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A bomb vessel, bomb ship, bomb ketch, or simply bomb was a type of wooden sailing naval ship. Its primary armament was not cannons (long guns or carronades) – although bomb vessels carried a few cannons for self-defence – but mortars mounted forward near the bow and elevated to a high angle, and projecting their fire in a ballistic arc. Explosive shells (also called bombs at the time) or carcasses were employed rather than solid shot. Bomb vessels were specialized ships designed for bombarding (hence the name) fixed positions on land. In the 20th century, this naval gunfire support role was carried out by the most similar purpose-built World War I- and II-era monitors, but also battleships, cruisers, and destroyers.
The first recorded deployment of bomb vessels by the English was for the siege of Calais in 1347 when Edward III deployed single deck ships with bombardes and other artillery.  The first specialised bomb vessels were built towards the end of the 17th century, based on the designs of Bernard Renau d'Eliçagaray, and used by the French Navy.    They were first called galiote à bombe (a word derived from the Dutch galliot, denoting a short, beamy vessel well suited for the powerful downward recoil of its weapons).  Five such vessels were used to shell Algiers in 1682 destroying the land forts, and killing some 700 defenders[ citation needed ]. Two years later the French repeated their success at Genoa.  The early French bomb vessels had two forward-pointing mortars fixed side-by-side on the foredeck. To aim these weapons, the entire ship was rotated by letting out or pulling in a spring anchor.  The range was usually controlled by adjusting the gunpowder charge.  The French later adopted the word bombarde for this vessel,  but it should not to be confused with the horizontal fire, stone throwing bombard of earlier centuries. 
The French design was copied by the Royal Navy,  who continued to refine the class over the next century or more, after Huguenot exiles brought designs over to England and the United Provinces. The side-by-side, forward-pointing mortars were replaced in the British designs by mortars mounted on the centerline on revolving platforms. These platforms were supported by strong internal wooden framework to transmit the forces of firing the weapons to the hull. The interstices of the framework were used as storage areas for ammunition.
Early bomb vessels were rigged as ketches with two masts. They were awkward vessels to handle, in part because bomb ketches typically had the masts stepped farther aft than would have been normal in other vessels of similar rig, in order to accommodate the mortars forward and provide a clear area for their forwards fire. As a result, by the 1800s British bomb vessels were designed as full-rigged ships with three masts, and two mortars, one between each neighboring pair of masts.  The full rig also meant that bomb vessels could be used as escort sloops between bombardment missions; in 1805 the Acheron bomb along with the Arrow sloop were both lost in a defence [ citation needed ] of their convoy. Bomb vessels often had the front rigging made of chain, to better withstand the muzzle blast of the mortars. 
Mortars were the only kind of naval armament to fire explosive shells rather than solid shot until the invention of the Paixhans gun. Since it was considered dangerous to have large stocks of shells on board the ships that were firing them, and because the reinforced mortar platforms occupied so much space below decks, bomb vessels were usually accompanied by a tender to carry ammunition as well as the ordnance officers in charge of firing the mortars. However, as naval warfare became more advanced, bomb ships were also accompanied by frigates to protect them from direct assault by faster, smaller vessels.
Bomb vessels were traditionally named after volcanoes, or given other names suggestive of explosive qualities. Some were also given names associated with the underworld. Vessels of other types which were later converted to bomb ships generally retained their original names.
Bomb vessels were highly specialized and expensive to fit out and maintain, and only marginally suited for their secondary role as cruisers. Because bomb vessels were built with extremely strong hulls to withstand the recoil of the mortars, several were converted in peacetime as ships for exploration of the Arctic and Antarctic regions, where pack ice and icebergs were a constant menace. Most famously, these ships included HMS Erebus and HMS Terror. In this case, the volcanoes – Mount Erebus and Mount Terror on Ross Island in Antarctica – were named after the ships, instead of vice versa.
Although horizontal fire naval guns propelling explosive shells had entered all major navies by the 1840s (see Paixhans gun), there was still room for a specialized vessel on occasion. During the American Civil War, the Union fleet included armored gunboats armed with 13 inch mortars; the weapon weighed 17,250 lbs and its bedding another 4,500 lbs. They fired 204-lb shells, with a bursting charge of 7 lbs of gunpowder, and had a range of three miles. At this distance, the projectile spent 30 seconds in flight. They were used to attack several forts, for example Fort Pulaski, Georgia.  [ failed verification ]
Commodore Hornblower (published 1945), a Horatio Hornblower novel written by C. S. Forester, features several actions by British bomb vessels. The text includes a highly detailed account of the procedures used to load the mortars and aim, which involved anchoring fore-and-aft, receiving range corrections from another vessel, precisely adjusting the aim using an anchor cable attached to a windlass, and by using fine adjustments in the amount of gun powder to correct the range. However, Forester erred in describing the vessels as ketches, which by the early 19th century had been replaced by full-rigged ships, and in assigning the management of the mortars to Naval officers, rather than the Royal Marine Artillery which had been formed for this specific purpose. A later book, Hornblower in the West Indies , features a small portable "ship's mortar" mounted in a boat, used to bombard a target during a riverine operation.
In a fictionalized account, war correspondent, author, and yachtsman G. A. Henty describes in vivid detail the deployment of ten bomb-ketches by the Spanish besiegers during the final period of the siege of Gibraltar. 
In The Ramage Touch by Dudley Pope (published 1979), Captain Lord Ramage and the crew of the frigate Calypso capture two bomb ketches, which they subsequently use to thwart a French invasion plan in the Mediterranean. Like the Hornblower books, The Ramage Touch describes in great detail the technical aspects of employing a bomb vessel during the Napoleonic era.
In H.M.S. Cockerell by Dewey Lambdin (published 1995), First Lieutenant Alan Lewrie is set ashore by his vindictive captain, for 'land service' during the siege of Toulon. There Admiral Goodall gives him a bomb ketch, which he commands for several weeks until it is blown out of the water and sunk by a young Colonel of artillery named Buonaparte.
A brig is a type of sailing vessel defined by its rig: two masts which are both square-rigged. Brigs originated in the second half of the 18th century and were a common type of smaller merchant vessel or warship from then until the latter part of the 19th century. In commercial use, they were gradually replaced by fore-and-aft rigged vessels such as schooners, as owners sought to reduce crew costs by having rigs that could be handled by fewer men. In Royal Navy use, brigs were retained for training use when the battle fleets consisted almost entirely of iron-hulled steamships.
Steam frigates and the smaller steam corvettes, steam sloops, steam gunboats and steam schooners, were steam-powered warships that were not meant to stand in the line of battle. There were some exceptions like for example the French Napoléon class steam ship of the line was meant to stand in the line of battle, making it the world's first steam battleship. The first such ships were paddle steamers. Later on the invention of screw propulsion enabled construction of steam-powered versions of the traditional ships of the line, frigates, corvettes, sloops and gunboats.
HMS Erebus was a First World War monitor launched on 19 June 1916 and which served in both world wars. She and her sister ship Terror are known as the Erebus class. They were named after the two bomb vessels sent to investigate the Northwest Passage as part of Franklin's lost expedition (1845–1848), in which all 129 members eventually perished.
Naval Gunfire Support (NGFS) (also known as Naval Surface Fire Support (NSFS) or shore bombardment) is the use of naval artillery to provide fire support for amphibious assault and other troops operating within their range. NGFS is one of a number of disciplines encompassed by the term naval fires. Modern naval gunfire support is one of the three main components of amphibious warfare assault operations support, along with aircraft and ship-launched land-attack missiles. Shipborne guns have been used against shore defences since medieval naval warfare.
The Paixhans gun was the first naval gun designed to fire explosive shells. It was developed by the French general Henri-Joseph Paixhans in 1822–1823. The design furthered the evolution of naval artillery into the modern age. Its use presaged the end of wood as the preferred material in naval warships, and the rise of the ironclad.
The Hecla class was a class of bomb vessels of the Royal Navy of the early 19th century. They were designed for use as bomb or mortar ships and were very heavily built. Eight ships were launched; all were converted for use as exploration or survey ships. Four ships of the class are known for the role they played in Arctic and Antarctic exploration.
Naval artillery is artillery mounted on a warship, originally used only for naval warfare and then subsequently used for more specialized roles in surface warfare such as naval gunfire support (NGFS) and anti-aircraft warfare (AAW) engagements. The term generally refers to tube-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.
The Commodore is a Horatio Hornblower novel written by C. S. Forester. It was published in the United States under the title Commodore Hornblower.
HMS Terror was a specialised warship and a newly developed bomb vessel constructed for the Royal Navy in 1813. She participated in several battles of the War of 1812, including the Battle of Baltimore with the bombardment of Fort McHenry. She was converted into a polar exploration ship two decades later, and participated in George Back's Arctic expedition of 1836–1837, the successful Ross expedition to the Antarctic of 1839 to 1843, and Sir John Franklin's ill-fated attempt to force the Northwest Passage in 1845, during which she was lost with all hands along with HMS Erebus.
HMS Aetna was the mercantile Success launched in 1803 at Littlehampton. The Admiralty purchased her in 1803 for conversion into a Royal Navy bomb vessel. Aetna participated in the second Battle of Copenhagen in 1807 and the Battle of the Basque Roads in 1809. Later, she participated in the attack on Fort McHenry in the Battle of Baltimore and the bombardment of Fort Washington, Maryland in 1814, during the War of 1812. The Navy sold her in 1816 and she returned to mercantile service under her original name. She sailed to Calcutta, to Rio de Janeiro, and more locally until she was wrecked in 1823.
HMS Heron was originally the merchant vessel Jason, launched at Newcastle in 1803, that the Admiralty purchased in 1804 for the Royal Navy for use as 16-gun ship-sloop under the name HMS Heron. During the Napoleonic Wars she served as a convoy escort on the Leeward Islands station. Then in 1810 the Admiralty had her converted into a bomb vessel and renamed her HMS Volcano. As Volcano she served during the War of 1812, and in particular participated in the Battle of Baltimore. The Admiralty sold her in 1816. New owners returned her to mercantile service under her original name of Jason. She was wrecked in 1821.
HMS Erebus was originally built as a Royal Navy fireship, but served as a sloop and was re-rated as such in March 1808. She served in the Baltic during the Gunboat and Anglo-Russian Wars, where in 1809 she was briefly converted to a fireship, and then served in the War of 1812. In 1814 she was converted to a rocket vessel to fire Congreve rockets. While serving off America, Erebus participated in the sack of Alexandria, Virginia, and launched the rockets that bombarded Fort McHenry in Baltimore on 13 September 1814. In March 1815, off Georgia, she fired the second-to-the-last-shot of the war. She was laid up in 1816 and sold for breaking up in 1819.
HMS Starr was a 16-gun Merlin-class ship sloop of the Royal Navy. She was built by Tanner, of Dartmouth, to plans by Sir William Rule, and launched in July 1805. As a sloop she served on convoy duty, though she also participated in the invasion of Martinique in early 1809. She was rebuilt as a bomb vessel in May 1812 and renamed Meteor. As Meteor she served in the Baltic and then off the United States, participating in attacks on up the Potomac and on Baltimore and New Orleans. She was sold in October 1816.
Naval artillery in the Age of Sail encompasses the period of roughly 1571–1862: when large, sail-powered wooden naval warships dominated the high seas, mounting a large variety of types and sizes of cannon as their main armament. By modern standards, these cannon were extremely inefficient, difficult to load, and short ranged. These characteristics, along with the handling and seamanship of the ships that mounted them, defined the environment in which the naval tactics in the Age of Sail developed.
The Raid on Alexandria was a British victory during the War of 1812, which gained much plunder at little cost but may have contributed to the later British repulse at Baltimore by delaying their main forces.
The Battle of Veracruz, also known as the Battle of San Juan de Ulúa, was a naval engagement that pitted a French frigate squadron under Rear Admiral Charles Baudin against the Mexican citadel of San Juan de Ulúa, which defended the city of Veracruz, from 27 November to 5 December 1838.
The siege of Fort St. Philip was a ten day long distance bombardment of exploding bomb shells - by two Royal Navy bomb vessels, mounting a total of four mortars - against the American garrison of Fort St. Philip. The fort was unable to retaliate at the start, as the bomb vessels were out or the range of its solid shot cannon, and its mortar did not have ammunition. This was remedied by supply boats, whereby the fort counter-attacked the bomb vessels with its mortar on January 17, and the British duly withdrew. This riverine engagement took place during the concluding hostilities of the War of 1812.
HMS Infernal was an 8-gun bomb vessel of the Royal Navy, constructed in 1757 and in service until 1763. Designed by Thomas Slade, she was the prototype for six subsequent Infernal class bomb vessels which saw service in the Mediterranean and the West Indies during the Seven Years' War with France. In 1760 she was refitted as a sloop and returned to active service in the Caribbean.