Fourth-rate

A fourth-rate was a ship-of-the-line mounting 50-60 guns. Though used largely during the Seven Year's War, by the time of the American Revolution and especially the French Revolutionary/Napoleonic Wars, the 4th rate was considered too weak to stand in the line of battle. The few that remained were increasing relegated to convoy escort, or as flagships on far-flung stations.

Some 4th rates did remain in active service even during the Napoleonic Wars, especially in the shallow North Sea, where the Royal Navy's main opponents would be the Baltic powers and the Dutch, whose own fleet consisted mainly of 50 and 64 gun ships. However, HMS Leander, 50 guns, was with Horatio Nelson at the Battle of the Nile. As late as 1807, 4th rates were active in combat zones, illustrated by the fatal incident between HMS Leopard, 50 guns, and the US frigate Chesapeake, 38 guns, which almost precipitated the War of 1812 five years early!