Hampton Roads Naval Museum

7. 18-Pounder Naval Cannon

Norfolk, VA

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The museum acquired on loan from its parent command an 18-pounder cannon used on the frigate USS Constellation. The Maryland Archaeological Conservation Lab restored and conserved the weapon before turning it over to HRNM. The weapon itself was typical of U.S. Navy ordnance in the early 19th century. It weighs over 4,700 pounds. Of note is that it is not an American-made weapon. Inscribed on the cannon are the letters "P WG 1798," which are the marks of the British arms dealer Wiggin and Graham. The "P" means that it was intended for merchant ship duty. The cannon is an important artifact of the War of 1812. British warships forced Constellation into Norfolk during the war. The ship's company used the frigate's 18-pounders in assisting the Virginia militia defend Craney Island during a major British assault in 1813. One descriptive characteristic which was commonly used was to define guns by their pound rating: theoretically, the weight of a single solid iron shot fired by that bore of cannon. Common sizes were 42-pounders, 36-pounders, 32-pounders, 24-pounders, 18-pounders, 12-pounders, 9-pounders, 8-pounders, 6-pounders, and various smaller calibers. In general, larger ships carrying more guns carried larger ones as well. The muzzle-loading design and weight of the iron placed design constraints on the length and size of naval guns. Muzzle loading required the cannon to be positioned within the hull of the ship for loading. The hull is only so wide, with guns on both sides, and hatchways in the center of the deck also limit the room available. Weight is always a great concern in ship design as it affects speed, stability, and buoyancy. The desire for longer guns for greater range and accuracy, and greater weight of shot for more destructive power, led to some interesting gun designs. The carronade was adopted by the Royal Navy in 1779; the lower muzzle velocity of the round shot when fired from this cannon was intended to create more wooden splinters when hitting the structure of an enemy vessel, as they were believed to be more deadly than the ball by itself. The carronade was much shorter, and weighed between a third to a quarter of the equivalent long gun; for example, a 32-pounder carronade weighed less than a ton, compared with a 32-pounder long gun, which weighed over 3tons. The guns were, therefore, easier to handle, and also required less than half as much gunpowder, allowing fewer men to crew them. Carronades were manufactured in the usual naval gun calibers, but were not counted in a ship of the line's rated number of guns. As a result, the classification of Royal Navy vessels in this period can be misleading, as they often carried more cannon than were listed.