The Pastry War, a brief conflict between France and Mexico from November 1838 to March 1839, was so named because it was triggered by the ill-treatment of French citizens, one of them a pastry chef. A French squadron was dispatched to blockade the Caribbean coast of the newly established Mexican Republic and to capture the port of Vera Cruz. The war would have been no more than a footnote in history, had the French action not included a naval bombardment of the formidable Mexican fortress of San Juan de Ulúa.
Vice Admiral Horatio Nelson once said—with good reason—that “a ship’s a fool to fight a fort,” because almost all the advantages rest with the fortification. Despite the great man’s warning, a squadron of French frigates unleashed such a devastating bombardment that the fortress was quickly silenced and forced to surrender. The reason for this remarkable victory was that the attacking ships were equipped with new shell-firing Paixhans guns, while the Mexicans could only respond with traditional cannonballs.
The concept of a shell that explodes on reaching its target has a long history, particularly in siege warfare. The Ottoman Turks were recorded as using such weapons as far back as the siege of Rhodes in 1522. Early versions consisted of a spherical iron case with a powder charge inside. A fuze was trimmed to a length judged to make it explode just after reaching the target and was lit prior to firing. The projectile was then launched from a mortar.
Toward the end of the 18th century, more-mobile shell-firing howitzers began to appear on the battlefield, although they were generally considered no more effective than cannonball-firing artillery. This was because the high launch trajectory made them less accurate, and the variability of fuze length resulted in many shells either detonating harmlessly in flight, or being extinguished on arrival before they could explode.
Most navies considered such inaccurate weapons to be of little value at sea. They were unsuited for the flat trajectory required to penetrate the thick wooden sides of opponents’ ships. Furthermore, handling exploding shells with lit fuses in the confines of a packed gundeck during battle would constitute a considerable hazard to the firing ship. As a result, shells were confined to specialist vessels called bomb ketches, armed with one or two large mortars for shore bombardment.
But one nation actively explored the possibilities of these weapons. France, faced with a widening gap in naval power with Britain, sought to bridge that divide by innovating. If in traditional naval battles cannonballs frequently penetrated the sides of ships and reached the interiors, then how much worse would it be if the projectiles exploded once inside?
Trials were carried out in 1795 at Toulon with 18-, 24-, and 36-pounder shells fired from conventional naval cannon against wooden targets. The tests proved inconclusive, but an undeterred Napoleon set up a special commission in 1798 to work on the problem. More tests were carried out using various shell and gun designs, but much of the problem centered around the fuze. The higher muzzle velocity of a cannon compared to a howitzer often extinguished the fuze in flight or when it struck the target.
Another problem arose in handling shells in action. Given how quickly a horizontally fired shell would reach its target, the fuze had to be very short to stop the enemy putting it out. As a result, shells would sometimes burst prematurely in the gun before they could be fired, exacerbating the concerns of the navy about handling such shells. Batches of 36-pounder shells eventually were issued, but only to coastal batteries. There is little evidence they proved effective against enemy shipping.
In 1809, French artillery General Henri-Joseph Paixhans began work on a shell-firing naval gun that could solve these problems. His solution was to replace a traditional fuze with a wooden one that would be lit by the discharge of the gun and robust enough not to be extinguished in flight. His shell had a round iron front, to penetrate the side of a ship, mounted in a wooden sabot that positioned the fuze toward the charge. Once Paixhans had perfected prototype guns capable of firing his new shells, he demonstrated his inventions to the French Navy. In 1824, a redundant ship-of-the-line, the Pacificateur, was supplied to serve as a target. To the shock of the naval observers, the ship broke up and sank after a brief bombardment. Paixhans’ guns were quickly adopted by the French Navy, followed soon afterward by the navies of Britain and Russia.
In 1839, following France’s capture of Vera Cruz, U.S. Navy Captain Mathew Perry was asked to conduct trials of the Paixhans guns that had so quickly reduced the port’s fortifications. Perry is often called the “father of the U.S. steam navy” and was a vocal proponent of modernization. He tested the new weapons on a gunnery range at Sandy Hook, New York, and was unequivocal about the results. He concluded that the U.S. Navy must adopt shell-firing guns to have any hope of competing with the navies of Europe. As a result, the first batches of Paixhans were ordered, and the new weapon began to be fitted in small numbers to U.S. warships, including four on the War of 1812 veteran Constitution.
The pace of international adoption was modest at first, but it quickened after news of a November 1853 naval battle in the Black Sea sent shockwaves around the world. A force of 12 Turkish warships armed with guns that fired conventional cannonballs was blockaded in the port of Sinop, Turkey, by a Russian squadron of similar size but whose vessels were armed mostly with Paixhans guns. With his ships anchored in a solid line and protected by the harbor’s fortifications, the Turkish commander was confident of victory. Even when the Russian fleet forced its way into the port, he was not alarmed—until the Russians opened fire.
The Paixhans shells were devastating, punching through the Turkish ships’ wooden hulls and detonating deep within. Several ships caught fire, others sank outright, and the frigate Navek Bakhri exploded. The only member of the Turkish squadron to escape the carnage was a small paddle steamer. Turkish casualties exceeded 3,000, with 37 Russian sailors killed and 229 wounded.
The Battle of Sinop had several lasting effects. The first was to hasten the adoption of shell-firing guns while spurring innovation in the next generation of naval weapons. The second was to generate the realization that the oak timber that had served in warship construction for centuries was too feeble to resist the new guns. Just as the cannonball would be replaced by the shell, oak would have to be replaced by iron.
The first warship with an iron hull was the Royal Navy gunboat HMS Nemesis, built at Birkenhead in 1839. The U.S. Navy’s first iron-hulled warship was the Michigan, launched on the Great Lakes four years later. Both vessels used iron as a core construction material, not merely as cladding for protection.
But iron would also armor the sides of wooden vessels, with plates several inches thick to resist the new shells. In 1859, the French Navy launched La Gloire, the world’s first ironclad battleship. Just two years later, following successful trials of the Royal Navy’s ironclad HMS Warrior, the British Admiralty took the momentous decision to move to an all iron-armored battle fleet. The Civil War, which broke out the same year, would demonstrate the wisdom of that decision, with even the sometimes crudely built ironclads of the Union and Confederacy easily able to dominate wooden opponents.
