Naval guns and gunnery

Naval guns are artillery weapons on ships; although they are descended from land-based weapons, they quickly became specialized weapons, because of the particular technical issues involved in their use on vessels. With the rise of naval artillery, firing projectiles at opposing vessels mostly replaced the previous methods of fighting at sea, including ramming and boarding.

They first appeared in Korea in the early 1370s, and they came into general use in the West in the 15th century, and in the East by the mid-16th century. The years between 1500 and 1941 comprised an era in naval history in which all the major fleets were built around platforms that could shoot bigger and more accurate guns. This era came to an end with the Battle of Pearl Harbor in 1941, when the Japanese aircraft carriers sank the American battleships. Naval guns are now used primarily as defensive measures against small boat or missile attacks, and for shore bombardment; the bombardment role is the primary area of active research and development, although some autocannon are under development for point defense (e.g., Oerlikon Skyshield) and against small boats (e.g., 25mm Bushmaster Mark 38 Mod 2), especially potential suicide attackers.

First guns in East Asia: 14th-16th centuries

The world's first naval guns appeared in Korea during the Goryeo Dynasty. In order to counter the increasing activities of the Japanese pirates with experienced fighters and speedy ships, the Korean goverment imported gunpowder and gunpowder weapons from China. The Koreans built new ships equipped with gunpowder weapons - 1373 was the year that a rocket was fired experimentally from a ship for the first time. In 1375 Korea began to mass-produce gunpowder, when Choe Mu-seon, a government civil servant, figured out the manufacturing techniques kept secret by the Chinese. With Choe's initiative within the Goryo government, the Koreans established in 1377 a weapons research institution - the first of its kind in Korea, and its main responsibilities were to mass-produce black powder, build gunpowder weapons, and construct ships designed for the new weapons. All these developments led to the world's first naval engagement with the cannons in action - the Naval Battle of Jinpo in 1380, in which a Korean squadron of 40 warships engaged a Japanese fleet that was attacking the present-day Gun-san area on the mouth of the Keum-gang River. The Korean ships sank all 500 of the Japanese ships with rockets and the Dae-ham-yong cannons. Although China was the first country in Asia to develop cannons, the Chinese never applied them in naval warfare until the later years of the Ming Dynasty.

First guns in Europe: 15th century

In Europe, the first authenticated mention of a naval gun came in the early 15th century, shortly after the appearance of land-based artillery. Italian and English warships carried guns by 1440. They were about 4 feet long with 4-inch caliber. The early guns were simple tubes built up from long bars of iron held together with iron bands. These guns were breechloaders with a separate gunpowder chamber, or servidor, which was wedged into the breech after the stone or iron cannon ball, had been inserted. Muzzle-loading cast-bronze guns came into use soon after the wrought-iron breechloaders. Cast-iron guns came into being soon after cast-bronze guns. Despite distinct advantages of cast iron, its heaviness, the rust factor and the great danger to crewmen when it burst meant that for centuries heavy cast-iron and lighter cast-bronze guns (which split rather than burst) were both used.

In the mid-16th century, cast-iron, cast-bronze, and banded wrought-iron guns were all used aboard ship, as is evidenced by the salvage of the Mary Rose the flagship of English King Henry VIII (sunk in 1545 and salvaged in 1836) which contained guns of all three types. Arrows and stones, used in early guns, gave way to cast-iron balls.

The earliest gunpowder was a finely ground mixture of charcoal, saltpeter, and sulfur. This mixture, known as "serpentine powder," tended to absorb moisture, to separate into its components while being transported; it did not burn if packed too tightly into a gun. By the 15th century gunners used corned powder which was pressed into pellets and screened to a uniform size.

Gun mounts were improved over time. In early galleys, a light gun was placed in a wooden holder and tied to the deck. A heavy post at the breech prevented recoil. Bigger guns would break loose so ropes were used to permit the holder to slide back. Eventually four small wooden wheels were attached to the holder, making a carriage. To check the recoil, a heavy rope or "breeching" was run from the breech of the gun to the side of the ship.

As guns were added to ships, the architecture of the ships was modified radically. Small oar-driven galleys gave way to larger ships powered by sails. In the Mediterranean, the galleass, which used both oars and sails, came into widespread use. Its guns were arranged at intervals along the sides and over the rowers' heads. In the North Atlantic, the galleys were abandoned in favor of small sailing vessels which gradually gave way to larger ships, such as the half-moon shaped galleons. The sailing ship had the advantage that the guns did not interfere with rowers. Large sailing vessels were built with sides curving inward ("tumbled home") above the waterline, thereby strengthening the ship and making it a more steady gun platform, while offering a sloping target to enemy shells.

The gunport, which could remain watertight when closed, was invented by Descharges of Brest, in 1501. They made it possible to post guns on different decks along the sides of the vessel and marked an important step toward the development of the broadside ship. One of the earliest of large armed ships, the new Swedish Makalos, destroyed by the Danes in 1564, carried 178 guns, including 67 cannons and smaller weapons which were mounted on swivels. The Spanish Philip which engaged the English in 1591 carried three tiers of guns on each side with eleven pieces to the tier. This ship also had eight guns forward and several astern. The heaviest gun then in use in the English Navy was the culverin weighing 4,500 pounds (2,000 kg) and firing a 17-pound (8-kg) ball with an extreme range of 2,500 yards. Next in size was the demicannon weighing 4,000 pounds (1,800 kg), which fired a 30-pound (14-kg) ball to 1,700 yards; smaller guns included the cannon-petroe or periers, sakers, minions, and falconets. The maximum range of these guns was at best 500 yards. The shells wobbled in flight, losing velocity as they sliced off in any which direction.

Technique for using guns in battle was described as follows in a Spanish lecture of about 1530: Bow guns or broadside guns on the side from which boarding was planned were fired only when the ships were relatively close to each other, the lower guns firing at the waterline and the upper guns and smaller cannon at the sides, sails, masts, and men on the poop deck. The crossbowmen and harquebusiers did not fire until the enemy was very close or in the act of boarding.

The decisive role of the new guns was shown in a sea fight off Preveza, Greece, in 1538 and was confirmed in the victory of the Christians over the Turks in the Battle of Lepanto in 1571. At Lepanto, heavy guns mounted on the galleasses, broke up the charges of Turkish vessels, which were using ramming tactics. Small arms such as harquebues, were probably more important than bows and other hand weapons in close-range fighting. Spanish novelist Miguel de Cervantes, hit three times at Lepanto by gunfire, has Don Quixote cry out, "Blessed be those happy ages that were strangers to the dreadful fury of these devilish instruments of artillery, whose inventor I am satisfied is now in hell, receiving the reward of his cursed invention." Lepanto marked the first major use of naval artillery in the west. The galleasses used sails, not oars; their high sides suited the harsh ocean conditions and made an ideal gun platforms. The Turks relied too long on oar-driven manpower-intensive galleys, unfit for long voyages or heavy seas. The great European sailing ships with their big guns and huge cargo capacity gave the West a decisive advantage in the conquest and colonization of the globe. The Ottoman Empire, still by far the leading Muslim power, fell further and further behind.

In 1588, the English repelled the Spanish Armada in part by using their guns from long range, which prevented the Spanish from closing for hand-to-hand fighting. Thus, in the 16th century, the gun proved to be an important and sometimes decisive factor in naval warfare. This was formally recognized in 1618 when the English Commission on Naval Reform reported that sea fights were "chiefly performed by the great artillery breaking down masts, yards, tearing, raking, and bilging the ships. ..."

Iron sheets hung over the sides were used in 16th century Venice and Korea to protect against enemy fire; it gave a "tortoise" look. In the 1790s the Americans protected the frigate Constitution (Old Ironsides) with 22 inches of oak wood at the waterline, and 19 inches above the gun deck.

Ships of the line

Mounting 60 to 80 heavy guns the battleships of the era, called "ships of the line" had to grow bigger. Smaller and more flexible were the frigates. Both were redesigned to maximize firepower. The "Royal Sovereign", launched in 1637, was probably the first three-decked English warship and she proved extremely serviceable. Its builder, Phineas Pett, described its armament in his journal:

Her lower tyre [tier] hath thirty ports which are to be furnished with demicannon and whole cannon; her middle tyre hath also thirty ports for demiculverin and whole culverin; her third tyre hath twentie six ports for other ordnance; her forecastle hath twelve ports, and her half deck hath fourteen ports; she hath thirteen or fourteene ports more within board for murdering pieces, besides a great many loope-holes out of the cabins for musket shot. Shee carrieth moreover, ten pieces of chase ordnance in her right forward, and ten right aft, according to lande service in the front and reare.

The 19th-century warship was superficially similar to its 17th-century counterpart. Alfred Thayer Mahan, the leading naval historian of the 1890s, greatly exaggerated the prowess of 17th century ships, endowing them with firepower, seakeeping capability, and crusing endurance of ships built in 1800. However much more is now known; for example the guns of the Santíssimo Sacramento, a Portugese galleon that sank in 1668 have been recovered and analyzed by naval archaeologists. Mahan assumed they were equally capable of operating for extended periods at some distance from their home ports, but they were not, and thus the opportunities for a decisive fleet battle like Trfalgar were much less.

The first of 12 Spanish three-deck ships-of-the-line was the Real Felipe (1732-50), which displaced 1,965 tons, carried a crew of 1,250, and mounted 114 guns. Its most significant action occurred with the French against the English in the Battle of Toulon in February 1744.

After victory in the Seven Years War (1756-63), Britain allowed its great fleet to literally rot--66 ships sank because of rotting wood. Reform came during the War for American Independence, and in the critical year 1781 the French, Spanish and Dutch allies had about 168 major warships of 60 or more guns, versus 114 for the British (and none for the United States). The French defeated the British off Yorktown in 1781, forcing the surrender of the main British army in America. Finally in 1782 the British recovered and sank the French fleet at the Battle of the Saints in the West Indies to regain control of the seas.

A "ship of the line" was a main battleship, built from 2,000 oak trees and carrying 74 or so guns, each effective out to 300 yards. Battles had to be fought close in, with marines essential as sharpshooters and boarding parties.

The techniques of gunnery remained fairly static before the 1870s. Constant drill speeded the maximum rate of fire from one round every five minutes (1660s) to one round a minute (1760s). Rate of fire and weight of the shells in a broadside was more important than accuracy when the enemy was close. The ship of the line, or broadside ship, with heavy guns mounted on the lower deck just above the waterline and with lighter guns on higher decks, remained the dominant factor in naval warfare despite many small improvements.

Frigates

The frigate was the most glamorous ship in the British navy during the era of Napoleonic seapower. Frigates made up a quarter of the 412-ship royal fleet in wartime, and were kept in active service during peacetime. The frigate had between 32 and 44 guns and a crew of 217 to 297 men. While not as big as the ship of the line, it could outrun anything with more firepower and catch commercial ships, sloops, and corvettes. It could handle a variety of tasks, including raiding coastlines, running down opposing ships, and scouting.

Frigates were used for reconnaissance, convoys and raids. Sloops were even smaller and cheaper; their 20 guns were enough to overpower any merchant ship, or control rivers and bays. In the American revolution John Barry, a 30-year-old Philadelphian and senior captain of the almost-landlocked American navy in 1778 Barry commanded the Raleigh, a 700-ton frigate with 36 guns and 235 crewmen. In late September 1778, the Raleigh engaged the Unicorn, a 22-gun ship, and the Experiment, a 50-gun ship-of-the-line. Barry lost the Raleigh and 135 men were captured, but he disabled the Unicorn and escaped with 86 men.

The era of dominance by frigates ended when "big" frigates like the "USS Constitution" appeared in the waters.

Gunnery science

Gunnery was a mysterious art because every element was variable. Shot was never uniform, because of careless manufacture and rusting in storage. Gunpowder varied even more in terms of strength and burning rate; the bore of the guns varied in size. Even the mathematical models proposed for predicting the trajectory of projectiles through the air varied among mathematicians. A British scientist, Benjamin Robins (1707–1751), in the 1740s, put forward basic theories and supporting experimental data which put ballistics into the framework of Newtonian mechanics and formed the basis of the science of ballistics. For example, by applying Newton's second law to velocity measurements at varying ranges, Robins measured the air-resistance that slowed balls in flight. Robins proposed that the bore of the cannon be enlarged, that they be equipped with snug-fitting balls, and that they be fired with decreased charges of powder. This, he argued would increase destructive power, since the larger ball with a relatively low velocity would do more damage than would a smaller one. He further urged that careful attention be given to designing new guns to eliminate unnecessary weight.

In A Proposal for Increasing the Strength of the British Navy (1747) Robins proposed a new naval gun design based on his models, and in 1779, the carronade was invented to incorporate Robins' ideas. These short-barreled, light-weight, large-bore guns used a small powder charge and the same projectile as did the long guns. As Continental scientists like Leonhard Euler developed Robins' ideas, Navies across Europe hurried to adopt Robins' proposals. The British put carronades on existing ships and armed many of the smaller warships, such as frigates, sloops, and brigs, entirely with carronades. Similar guns were put into service by the Dutch, French, Spanish, and American navies. The carronade's short range eventually led to loss of interest in it as a naval weapon. In two actions during the War of 1812, this shortcoming was an important factor in determining the victor. In the Battle of Lake Erie, American forces fought with long guns from beyond the range of British ships, and the English commodore reported, "We remained in this mortifying situation five hours, having only six guns in all the squadron that would reach the enemy, not a carronade being fired." In another action, the British ships Phoebe and Cherub, armed with long guns, captured the American frigate Essex, which was equipped almost entirely with carronades. Despite its shortcomings, the carronade demonstrated the importance of quick-firing weapons and the need to use projectiles which fitted snugly into the bore of the gun.

Fire ships and mortars

Naval gunnery focused on the broadside ship and the long guns that served as decisive elements in combat. For other naval purposes, however, other gunnery devices were used. The "fire ship" which was loosed into enemy ship concentrations was a weapon of antiquity. With the development of gunpowder, powder ships were used in preference to fire ships. For example, in a 1693 attack on the French port of Saint-Malo, the British Commodore Benbow loaded a galliot with 100 barrels of powder and 340 chests containing cannon balls, iron chains, large pieces of metal, and other destructive missiles. This ship was cast adrift and grounded on a rock in the harbor where it exploded, blowing down part of the town wall and severely damaging the houses.

In addition to powder boats, bomb ketches were used for attacking facilities ashore. These were equipped with mortars, cannon with a large bore and a short barrel which threw their projectiles at a high angle and were particularly well suited for attacking targets protected by heavy walls. The French in the siege of Algiers in 1681 used seven bomb ketches, or galliotes-à-bombes, each mounting two mortars, some of which were 14-inch caliber and threw 140-pound projectiles. These projectiles were perforated or laced envelopes containing conbustibles and were ignited by the explosion of the propellant charge.

Explosive shells

Hollow shells filled with gunpowder proved more effective than fire ships. The powder was exploded by means of a slow match (burning fuse). Bomb ketches were often used to bombard ports and shore fortifications. However, the risk of fire or premature explosion was so serious that captains avoided firing explosive shells from their long guns. In 1788, the Russian navy sent Admiral John Paul Jones with a flotilla of long boats fitted with brass ordnance to attack a Turkish squadron on the Sea of Azov; the use of explosive shells gave Jones complete victory.

Explosive shells became popular thanks to a French artillery officer, Henri-Joseph Paixhans, who in the 1820s proposed a new system of gunnery. Paixhans showed how the new steam-powered ship could become a warship. He argued that all guns aboard a ship be of the same bore--and that explosive shells be used, thereby simplifying their use and augmenting their destructiveness. Paixhans demonstrated that explosive shells could destroy wooden ships, and he proposed to protect the ships by encasing their sides with iron plates; this led to the development of armored naval vessels. The French in 1829 standardized on a single caliber (a 30-pounder) which was made in different weights for use on the various decks and classes of ships. In 1837 France adopted a Paixhans-design shell gun, but of much larger bore than the 30-pounder. The Royal Navy in 1839 adopted six patterns of 32-pound long guns, associating with them a few eight-inch shell guns. Other countries quickly added Paixhans-style guns.

Projectiles

The projectiles which were used through the early 19th century varied depending upon the target. Solid cast-iron balls were used in attacking the hulls of other ships. Chain shot, consisting of two shot secured to each other with a length of chain, and bar shot, consisting of two solid hemispheres secured by a bar, were effective at short range against sails and rigging but were very inaccurate in their flight. Canister and grape shot were used against the crews. Canister was a tin cylinder fitting the bore of the gun and packed with musket balls. Grape shot was larger balls held in a cylindrical frame. Both types broke up on leaving the muzzle, with the clustered balls dispersing.

Shrapnel

Grape and canister were replaced after Henry Shrapnel in 1784 devised a thin-cased shell containing musket balls and a powder bursting charge. A burning fuse ignited the powder while the shell was in flight and liberated showers of small missiles. Hot shot also came into use against wooden hulls. It was fired with just sufficient velocity to splinter the wooden sides and render them favorable for burning when ignited by the red-hot cannonball.

The 19th century gunnery revolution

The 19th century saw striking advances in technology. The steam engine was adopted for marine propulsion after 1820; ships were built of iron after 1850; guns increased in size and power, and steel armor was added to battleships. High explosives were invented and better powder. These innovations came about almost simultaneously and affected each other. Steam power was used to manipulate heavy guns. Iron hulls allowed larger ships than had been possible with wood, and larger guns could consequently be carried. Advances in metallurgical led to stronger hulls, stronger guns, and armor plate to protect against the enemy's shells. As the armor grew thicker and stronger the guns had to be more powerful, and the entire warship became much larger and more stable.

Many steps were involved in this process and basic advances were sometimes abandoned because they were beyond the technology of the day. For example, the first naval vessel to be fitted with screw propellers, the U.S. Navy's Princeton, was also fitted with two 12-inch, wrought-iron guns. These guns proved to be beyond the metallurgy of the period and during a public demonstration in 1844 one of them burst, killing five people including high officials. In 1854 a British engineer, William Armstrong, perfected techniques for making guns of wrought iron. Almost simultaneously, Alfred Krupp of Germany began making guns from cast steel ingots. Their fabrication techniques made possible the high-power guns which came to characterize naval ordnance. Krupp and Armstrong each designed breech-loading mechanisms and fitted their guns with both rifled and smooth-bore barrels. Breechloaders achieved definite superiority over muzzle-loaders. The greater range, velocity, and accuracy which were the advantages of rifled guns were offset by the higher stresses imposed on the barrel and by other design problems. Rifled small arms had been in use for hundreds of years, but their advantages of greater accuracy and longer effective range were largely offset by the disadvantage of slow rate of fire until, in the 1850s, elongated bullets permitting rapid loading. To provide strength to withstand the increased working pressure of large rifled guns, the French in 1859 introduced a technique of reinforcing with hoops of puddled steel.

During the American Civil War, Lt. John M. Brooke of the Confederate Navy built rifled cast-iron guns hooped with wrought-iron rings. The American effort, however, went into improving cast-iron smooth-bore guns. John A. Dahlgren of the U.S. Navy greatly improved the shape of long guns. He measured the exact amount of strain and its location within the gun and proportioned the parts of the gun with reference to this strain. He abandoned both the ornamentation and the traditional shape for heavy guns. T. J. Rodman invented a way to cast guns hollow and cooling the inner surfaces while the metal hardened. This redistributed the strains within the gun and overcame the elastic peculiarities of cast iron, making it possible to cast guns with a bore of up to twenty inches and a gross weight of nearly 60 tons, but with a life comparable to that of smaller guns.

Turrets

The old wooden naval gun carriages mounted on wheels and using a heavy rope breeching to absorb recoil were replaced by iron carriages fitted on an inclined slide. Various devices, such as the friction of interlaced iron plates, were used for absorbing recoil. The gun carriages were fitted with wheels running on concentric tracks, thereby simplifying the training of the guns. The pivot gun, achieving its best development during the War of 1812, offered a 70 degree arc of fire but still required the ship to be turned for fore and aft targets.

American John Ericsson and Royal Navy Captain Cowper Phipps Coles developed the first practical revolving turrets. Ericsson's 1854 design was used on the Monitor (1862) and the coastal ships of that type during the Civil War. Coles designed a turret for a raft in 1855 and took out a patent for an improved design in 1859. A Danish warship built in Britain in 1863 had two revolving turrets based on Coles's design. The Royal Navy began using turreted guns in 1864. Seagoing Royal Navy turret ships of the 1860s had masts and rigging, a protective forecastle, and a poop, which limited the arc of fire to 120 to 132 degrees. The weight of the hull armor, turrets, and masts made these ships dangerously top heavy. The steam-powered Devastation, built in Britain in 1873, was the first ocean-going turreted warship and the first modern battleship. The Coles turret system became the standard until the 1890s. Steam powered turntables, however, offered far from perfect control of the turning motion, and in the mid-1870s, William Armstrong perfected the application of hydraulic power to gun turrets. As developed by the Armstrong Company of Britain and first used in the Dreadnought (1875), hydraulic power was applied to all the principal operations of working the gun, such as checking the recoil and moving the gun in or out along the slides and ramming home the powder and charge. Thus, the basic problems of designing carriages for heavy naval guns were solved. The U.S. Navy adopted electric drives, which were eventually superseded by variable-speed gears. Power drives also operated the smaller secondary batteries which served tactically for close-range attacks. The battleship turret, developed in the 1860s, was a mainstay of naval armament from the 1870s until the 1940s.

Naval race

Paixhans and his followers immediately realized the need to protect their ships from the penetrating power of rifled shot. Iron plates 7 inches thick proved vulnerable to 8-inch shells. As a rule of thumb, another inch of armor was needed for every inch of shell diameter. Armor was very heavy, so the ship had to be enlarged to carry big guns and thick armor. The French breakthough came with the Gloire (1859), built wood covered by 4.5 inch iron plates from the main deck to below the waterline; the 5600 ton battleship carried 30 6.5 inch guns and boasted a top speed of 14 knots. It was a major breakthough and but Britain leapfrogged it in 1860 with the Warrior (1861), which was twice as big and had an all-iron hull.

The battle of the ironclad Virginia (previously known as the Merrimac) and the all-iron Monitor in the U.S. Civil War in March 1862 was the first battle between ironclads. The Confederacy lacked the resources to buld more, but the Union Navy built dozens of turreted ships of the Monitor type, as well as many casemated ironclad paddle-boats with heavy gus to control the inland rivers. Eirope followed these developments closely, making Gloire, Warrior, and Monitor the models for ship design until 1900; France and Britain took the lead, with the U.S. trailing far behind Italy and Germany.

The naval race in technology pitted the Italian Duilio and the British Inflexible, both completed in 1876. The Italians first planned to use four 35-ton guns on the "Duilio", but in response to the manufacturer's offer to make guns of much greater weight and power determined to adopt 60-ton guns. The British, who had planned to install 60-ton guns on the Inflexible, then decided to mount 16.5-inch guns weighing 80 tons. The Italians in turn adopted 17.7-inch guns weighing 100 tons for the Duilio. This competition indicated that the striving for superiority in individual ships was one of the guiding principles of naval construction.

Innovations in powder

To obtain maximum effectiveness from the longer barrel, the burning rate of the gunpowder needed to be closely controlled. Experiments allowed chemical engineers to optimize the size and shape of powder particles in terms of rate of burning. In the 1880s brown powder made from under-burnt charcoal was adopted as one means of slowing the burning rate. However, only half of the mixture was converted into gas, the remainder becoming a dense smoke. The French in 1886 adopted smokeless powder made of nitrocellulose (gun-cotton). Four years later, the Royal Navy began using smokeless powder made from a nitroglycerine base. Both these compounds liberated four to five times as much energy as did the black powder used earlier. In addition, these chemically homogeneous powders could be shaped into hollow grains so shaped as to control the rate of burning. This gave a uniform pressure, permitting a higher projectile velocity without straining the gun. Propellants based on nitrocellulose or nitroglycerine were described as "single-base" powder; others containing both were described as "double-base"; and a third category containing nitrocellulose, nitroglycerine, and other chemicals was called "triple-base" or "multiple-base." By 1900, the U.S. Navy followed the lead of the French and adopted a nitrocellulose powder as a propellant charge.

20th century

Armor was the central issue by the late 1880s. If any one factor can be isolated as stimulating developments of the later years of the 19th century--improved materials (wrought-iron and then steel), increases in size, improvements in projectiles, mechanization, and improved powder--it was the necessity of penetrating armor, which was itself also rapidly improved. The ranges of guns were also being greatly increased.

Fire control

The necessity of fighting at maximum range, which was gradually recognized, called for a high degree of accuracy, so that shells could be placed on a target many miles distant. The ship with longer range would have a decisive advantage, since it could fire from outside the enemy's range. In 1892, Bradley A. Fiske of the U.S. Navy invented the telescopic sight for accurate shooting at long range. By 1906, periscopic gun sights greatly improved accuracy, while range finders provided an accurate measure of the distance to a target. Percy Scott of the British Navy and William S. Sims of the U.S. Navy championed the importance of accurate long-range shooting, and devised training techniques whereby the potential which had been given to naval guns could be achieved.

Scott developed the director firing system, which enabled all the guns of a ship to be laid onto a single target from a central aiming position. After early experimental installations from 1907 the system was fully adopted by the Royal Navy in 1913 and was critical for long-range gunfire during World War I. The Germans developed a similar system. Guns could now be aligned in parallel, and aimed and fired in salvos, all controlled from an elevated position. Optical range finders and electrical instruments to aid in fire control were mounted in these elevated positions. Not only was the fire of all guns controlled centrally, but the shots could be "spotted" on the target. This led to a great extension of range and made it possible to fire in weather which obscured the vision of the gun crews. The elevation that could be given to guns on British ships was increased from 13° in 1909 to 40° in 1917. In the 1920s the U.S. Navy made refinements in fire control, such as having each ship fire shells with a distinctive color in bursting so that the shots of each could be distinguished. Techniques were also developed for spotting by use of cruisers or aircraft, and night firing was perfected through the use of star shells which burst over the enemy. Through such techniques the effective range of the modern 16-inch (41-cm) naval gun came to be approximately 20 miles (32 km).

The vulnerability of large but weakly protected battle cruisers at the Battle of Jutland (1916) left battle cruisers with an uncertain role in the postwar fleets. The Washington Treaty (1922) designated battle cruisers as capital ships because they were armed with guns over 203 mm. The treaty designated heavy cruisers as those with guns over 155 mm, and light cruisers as those with guns under 155 mm. The signatory navies of the U.S., Britain, Japan, France, and Italy at first concentrated on heavy cruisers and later on light cruisers. Spain also built two heavy and six light cruisers. Just before 1939 new types appeared, such as antiaircraft cruisers, submarine cruisers, and new battle cruisers; the U.S. built the world's last battle cruiser in 1944.

World War I

The encounter of great battleship fleets was the centerpiece of all war planning from 1900 to 1945, following the strategic ideas of American Alfred Thayer Mahan. Yet it happened only once, and that was short and inconclusive. At the Battle of Jutland (May 31-June 1, 1916), the British battle cruiser squadron, consisting of six battle cruisers and four battleships, by chance encountered a scouting squadron of five German battle cruisers. They engaged each other in a running battle. Unknown to each side, each squadron was closely followed by their main battle fleet, and soon the entire main fleets of both sides were in view. The British fleet was stronger and the Germans decided to retreat instead of fight; they narrowly escaped. Although the German forces were outnumbered and their guns were of shorter range than those of the British, they still managed to inflict more damage on the British than they suffered in return. The military importance of the engagement was not great. The British lost three battle cruisers, three armored cruisers, and eight destroyers, while the Germans lost one battleship, one battle cruiser, four light cruisers, and five destroyers. The Germans claimed a victory, pointing out the greater losses of the British fleet. The British battle cruisers blew up when hit by German shells because of their faulty gunnery technique. In an effort to increase the rate of fire, gun crews kept far more than the regulation charges inside their turrets, and also kept loaded not only the primary ammunition supply system, but also the auxiliary hoists and waiting positions. Thus, many charges were exposed to flash when the turret was struck by a German shell, resulting in an explosion sufficient to sink the ship.

The tactical objectives of gunnery policy were accurate deliberate fire at long ranges in good visibility, and effective rapid fire at short ranges in the event of poor visibility. By 1914, the British Admiralty developed a tactical doctrine, intended to destroy the German fleet with medium-range independent gunfire, while avoiding German torpedoes. The methods were never tested in battle, however, for the Germans did not act as the British expected.

Moreover, by emphasizing this approach, the British failed to acquire adequate gunnery equipment for shooting at long range, creating vulnerabilities when the Grand Fleet encountered the German fleet at the Battle of Jutland in 1916. Brooks (2005) seeks to correct what he sees as the negative prevailing view of the Dryer Table system of gunnery fire control used by British warships at Jutland. He argues that the system worked well in the battle and that it was a superior system to the competing Argo method. Brooks further alleges that the British cruiser losses in the battle were due to tactical errors made by Vice Admiral Sir David Beatty rather than any flaw in the Dryer Table.

Although the British were disappointed with their showing, the German fleet was driven back to its ports and rarely, in the two remaining years of the war, was it able to leave them. The great German fleet was indeed useless in the face of the more powerful Royal Navy. so hundreds of naval guns up to 380mm bore and 47,000 meter range were removed from the ships and sent by railway to deploy on the Western Front.

Further development of powder

In World War II night engagements proved that standard smokeless powder created a flash that temporarily blinded the ships' crews. Various flash suppressors were devised and mixed with the powder, which was formed into grains for small guns and into pellets for the larger guns. The British used a multiple-based powder, Cordite N, which was relatively flash-free, but which the U.S. Navy considered to be brittle, unduly sensitive to shock, and hazardous in hot climates. As a result the U.S. developed other flashless powders and was placing one of them, Albanite, in large scale production at the end of World War II.

Despite the adoption of smokeless powder, black powder still continued in use as a burster charge for projectiles until just before World War I, when more powerful and less sensitive explosives were adopted. In the U.S. Navy, trinitrotoluene (TNT) was adopted for smaller projectiles and Explosive D (ammonium picrate) for the larger ones. These continued in use throughout World War II, although by the end of the war more powerful explosives had come into use, particularly in the smaller antiaircraft projectiles. If the entire spectrum of powder uses is considered--torpedoes, mines, aerial bombs, and rockets, as well as large and small projectiles--the trend in explosive development, beginning with the adoption of smokeless powder, was to recognize the special demands of various uses and to formulate specialized compounds tailor-made to particular requirements.

End of the battleships

The Royal Navy sank the Italian fleet in Nov. 1940 at the Battle of Taranto using warplanes from aircraft carriers. The Japanese took note and at the Battle of Pearl Harbor (Dec. 7. 1941), sank nearly the entire American battleship fleet using carrier planes. Immediately the carrier replaced the battleship as the capital ship of seapower. The era of big-gun battles between fleets at 30,000 yards was (almost) over, with the final engagement being the Battle of Surigao Strait during the Battle of Leyte Gulf in 1944. Heavy guns were useful for shore bombardment, but for combat were replaced by bombs and rockets delivered by air. Against ships, submarine and surface torpedoes, and aerial bombs, became the most important weapons.

The role of naval gunfire in supporting amphibious operations remains controversial, especially as to whether there are advantages to shells of greater than 155mm. Beyond the scope of this form of bombardment, seaborne weapons also have a share in the delivery of nuclear ballistic missiles against targets deep in continental landmasses; this mission involves the use of missiles fired underwater from submarines.

Anti-aircraft gunnery

The rapid development of the warplanes after 1914 necessitated a means of defense. Guns of secondary batteries were given sufficient elevation for use in air attacks, and projectiles and fuses for use against aircraft were developed. With the onset of World War II, 20mm Oerlikon (which were too light) and especially 40mm Bofors automatic guns were used in increasing numbers, especially against Japanese Kamikaze planes.

Anti-aircraft gunnery was a tradeoff between 5" guns, with their long range, and 20 and 40 calibre short-range guns with a high rate of fire. The breakthrough came in 1943 with the introduction of the proximity fuze (or "VT fuze") in 5" shells. It had a radio and receiver and when a signal bounced back, it was within range of the target, and exploded. The effect was to make the target 50 times bigger and thus much easier to hit. The fuzes played a decisive role in defeating the Japanese Kamikaze attacks of 1944-45.

The British had invented the device but lacked the massive industrial capacity needed to produce it in quantity, so shared the blueprints with the U.S. Navy. The basic components are a vacuum tube (six inches long and three inches in diameter) a battery, and a radio transmitter and receiver, all of which have to be rugged enough to withstand 20,000 Gs when shot out of a gun at high velocity. After the shell is fired and begins rotating, a chemical reaction produces an electrical charge which in turn arms the shell and sends out a radio impulse. The return signal, reflected from the target, detonates the shell prior to impact and produces the devastating effects.

To the 21st century

Since the end of World War II, the emphasis within antiaircraft defense batteries has shifted from these weapons to 3- to 5-inch (75 to 127mm) guns fitted for automatic loading and aiming. The rate of fire of these guns has been greatly increased over that of earlier guns of similar sizes.

Missiles

After 1960 another revolution was initiated--that of the guided missile. The influence of the guided missile on warfare has been comparable in effect to the introduction of the gun in the 14th century, steam and mechanization in the 19th century, or the aircraft in the 20th century. Early missiles were launched from shore bases or from aircraft, and with the exception of the German V-2 rocket, were essentially unmanned aircraft; however, the overall capability of missiles has been greatly extended in the postwar years.

Missiles are classified by their launching vehicle and target as air-to-air, air-to-surface, surface-to-surface, underwater-to-surface, or surface-to-air. This classification clearly indicates their relationship to other naval weapons: the air-to-air missile is replacing the gun in naval aircraft; the air-to-surface missile, the aerial bomb; the surface-to-surface and underwater-to-surface missiles the long-range heavy gun; and the surface-to-air missile is replacing the antiaircraft battery. Many U.S. cruisers, destroyers, and aircraft carriers are fitted with surface-to-air missiles. Other naval powers also have guided-missile ships in operation. Most guided-missile ships are still equipped with guns, although the trend is toward increasing the number of missile batteries and decreasing the number of guns.

Aegis system

The threat of enemy missile attacks required a radical rethinking of command and control operations. Traditional reaction time, firepower and operational availability in all environments no longer matched the threat. In the 1960s the U.S. Navy developed an Advanced Surface Missile System (ASMS), renamed AEGIS in 1969.

AEGIS is designed as a complete system, integrating radar, guided missile and battle management computer systems, but no guns. This makes the AEGIS system the first fully integrated combat system built to defend against advanced air, surface and subsurface threats. The AEGIS combat system is highly integrated and capable of simultaneous warfare on several fronts -- air, surface, subsurface and strike. Anti-air warfare elements include the radar system AN/SPY-1B/D command and decision system and weapons control system. AN/SPY-2 is a newer version with general enhancements, while AN/SPY-3 adds ballistic missile defense capability.

21st Century

While many gun applications have been replaced by missiles, such as close-in weapons defense, there are two areas where new vessels still receive guns. Autocannons for defense against small warships, variously suicide boats or pirates, are preferable to machine guns with shorter range.

There are also advanced long-range guns for shore bombardment, sometimes with rocket-assisted guided shells. The most exotic approach, the Vertical Advanced Gun System, has been deferred in favor of a modern advanced automatic turret mount, remotely fired and loaded from a magazine. Rather than the 127mm/5" guns common to contemporary destroyers, the new AGS will use a 155mm caliber, the standard size for shore-based weapons, which will allow more common development.

Further reading

for a more detailed guide see Naval guns and gunnery/Bibliography

• Bastable, Marshall J. "From Breechloaders to Monster Guns: Sir William Armstrong and the Invention of Modern Artillery, 1854-1880." Technology and Culture 1992 33(2): 213-247. Issn: 0040-165x Fulltext: in Jstor
• Brown, David K. Eclipse of the Big Gun: The Warship 1906-45 (1992)
• Curtin, Roland Irvin, and Thomas Lee Johnson. Naval Ordnance: A Text-book (1915), esp ch 13-15 on gunpowder and shells complete text online
• Friedman, Norman. U.S. Naval Weapons: Every Gun, Missile, Mine and Torpedo Used by the U.S. Navy from 1883 to the Present (1983), highly detailed guide
• Friedman, Norman, and A. D. Baker. Naval Firepower: Battleship Guns and Gunnery in the Dreadnaught Era (2008)
• Garcia Y Robertson, Rodrigo. "Failure of the Heavy Gun at Sea, 1898-1922." Technology and Culture 1987 28(3): 539-557. Issn: 0040-165x Fulltext: in Jstor
• Greene, Jack, and Alessandro Massignani. Ironclads at War: The Origin and Development of the Armored Warship, 1854-1891 (1998) online edition
• Guilmartin, John F., Jr. Gunpowder and Galleys: Changing Technology and Mediterranean Warfare at Sea in the Sixteenth Century (2nd ed. 2003)
• Hodges, Peter. The Big Gun: Battleship Main Armament 1860-1945, (1981), highly detailed coverage
• McBride, William M. Technological Change and the United States Navy, 1865-1945 (2000) excerpt and text search
• Morison, Elting E. Men, Machines and Modern Times (1968) excerpt and text search
• Mulligan, Timothy. "Ship-of-the-Line or Atlantic Raider? Battleship Bismarck Between Design Limitations and Naval Strategy," The Journal of Military History 69#4 October 2005, pp. 1013-1044 in Project Muse
• Sondhaus, Lawrence. Naval Warfare, 1815-1914 (2001) online edition
• Turnbull, Stephen, and Wayne Reynolds. Fighting Ships of the Far East (1) (2002), Osprey Publishing. ISBN:1841763861 Google books
• Sumida, Jon Tetsuro. "Gunnery, Procurement, and Strategy in the Dreadnought Era," The Journal of Military History v69#4 (2005) 1179-1187 online at Project Muse