Do submarines have a future? They are the oldest stealthy vehicles. It is often argued (recently by the chief of naval operations himself) that accelerating computer power (Moore’s Law) is likely to erode anti-radar stealth for airplanes and, presumably, for surface ships. Can the end of submarines be far behind? After all, for years there have been claims that the seas would soon be rendered transparent.
During the Cold War, advocates of the mobile MX missile claimed that the Soviets were on the brink of doing exactly that, and therefore that their weapon should be bought instead of the expensive U.S. Navy Trident missile and the big submarine carrying it. Those claims collapsed. After the end of the Cold War, it became clear that the Soviets were nowhere near the point at which the oceans would become cloudy, let alone transparent. But many generations of computer chips have come and gone since then. Is the end nigh?
Obviously, efforts to detect submarines in exotic ways are highly classified – but that does not mean they work, or that they are likely to work. The sea is a far more complex medium than the air through which radar (to deal with stealthy airplanes and ships) passes.
The more we know about the sea, the more a submarine commander can take advantage of its quirks. At least as important, it seems that it is difficult or impossible to sense remotely local details of the sea – such as the precise way in which temperature changes with depth – with enough precision.
Apparently you have to be in the sea to sense what is happening around you, and even then you cannot know what is happening nearby, where a submarine may be. We can probably reliably detect a submarine within a few miles – but that is very different from rapidly searching a wide area in which a submarine may be. And even that is a very expensive proposition available to very few countries.
There is concrete evidence that the submarine detection problem is far from solved, in the form of active building programs (including long-range plans) in many countries, including the United States and Russia. Those imagining that the submarine detection problem has been solved may argue that navies are unwilling to admit that a favored kind of warship is finished, or is about to die – in much the same way that it used to be said that “battleship admirals” prolonged the life of big-gun ships.
However, the reality of the battleship story is a lot less discreditable, and in many countries – certainly in the United States – there are powerful groups with vested interests in cutting spending, which means eliminating any kind of weapon system whose effectiveness can be denied. The U.S. Air Force’s attempt to kill Trident is a case in point. Precisely because of fear that the Navy was somehow concealing an uncomfortable reality, investigation of the supposed Soviet anti-submarine warfare (ASW) system was assigned to the CIA – which tried heroically to prove that there was some truth in the idea. It failed spectacularly. Nothing that emerged after the end of the Cold War changed that verdict. That is why the U.S. Navy continues to build nuclear submarines, and why nuclear ballistic missile submarines are assuming a more and more important role in U.S. national deterrence.
In fact, we see continued construction of large expensive nuclear submarines by all the countries that can afford them – the United States, Russia, the United Kingdom, France, and China, with India trying to join that club, and Brazil definitely interested. Meanwhile many countries, particularly in and around Asia, continue to buy non-nuclear submarines, in some cases equipped with air-independent power plants whose advocates claim that they offer a new kind of non-nuclear performance (and invisibility).
At the same time, the unit cost of submarines is high and growing, so the numbers in each fleet are declining. The U.S. Navy, for example, is building nuclear attack submarines at a rate that will support a stable fleet of about 30 to 40 – compared to 100 during the Cold War.
The Chinese People’s Liberation Army Navy (PLAN), which is certainly an enthusiastic submarine operator, has seen its numbers collapse after discarding a mass of submarines built to Russian designs of the 1950s. As in the West, the result is a much less numerous fleet of individually far more effective submarines.
What follows concentrates on the U.S. Navy, and to a lesser extent on the Royal Navy, and on missions beyond the classical one of attacking surface ships.
To guess where all this is leading, think about what a submarine offers. Above all else, it offers stealth. For example, both a submarine and a satellite can collect signals intelligence. The victim is probably aware that the satellite is overhead (although considerable effort is spent concealing the identity of the signal-collecting birds). He can turn off some critical transmitters; he can even deliberately emit misleading signals, because he has a good idea of what is being picked up. By way of contrast, a submarine offshore may well be invisible, at least to whomever is emitting. It may pick up only a fraction of what a satellite or airplane does – but it is far more likely to pick up what matters.
Moreover, sending overt intelligence collectors into an area inevitably raises tensions. A government interested in finding out what is happening without affecting events (until it wants to) has almost no alternative to a submarine.