Claim: The USS Constitution is a United States Navy ship.

A frigate -LSB- ˈfrɪɡᵻt -RSB- is any of several types of warship , the term having been used for ships of various sizes and roles over the last few centuries .   In the 17th century , this term was used for any warship built for speed and maneuverability , the description often used being `` frigate-built '' . These could be warships carrying their principal batteries of carriage-mounted guns on a single deck or on two decks -LRB- with further smaller carriage-mounted guns usually carried on the forecastle and quarterdeck of the vessel -RRB- . The term was generally used for ships too small to stand in the line of battle , although early line-of-battle ships were frequently referred to as frigates when they were built for speed .   In the 18th century , the term referred to ships that were usually as long as a ship of the line and were square-rigged on all three masts -LRB- full rigged -RRB- , but were faster and with lighter armament , used for patrolling and escort . In the definition adopted by the British Admiralty , they were rated ships of at least 28 guns , carrying their principal armaments upon a single continuous deck -- the upper deck -- while ships of the line possessed two or more continuous decks bearing batteries of guns .   In the late 19th century -LRB- beginning about 1858 with the construction of prototypes by the British and French navies -RRB- , the armoured frigate was a type of ironclad warship that for a time was the most powerful type of vessel afloat . The term `` frigate '' was used because such ships still mounted their principal armaments on a single continuous upper deck .   In modern navies , frigates are used to protect other warships and merchant-marine ships , especially as anti-submarine warfare -LRB- ASW -RRB- combatants for amphibious expeditionary forces , underway replenishment groups , and merchant convoys . Ship classes dubbed `` frigates '' have also more closely resembled corvettes , destroyers , cruisers , and even battleships . The rank `` frigate captain '' derives from the name of this type of ship .