Naval artillery

The term generally refers to powder-launched projectile-firing weapons and excludes self-propelled projectiles such as torpedoes, rockets, and missiles and those simply dropped overboard such as depth charges and naval mines.

In the Battle of Tangdao in 1161, the Southern Song general Li Bao used huopao (a type of gunpowder weapons, possibly cannons) and fire arrows against the Jin dynasty fleets.

King John II of Portugal, while still a prince in 1474, is credited with pioneering the introduction of a reinforced deck on the old Henry-era caravel to allow the mounting of heavy guns for this purpose.

[13] By the early 16th century, the navies of the Mediterranean had universally adopted lighter and more accurate muzzleloaders, cast in bronze and capable of firing balls or stones weighing up to 60 lb (27 kg).

Trials made with replicas of culverins and port pieces showed that they could penetrate wood the same thickness of the Mary Rose's hull planking, indicating a stand-off range of at least 90 m (295 ft).

The port pieces proved particularly efficient at smashing large holes in wood when firing stone shot and were a devastating anti-personnel weapon when loaded with flakes or pebbles.

However, the desire to reduce weight in the ends of the ship and the relative fragility of the bow and stern portions of the hull limited this role to a 9-pounder, rather than one which used a 12 or 24 pound shot.

The larger size of the grapeshot projectiles was desirable because it was more capable of cutting thick cordage and smashing equipment than the relatively smaller musket balls of a canister shot, although it could rarely penetrate a wooden hull.

A more specialized shot for similar use was the chain-shot, which consisted of two iron balls joined together with a chain, and was particularly designed for cutting large swaths of rigging, such as boarding nets and sails.

Bags of junk, such as scrap metal, bolts, rocks, gravel, or old musket balls, were known as 'langrage', and were fired to injure enemy crews (although this was not common, and when it was used, it was generally aboard non-commissioned vessels such as privateers, actual pirate ships, merchantmen, and others who couldn't afford real ammunition).

In Western naval warfare, shore forts sometimes heated iron shot red-hot in a special furnace before loading it (with water-soaked wads to prevent it from setting off the powder charge prematurely.)

The bomb ketch was developed as a wooden sailing naval ship with its primary armament as mortars mounted forward near the bow and elevated to a high angle, and projecting their fire in a ballistic arc.

In the Action of 4 September 1782, the impact of a single carronade broadside fired at close range by the frigate HMS Rainbow under Henry Trollope caused a wounded French captain to capitulate and surrender the Hebe after a short fight.

[35] Flintlock firing mechanisms for cannon were suggested by Captain Sir Charles Douglas and introduced during the American War of Independence in place of the traditional matches.

Prior to this the Royal Navy introduced the use of goose quills filled with powder during the Seven Years' War giving an almost instantaneous burn time compared with earlier methods of detonation.

Canister shot was already in widespread use at the time; a tin or canvas container filled with small iron or lead balls burst open when fired, giving the effect of an oversized shotgun shell.

[36] These guns were the only weapons capable of piercing the ever-thicker iron armour on the later ironclads, but required steam powered machinery to assist loading cannonballs too heavy for men to lift.

The incendiary properties of exploding shells demonstrated the obsolescence of wooden warships in the 1853 Battle of Sinop;[18]: 241  but detonation effectiveness was limited by use of gunpowder bursting charges.

This spin, together with the elimination of windage as a result of the tight fit, enabled the gun to achieve greater range and accuracy than existing smooth-bore muzzle-loaders with a smaller powder charge.

This "cap" increased penetration by cushioning some of the impact shock and preventing the armor-piercing point from being damaged before it struck the armor face, or the body of the shell from shattering.

(See: APCBC ammunition) Increased armor penetration became possible when projectile velocities of 800 m/s (2,600 ft/s) were obtained as smokeless powder propellants[36] replaced gunpowder around the turn of the 20th century.

[70] When gunnery ranges increased dramatically in the late 19th century, it was no longer a simple matter of calculating the proper aim point, given the flight times of the shells.

Increasingly sophisticated mechanical calculators were employed for proper gunlaying, typically with various spotters and distance measures being sent to a central plotting station deep within the ship.

[72] Lord Kelvin, widely regarded as Britain's leading scientist, first proposed using an analogue computer to solve the equations which arise from the relative motion of the ships engaged in the battle and the time delay in the flight of the shell to calculate the required trajectory and therefore the direction and elevation of the guns.

As battle ranges were pushed out to an unprecedented 6,000 yards (5,500 m), the distance was great enough to force gunners to wait for the shells to arrive before applying corrections for the next salvo.

As destroyers began to assume ASW roles to include protection of the fleet from submarines, they were fitted with high-angle depth charge mortars (called Y-guns, K-guns or squid).

The practice reached its zenith during World War II, when the availability of man-portable radio systems and sophisticated relay networks allowed forward observers to transmit targeting information and provide almost instant accuracy reports—once troops had landed.

However, given the relatively primitive nature of the fire control computers and radar of the era combined with the high velocity of naval gunfire, accuracy was poor until troops landed and were able to radio back reports to the ship.

Naval gunfire was used extensively throughout Normandy, although initially the surprise nature of the landings themselves precluded a drawn-out bombardment which could have reduced the Atlantic Wall defences sufficiently, a process that fell to specialist armoured vehicles instead.

Also, the Japanese fired San Shiki "beehive" shells for anti-aircraft defense, as did the German battleship Tirpitz, but this largely proved ineffective against attacking aircraft.