for under the recent Law of the Sea treaty con- to UtfS *° mount as exploitation of ocean-bottom resources (at least out he edge of the continental shelf) becomes more and more viable eco- n°hiically. and°S'*'Ve contr°i involves the protecting offshore sites, such as oil rigs, In 'htercepting vessels and aircraft operating illicitly within the zone, su i *,ast tdat ^as generally meant illegal fishery, but the future e y holds much more. After all, the technology probably exists to | War role. It would be justifiable in view of U.S. dependence on free worldwide trade, much transported by sea, and also because it is probably against U.S. interests for any of the local powers—particularly Japan—to build up the sort of sea power required for policing. The loss of Subic Bay would of course make any such role far more expensive and far more difficult. One wonders whether the potential loss of trade due to greatly increased piracy has entered the Philippine Senate’s calculations of the cost to their country of terminating the U.S. naval presence in the area. For local navies, the symbols of the new security role are the small maritime patrol aircraft—equipped with a good surface-search radar but not with the sort of elaborate sonobuoy system common in antisubmarine aircraft like the P-3—and the offshore patrol vessel. Most Third-World maritime patrol aircraft are converted short-haul airliners such as the Spanish CASA 212. Indonesia was unique in buying Boeing 737s equipped with side-looking radars, but it is unlikely that these sophisticated aircraft will continue in this role. The offshore patrol vessel, in effect a coast guard cutter, may well supplant the frigate or corvette as the most typical ocean-going warship in many smaller navies. Such vessels differ from corvettes and frigates both in performance and in sophistication of armament. They must keep the sea for extended periods, which means that they should be fairly large, with a substantial fuel capacity, and high speed is not a firm requirement. Ideally, they should support at least one helicopter. They need not be very well armed, at least during peacetime; during war, the displacement should buy options for considerably enhanced armament. In some ways the Danish “StanFlex 300” class exemplifies this concept: the ships can be lightly-armed in peacetime, and in wartime the modules for more powerful weapons can be added. This flexibility is bought largely by providing, even in peacetime, sufficient numbers of combat information center consoles and computers to accommodate the maximum projected wartime armament. Some features—wartime electronic warfare suites, for example—cannot be fitted very quickly and so must be built-in. The French Floreal class, with its merchant- grade construction, is probably the largest of the offshore patrol vessels, even though the French Navy considers it a frigate. The new significance of such vessels was highlighted at the Royal Naval Equipment Exhibition, held in Portsmouth, England, in September: preliminary agreements were announced for the sale of four such ships—the first substantial new-build warships exported by Britain since the 1960s; two to Malaysia and two to Oman. It is only fair to mention that the sale of three such vessels to Brunei, announced at the 1989 British show, ultimately fell through. Once it could be assumed that while drug or other smugglers might outrun their pursuers, they could neither intercept sophisticated modern communications systems nor detect that they were being painted by mil- |
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!ed'ngs / November 1991
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Proceedings / November
itary radar. That is clearly no longer the case, partly because modern electronics have become so much less expensive so quickly. Pursuers using active sensors run a real risk that they will alert their prey. Truckers and automobile drivers in the United States have for years used simple radar warning receivers—fuzz-busters, to be colloquial. For a time, U.S. Navy fighters were equipped with just such devices, pending the development of a more satisfactory warning receiver for some particular frequencies.
The Royal Australian Navy is sponsoring development of an inexpensive electronic support measures system, the AWA Defence Industries Type 133 for its next-generation patrol boat, specifically to regain some advantage over the smugglers it pursues. Presumably it is not alone; anti-smuggling would seem to be a very likely future market, particularly when the electronic support measures set in question can be optimized to deal with communications.
The smugglers’ new sophistication makes passive sensors more and more attractive, and infrared surveillance devices are now commonplace. At the British equipment show, for example, one manufacturer announced the sale of an electro-optical surveillance device to the U.S. Coast Guard. Such devices are not too different from those used in the Gulf to spot floating mines, although generally they do not continuously scan the scene around them. They are natural adjuncts to the laser “dazzler” that the Royal Navy has been using since the early 1980s as a non-lethal counter to aircraft and attack boats.
Laser dazzlers illuminates the cockpit of a hostile airplane or boat; the occupants either turn away or are temporarily blinded. Reportedly, one such dazzling caused an Argentinian pilot to crash during the Falk- lands Conflict. Such a device would seem particularly useful to a law enforcement officer approaching a potentially dangerous suspected smuggling boat. The U.S. Coast Guard already uses a conventional searchlight, slaved to a combination infrared and visual camera.
Towed arrays are also potentially valuable passive sensors. Like submarines, surface ships can be detected by the noise they put into the water. The difference is that surface contacts are far louder and also far more numerous than submarines. Thus a towed array system for surface tracking would differ from its submarine-detecting cousin mainly in signal processing.
In each case, processing is done in two stages. First, individual targets are distinguished from noise; second, tracking commences. Targets are differentiated by their apparent motion relative to the array. Given sufficient time, targets can even be localized by analyzing their motion relative to the ship towing the array. In ASW, this procedure is called target motion analysis. Manual target-motion analysis can be performed adequately on a single target, but even the submarine detectors generally encounter multiple targets (most of them not submarines, and distinguishable by their apparent motion).
Modern towed array submarine-detecting systems, such as the U.S. Navy’s AN/SQQ-89, therefore incorporate target-motion computers. Target motion would become particularly important for the surface tracker, given the very large number of targets it might detect. A British company, MUSL, is marketing a small-ship towed array called Comtas. Com- tas was initially advertised as a small-ship submarine detector, but MUSL has shifted toward the surface security role. HMS Atherstone, a British minehunter that served in the Gulf War, was present at the September show carrying a short towed array. It may well have been a Comtas on trials.
Smuggling is a three-dimensional problem. Patrol vessels must deal not merely with seagoing craft, but also with airplanes passing through their patrol zones. Current patrol vessels, however, are generally equipped only with surface-search radars. Although such radars have some capability against low-flying aircraft, they are extremely limited in that respect. On the other hand, existing air-search radars tend to be too large and expensive for small coast guard craft. At the recent Portsmouth show, Siemens-Plessey and Kelvin Hughes jointly announced a new lightweight C-band air-search radar, called Lookout, intended to fill this gap.
This kind of air-search radar would also have two other possible markets: fast attack craft and mine countermeasures craft.
One apparent lesson of the Gulf War is that missile-armed helicopters can disable even fairly sophisticated gun-armed attack boats by attacking from beyond gun range. The obvious solution is to arm the boats with small missiles, such as the French Mistral, the British Seastreak, or the U.S. Stinger; but these missiles will be effective only if their op124 erators can be cued by a radar with sufficient range. Many of the boats carry only surface-search radars, which have some air capability, but are matched to their short-range guns. Thus, a lightweight air-search radar might be the answer.
The other likely market is mine countermeasures craft. Although it may outwardly resemble its cheap and numerous predecessors, a modem mine hunter is quite expensive. Its combat direction system is little different from that on board a corvette or a frigate. Its sonar is more elaborate than that typically used to detect submarines, albeit much shorter-ranged. The minehunter’s hull is expensive because it is magnetically and acoustically silenced. Any reader of the naval reference books will see this rise in price reflected in drastically reduced numbers of mine countermeasures craft. The strong implication is that mine hunters are well worth attacking. Existing ones have very little in the way of air defenses, largely because such defenses carry considerable magnetic signatures. The main exception currently is the German mine countermeasures fleet, which is armed with both guns and with Stinger missiles.
In the Gulf War, many mine hunters were armed with hand-held missiles and others were up-gunned. The British found that quite minor air- defense improvements to their Hunt-class vessels grossly increased their magnetic signatures, a fact discovered only because they had brought a mobile magnetic measurement range to the Gulf.
That raises an interesting question. It may no longer really be practicable to keep a valuable mine countermeasures ship within easy range of enemy antiship weapons. The best alternative may be to use remotely operated or semi-robotic vehicles, controlled or launched from well outside the suspected mined area. In the past, such an approach would have been rejected out of hand because the vehicles could not have navigated precisely enough, but the combination of the GPS system and ring-laser gyros has probably solved this problem. One might envisage one vehicle used to chart the mine field, followed by a second intended to destroy the mines. Unless the path followed by the first one could be duplicated fairly precisely, the exercise would be futile.
Real-world Stealth Problems
Readers of this column may recall a certain skepticism regarding the B-2 bomber and stealthy aircraft in general. In mid-September the Defense Department announced that the B-2 had done worse than expected in its radar signature tests; it had not been as stealthy as advertised. Nor does it seem likely that the problem can easily be fixed.
An airplane like the B-2 reduces its radar signature in two ways. K is made out of radar-absorbent (or -transparent) material and its shape reflects signals away from the antenna pointing at it. Every account of the B-2 has emphasized the importance of precise shaping, to the extent that special computer-controlled tools had to be developed merely to manufacture it. Moreover, the shape was so important that the prototypes had to be built with production tooling. For a time, the Air Force even demanded that special climate-controlled hangars be built, so that B-2s would not distort on the ground.
Even so, the shape apparently was not quite good enough. That may reflect some failure in the computer program used to design the airplane in the first place (the airplane, after all, does not quite duplicate the shape in the computer; nor does the radar beam). It may also reflect the in' evitable bumping and distortion of flight, which would be far less devastating than the (also inevitable) effects of service usage. Just how accurately could an airplane be repaired after a landing mishap, t°‘ example?
This would not be the first example of an airplane shape failing the test of service. The best known is probably the the P-51 Mustang’s laminar-flow wing. It was brilliant in concept, but in practice laminar flo'*' was a failure, because no wing ever remained clean enough for very long.
Lest the columnist be accused of anti-Air Force bias, he recalls a somewhat similar story about a laminar-flow torpedo shape. The exotic shape was remarkably effective in test tanks, but it never entered service. The reason? Seawater is never clean enough, and it took very little in way of impurities to destroy laminar flow.
It probably takes very little to upset the stealthiness of an airplane li^e the B-2, whose invisibility depends on a detailed shape accurate to with"1 a few thousandths of an inch.
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