Numbers Matter

For many years, the debate about the Navy’s future force structure—and subsequent planning for it—has been confined to a small decision space at the high end of capability and cost and the low end of force size. A wide range of factors, from politics to flawed notions about the purpose of warships to the changing attitude of the American people and the nature of war, have restricted decision makers to choices between only superficially different options, all of which are poor.

The result of the profound disconnect among budget decision makers, planners, and reality is, as retired Navy Captain Arthur Barber described in a recent Proceedings article, “The U.S. Navy’s current fleet design does not match today’s conditions, much less those expected over the next 20 years.”¹ That proclamation is true, but it also is a gross understatement. In fact, the Navy’s current fleet design is the opposite of what would be required to defeat a peer adversary.

One does not need perfect foresight of the types and characteristics of the platforms and weapons that would be involved in a naval conflict with a peer adversary to make predictions as to its outcome; the deciding variable almost certainly will be the quantity of both. Indeed, parity of technological performance of both platforms and weapons is one of the intrinsic meanings of the term “peer adversary.” Although not designed to be a predictive tool, the salvo model developed by retired Navy Captain Wayne Hughes of the Naval Postgraduate School offers a mathematically demonstrable and logical illustration of why quantity would be the primary, if not only, variable among nearly countless others that would determine the victor in a future conflict between equally advanced fleets.²

Hughes’ salvo model is a mathematical description of modern naval combat that recognizes that combat in the missile age is “pulsed.” In other words, each side delivers firepower to the enemy in pulses (i.e., salvos of antiship cruise missiles). These salvos are independent of each other, and their success in dealing damage to the enemy is subject to a number of mitigating factors, including the defensive capability of the target ships, the quality of the targeting data, and the survivability of the target ships. The quality of known, or reasonably assumed, data and the desired complexity of the model determine the number of mitigating factors considered. 

The damage, if any, inflicted by a salvo adversely affects the adversary’s follow-on salvo and vice versa, keeping in mind their potentially simultaneous nature. In other words, both sides may have salvos in flight at the same time. The salvo equations themselves are readily available from many sources online and in print, most notably in Hughes’ Fleet Tactics and Naval Operations, but the equations themselves are not the key point in this conceptual approach to desired force structure.More important is what general conclusion one should draw from them.

Given the large warheads of modern antiship cruise missiles, the survivability of modern warships, if hit, is likely low. Even with optimistic assumptions about the effectiveness of soft-kill missile defense, it is clear the primary driving variables in the salvo equations are the number of missiles one can deliver per salvo and the number of friendly platforms one has to “absorb” the adversary’s salvos. Nothing beyond extreme and highly unrealistic adjustment of any number of potential mitigating factors would make this result invalid. If in doubt, “do the math” with whatever complexity of salvo equations one wishes and see for oneself. 

In short, the fleet needs a large number of platforms able to deliver large salvos of missiles and live past the adversary’s opening salvos.