Littoral Combat Ship
Concepts and End Products
Both competing prototypes of the Littoral Combat Ship (LCS) are now complete, and as of spring 2010, the U.S. Navy planned to choose one or the other for further production. The force goal is more than 50 such ships. The project can be traced back to the late 1990s and to a search for a new low-end surface warship to complement the high-end destroyers and cruisers. From a numerical point of view, the low-end ship replaced existing frigates, but the emphasis was very different. Frigates were conceived mainly to deal with the mass of Soviet submarines the West faced during the Cold War. Like other warships, they had other capabilities, but above all they were intended to defend Western control of the open oceans. Much the same could be said of the frigates built by other NATO countries. With the end of the Cold War, naval attention turned to the need to deter war (or to fight) in a restive Third World. Exactly what that meant was a subject of intense debate. The U.S. Navy began to discuss littoral operations, meaning operations in the strip of offshore water in which events would likely influence events ashore, and in which maritime operations were in turn influenced by what happened ashore. This was much more than coastal warfare, but it emphasized the central role of the post-Cold War Navy. The blue-water threat to free use of the sea had, for the moment, largely gone.
It did seem obvious that littoral operations would involve much greater numbers of ships, although exactly what they might be was unclear. At the Naval War College in Newport, R.I., the late Vice Adm. Arthur K. Cebrowski suggested that a new kind of surface force might resemble the attack aircraft wings with which he had flown. He thought that existing surface combatants were far too large for the weapon payloads they carried, and he proposed a more heavily armed ship based on a fast trans-Atlantic yacht. This “Streetfighter” could contest littoral areas with the fast missile craft many littoral navies had bought. Critics pointed out that warships are far more than platforms for weapons, and that fast missile boats were hardly the only means that foreign navies bought to prevent U.S. naval access. For his part, Cebrowski suggested that expendable Streetfighters could force an enemy to reveal concealed anti-ship resources, opening them to destruction either by other Streetfighters or by other elements of an offshore U.S. force. The heavy armament of these craft would, presumably, make it mandatory for an enemy to attack them. In a war game, for example, Streetfighters were deployed in the expectation that enemy submarines waiting inshore would be compelled to attack them and thus to open themselves to counterattack.
Skeptics appreciated that something smaller than a valuable missile destroyer or cruiser might be needed for littoral operations, but they found Streetfighter impractical. In the late 1990s, an alternative frigate-size surface combatant, optimized more for surface warfare than for anti-submarine operations, performed well in war games. It was called a Littoral Surface Combatant, but it was essentially undefined, and no program for such ships was set up. The surface shipbuilding budget was dominated by higher-end ships, and particularly by the program to replace the aging Spruance class. That project eventually created the current Zumwalt class (which, ironically, began as an inexpensive destroyer). U.S. naval force structure was based on the national requirement that the armed forces be able to fight one war while deterring a second.
The situation changed dramatically after the 9/11 attacks. The existing strategy was based on the idea that no enemy would attack the United States without amassing considerable resources. It was very unlikely that the United States would face many wars more or less simultaneously. That had not been entirely irrational during the Cold War, when the Soviet Union alone was the likely enemy. The 9/11 attacks showed that such assumptions had to be discarded. It took far less to mount an attack than anyone had imagined. The U.S. Navy developed a new concept of operations. The supporting set of slides included one entitled “A Bad Day in 2003,” which showed four entirely plausible crises, each involving an entirely independent actor. The two-war Navy (and military) could not be expected to cope.
The Navy’s approach to this new kind of world was to multiply the number of independent striking forces it could muster. Alongside the existing carrier strike forces it decided to create Expeditionary Strike Groups built around large-deck amphibious ships, and Surface Action Groups. The major ships around which the forces could be built already existed, but it was obvious that the Navy would need many more surface combatants. The only candidate was the undefined Littoral Combat Ship. The secretary of defense approved the idea; the concept of operations required more than 60 such ships (numbers have since varied). The need for numbers and budget reality defined the ship: Each should cost no more than a quarter as much as a destroyer, which meant about a quarter-billion dollars.
The sheer size of the program and the fact that it received support in the wake of 9/11 together made development urgent. The main question was how to create a useful and affordable ship. In 2001, the U.S. Navy operated a fairly large force of littoral ships, in forms such as mine countermeasures ships and patrol craft. It was unlikely that these ships could be replaced while the new LCS program proceeded and also while the essential high-end surface warships continued to be built. Somehow LCS would have to replace the mass of existing littoral craft, which had little to do with the strike operations now envisaged, while also providing the strike force capabilities envisaged. The Navy hit on the idea of modularity. LCS would be a “seaframe” that could switch missions as required. To hold down its cost, each LCS would carry, at any one time, only a single type of module, including the specialist crew involved. There was already a model for such operation in the form of the StanFlex corvettes of the Royal Danish Navy. The Danes built hulls into which containerized weapons could fit. The U.S. Navy found the idea attractive, but it also wanted helicopter capability (for a fairly large MH-60 helicopter), and it wanted an ocean-going ship.
By about 2003, the U.S. naval staff was also interested in high sustained speed. The origin of this requirement was never clear. Cebrowski had emphasized speed in his Streetfighter, and there may have been a feeling that to survive in a littoral area, in the face of enemy fast missile boats, speed was vital. Those pressing for high sustained speed probably did not realize that this characteristic would trump most others – and would prove quite expensive.
Production was urgent, both because money was available (and might dry up) and because there was no way other than LCS for the Navy to grow to the numbers now considered essential to meet expanding global commitments. That was unfortunate, because it demanded quick development of requirements for the ships while the concept of modularity began to shift. Roughly parallel to the evolution from Streetfighter to LCS, the U.S. Navy became intensely interested in network-centric warfare (which, as it happened, had been popularized by Cebrowski). The hallmark of this new concept was the use of distributed sensors to form a tactical picture. Given the picture, targets such as submarines could be struck. Instead of having one ship detect and then attack a potential target, a networked force would use the mass of sensors to find targets. The attack might be conducted by some other ship or aircraft. If the picture were good enough, an unmanned vehicle would do. Instead of a containerized gun or missile, the ideal module might be a combination of unmanned vehicles strewing sensors, the sensors themselves, the data fusion device used to process the sensors, and possibly the attack vehicle.
The networked idea was particularly important in a littoral or coastal context. In the past, littoral operations required either vast numbers of craft or else a great deal of time, because no single ship could see very far. That is why, as mine hunting has become more complex, the act of clearing mines off a beach has become so protracted. It is why the littoral operations mounted at the end of World War II, such as the invasion of Okinawa, involved huge numbers of small combatants – which are no longer affordable. In effect, a network concept replaces those small combatants with inexpensive remote sensors. While it was being conceived, LCS went from a Danish-style modular warship to a platform intended to strew sensors. It would process their data and send the result up the line into a fleet command system.
The modular idea was reflected in requirements for internal space (for containerized modules) and for a plug-and-play command system that could automatically adapt as different modules were installed. Unfortunately the modules themselves were not (and could not be) defined very precisely when the prototype LCS designs were being evaluated. There seems, too, not to have been much attention paid to the question of support. LCS was a large ship, but it was conceived more as an overgrown coastal combatant than as a blue-water ship. For example, it was minimally crewed. One operating concept had such craft operating in groups of three, normally based abroad, their crews changed on and off like the blue and gold crews of strategic submarines. Money was tight, and the program made no allowance for supporting ships. In the past, the U.S. Navy had often used major amphibious ships for that purpose (for example, to support fast motor gunboats (PGMs) used as “tattletales” in the Mediterranean Sea). By 2001, the U.S. Navy was far smaller, and it no longer had a substantial surplus of such ships. A few years later the cry was for all ships to be self-supporting (i.e., not to need a fleet train), but that hardly seemed true of the LCS. LCS is intended to operate autonomously for 21 days, well short of typical U.S. warship endurance.
An LCS carries up to seven modules, all of one type; current plans call for mine warfare, surface warfare, and anti-submarine warfare modules, and probably there will be others. Modules are associated with sensors strewn largely by unmanned craft, which may be helicopters (Fire Scout), surface craft, or underwater vehicles. Thus it is an important requirement that the LCS be able to launch, retrieve, and service all such craft. A peculiarity of the program is that it followed the new Defense Department guidelines, in which the contractor was responsible not only for the hull but also for all components, including the sensors. That made for greater freedom to select non-standard items, but it raises questions about logistics and training. As of 2010, it seemed likely that the ASW module would include a sonar towed from the boat-launching ramp.
The ships have provision for vertically launched anti-ship missiles, using the non-line-of-sight (NLOS) system originally developed for the U.S. Army. This is a networked missile that can be directed onto a target based on remotely determined target location. The ships can accommodate four 15-missile box launchers in their hulls or superstructures. The small missile is considered ideal for dealing with enemy coastal craft. Reportedly the designers were forbidden from providing space for anything larger so as not to threaten the Zumwalt program, which was justified as a land-attack ship (it is now dead, however). [Editor's note: NLOS-LS was canceled by the Army after this article was written, and the fate of the program remains in question.] The only organic weapons are a 57 mm gun and the RAM air defense missile. The 57 mm gun was chosen because, when the LCS program was being formulated about 2004, the U.S. Navy was considering abandoning its 76 mm gun as a way of cutting its budget. That did not happen.
Ironically, as the wars in Afghanistan and in Iraq have developed, the U.S. Navy has found that it needs ships for maritime interdiction, a traditional naval role, more than for combat roles such as mine countermeasures. Interdiction demands endurance on station and probably also the kind of helicopter capacity built into LCS, but not the exotic modules. It may turn out that the most useful modules will be currently non-existent ones offering extra bunks and extra supplies. USS Freedom went to the Caribbean for drug interdiction for her first deployment. The interdiction operation in the Arabian Sea has turned out to be an excellent way of denying al Qaeda the freedom to set up a replacement for its defeated Afghan operation. Anti-piracy is very much an interdiction operation, at least at present. In all of these cases, the ability to operate a helicopter freely (i.e., in various sea states) is more valuable than high speed, as the helicopter can catch craft the ship cannot.
Perhaps inevitably, the competition for the LCS contract focused on the fixed and measurable issues of speed and endurance rather than less well-defined ones such as capacity for modules and the ability to communicate the tactical picture to other fleet units. Three approaches competed after a July 17, 2003, pre-selection: a semi-planing hull related to the trans-Atlantic yacht which had fascinated Cebrowski; an Australian trimaran; and a surface-effect craft based on the Norwegian Skjold. The other exotic high-speed hull form, the hydrofoil, was presumably ruled out for a frigate-sized ship. The surface-effect solution was ruled out, and prototypes of the two other alternatives were bought (announced May 27, 2004). For a time, the Navy said that it planned to buy both types in quantity, but as of early 2010, it is to decide between them.
Lockheed Martin’s LCS 1 (USS Freedom) is the semi-planing design, Sea Blade. It is broadly related to the “short fat ship” proposed in the United Kingdom in the 1980s. Its virtue is that, because of its broad beam, it provides the sort of stability normally associated with a considerably larger ship. That is essential for operating a helicopter. Because it is a displacement hull, it offers considerable internal capacity. It has a well deck aft, from which small boats, manned or unmanned, can easily be launched, and it has spring-loaded doors alongside the well deck for boat servicing. However, the short, fat hull form requires enormous power. Freedom was possible to build only because gas turbines offer exactly that in a small space and with little weight. The ship requires a total of about 113,000 horsepower (two 48,000 horsepower MT-30 gas turbines and two diesels, the latter for cruising). That is more than a destroyer needs for more than three times Freedom’s displacement. Gas turbines drink fuel, hence the diesels to achieve the desired range. The ship is driven by four water jets. They solve the cavitation problem that might have been associated with small-diameter (for the desired shallow draft) propellers. Rated or claimed speed is 45 knots. Endurance is 1,150 nautical miles at 45 knots, 3,550 nautical miles at 18 knots. By way of comparison, a Perry-class frigate is rated at 29 knots and has an endurance of 5,000 nautical miles at 18 knots.
The air search radar is EADS’ TRS-3D, and the optronic fire control system is the Spanish Dorna. Freedom displaces 2,840 tons (3,000 fully loaded), which is about the size of a frigate. She is 379 feet long. Freedom is designed to carry up to two MH-60 helicopters in the large, 4,680-square-foot hangar, or one MH-60 and three Fire Scouts. Base complement (without modules) is 40. Capacity with module specialists is 75. By way of comparison, a Perry-class frigate of about the same dimensions, with its Mk. 13 missile launcher removed, requires a crew of 216. In this sense, LCS succeeds where the more ambitious Zumwalt has failed, in dramatically reducing crew size. It is not of course clear whether that has gone too far. In theory, the very small crew is possible because all will be highly rated and cross-trained (it is not clear whether the U.S. Navy training system is adapted to this kind of crew). Overall, the crewing concept is closer to that of an airplane than to that of a conventional ship.
The alternative is General Dynamics’ Independence (LCS 2), which uses the Australian (Austal) trimaran hull form. The hull design is based on Austal’s Benchijigua Express ferry, built for Spain. She displaces 2,675 tons fully loaded and is 417 feet long. The air search radar is the Swedish Sea Giraffe AMB (the 3-D version), and the combat direction system is based on the Thales TACTICOS. Like Freedom, Independence has a crew (without modules) of 40. A trimaran offers an attractive combination of steadiness (for helicopter operation) and low resistance (for speed), but it lacks the internal volume associated with the semi-planing hull. The trimaran supports a larger (11,086 square feet) helicopter deck but a smaller 3,500-square-foot hangar. Independence is credited with two MH-60s or one MH-60 and three unmanned Fire Scouts. Like Freedom, Independence uses a diesel plus gas turbine power plant, but needs less gas turbine power (two LM-2500 gas turbines, 30,000 horsepower each). Despite her smaller power plant, she is rated at a higher speed of 50 knots. Claimed endurance is 1,940 nautical miles at 46 knots or 4,300 nautical miles at 20 (a Perry is rated at 4,200 nautical miles at 20 knots).