Fourth-rate
In the rating system of the Royal Navy, a fourth-rate was a ship of the line with two gun decks which mounted between 46 and 60 guns. They served in all conflicts the Royal Navy participated in during the early modern period until they were gradually phased out of active service during the French Revolutionary and Napoleonic Wars, as their usefulness was declining; though fourth-rates often remained in service on distant stations such as the East Indies. Several fourth-rates were created by razeeing larger ships of the line, and occasionally from East Indiamen such as HMS Calcutta.