30-pounder long gun

• Name — 30-pounder long gun • Origin — France • Type — naval gun • Is Artillery — yes • Is Uk — yes • Service — 19th century • Used By — French Navy • Wars — Invasion of Algiers, Battle of the Tagus, Battle of Veracruz • Manufacturer — Factories of Saint-Gervais, Nevers and Ruelle • Unit Cost — 1517.5 Francs • Weight — 3035 kg • Length — 315.8 cm • Part Length — 282.9 cm • Caliber — 164.7 mm

Installed on the lower deck of the larger warships from the 1820s, the 30-pounder long gun was the largest caliber used in the late Navy of the Age of the Sail, used on the ships defined by the Commission de Paris. On three-deckers, the middle deck used 30-pounder short guns, and the upper deck used 30-pounder carronades. The flagship Bretagne was an exception to this rule, retaining the older 36-pounder long gun as to maximise the weight of her broadside.

In the wake of the Napoleonic Wars, the French Navy undertook a number of reforms, most notably a reform in the artillery system. In contrast with the 1788 system, where large warships armed their main batteries with large 36-pounder long guns and upper deck with smaller long guns using smaller shots, it was decided to standardise on the 30-pound calibre, and deploy a variety of guns of different weights, as not to overload the tops. The differences in weight were obtained by fielding a large 30-pounder long gun, a shorter 30-pounder with a thinner barrel, and a 30-pounder carronade. This allowed a much simplified handling of ammunition, and significantly increased the broadsides of warships. A first-rank 60-gun frigate of the 1840s thus armed had a heavier broadside than a 74-gun ship of the line of the 1780s.