The mainstay of the American surface fleet today is its cruiser/destroyer (CRUDES) force, comprising 22 Ticonderoga-class cruisers and 62 Arleigh Burke-class destroyers. Equipped with the state-of-the-art Aegis combat system, these ships are among some of the most formidable naval platforms in the world. However, their anti-surface warfare (ASuW) repertoire leaves much to be desired because of the neglect of this form of combat since the end of the Cold War. As of late, however, Washington has been taking concrete steps to get its CRUDES complement back into the maritime-strike business again.
Earlier this week, American defense firm Raytheon announced that the destroyer USS John P. Jones had successfully tested in January the new ASuW capability of the Standard Missile-6 (SM-6) on a decommissioned frigate, sinking it. This came after the revelation by U.S. Defense Secretary Ashton Carter last month that the surface-to-air missile, which is manufactured by Raytheon, was being modified to attack ships. He said, “We are going to create a brand-new capability. We’re modifying the SM-6 so that in addition to missile defense, it can also target enemy ships at sea at very long ranges. This is a new anti-ship mode. It makes the SM-6 basically a twofer.”
To a certain extent, the advent of the dual-purpose SM-6, which could be stored aboard every Ticonderoga- and Arleigh Burke-class vessel, would alleviate the ASuW deficiency endemic in the U.S. surface fleet. This is because the modified SM-6 will extend the striking reach of each American cruiser/destroyer and equip every single one of them with a credible anti-ship capacity.
The deficit in ship-attack capabilities
In the decade or so after the collapse of the Soviet Union, the United States Navy (USN) markedly shifted its gaze away from the high seas and towards the littorals as the possibility of confrontation with another enemy fleet of considerable standing was deemed remote. Power projection was now the emphasis for the United States as sea control was deemed a given. Two landmark documents released during the 1990s signify this shift. From the Sea (1992) and Forward … From the Sea (1994) stress the need for power projection in the littorals with no mention of force-on-force operations at sea against a near-peer competitor.
The land-centric conflicts in Southwest Asia of the early 21st century further accentuated the de-emphasis on sea control as the primary role of the USN during the wars in Afghanistan and Iraq was to support shore operations. Unsurprisingly, the focus on power projection saw a decline in the discipline of anti-surface warfare in the USN and the concomitant atrophy of its ship-attack capabilities. It is only in the past several years, especially with the upsurge in China’s anti-access/area-denial (A2/AD) capabilities, that maritime strike is being taken more seriously in the USN again. The aforementioned atrophy is such that the sole ASuW weaponry currently deployed on U.S. cruisers and destroyers is the RGM-84 Harpoon anti-ship cruise missile (ASCM) that can only be fired from eight single-cell launch canisters with no reloads. Most importantly, the Harpoon has a relatively short range.
Weapon range is a critical consideration in combat as having armaments with a greater reach enables one to attack the enemy without getting into his engagement envelope. Indeed, the doyen of naval tactics, USN Captain (Retired) Wayne P. Hughes, maintains in Fleet Tactics and Coastal Combat that being able to attack effectively first is the “great naval maxim of tactics”, adding that this principle should be regarded as the “very essence of tactical action for success in naval combat.” To be sure, sensory capacity is crucial in detecting the opponent in order to get the chance to shoot at him; but ceteris paribus, having a weapon that is longer-ranged than your enemy’s would go a long way toward striking effectively first, Hughes notes.
That said, with a range of only about 70 nautical miles (nm), the Harpoon is simply outmatched by ASCMs belonging to nations regarded as Washington’s strategic rivals. To illustrate, Moscow’s 3M80MVE Moskit has a reach of 130 nm, while Beijing’s YJ-18 can strike targets up to 290 nm away. It is also worth noting that the USN last fielded a long-range ASCM – the anti-ship variant of the Tomahawk – in the 1990s. In addition, the Moskit and YJ-18 are capable of flying at Mach 3 compared to the Harpoon’s Mach 0.7. This point is crucial as the faster the missile, the less reaction time opposing defenses will have.
To compound matters, out of the 84 unit-strong American CRUDES force, an eye-raising 34 of them – a good 40 percent – are not even armed with the Harpoon and hence do not have a dedicated ASuW capability whatsoever. The 34 ships in question are the Flight IIA Arleigh Burke-class destroyers that were built from the keel up without an anti-ship weapon, most of them having been conceived and constructed during the late 1990s and the early 2000s when the prospect of a sea-control threat emerging appeared remote. All in all, a good portion of the U.S. surface fleet is armed with only eight relatively short-ranged ASCMs; in any confrontation with a potential adversary in the mold of China, the Americans might invariably find themselves outranged and outgunned.
The modified SM-6 and its implications for the U.S. Navy
The introduction of the modified SM-6 would redress the U.S. surface fleet’s maritime-strike shortfall in various ways. First, it extends the CRUDES force’s striking reach. While the exact range of the SM-6 is classified, various sources put it as 200 nm, and this is a profound step up from the Harpoon’s 70 nm. What is more, the SM-6 can make Mach 3.5 as opposed to the subsonic speed of the Harpoon. To be certain, naval commanders might be reluctant to use the SM-6 in its secondary, maritime-strike mode as doing so reduces the number of the precious missile available for its primary role of anti-air warfare. What is worth noting, however, is that the SM-6 Mod gives commanders, especially those of the ASuW-less Flight IIA Arleigh Burke-class destroyers, the flexibility of exercising a potent, albeit secondary, ship-attack capability.
Hence with the modified SM-6 mitigating the U.S. cruiser/destroyer force’s ASuW deficit, putting into practice the much talked-about idea of “Distributed Lethality” (DL) becomes more viable. According to naval analyst Bryan Clark, the crux of this concept is that:
… deploying a large number of U.S. ships able to threaten enemy ships… will create a potentially unmanageable targeting problem for potential adversaries. This, it is argued, could deter opponents from pursuing aggression and in conflict could compel adversaries to increase their defensive efforts, constrain their maneuver, and spend valuable time finding and defeating U.S. forces in detail.
Before the SM-6 Mod, just over half of the USN CRUDES force has an ASuW capability and a relatively short-ranged one at that. With the “twofer” Standard missile in service, the entire USN cruiser/destroyer force could now threaten an opponent with an anti-ship weapon that is also longer-ranged.
The ASuW-capable SM-6 could also go some way towards ameliorating the navy’s forward presence problem. In recent years, the USN has struggled with this issue because of a reduced force structure; for instance, there was a notable carrier “gap” in the Persian Gulf in late 2015. With the modified SM-6 on board, independent U.S. Surface Action Groups (SAGs) comprising Ticonderoga-class cruisers and Arleigh-Burke destroyers would have more “teeth” and could operate more confidently in permissive operating environments such as those without a significant air threat. This frees up the resource-strapped navy’s valuable carrier and amphibious groups for operations in areas that truly necessitate the presence of such high-value assets.
The SM-6 Mod’s limitation: how serious is it?
All that being said, critics can argue that armed with a 140-pound blast-fragmentation warhead as opposed to an armor-piercing one, the SM-6 lacks the means to penetrate a large warship’s armor. They can maintain that the decommissioned frigate sunk during the January SM-6 test-firing, the 4,100-ton USS Reuben James, was a relatively small vessel and that the SM-6 could not scuttle larger vessels.
This line of reasoning is somewhat problematic, however. The 1.5-ton SM-6 approaches its target at Mach 3.5, amassing a huge amount of kinetic energy as a consequence. Even if a missile moving that fast could not breach a large warship’s armor, the former could inflict tremendous topside damage, especially on the vessel’s fragile sensory and communication systems. As such, while the SM-6 may not be able to sink its target outright, the missile can render the ship a “mission kill.” In other words, the vessel’s combat efficiency is degraded by damage to the point that it cannot perform its primary task(s). Take out the sensors of any modern weapon system, or for that matter, a warship, and it simply cannot “see”, let alone shoot.
Having said that, while the notion of the dual-use Standard missile is fundamentally sound, it is at best an interim solution to a long-standing problem. The likelihood of commanders utilizing its anti-ship capacity only as a second choice has been mentioned earlier, and the SM-6 Mod is arguably a stop-gap measure in addressing the navy’s maritime-strike deficit before the new 1000nm-ranged Tomahawk ASCM comes on board in 2021. And with the SM-6 slated to reach full operational capability in 2017, there will be a period of four years where the dual-use missile could hold the fort with respect to the U.S. CRUDES force’s ASuW capabilities.
Ben Ho Wan Beng is a Senior Analyst with the Military Studies Programme at Singapore’s S. Rajaratnam School of International Studies, and he holds a master’s degree in strategic studies from the same institution. Ben has a profound interest in naval affairs, and his work in this area has been published in the likes of Breaking Defense, RealClearDefense, The Diplomat, as well as The Center for International Maritime Security’s NextWar blog.