Kicking Down the Door: Ohio-Class Subs vs. China's A2/AD

Kicking Down the Door: Ohio-Class Subs vs. China's A2/AD

Cruise-missile submarines are the best answer to Beijing's tactics.

How best could the United States metaphorically “kick down” the anti-access/area-denial (A2/AD) “door” of a near-peer adversary during a conflict? This has been an idée fixe for American defense planners during recent years, in view of the rising A2/AD capabilities of strategic competitors such as China. There seem to be no clear answers to this question.

What is quite unanimous, however, in the defense community is that the relatively short striking reach of America’s naval crown jewels—its large-deck aircraft carriers—means that they would have to operate well within the enemy’s A2/AD envelope , rendering the flattops vulnerable to attack. As such, they are unlikely to partake significantly in “first day(s) of war” operations, that is, to be involved in the opening kicks on the adversarial A2/AD door when enemy defenses are at their strongest.

That said, the U.S. possesses two deep-strike capabilities that stand a much better chance of circumventing the access-denial barrier: Air Force stealth bombers, and the navy’s Tomahawk land-attack cruise missiles (TLAMs), which is deployed on cruisers, destroyers and submarines. And with regard to the Tomahawk-armed naval platforms, the Ohio-class nuclear-powered cruise-missile submarine (SSGN) is undoubtedly the most potent in terms of TLAM capacity, as well as being the most survivable, owing to its extremely low observability. Hence with its stealth and firepower, the Ohio SSGN is arguably the ideal counter–A2/AD naval platform in the U.S. arsenal.

 

Considerable Firepower

The Ohio SSGNs began life as ballistic missile submarines (SSBNs) before they were refitted as underwater Arsenal Ships during the early-to-mid-2000s. During the conversion, twenty-two of the boat’s twenty-four ballistic-missile tubes were modified to receive a special canister that enables the storage and launch of seven TLAMs each, with the other two missile silos being adapted to support special operations for at least sixty-six Navy SEALs.

Following the conversion, the Ohio SSGN can carry 154 TLAMs, which is slightly more than half the total number of missiles expended during Operation Desert Storm. Moreover, the sub can launch its entire arsenal of Tomahawks in as little time as six minutes , making it an ideal platform to deliver a large “pulse” of firepower that would be crucial during the opening stages of a counter-A2/AD campaign. This pulse could be unleashed on air defense, command-and-control, and other key installations that enable the access-denial door to be knocked down. When that happens, carrier planes and the Air Force’s non-stealthy aircraft would then find it easier to “enter” the door in follow-up operations.

It is worth noting that during the deployment of USS Florida to Operation Odyssey Dawn—the first time the Ohio SSGN was in combat— some fifty of the 112 TLAMs that were used to cripple Libya’s air-defense network came from the Florida. Acknowledging the contributions of the TLAM-armed American submarines (the Florida and two smaller attack boats) in softening defenses during the Libyan campaign, then Rear Admiral Rick Breckenridge of the U.S. Navy noted that:

***“This [using subs to fire TLAMs] gets back [to the] principle (that if) we don’t have superiority in the air to have our way at the onset of a crisis, we’re going to need somebody who can penetrate the defenses and soften up the adversary so then we can flow those other forces in to establish air dominance. . . . So in the onset of that campaign. . . the undersea forces. . . were called upon to attack land targets in Libya.”

Tellingly, the Florida fired ninety-three of the 199 TLAMs used during the two-week-long Operation Odyssey Dawn.

In addition, the American SSGN’s large TLAM payload makes it unrivalled in terms of land attack compared to other similarly-armed U.S. Navy assets. To illustrate, the two most numerous nuclear-powered hunter-killer boats (SSNs) in Navy service—the Virginia- and Improved Los Angeles–class—carries only twelve Tomahawks. Similarly, the slated replacement for the Ohio SSGN , the Virginia-class SSN fitted with the Virginia Payload Module (VPM) is armed with a relatively meager forty TLAMs. While the VPM-equipped platforms are essentially SSGNs in all but designation, given that they carry forty missiles, this inventory could be depleted quickly during high-tempo operations against an opponent employing A2/AD measures.

The Ohio SSGN also overshadows its surface brethren in terms of TLAM capacity. While the Ticonderoga-class cruiser has a 122-cell VLS, one must bear in mind that a significant number—definitely more than half—of these cells will be taken up by surface-to-air missiles for fleet air defense. Ditto the Navy’s workhouse: the Arleigh Burke–class destroyer, with its either ninety- or ninety-six-cell VLS.

Given that a typical U.S. carrier strike group comprises a Ticonderoga and two Burkes, their combined Tomahawk payloads might not even match that of just one Ohio SSGN. To be sure, once the submarine fires off its entire inventory of TLAMs, it must return to port for resupply. However, this is also a problem that afflicts the American cruiser/destroyer force, as the U.S. has yet to solve the problem of how to carry out at-sea VLS replenishment . And while carrier aficionados may make the counterargument that the total firepower that could be delivered by the U.S. carrier air wing alone is equivalent to four thousand Tomahawks , such an assertion ignores the fact that the flattop would have to operate close to the enemy, as mentioned earlier.

 

Low Observability

Getting this immense firepower of the Ohio SSGN to bear on the enemy’s access-denial barrier is then greatly facilitated by the submarine’s stealth. For one, it goes without saying that the submarine is much harder to detect compared to the various U.S. Navy Tomahawk-armed surface combatants, and this eases considerably its penetration into an enemy’s inner sanctum.

Such is the Ohio SSBN’s quieting that Soviet/Russian hunter-killer boats loitering near American boomer bases have often been said to lose contact with their Ohio quarry not long after the former leave port for deployment. And out in the open sea, the Ohios operate almost silently, which is hardly surprising as they were designed to be credible nuclear second-strike platforms.

Moreover, the stealth of the Ohio SSGN means that it could launch its cruise missiles from a position further within the enemy’s A2/AD envelope. TLAM-armed surface ships would hesitate to operate any closer than nine hundred nautical miles (the range of the TLAM) from the enemy’s shore if the latter possesses credible anti-surface systems. On the other hand, the Ohio SSGN does not face this problem; as such, it could operate much nearer to the enemy and concomitantly be able to hit more targets inland.

Critics can contend that the firing of TLAMs would nullify the Ohio’s low-detectability advantage. This is because the launch of a missile underwater is a noisy affair, and the “flaming datum” would give away the position of the submarine, making it susceptible to enemy counter-attack. However, when the Ohio SSGN fires off its TLAMs, “clears datum” and resumes silent running, it becomes once again a virtual shadow in the sea.

 

The First. . . and Last of Its Kind?

All in all, the Ohio SSGN’s attributes of stealth and firepower makes it a robust candidate for partaking in “first day(s) of war” operations against near-peer competitors. However, the four American SSGNs currently in service are scheduled to retire in the period 2023–26, without a like-for-like replacement. With that, the U.S. Navy will lose a significant amount of its force-projection capabilities. To be sure, the Ohio SSGN’s supposed replacement—the VPM-equipped boat—scores high in the area of quieting, but it simply cannot stack up in terms of firepower, as its TLAM inventory is only one-quarter that of the Ohio.