HMS Britannia was a 100-gun first rate ship of the line

Ship of the line

A ship of the line was a type of naval warship constructed from the 17th through the mid-19th century to take part in the naval tactic known as the line of battle, in which two columns of opposing warships would manoeuvre to bring the greatest weight of broadside guns to bear...

 of the Royal Navy

Royal Navy

The Royal Navy is the naval warfare service branch of the British Armed Forces. Founded in the 16th century, it is the oldest service branch and is known as the Senior Service...

. She was ordered on 25 April 1751 from Portsmouth Dockyard to the draught specified in the 1745 Establishment

1745 Establishment

The 1745 Establishment was the third and final formal establishment of dimensions for ships to be built for the Royal Navy. It completely superseded the previous 1719 Establishment, which had subsequently been modified in 1733 and again in 1741...

. Her keel was laid down on 1 July 1751 and she was launched on 19 October 1762. The cost of building and fitting totalled £45,844/2s/8d. Her main gundeck armament of twenty-eight 42-pounder guns was later replaced by 32-pounders. In the 1790s ten of her quarterdeck guns and two of her forecastle guns were replaced by the same number of 32-pounder carronade

Carronade

The carronade was a short smoothbore, cast iron cannon, developed for the Royal Navy by the Carron Company, an ironworks in Falkirk, Scotland, UK. It was used from the 1770s to the 1850s. Its main function was to serve as a powerful, short-range anti-ship and anti-crew weapon...

s.

Britannia was first commissioned

Ship commissioning

Ship commissioning is the act or ceremony of placing a ship in active service, and may be regarded as a particular application of the general concepts and practices of project commissioning. The term is most commonly applied to the placing of a warship in active duty with its country's military...

 in September 1778, and saw service during the War of American Independence. From 1793–1795 she was the flagship of Vice-Admiral Hotham

William Hotham, 1st Baron Hotham

Admiral William Hotham, 1st Baron Hotham was an officer in the Royal Navy. He was the son of Sir Beaumont Hotham , a lineal descendant of Sir John Hotham....

. She fought at the Battle of Cape St Vincent

Battle of Cape St. Vincent (1797)

In the Battle of Cape St Vincent a British fleet under Admiral Sir John Jervis defeated a larger Spanish fleet under Admiral Don José de Córdoba near Cape St. Vincent, Portugal.-Origins:...

 and at the Battle of Trafalgar

Battle of Trafalgar

The Battle of Trafalgar was a sea battle fought between the British Royal Navy and the combined fleets of the French Navy and Spanish Navy, during the War of the Third Coalition of the Napoleonic Wars ....

, where she carried the flag of Rear-Admiral of the White William Carnegie

William Carnegie, 7th Earl of Northesk

Admiral William Carnegie GCB, 7th Earl of Northesk was born in Hampshire to Admiral George Carnegie, 6th Earl of Northesk and Anne Melville.-Naval career:...

, Earl of Northesk. She lost 10 men killed and 42 wounded at Trafalgar, and following that battle she was laid up in ordinary in the Hamoaze

Hamoaze

The Hamoaze is an estuarine stretch of the tidal River Tamar, between the River Lynher and Plymouth Sound, England.The Hamoaze flows past Devonport Dockyard, which belongs to the Royal Navy...

 at Plymouth in 1806.

The ship was renamed on 6 January 1810 as HMS Princess Royal, then on 18 January 1812 as HMS St George and once more on 2 June 1819 as HMS Barfleur.

She was third of seven ships to bear the name Britannia

HMS Britannia

Six ships and a shore establishment of the Royal Navy have borne the name HMS Britannia, after Britannia, the goddess and personification of Britain....

, and was broken up at Plymouth in February 1825.

She was known as 'Old Ironsides' long before USS Constitution

USS Constitution

USS Constitution is a wooden-hulled, three-masted heavy frigate of the United States Navy. Named by President George Washington after the Constitution of the United States of America, she is the world's oldest floating commissioned naval vessel...

.