Hail to the Deep: A Strategy for Submarines

Hail to the Deep: A Strategy for Submarines

The grandmasters of naval strategy died before the sub came into its own. Can their insights be salvaged for a new era?

Second, certain basic principles that Corbett spelled out endure. Questions of concentration and dispersal, for instance, appear timeless. Corbett urges commanders to disperse the fleet across as broad an area as possible, scouring vital expanses of opponents and protecting friendly shipping. They must do so while keeping ships close enough to one another that they can “condense” at the “strategical center.” This would be the site of battle should an antagonist agree to fight. Such “elastic concentration” permits a navy to police the sea while massing assets quickly to outmatch an opponent. Highly mobile ships like SSNs can spread out widely because they can rush to scenes of action, vectored in by intelligence, surveillance and reconnaissance assets.

But concentration is mainly about focusing firepower at decisive places rather than assembling large numbers of ships at point-blank range from one another. Accordingly, the firing ranges and accuracy of shipboard weaponry are crucial determinants of combat effectiveness. A submarine outfitted only with torpedoes must get much closer to targets than a missile-armed boat. Extreme firing range for a U.S. Navy Mark 48 heavyweight torpedo, for instance, is about twenty-seven nautical miles. (Effective firing range, at which the shooter stands an excellent chance of a hit, is shorter than this figure—in all likelihood much shorter.) By comparison, the navy’s Harpoon antiship missile—a missile of very modest reach by today’s standards—lets American SSNs engage targets over sixty nautical miles away. Doubling the combat radius quadruples the area covered by a weapon system. Simple geometry determines how far vessels can disperse while still bringing combat power to bear. Long-range precision ordnance thus helps fleets meet the demands of elastic concentration.

Third, it would be a mistake to draw too sharp a distinction between offense and defense, or between conventional and nuclear-powered submarines. Depending on the circumstances, any submarine can act either defensively or offensively. Indeed, Corbett observes that even offensive warfare has a pronounced defensive component. No force is strong enough to take the offensive everywhere, so offensive-minded strategists must mount an effective defense of weaker areas. Even defensive forces, moreover, should maintain an attitude of “alert expectation” in case the chance arises to strike an offensive tactical blow.

Both conventional and nuclear-powered boats, then, have parts to play in hybrid offensive-defensive warfare. If the maritime terrain permits, mixed fleets of diesel and nuclear-powered subs could prove ideal for seizing and holding critical sea areas. An apt division of labor would assign diesel boats the primarily defensive functions and nuclear attack boats the offensive ones. Conventional attack submarines (SSKs), for instance, can guard rear areas, shielding the homeland against seaborne assault while freeing SSNs to pursue operations in distant seas. As undersea capital ships, SSNs can help bottle up or defeat opponents close to their coasts—evening the balance before winning partial or complete control of the sea. If usable bases are among the fruits of victory, in turn, SSKs could forward-deploy to hold zones cleared by the battle fleet. Nearby logistical support would let them stage a forward tactical defense of gains won through strategic offense. Commanders should stay on the lookout for such inventive options.


EXPLOITING SEA control is the function to which submarines are least suited. Nevertheless, they have some part to play. Generally speaking, a navy must win command before exercising command. But what happens if an enemy navy refuses to fight? Or what if circumstances demand that a navy land troops or execute other missions before it controls the sea? Corbett observes that, in these cases, commanders may have to do things out of logical sequence. War, he says, is

not conducted by logic, and the order of proceeding which logic prescribes cannot always be adhered to in practice. We have seen how, owing to the special conditions of naval warfare, extraneous necessities intrude themselves, which make it inevitable that operations for exercising command should accompany as well as follow operations for securing command.

Navies, in other words, may have to use the sea before they control it. So long as an adversary declines to risk his fleet, he poses little menace. That allows cruisers—ships incapable of fighting capital ships but optimal for controlling permissive waters—to assume their central role in maritime strategy. They can raid enemy shipping from day one of a conflict, inflicting economic harm. Submarines are a natural platform for such guerre de course operations. Depending on logistics, SSKs may be able to hover off enemy ports or at focal points such as straits, intercepting enemy shipping. SSNs can do the same, or they can pursue merchantmen or warships. Subs of all types can distort enemy shipping patterns simply by making their presence known. Few mariners will approach a narrow sea knowing enemies skulk below. But detouring around undersea dangers costs time, fuel, and wear-and-tear on machinery and hulls.

Nor must submarines confine their efforts solely to enemy shipping. Cruise missile–armed subs, particularly SSNs, can use their armament to project power directly onto enemy shores. U.S. Navy SSNs were fitted with Tomahawk land-attack cruise missiles during the 1980s and fired on ground targets in Operation Desert Storm and ensuing campaigns. During the 1990s, the navy converted four Ohio-class submarines to carry Tomahawks. Redesignated SSGNs, or nuclear-powered guided-missile submarines, these boats number among the navy’s principal platforms for direct power projection. Or SSNs and SSGNs can act together. In Operation Odyssey Dawn in 2011, the SSNs USS Providence and Scranton joined the SSGN USS Florida in lofting cruise missiles against targets within Libya. And some SSNs and SSGNs are equipped to land special-operations forces along enemy coasts, supplementing power projection through covert means.

Submarines, then, offer potent capabilities both during and after the fight for sea control. When fitted with systems enabling them to project force onto land, they become truly maritime platforms. “Naval,” explains Corbett, is a subset of “maritime.” Why? Because “men live upon the land and not upon the sea.” Land is where great matters are decided. Accordingly, maritime strategy is the art of determining “the mutual relations of your army and navy in a plan of war.” It’s about dominating the land-sea interface, the natural preserve of sea power.

So maritime strategy isn’t all about navies. To be sure, winning, denying and exploiting command are about stifling enemy commerce and naval operations. But these functions also open avenues into coastal zones through which joint land/sea forces can shape terrestrial events. No longer can navies be partitioned cleanly into a battle fleet, a swarm of cruisers and the flotilla. SSKs fit most closely into the flotilla, SSNs into the battle fleet. But submarines defy easy classification. Their capabilities span all three domains while adding missions of which previous sea-power theorists could never have dreamed.

All this only adds to the need for commanders to use sea-power theory to unlock the full potential of structureless fleets—including their silent services. Imagine what a Lucky Fluckey versed in sea-power theory could accomplish today.


James Holmes is a professor of strategy at the Naval War College. The views presented here are his alone.