As reported by Navy Times website, Adm. Jonathan Greenert, Chief of Naval Operations, listed his technology and developmental priorities while speaking at the Naval Future Force Science and Technology Expo (1). Prominent among those priorities was,
“Getting off gun powder. Lasers and railguns will provide an incredibly deep magazine at remarkably low cost, he said.”
ComNavOps fully supports laser and railgun development efforts while, at the same time, recognizing the many technological challenges still to be overcome before those technologies can be applied on a practical basis. Let’s set the technological challenges aside and look at some of the tactical and application issues that may not have been fully explored, yet.
Consider an arrow shot at a piece of paper. The arrow will pass through the paper and leave a fairly large hole in the paper although the rest of the paper will be unaffected. Fast forward on the technology scale and consider a bullet fired from a handgun at a piece of paper. The bullet is much more advanced technology and much more powerful than an arrow so it should do much more damage, right? Well, the bullet will pass through the paper and leave an even smaller hole than the arrow. How can that be?! The bullet is faster, more advanced, and more powerful. The problem is that a bullet is an inappropriate weapon choice for a paper target.
With that example in mind, let’s consider a railgun firing at a modern, small naval vessel. You’ve probably seen the videos of test firings of railguns penetrating a foot of steel and the resulting destruction due to the kinetic effects. However, as you know, modern small vessels such as corvettes and frigates are lightly built and thin skinned. What will happen when a railgun projectile traveling at several times the speed of sound hits a modern vessel? Well, the projectile is inert so there won’t be any fused explosion. It has no unexpended fuel to disperse and ignite. That leaves only kinetic effects but will the projectile encounter enough resistance to transfer its kinetic energy to the target, thereby causing damage or will the projectile pass through the thin skinned vessel without doing significant damage much like the bullet passing through the paper? One could imagine a targeted vessel with a bunch of small, clean holes but otherwise largely undamaged after being engaged by a railgun. I can’t answer this question and I may be completely off base but it’s at least a plausible scenario to ask about.
Now, let’s look at area effects. One of the main uses for a naval gun has, historically, been to produce area explosive effects during land bombardment for area damage, suppressive fire, and similar uses. Once again, consider how a railgun works. The projectile is non-explosive and depends on the transfer of kinetic energy for its effect. In short, it does not produce an area effect. It is not really possible to provide area bombardment or suppressive fire from a railgun. A railgun projectile hitting ground will kick up little dirt and bury itself.
What about guidance? Railguns are touted as shooting projectiles at such great speeds that they will strike before the target can move. At close range, that may be true but railguns are being looked at as deep strike weapons hitting targets hundreds of miles away. Do the math. It still takes significant time to cover that distance. Mobile targets, such as vehicles, will be well out of the path of a railgun projectile by the time it arrives. Remember, with no explosive effect, a projectile must have a direct hit to be effective. A miss of one foot is a total miss. There is no area explosive effect to compensate for small misses. Well, why don’t we add a guidance package to the railgun projectile? Wouldn’t that solve the problem? The answer is no, for two reasons. First, we don’t have the technology to fit a guidance package into a projectile and have it survive the firing. The stresses on the projectile are immense. Second, if we start adding guidance packages (or ECM, or active radar, or whatever) we negate the main advantage of the railgun which is its cheap projectile cost. Instead of shooting free rocks as projectiles, we’ll be right back to $50K+ projectiles like we have now.
Now let’s consider a railgun in an AAW/CIWS role. Similar to a Phalanx CIWS, a railgun could be an effective AAW weapon especially given its very high speed and, thus, short travel time to the target. Further, the low cost of projectiles makes it an economically viable counter to modern missiles. The downside is that the great speed of the projectiles ensures a very long range which, if the projectile misses, makes it a potential friendly fire hazard for ships and aircraft much further downrange as opposed to the relatively very limited range of a Phalanx CIWS, for instance.
We see, then, that a railgun is akin to a sniper weapon. It’s great for specific, fixed targets but suffers from significant limitations due to its non-explosive characteristic and inability to be guided. A railgun could supplement and complement a conventional gun but it can’t totally replace it.
(1) Navy Times, "CNO wants more high-tech assets, delivered quickly", Lance M. Bacon,