Recent events in the Red Sea have shown the unique value of capable surface combatants. Looking at the environment where surface combatants operate, billions of tons of cargo on tens of thousands of ships move goods around the world every day. Enabling the continued movement of that shipping is a fundamental mission of a navy, particularly one like that of the United States, which includes among its missions protecting the global commons. In the Red Sea, U.S. Navy Burke-class destroyers are providing air and surface defense in ways few other joint force capabilities can provide. Surface ships are not the best capability everywhere, but they remain for the most part highly useful and effective platforms across a spectrum of missions and conflict scenarios.
The original question posed to me by Naval News was which modules should be developed for the prospective DDG-X class, given the possibility that modular development might become the preferred course. Although I understand the desire for some level of certainty on preferred combat systems, this seems to me an unduly specific question at this point. I've accordingly modified the question to one about requirements, specifically capability requirements, and then have added an additional question about numbers needed to be effective.
Too often, individual systems have been developed to very high levels of capability but were then so expensive that only a few could ever be developed. There are times when only a few very capable platforms are the best choice to meet threats and challenges. But, for ships, they can only be in one place at once. The questions cannot be just “what,” but also “how many?”
What do surface ships do for the Navy?
Far back into antiquity and likely well into the future, the majority of ships in the Navy are surface ships. These ships may have widely different purposes and armaments. Aircraft carriers are surface ships just as surely as are minesweepers. Surface combatants are defined primarily by missions they are capable of performing using the weapons and systems installed. U.S. Navy surface combatants are generally multi-mission and have systems to carry out anti-air, anti-surface, and anti-submarine warfare. All can land and refuel helicopters; many can host and maintain helicopters. For our purposes, we will identify surface combatants as guided missile cruisers (CGs), guided missile destroyers (DDGs), guided missile frigates (FFGs), and littoral combat ships (LCS).
Surface combatants are defined primarily by missions they are capable of performing using the weapons and systems installed.
Every surface combatant except LCS is multi-mission, in the sense that each ship has systems allowing it to conduct several different warfare missions, ranging from multi-domain defense of the whole force to strikes against land targets. The ships are also able to carry out more than one mission at a time. For example, CGs and DDGs have simultaneously launched strikes and performed area air defense, and could conceivably conduct anti-surface warfare at the same time. Embarked helicopters could also be carrying out anti-submarine warfare in conjunction with ship systems. In short, a single ship can perform a wide variety of missions, either by itself or as part of a larger task force. These ships can, moreover, protect themselves, participate in command-and-control networks, receive and process intelligence, and carry out electronic countermeasures. The FFG-62 class now under construction is also conceived as multi-mission, although with a smaller ordnance load and with the understanding that it will not have the same capacity as DDGs or CGs.
Ability to carry out a variety of missions is facilitated by the system for weapons load-out. U.S. Navy destroyers and cruisers keep their strike, anti-air, and anti-surface weapons in vertical launching canisters, which allows considerable variation in mission package load-out. This same system will be used in the Constellation-class guided missile frigate. However, these weapons have to be connected to some kind of weapons direction system. Spruance-class destroyers were equipped with the vertical launching system, but were not equipped with a three-dimensional air defense radar system, which meant there was little point in putting anti-aircraft missiles into the launching cells.
LCS differs from other combatants in being configured to carry out one primary mission at a time. Each platform has self-defense and basic control and mobility systems and can embark helicopters. But the mission modules are for single missions—which equip the ship for anti-surface or mine countermeasures missions—and there is no means to allow a rapid shift of mission focus. If, for example, an LCS receives a mine countermeasures mission module, that is the mission that the ship is likely to perform for years following. This concept is to a degree different than the original mission module conception, which implied that modules could be changed with relative ease, even in expeditionary conditions. Delays in module development and recognition that integrating new modules would be a time-consuming process seem to have forced a change to effectively make these ships either escorts or mine countermeasures vessels for their service lives.
What force structure mix is needed?
Whatever a warship's capability might be, it can only be in one place at one time, and there are situations where only parts of a warship's capability are essential. For example, during the “tanker wars” of the late 1980s, several surface ships were involved in escorting oil tankers and natural gas carriers through the Persian Gulf to Kuwait and then back. The ships needed anti-air and anti-surface capabilities, but the major consideration is that they needed to be in the area. The key was not to have one or two ships with perfect capability, but enough ships with sufficient capability to carry out a mission that was likely to take several months with many Persian Gulf transits.
For many years, from the 1970s until after the Cold War, the U.S. Navy sought a “high-low” mix of surface combatants, in which there were both very capable combatants that were assessed as able to perform specific warfare missions effectively and a large number of smaller ships. The smaller ships might be less inherently capable than the high-end combatants, but they would be sufficient and, most importantly, they would be available.
The Navy moved away from this concept for several years as the Perry-class frigate went out of service and the LCSs continued to experience program delays. DDGs came to be not just a capable high-end combatant, but also an all-purpose deployer for situations requiring far less in terms of capability. This high use has created material readiness problems for these ships as they were deployed for a whole variety of missions, sometimes at the expense of scheduled maintenance. There were a few cases where the Navy failed to meet presence missions because ships were not available. A considerable body of evidence indicates that ships, specifically surface combatants, were experiencing lengthy delays once in maintenance periods due to issues caused by lengthy deployments.
So, what seems clear is that there probably is no single ship that can meet the complete spectrum of demand. Different threat circumstances require different capabilities, and trying to fit all these capabilities on to one platform is unrealistic, at least at any kind of realistic cost. Even if we were hoping to create a modular design allowing substitutions of different capabilities, the fundamental issue is that any ship can only be in one place at one time. So, the Navy cannot realistically separate capability development from force structure requirements.
What should the overall surface force structure look like?
There are several key characteristics that should be considered in the surface combatant force structure. Note that these should be thought of as applying across the force: That's not to say the whole force has identical characteristics, but that in totality, ships exist in sufficient quantity with sufficient capability to meet the range of missions.
There are several characteristics that every ship should possess. These key common core characteristics should include:
- Ability to be produced in sufficient quantity to meet worldwide presence demands. This implies the procurement cost is within the nation's ability to pay for and produce.
- Closely related is the ability to be sustained over a long period. This requirement implies that the manning requirements must be in line with the nation's demography, that the maintenance requirements not be as onerous as they've historically been, and that ease of maintenance and repair is built into the platforms.
- Sufficient self-defense capabilities against every class of threat so that ships do not become easy targets. For example, a ship might not be able to serve as an area air defense platform, but it should have the ability to provide point defense to protect itself.
- Ability to securely connect with and routinely use worldwide communications and intelligence networks. Although ability to securely communicate has long been a requirement for deploying Navy ships, current requirements are for nearly continuous communication and future requirements are likely to grow. There are vulnerabilities associated with being part of a network, which can be even more acute when there's a requirement to transmit, but the world will likely not return to a place where ships could rely on broad and infrequently transmitted orders.
- Ability to embark a helicopter or comparable unmanned aerial system. This should also be considered a key common feature, enabling multiple different mission areas, and indeed sometimes providing a capability the ship by itself could not effectively deliver.
After all other basic requirements are met, the issue of capability to meet broader mission requirements comes to the fore. Here, very real trade-offs between costs, capabilities, and numbers are encountered.
Share on TwitterAfter all these other basic requirements are met, the issue of capability to meet broader mission requirements comes to the fore. Here, very real trade-offs between costs, capabilities, and numbers are encountered. We will examine these trade-offs in more detail.
As in the Red Sea, threats to international shipping can come from a variety of different sources, but the threat from air and missile sources seems particularly acute, with aerial drones, for example, becoming particularly widespread. That suggests that area air and missile defense is a particularly critical mission. However, making a ship capable in this area adds considerably to the cost when we consider the sensors and weapons direction capabilities required. To illustrate, an LCS class without such systems costs about $700 million while a Constellation-class frigate, similar in size to LCS but with a SPY radar for air defense, will likely cost over $1.3 billion (PDF). This makes clear that including the capability for area air defense would mean there would have to be fewer ships. Making a ship into a capable air defense platform is the equivalent of half a ship without such equipment. If simple numbers are part of the calculus, air defense capability for a large number of ships is likely out of reach. The exact number of ships that should have this capability requires more analysis than we can provide here. But we can say that not every surface combatant can have this capability, not if there's to be a sustainable and sufficiently numerous surface fleet.
It's important to consider the question of numbers because there are other missions surface ships might reasonably have to provide. If we look at Red Sea operations, the threat is not just from missiles and drones but also from boarding teams harassing transiting ships. Looking at other theaters, unmanned surface vessels (USVs) have attacked and sunk Russian combatants in the Black Sea. Air defense capabilities would not be relevant in defending against these threats. Indeed, trying to do operations against boarding teams or USVs while also providing air defense across a wide area might be incompatible. A ship could possess both sets of capabilities, but the reality is that doing more than one thing in more than one area would take two ships. In fact, the overall capability might best be served by having several ships with different capabilities than a small number with multiple capabilities.
We should note here also that the U.S. Navy is developing its own USVs, which can to a degree add capability and capacity for many of these missions. USVs can be networked, armed a variety of different ways, and could be an important addition to surface ship force structure and capability. Their potential roles have some limitations—visit, board, search, and seizure, for example, requires a boarding team—but their potential capabilities and missions require as much consideration as those of larger manned platforms.
How should the requirements be established?
The U.S. Navy regularly conducts a force structure assessment to arrive at a number of ships needed to meet a set of planning and presence requirements. This assessment, however, assumes a set of capabilities and does not attempt to balance numbers against systems capabilities. There is a complete joint process for the validations of capabilities requirements—the Joint Capabilities Integration and Development System. This system has long been criticized for being cumbersome, but the issue in this particular instance is that the focus on capabilities may cause insufficient focus on numbers.
The most complete answer is to first consider the most likely missions, which are not necessarily the ones requiring individual platforms and the most advanced capabilities. Those missions could then be associated with a number that could then be connected with a set of capabilities residing in a joint and fleet architecture.
That approach could yield a better mechanism for determining the capabilities particular ship classes might require. A modular approach might be effective in some cases. A ship could conceivably have modules that augment its ability in one scenario and then have them replaced by some other augmentations in another. Some examples might be ballistic missile defense or advanced electronic attack or intelligence collection. In some cases, the modular augmentations might not be difficult, but in some others, they could be extremely complicated and might require shipyard periods to complete. The history with the LCS modules does not suggest that this will be an easy process. Modules also do not solve the problem of force structure. However a ship is configured, it can still only be in one place at one time.
However, an architectural approach where numbers are considered as well as capabilities across a spectrum of use, from steady state to global protection of trade routes to intense warfare, might illuminate when a modular approach is the best. There likely will be times when a rapid change-out of modules might be the most effective way to keep a credible presence. However, what has not to date been designed is a force that together creates a flexible and effective capability. Such a force would likely include a mix of ships, large and small, sophisticated and simple, multi- and single-mission, manned and unmanned.
Bradley Martin is director of the RAND National Security Supply Chain Institute, and a senior policy researcher at RAND.
This Q&A originally appeared on Naval News on April 25, 2024.
