Even in their earliest applications, naval guns were part of what would today be termed a weapons system, and their use was closely connected with other elements of ship design. The first guns were smoothbore cannon mounted in a ship's “castles,” where they could be fired down at the enemy deck. As improved metallurgy made heavier guns possible, however, it became necessary for balance to carry them closer to the waterline, a development that led to the cutting of gun ports into the sides of ships. Wheeled gun carriages followed, allowing the muzzle to be drawn back for reloading. Lowering the gun mountings to, and then below, the weather deck in turn made the ships themselves, rather than their crews, the immediate targets of gunfire—though experience soon showed it was not easy to sink a heavily timbered ship by fire with solid shot.
Throughout the age of sailing warships, naval guns did their work primarily by killing enemy sailors in a hail of splinters, and by disabling the opposing ship's rigging. More combats ended by boarding than by sinking, a process made easier because all guns of this era were so inaccurate that effective fire was impossible beyond a few hundred yards. Gun laying (aiming the guns) was a matter of ship handling. Tactics evolved accordingly, most fruitfully in the practice of sailing in “line ahead,” to allow multiple ships to concentrate their broadside fire against a single target.
The history of naval guns in the preindustrial era is thus a tale of evolving consensus, driven by the well‐understood characteristics of weapons whose superiority was unquestioned, and which changed only very slowly over several centuries. From the middle decades of the nineteenth century onward, this consensus—embodied in the long careers of ships like the USS Constitution, a forty‐four‐gun frigate laid down in 1797, and still a plausible choice as flagship of the Pacific Squadron in 1839—would be shattered by rapid technological innovation.
The Industrial Revolution introduced two basic changes in the character of naval guns. Improved gun founding (casting) and precision machining allowed the production of ever larger guns, strong enough to stand rifling, breechloading, and vast increases in tube pressures. At the same time, advances in chemistry and industrial design made it possible to replace solid shot with exploding shells. These developments necessitated fundamental changes in ship design. Rifled weapons were more accurate at longer distances than their smoothbore predecessors, characteristics that combined with the superior maneuverability of ships afforded by steam propulsion to increase the range of effective fire from a few hundred to a few thousand yards. The practice of mounting a ship's main batteries of guns in turrets on the center line by the end of the century was also linked to the characteristics of steam propulsion: the advantages of tactical movement in any direction could only be realized by ships that could also fire in any direction. Center‐line turrets also allowed much larger guns to be mounted safely.
The rifled shell gun placed a great premium upon the protective qualities of armor plate. The inconclusive four‐hour duel in the Civil War between the USS Monitor and the CSS Virginia (formerly the USS Merrimack) off Hampton Roads, Virginia, in March 1862 introduced the world to the spectacle of ironclad warships in action; but it was scarcely typical of what the future would hold, because both ships fired only solid shot. Their encounter confirmed initial impressions that the use of armor would increase a ship's defensive staying power. Early steam‐powered ironclads were routinely fitted with rams to make up for any possible deficiency in offensive capability. Once large‐caliber explosive shells become the norm in the 1880s and 1890s, however, it was rare for the resistive power of a ship's armor to equal the penetrative power of its biggest guns. At the same time, it became increasingly clear that against heavily armored ships, it was only the biggest guns that mattered, a principle that culminated in the all‐big‐gun design of the HMS Dreadnought (1905), the type for all subsequent battleships.
The aggregate effect of all these changes from the 1880s onward brought an almost unmanageable increase in naval firepower, which in the nineteenth century was calculated in terms of “broadside muzzle energy”: the total kinetic energy generated by the maximum number of guns on a ship capable of firing in a single direction. In 1860, the best ironclad warships disposed of just under 30,000 foot‐tons of muzzle energy. For capital ships laid down on the eve of World War I, the figure was about 600,000 foot‐tons—a comparison that does not take account of the fact that it took at least four or five minutes (often much longer) to reload a large naval gun in 1860, and less than one minute fifty years later.
Neither, however, does this comparison take account of the difficulty of actually hitting anything with these formidable weapons. At the start of the twentieth century, naval guns were still direct‐fire weapons in the strictest sense: they could be fired only at targets the operators could see, and effectively only at distances close enough to allow the gun to be laid horizontally (without regard to range). Even then, results could be disheartening: in the Spanish‐American War, the American squadron that sank four Spanish cruisers off Santiago, Cuba, in 1898, fired its guns at ranges closing to 1,000 yards, and still managed a hit rate of only 4 percent—with no hits at all by the main 13‐inch batteries. It was not until World War I that improved range keeping and fire control equipment permitted ships to employ indirect plunging fire at longer distances; and not until World War II that radar allowed guns to acquire targets beyond visual range.
By the 1940s, however, naval guns were losing their preeminence as the arbiters of combat at sea, first to airplanes, and most recently and more decisively, to guided missiles. Naval guns survive today only in vestigial form, as weapons for close‐in defense and as instruments of communication: despite far‐reaching technological change, there remains no substitute in naval communication for a shot fired across the bow.
[See also Battleships; Dahlgren, John; Precision‐Guided Munitions; Rodman, Thomas; Weaponry, Naval.]
James P. Baxter , The Introduction of the Ironclad Warship, 1933.
Bernard Brodie , Sea Power in the Machine Age, 1944.
John D. Alden , The American Steel Navy, 1972.
Stanley Sandler , The Emergence of the Modern Capital Ship, 1979.
Andrew Lambert , Battleships in Transition, 1984.