Convoy Escort: The Navy’s Forgotten (Purpose) Mission


Tom Hanks’ most recent World War II film, Greyhound, tells the story of an escort group shepherding its convoy to safety across the Atlantic. Over several days of desperate fighting, the escorts attempt to defend merchant ships and troop transports from German U-boat attacks. This fictional story is representative of the U.S. Navy’s struggle in the Atlantic during the war. While the invasion of Europe and subsequent march to Germany captured headlines, it was all made possible by the Allied navies in the Atlantic. Winston Churchill perhaps best explained its importance, writing, “The Battle of the Atlantic was the dominating factor all through the war. Never for one moment could we forget that everything happening elsewhere, on land, at sea or in the air depended ultimately on its outcome.”

Unfortunately, the Navy appears to have forgotten the importance of its Atlantic campaign. Since 1945, the Navy has prioritized offensive maritime missions — power projection and destruction of enemy fleets — over more essential defensive maritime missions, namely convoy defense. This is a flawed strategy resulting in three deleterious effects. First, it jeopardizes wartime success by abrogating the Navy’s ability to escort critical convoys. Second, it risks narrowing military options available to policymakers and increases the risks of escalation. Third, it results in a smaller fleet than might otherwise be possible, with a commensurate reduction in the ability to show the flag during peacetime. A reevaluation of the Navy’s strategy is necessary, and there is no better time than the present.



The Evolution of Naval Strategy

Convoy defense was a critical function of the Navy during World War II. Yet despite its importance, the Navy sought to divest itself of the convoy escort mission almost immediately after the war. The Navy’s postwar plan, as told in a 1946 testimony by Adm. Forrest Sherman, showed the most marked reductions in the vessels essential to the defensive war in the Atlantic. The Navy would inactivate or place in reserve 84 percent of escort carriers and 90 percent of destroyer escorts, compared to just 68 percent of fleet carriers. When forced to choose between offense and defense, the Navy would choose the offensive. The absence of any real maritime threat in the immediate postwar period and the greater, albeit more expensive, capability provided by fleet carriers and their escorts made such a choice easier to justify.

This trend was only reinforced by the broader security environment. Naval strategy in the 1950s was dominated by two factors: the stated U.S. policy of massive retaliation and the reality of proxy conflict during the Cold War. These factors contributed to the continual atrophy of the convoy escort mission. In a high-end conflict, the war would quickly turn nuclear and end before convoy escort was required. In a low-end conflict, convoys would not be threatened, and the Navy’s power projection and amphibious forces would add the most marginal value. In short, there was no expectation of a protracted conventional conflict against a capable enemy where convoying might be required.

In the 1960s, the Kennedy administration’s doctrine of flexible response changed this assumption. Under this doctrine, the United States would be prepared to deter and, if necessary, win a conventional war without resorting to nuclear weapons. Little changed for the Navy at first, however. From 1961 to 1970, the Navy was led by three successive naval aviators who continued to prize the power-projection mission. The Navy’s welcome contributions to the Cuban missile crisis and Vietnam War only backed this institutional preference for power projection. While the convoy escort mission received some attention, the Navy largely planned to rely on its NATO allies. Navy escorts would primarily serve to escort the Navy’s striking force and a limited number of military convoys — those transporting American soldiers and equipment overseas — while NATO forces escorted the bulk of the convoy volume, including merchant convoys.

An attempt at change came in 1970 with the appointment of Adm. Elmo Zumwalt as chief of naval operations. Zumwalt faced two large force structure problems when he began his tenure. First, the “block obsolescence” of vessels built during World War II meant the Navy would experience a large reduction in available vessels, especially escorts. Second, the buildup of Soviet naval forces challenged the Navy’s dominance at sea. Under Project 60, Zumwalt critically examined the Navy’s priorities given these problems. Zumwalt placed the control of sea lanes second only to the assured second-strike capability, writing, “Heavy reliance on sealift is an integral part of the U.S. role as a sea power. It emphasizes the absolute need to be able to control the seas if the nation is to exist.” Notably, he deprioritized power projection.

To deal with the problems facing the Navy, Zumwalt proposed a “high-low” mix of forces. Under this plan, the Navy would reduce the number of carriers and other “high-end” ships it planned to build to fund larger numbers of lighter vessels. These vessels would primarily be hydrofoil patrol craft, frigates, and sea control ships, the last being a sort of light carrier built with the escort mission in mind. Far from dispensing with the more capable ships entirely, Zumwalt instead believed the light forces would allow the Navy to accomplish its mission of sea control and protect merchants while also freeing up the heavier forces to conduct other operations. While Zumwalt was unable to secure funding for his entire program, the Navy did place the first orders for what would become the Oliver Hazard Perry class of frigates.

Unfortunately, Zumwalt’s emphasis on sea control, in the sense of defending convoys, and a balanced force was to be short lived. The combination of Adm. Thomas B. Hayward, named CNO in 1978, and Secretary of the Navy John Lehman, named in 1981, took the Navy in a different direction entirely. Hayward and other Navy flag officers believed there was too much emphasis on the convoy escort mission during Zumwalt’s tenure. Hayward, a career naval aviator who had come from command in the Pacific, argued the Navy should ensure sea control by going on the offensive against the Soviets. He found an ally in Lehman, a former A-6 Intruder naval flight officer. Together, and with the support of the Reagan administration, they pushed for a “global, forward, and aggressive” Navy.

The centerpiece of the Maritime Strategy was a naval offensive against Soviet forces. Naval intelligence had identified the top priority of Soviet naval forces as defense of ballistic missile submarine bastions and the homeland. Thus, by going on the offensive, the Navy believed it would be able to simultaneously threaten Soviet ballistic missile submarines and prevent the Soviet navy from attacking sea lanes. To support this strategy, the Navy would surge to 600 ships geared toward power projection. While the number of carriers and battle group escorts would increase, the number of frigates — essential to the convoy escort mission — would decline.

The irony of the Maritime Strategy was that it seems to have had little impact on Soviet naval thinking. Analysts had identified the Soviet bastion strategy as early as the late 1960s, and Soviet forces were implementing it by the mid-to-late 1970s — before the Maritime Strategy was promulgated. Moreover, if the Soviets never intended to use their naval forces offensively, then it is unclear how the Navy’s offensive strategy would result in the Soviets withholding those forces. The Soviets were going to withhold their assets to defend ballistic missile submarines regardless of what the Navy did.

There were many contemporary critics of the Maritime Strategy as well. Academics John Mearsheimer and Barry Posen both criticized the potentially escalatory nature of going after Soviet nuclear forces. Posen additionally realized the constraints of only having a navy oriented toward the offensive, writing, “NATO should never have so many aircraft carriers and so few convoy escort vessels … that, once war breaks out, offensive operations against the Kola Peninsula appear to be the only feasible way to effectively protect the SLOC [sea lines of communication].” Simultaneously, a subset of naval officers argued the Navy was losing sight of the convoy defense mission. Congressman Bill Chappell perhaps summarized the situation most directly: “The most recent Navy testimony comes down to this: YES — the mercantile convoy escort mission is vital. NO — our Navy does not have the assets to meet this requirement in many of the more likely scenarios.”

The Navy was betting everything on a forward offensive strategy. Left unaddressed by the Maritime Strategy was what would happen if the Soviets went on the offensive against the sea lanes, if the Navy were badly mauled during an offensive, or if political decisions required the Navy to assume a defensive posture or otherwise limited offensive options. While some argue the strategy helped accelerate the fall of the Soviet Union, it is unclear if that acceleration was worth the risks involved.

The Navy Today

Today, the Navy is faced with new challenges. China is undertaking a massive naval construction program. America is again faced with the task of supporting allies overseas. There is uncertainty about the nature of a confrontation with China and what is necessary to deter a conflict. Yet the Navy seems poised to make the same errors it made during the Cold War. Current navy force structure proposals, part of the Future Naval Force Study, are too focused on the offensive at the expense of the convoy escort mission. For example, neither the Hudson Institute’s nor former Defense Secretary Mark Esper’s plans appear to allocate any vessels to this vital mission. While the plans do include several frigates and other escort vessels, those appear to be tasked with escorting replenishment groups or other striking forces — not merchant convoys. The force structures ultimately paint the picture of a Navy built for itself: offensive power and ships to sustain offensive power. The Navy is potentially preparing for the wrong war entirely.

It is perhaps geography leading naval strategists astray. Although a conflict with China would likely take place in the Pacific, it is unclear if the Pacific theater of World War II is an appropriate guide for military thinking. For the U.S. Navy, the war in the Pacific was a strategic offensive after 1942. The massive carrier groups and submarine forces dominating naval thinking were meant to destroy Japan’s navy, strangle its economy, and support an amphibious drive across the Pacific. Today, however, America would be on the strategic defensive. Thus, unlike the war in the Pacific where Japan’s navy sought a decisive naval battle against America, a conflict could be more like the Atlantic, where Germany used its navy to try to interdict commerce and supply convoys. It is very possible future maritime conflict in the Pacific would be dominated by the battle to resupply forward allies.

Nowhere is this more evident than in a potential conflict over Taiwan. Taiwan is extremely dependent on secure access to the sea. In 2018, Taiwan was 98 percent dependent on energy imports and 65 percent on food imports. Independent of energy or food, Taiwan’s economy is dependent on trade. Taiwan’s total trade volume was $622 billion, more than its GDP of $590 billion. By comparison, the United States in the same year had a trade volume of approximately $4.2 trillion, but this was with a GDP nearly five times greater. To support this economic activity, Taiwan relies on shipping. In 2018, Taiwan saw a shipping volume of 75,321 vessels totaling nearly 1.6 trillion tons.

Taiwan’s reliance on shipping is its real vulnerability. While it is unclear whether China could accomplish a fait accompli invasion of Taiwan, it could very well destroy, threaten to destroy, or blockade merchant shipping. Interdicting merchant shipping would ravage Taiwan’s economy. Similarly, the threat of destroying shipping could cause many shippers to decline to sail to Taiwan with equivalent results. While the ripple effects of such acts would be huge, it is important to remember these actions could be viewed as lower forms of escalation than an invasion.

In any scenario — invasion, destruction of merchant shipping, or threat of the same — Taiwan’s ability to resist would depend on the United States escorting merchant shipping to the island. Although Taiwan’s reserves of food and energy supplies make it resistant to all but an extended blockade, the destruction of Taiwan’s economy could eventually force a referendum on the Taiwanese people’s will to resist. Similarly, an inability to supply Taiwan with arms would seal its fate in the event of an invasion. To prevent such an occurrence, the United States should signal its will and capability to continue to supply Taiwan over a range of scenarios.

A fleet geared toward conducting the convoy escort mission would be vastly different than the current one. While many of the technologies the Navy is investing in could prove useful for escorting convoys, capability is not enough. The convoy escort mission requires capacity and institutional knowledge to be successful. For example, it is not unreasonable to assume the requirements of escorting convoys to Taiwan or other allies might take over 100 frigate-sized escort vessels — five times what the Navy is currently programmed to buy with the Constellation class. Additionally, it would likely require more anti-submarine helicopters, more maritime patrol aircraft, and, ideally, a light carrier and air wing optimized for air defense and anti-submarine warfare. Japan’s Izumo-class destroyers provide a notable example of this capability. These forces would need to practice operating together to defend unarmed merchants against capable adversaries. Other capabilities might take on a reduced importance. For example, unmanned vessels might be less useful — protecting merchants while fighting an enemy is significantly more complex than mere offensive action. Additionally, it is unclear if the fleet would need as many amphibious ships or other power-projection forces such as aircraft carriers and strike aircraft, although such a reduction would be contingent on total joint force requirements and capabilities.

By building a fleet capable of escorting convoys, the Navy will accomplish three things. First, it will signal its potential to sustain Taiwan in the event of conflict, improving America’s ability to deter aggression. Second, it could provide flexibility to policymakers by allowing the nation to respond effectively to Chinese actions short of an invasion. Lastly, a fleet capable of escorting convoys is a fleet with numbers. By building the numbers capable of escorting convoys in wartime, the Navy will have the assets necessary to conduct presence operations in peacetime without undue strain on major combatant vessels.


To ensure the United States can effectively defend Taiwan, with the critical requirement being sustainment via the sea, the Department of Defense should take the following actions. First, determine the Navy’s readiness to escort convoys through wargames, analysis, and exercises. Second, reevaluate the requirement for ship-based offensive firepower, given other relevant joint force capabilities. Third, begin studies on an alternate Navy force structure emphasizing contested convoy escort as an essential mission. Fourth, explore the possibility of sharing the convoy escort responsibility with allies. It is important to note the convoy escort mission advocated here is not necessarily an argument for a return to World War II-style convoys. Instead, present and future threats may necessitate innovative tactical experimentation along the lines of Navy exercises during the Cold War. Nevertheless, it is this author’s belief that some sort of convoying will be necessary, even if its exact form remains unknown at present.

The ultimate test of naval power is the ability of cargo ships to move across the sea, not the number of weapons fired at an enemy. During both World War II and parts of the Cold War, the U.S. Navy built a fleet capable of escorting convoys to support allies abroad. It should do so again today. It is a uniquely naval mission, and, given the geography of the United States, perhaps the most important mission in the U.S. military, save for strategic deterrence. As Steven Roskill wrote in the official history of Britain’s naval operations during World War II, “If it is inevitable that, in maritime war, the actions fought by the warships and aircraft gain most attention, it must never be forgotten that the purpose of those actions is, nearly always, the protection of the merchantmen.”



2nd Lt. David Alman is an officer in the Air National Guard. In his civilian career, he has worked as an engineer, defense analyst, and management consultant. The views expressed here are his own and do not reflect those of his civilian employer, the U.S. Air Force, or the Department of Defense. The author is grateful to numerous individuals for their helpful comments — any errors are the author’s alone.

Image: North Atlantic Convoy. USS McCawley (APA 4), starboard view, along with ships in a North Atlantic Convoy, probably February 1942. During this time, she was bringing troops to Iceland. Note, dirigible above. Official U.S. Navy Photograph, now in the collections of the National Archives.