What a frigate was
The word frigate has changed meaning more than once. Today it refers to a modern escort warship. In the age of sail it meant something quite different: a fast, relatively light warship, with its guns usually on a single continuous deck plus smaller guns on the upper works, and with enough sail area to outrun most larger ships. The name probably began in the Mediterranean, where it referred to small, fast oared craft, and by the seventeenth and eighteenth centuries it was applied to sailing warships of this lighter type.
Typical eighteenth-century frigates carried somewhere between roughly twenty-eight and forty-four guns, though precise numbers varied by navy and period. They were too weak to stand in the line of battle against a ship of the line, and so they were not expected to. Their strength lay in speed, handling and the ability to range far from the main fleet.
Scouting for the fleet
A battle fleet in the age of sail could not see far. From a masthead, lookouts could spot sails perhaps a dozen or so miles away in good weather, and often much less. If a commander wanted to find an enemy, he needed ships spread out over a wide area. Frigates were the usual answer, and they were often called the eyes of the fleet.
The cost of lacking them could be serious. Horatio Nelson, searching the Mediterranean in 1798 for a French fleet carrying Napoleon’s expedition to Egypt, is often said to have been hampered by a shortage of frigates, after a storm in May damaged his flagship and scattered his scouting ships. Historians still debate how much difference it made, but the episode is often cited to show how much a fleet depended on fast scouts.
Frigates also repeated signals between ships too far apart to see the flagship, carried dispatches, and sometimes stood by during battle to tow damaged ships or pick up survivors. In a large fleet action, they typically stayed outside the line, ready to help.
Convoy escort and commerce raiding
A second large part of the job was protecting trade and attacking an enemy’s. Merchant ships sailed in convoys when enemy cruisers or privateers were about, and frigates were the ships that escorted them. A convoy gave the escort a defined group to defend, but it also meant the merchantmen moved at the pace of the slowest member.
The same speed and range made frigates effective raiders. A frigate on a cruise could capture merchant ships, bring them in as prizes, and force the enemy to divert ships to hunt it. Navies often used them alongside privateers, and the captured cargoes and ships could be a source of reward for crews. Because a single frigate action was often small and personal, such engagements gained fame out of proportion to their strategic weight.
Frigates and the single-ship action
One consequence was a series of duels between individual frigates. These were popular with the public and the press, and several became well known, particularly during the War of 1812 between Britain and the United States. The United States built a few unusually large frigates, such as USS Constitution, rated at 44 guns, which were heavier than many European types and were sometimes described as a different kind of ship altogether.
Duels like these show how finely balanced the frigate class was. A frigate could defeat smaller opponents and escape larger ones, but a bad meeting with a ship of the line was a good reason to run. Captains and their crews were typically judged on their ability to choose the right fight.
From sail to steam and the modern frigate
When steam and iron arrived, the frigate went through a period of transition. Mid-nineteenth-century steam frigates were large, powerful vessels, and for a short time the term was applied to ironclad ships too. Later the cruiser took over many of the frigate’s old duties of scouting and commerce protection, and the frigate name faded.
It returned in the Second World War, when Britain applied it to a type of escort vessel built to protect convoys against submarines, larger than a corvette and smaller than a destroyer. Since then the word has been used by many navies for general-purpose escort ships. The original idea survives, however: a ship that is not meant to be the heaviest in the fleet but is built to find, guard and screen. The general pattern of how naval roles are redistributed as technology changes is outlined in the history of warships.