HMS Neptune was a 98-gun second-rate ship of the line of the Royal Navy. She served on a number of stations during the French Revolutionary and Napoleonic Wars and was present at the Battle of Trafalgar in 1805. Neptune was built during the early years of the war with Revolutionary France and was launched in 1797. She almost immediately became caught up in the events of the mutiny at the Nore, and was one of a few loyal ships tasked with attacking mutinous vessels if they could not be brought to order. The mutiny died out before this became necessary and Neptune joined the Channel Fleet. She moved to the Mediterranean in 1799, spending the rest of the French Revolutionary Wars in operations with Vice-Admiral Lord Keith's fleet. After refitting, and spending time on blockades, she formed part of Lord Nelson's fleet at the Battle of Trafalgar, and was heavily involved in the fighting, sustaining casualties of 10 killed and 34 wounded. She was not fully repaired and returned to service until 1807, when she went out to the Caribbean. In 1809 she participated in the successful invasion of Martinique, and the subsequent battle with Troude's squadron. Returning to Britain towards the end of the wars, she was laid up in ordinary, and in 1813 became a temporary prison ship. She was finally broken up in 1818. Construction and commissioning Neptune was ordered from Deptford Dockyard on 15 February 1790, to a design developed by Surveyor of the Navy Sir John Henslow. She was one of three ships of the , alongside her sisters and . Neptune was laid down at Deptford in April 1791, receiving her name on 24 July 1790. The initial stages of her construction were overseen by Master Shipwright Martin Ware, though he was succeeded by Thomas Pollard in June 1795, and Pollard oversaw her completion. Neptune was launched on 28 January 1797 and sailed to Woolwich to be fitted for sea. Arriving at Woolwich on 12 February, she was immediately docked to have her copper sheathing fitted, a process that was completed by 1 March. Launched again, she finished fitting out, and received her masts and yards. Her final costs came to £77,053, and included £61,172 spent on the hull, masts and yards, and a further £15,881 on rigging and stores. She was commissioned on 25 March 1797 under Captain Henry Edwyn Stanhope, becoming the