30-pounder long gun

30-pounder long gun
30-pounder without rigging.
Type	naval gun
Place of origin	France
Service history
In service	19th century
Used by	French Navy
Wars	Invasion of Algiers, Battle of the Tagus, Battle of Veracruz
Production history
Manufacturer	Factories of Saint-Gervais, Nevers and Ruelle
Unit cost	1517.5 Francs
Specifications
Weight	3,035 kilograms (6,691 lb)
Length	315.8 centimetres (124.3 in)
Barrel length	282.9 centimetres (111.4 in)
Calibre	164.7 mm

The 30-pounder long gun was a large piece of artillery mounted on French warships of the Age of sail. They were the heaviest component of the unified system standardised on the 30-pounder calibre, replacing both the 36-pounder long guns in their usages, and even some 24-pounders.

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 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.