Eighteenth Century Bomb Ketch by Harry Schenawolf

Galiot - A French Bomb Ketch (per Dictionnaire de la Marine)
Galiot – A French Bomb Ketch (per Dictionnaire de la Marine)

Bomb Ketch, galiote a bombe, or simply Bomb, were men-of-war sailing vessels that were in use for approximately 150 years (circa 1680 – 1835). The main armament was not cannon and therefore they did not take their place in line of battle during major sea battles. Their design, the brainchild of mathematician and Inspector General of the French Navy, Bernard Renau d’Elicagaray (Armendarits, France 1652-1719), placed them in a support position of the attacking fleet. They carried 10 to 13 inch mortars, sometimes called petit Renaus – named for the bomb ketch inventor’s nickname, little Renau. These mortars could pivot back and project hot shot and exploding shells, called carcasses, in a long arc, 1,300 meters or better, far beyond the range of cannon. The range was controlled by adjusting the gun powder charge. Two hundred pound shells rained destruction on coastal defenses, moored shipping, and town inhabitants, in many cases killing and maiming hundreds. In perspective, the largest cannon of the time fired 48 pound shot.

A Ketch-rigged Royal Yacht
A ketch-rigged Royal Yacht

Projecting a shot upwards from a sailing ship to fall behind defensive land positions or down onto anchored shipping, known as bombardier, was a dilemma for early ship builders. If a cannon or mortar were arched back to fire a high trajectory shell, it would no doubt rip through masts and rigging before damaging the enemy. Also the large charge needed to send two hundred pound projectiles in these ‘long’ shots would send an enormous shudder through the hull and frame, soon tearing the ship apart. Renau d’Elicagaray’s solution was simple. Place the mortar (no more than two) at the bow of the ship. Masts were moved further to the stern leaving a large gap between the forward mast and the prow, front of the ship. The masts were ketch-rigged hence the name bomb ketch. A ketch is a sailing ship with two masts. The forward or mainmast is larger than the after mast or mizzen. To absorb the extreme downward recoil from the high explosive mortar, these ships were made sturdy. Broad in the beam, or beamy, with stout hull construction, the shock from the mortar was therefore evenly distributed throughout the ship. Eventually, lines supporting the mainmast where made of chain to avoid the risk of fire and to help withstand the immense stress during a bombardment. All this added support and aft placement of the masts made the ships incredibly awkward to handle.

Exploding carcusses bombard a village
Exploding carcasses bombard a city

Whereas other war ships could fire during sail, the bomb ketch had to be anchored prior to engaging the enemy. The mortars were fixed and faced forward requiring the ship to be pointed in the direction the shell was to follow. They were aimed by reeling in or paying out double anchor cables at the prow known as a spring anchor. Not until the early 19th century, with the advent of mortars mounted on torrents, could the mortar be re-positioned without adjusting the ship’s anchorage.

In 1682, Abraham Duquesne, Marquis du Bouchet (c.1610-1688) introduced d’Elicagary’s bomb ships to the French navy. It is known that in that year, five of d’Elicagaray’s bomb ketches were used against the Barbary Pirates in the siege of Algiers. In 1684, the French repeated their success at Genoa. These early French bomb ships had two forward faced mortars fixed side by side. It is thought that French Huguenot exiles brought the bomb ketch technology to England. However, in 1684, about the time of the action at Genoa, the Royal Navy draughtsman Edward Dummer (1651-1713), studied the French bomb ships. He had been sent to the Mediterranean to observe foreign ports and most particular shipping. Though not allowed on board, he made detailed sketches of the French Bomb designs and operation and later presented them to King Charles II of England. Royal approval was granted in 1687 for two Royal Navy bomb vessels to be constructed in accordance with Dummer’s drawings. The ships were named Salamander and Firedrake. Construction was completed in 1688. They had 12 ½ inch mortars in fixed forward positions. Firedrake was by far the larger, measured 279 tons with a gun deck length of 84 ft. 9 in and a keel of 68 ft. She was manned by 50 men.

Model of a French Bomb Ship with side by side mortars at the bow
Model of a French Bomb Ship with side by side mortars mounted at the bow.

Though many bomb ships were constructed in the late 17th and early 18th century, wartime demands proved more fruitful by converting merchant vessels or other warships to bomb vessels. British ships were often named after volcanoes and concepts of hellish fire: Blast, Explosion, Thunder, Dreadful, Vesuvius, Furnace, Terror, Aetna. Since the bomb was used primary during bombardment and siege operations, they were not expected to engage the enemy and thus received light conventional armament. Besides the two mortars, they had few cannon for use in self-defense only. By 1790, the two masts or ketch-rigging was replaced with the three masts or ship-rigging.

Bomb vessels usually were attended by an accompanying tender. With all the additional reinforced structure to shoot the mortars, there was little space aboard to hold the ordinance and powder. Also explosive shells (bomb ketches were the only ships in the Royal Navy’s arsenal to use exploding shells) proved the most dangerous and needed to be kept further away from the primary source of fire.

Converted Bomb Erebus in polar exploration
Converted Bomb Erebus in polar exploration

The Royal Navy began to phase out bomb ketches and bomb vessels by the 1830’s. The last bomb vessel to serve in that role was the Sulpher. It was later converted to a survey ship in 1835, a receiving ship in 1843, and in 1857, was broken up. Because of their sturdy design to resist the immense strains of recoil from the massive mortars, several former bombs were used for polar exploration. Their reinforced hulls could resist the pressure of the ice far longer than conventional shipping. Some of the former Bomb ships that went on to serve as exploration vessels included: Racehorse, Furnace, Carcass, Fury, Hecla, Terror, and Erebus. The last, Erebus, during her Antarctic explorations, is the only known ship for which a mountain was named for, usually being the other way around.


Bull, Stephen. Historical Guide to Arms and Armor. 1991: Facts on File Inc., New York, NY.
Colledge, J.J.; Warlow, Ben. Ships of the Royal Navy: The Complete Record   of All Fighting Ships of the Royal Navy. 1969: Chatham Publishing Co.,  London, UK.
D’Elicagaray, Bernard Renau. The Theory of the Handling or Working         of Ships at Sea, Translated from the original printed at Paris  by the express command of his Majesty. 1689. Cir. 1705: Printed by James Humfreys, London, UK.  Digitized on June 5, 2013.
King, Dean; Hattendorf, John; Estes, J. Worth: A Sea of Words. 1995: Henry Holt & Co., New York, NY.
Willis, Sam. Fighting At Sea in the Eighteenth Century; The Art of Sailing Warfare. 2008: The Boydell Press & Boydell & Brewer Ltd, Woodbridge, UK & Rochester, NY.
Internet: How Effective was Naval Bombardment at Revolutionary-Napoleonic Age (in Sieges and Field Battles at the Coast)? https://www.quora.com/How-effective-was-naval-bombardment-at-Revolutionary-Napoleonic-age-in-sieges-and-field-battles-at-the-coast.

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