Development of submarine lethality
has been a matter of debate—often heated—since David Bushnell’s Turtle. However, once separated from specific programs or platforms, the concept often becomes somewhat amorphous. In a sense, increasing lethality means increasing the warfighting effectiveness of naval forces, which is exactly what Bushnell had in mind as he hand-cranked his submersible barrel across the Hudson River in 1776.

This article seeks to identify specific milestones in the development of submarine lethality since the beginning of the 20th century. In any such endeavor, no list can be complete to the satisfaction of all readers, so visit UNDERSEA WARFARE Magazine’s Facebook page ( and share historic developments in submarine lethality we left out. Extra credit will be awarded to those who provide not just an innovation but a historical example of its use or effect.


by Carsten Fries, Naval History and Heritage Command, Communication and Outreach Division

Hull Design
The basic hull profile of early operational submarines was limited by diesel-electric propulsion systems. Despite the additions of periscopes and rudimentary escape trunks, World War I-era submarines in many ways remained surface vessels adapted to submersible operations. Despite increases in capacity, speed, and cruising range, necessity to surface forced retention of some construction features of surface vessels, invariably placing limits on a boat’s operational flexibility and survivability. The hull design of the late-World War II German Type XXI and XXIII U-boats, both equipped with snorkels, began to erode this paradigm and was adopted in the U.S. Navy’s innovative post-war Tang class, the Barracuda class with its specialized sonar array, and the Sailfish-class of radar-picket boats. During the early Cold War period, both NATO and Soviet navies followed suit.

In 1953, two years before construction began on the Navy’s Skate class, an evolution of the Tangs and the service’s first nuclear-powered boats, a fully streamlined teardrop hull design was tested with the diesel-electric USS Albacore (AGSS 569). This was to lead to the single-screw “body-of-revolution” hull design and sail-mounted dive planes of the nuclear-powered Skipjack class in 1956. The nuclear-powered Soviet Alfa-class (Project 705) attack submarine, first conceptualized in 1957, represented another leap forward. Despite some loss of surface maneuverability, the teardrop hull vastly heightened underwater performance.

The United States, Britain, France, Russia, China, and India have since successfully adapted the nuclear-powered teardrop-shaped hull to a variety of operational and strategic missions. To some extent, navies solely equipped with modern, conventionally powered submarines have followed suit.

Despite the attempts of individual inventors to find a satisfactory alternative to a combined combustion-electrical propulsion system, diesel-electric propulsion had become institutionalized in modern navies by World War I. As noted above, despite ongoing modernization of submarine design, this type of propulsion inevitably imposed limits on operations.

In 1954, the launch of USS Nautilus (SSN 571), the first nuclear-powered submarine, represented a quantum leap forward in this regard. Hand in hand with the consistently high degree of operational reactor safety practiced by the U.S. Navy, nuclear propulsion has freed our submarines—as well as those of potential adversaries—from many previous operational boundaries. It will be interesting to see if the still-evolving air-independent propulsion systems will similarly revolutionize non-nuclear navies.

Weapons Systems
Until the advent of submarine-launched ballistic and cruise missiles, the evolution of the torpedo as a submarine weapon was illustrative of submarines’ expanding operational role. Improvements in torpedo propulsion, fuses, warheads and, ultimately, sensors have spanned the gamut from Robert Whitehead’s simple compressed-air design to the highly accurate Japanese World War II–era Type 95 “Long Lance” to the U.S. Navy’s Mark 48 Advanced Capabilities weapon with its sophisticated guidance system, depth adaptability, and counter-countermeasures.

Arming nuclear-propelled submarines with ballistic nuclear missiles and giving these platforms a strategic mission arguably changed the nature of the Cold War confrontation between the United States and the former Soviet Union. The creeping retirement of some U.S. land-based strategic strike systems gives continued relevance to our SSBNs’ mission.

Although the U.S. Navy armed submarines with cruise missiles as early as 1958 with the Regulus, regular combat deployment of these weapons (today’s Tomahawk Land-Attack Missiles) is a relatively recent addition to the mission profile of U.S. missile and attack boats, beginning with the Gulf War in 1991. Nonetheless, the addition of these weapons to the Submarine Force’s arsenal has greatly increased both operational flexibility and lethality of U.S. submarines.

Before World War II, limits in range, capacity, and endurance relegated the submarine to a coastal defense mission or tethered it to operating areas in relative proximity to its base. However, German development of true ocean-going boats just prior to and during World War I demonstrated the potential of the submarine in a commerce-raiding role—and as a growing threat to surface navies.

During the inter-war period, schools of thought concerning a submarine force’s mission(s) varied, leading to such anamolies as the “cruiser-submarines” employed by the British and French navies, and the very variegated submarine fleet developed by the Imperial Japanese Navy. Although takeaways from the Naval War College war games carried out during this interval contributed much to the Navy’s development of aircraft carriers and their central role in the then still notional future Pacific War, insights regarding submarines were few, in some instances merely relegating the boats to scouting.

Until 1943, when development of antisubmarine warfare (ASW) tactics and weapons became centralized functions in the U.S. (with the establishment of the Tenth Fleet) and British navies, the German submarine force severely impacted the Allied war effort in the Atlantic. The early-war successes of the Kriegsmarine U-boats and the maximum pressure applied against the Japanese surface navy and mercantile fleet that U.S. Navy submarines eventually brought to bear amply demonstrated the potential of the undersea forces.

Aside from targeting adversaries’ surface vessels, most navies also used submarines for other missions such as minelaying, special operations, search and rescue, and surveillance—harbingers of what most modern boats are capable of today. Expanding mission profiles helped power improved innovative design, improved construction techniques, and employment of better search radar, sonar, dedicated communications systems, and rudimentary electronic countermeasures. In turn, all of these contributed much to the growing operational versatility and lethality of submarines into the Cold War era.

The decades-long confrontation with the Soviet Union and its allies had the effect of applying various degrees of mission specificity to submarine types. To some extent, this approach hastened obsolescence for certain platforms as illustrated by the post-Soviet Russian navy’s submarine boneyards. However, the relatively few classes of U.S. submarines commissioned by the Navy since the dawn of the nuclear era speak both for the design quality as well as excellent adaptability to Cold War and post-Cold War operational realities. A 2006-2008 case in point is the modification of four Ohio-class ballistic missile boats to carry both cruise missile vertical launch systems and lockout chambers for special operations missions—both features indicative of evolving mission roles within the changing nature of conflict.

Any discussion of our Submarine Force’s quality must take into account the professionalism of each and every U.S. Navy Submariner, volunteers within an all-volunteer force. Ever since the steep learning curve experienced and overcome by crews of the World War I–era “pig boats,” consummate technical expertise, adaptability, and not a small dose of personal courage have been called for.

Submariners of all nations have progressed from a distant era in which the survivability of their boats was very low through the period when rescue vehicles and apparatuses were essentially experimental (rescue of USS Squalus (SS 192) in 1939, Momsen escape lung, etc.) to the high level of survivability today. However, constant maintenance of this standard has always required difficult training unique to the Submarine Force—and the professional dedication of each and every Submariner.

The loss of the Argentine navy’s ARA San Juan (S-42) last year, as well as the tragic saga of the Russian navy’s “Oscar II” Kursk (K-141) in 2000, only serve to underline this point. If the U.S. Navy did not identify and continually develop the high caliber of personnel serving as Submariners, submarines would not fill the key mission roles they do and, in the end, not be the lethal platforms they are.

Two important contributing elements to the five innovations raised in the article make U.S. submarines the dominant lethal force they are. First are the engineers, planners and builders generating cutting-edge technology and giving form and substance to ideas and plans. Second are the Submariners themselves, who are historically known for their ability to work together to find inventive solutions to overcome challenges. Innovation has made the U.S. Submarine Force a stabilizing influence on the world stage since the Cold War, and it is continued innovation that will enable it to be that stabilizing force going forward.