It was very difficult to sink a battleship in naval warfare in the era of sail battleships, because the naval guns at that time fired solid bullets, like rough and thick sail battleships, even after hundreds of bullets, they could still continue to fight alive. In contrast, the danger of the storm at sea to the battleship was much greater than the enemy's shelling, so the tactic of jumping gangs was popular at that time, and if it could not be sunk, the enemy ship would be captured. This phenomenon did not change until the advent of the bombardment, but the bombardment also needed to hit many rounds to sink the enemy ship, but the efficiency was much improved. The real threat to wooden warships was the large-caliber front-loading smoothbore gun, which weighed hundreds of pounds per shell, the Dahlgren 15-inch cannon, invented in the mid-19th century.
15-inch caliber Dahlgren gun
First of all, a brief introduction to the bombardment, the essence of the bombardment is to fire an explosive spherical projectile, which is commonly known as a flowering bomb filled with black explosives inside. In 1823, after the Napoleonic Wars of the early 19th century, a French artillery officer, Henri Joseph Péxan, developed a cannon that fired explosive shells, with a separate chamber with an inner diameter slightly smaller than the inner diameter of the barrel at the tail, making it easier to fire explosive spherical shells. This cannon, also called Paixhans gun, is 2.8 meters long, has a caliber of 8 inches, weighs more than 3 tons, and fires shells with black explosives (weighing 59 pounds), which is a bombardment gun. In the 1853 Battle of Sinop, the Russian fleet was equipped with dozens of guns of this type, which severely damaged the Ottoman Turkish fleet in the battle!
Although the bombardment gun is much more powerful than the traditional shipborne cannon that fires solid shells, one of the major drawbacks is the unreliability of the fuse of the shell. The explosive bomb is a fuse index letter hole directly left on the spherical cast iron shell, which is filled with black gunpowder, and the fuse is usually inserted directly into the hole. When firing, the fuse of the cannonball is lit before it is loaded into the chamber, and once the shell is trapped in the chamber, there is a risk of exploding. Although it was later changed to the ignition of the gunpowder in the breech when fired, if the shell rolls in the chamber and the fuse is facing the propellant, it is easy to cause the fuse to ignite quickly or directly detonate the explosive projectile. At the same time, the storage of explosive bombs on battleships also has a huge risk, once they are detonated in battle or ignited by other unexpected reasons, it is a catastrophe for expensive sail battleships, so the navies of various countries are cautious in the use of large warships, and the number of equipment is not large.
However, on the other side of the ocean, the United States, which was in the midst of the Civil War, began to apply a new type of naval artillery, which was the Dahlgren cannon. The gun is a front-loading smoothbore gun, generally about 12 to 15 times the length of the caliber, in the appearance of a beer bottle, invented by the US Navy Admiral Dahlgren. Dahlgren cannons were not rifled, and hollow lugs were cast with cavities that allowed cold water to circulate when cooled. This method of cooling from the inside gave the gun such a great strength that it could be cast into a 15-inch cannon capable of withstanding five hundred heavy shots without any danger. The Dahlgren cannon is the ultimate form of front-loading smoothbore guns.
"Duke of Wellington"-class sail battleship
Dahlgren cannons were available in a variety of calibers, from 8 inches to 15 inches, and even 20 inches in the later period. The 8-inch Dahlgren cannon can fire 68-pound spherical shells, the 15-inch Dahlgren cannon can fire 440-pound spherical cannons, and the 20-inch Dahlgren cannon fires more than 800-pound spherical cannons! The 20-inch Dahlgren cannon was not equipped on the battleship because it was too bulky, and the Dahlgren cannon equipped on the battleship had a maximum caliber of 15 inches. In the middle of the 19th century, no warship could withstand the bombardment of this gun, and the Dahlgren cannon was the most powerful naval gun of its time.
The ironclad ships built by the US Navy at that time were equipped with Dahlgren 15-inch cannons, and 1 ironclad ship was equipped with 2 guns, and the cannons were installed in the turret in the center of the ship. Some of the larger ironclads of the late Civil War had multiple turrets and were equipped with more Dahlgren cannons.
In the middle of the 19th century, the large warships of the European powers, such as the first-class sail battleships equipped with 120 cannons in Britain, France, and Russia, were equipped with the largest caliber cannon on the lower gun deck, and the 68-pound solid bullet could not penetrate the multi-layer ironclad of the American ironclad ship at all, and the power was very limited. On the other hand, if the European powers' first-class sail battleships were hit by the Dahlgren's 15-inch cannons of the American ironclads, it would be fatal, and only one shot hitting the hull at the height of the waterline would be enough to sink the warship!
The armored ship "Warrior" that has been preserved to this day
Even in the 60s of the 19th century, Britain commissioned the armored ship "Warrior", although the "Warrior" was inlaid with 18 to 24 inches thick planks and 4.5 to 5 inches thick iron armor, it still could not withstand the bombardment of Dahlgren's 15-inch cannon, and the 440-pound shell was enough to penetrate its iron armor. The armored ship "Warrior", although the most powerful battleship in Europe at that time, was outdated in the face of Dahlgren's 15-inch cannon!
The invention of the Dahlgren 15-inch cannon eliminated all wooden battleships, including broad-gun armored ships. In order to withstand the bombardment of heavy artillery, in addition to using steel as the main material, the battleship had to change the traditional layout design of the gunwales.