The 34-gun 'Defiant' Frigate
Traditionally, a frigate is a rated warship of about 30 guns that is used primarily for smaller actions, signal running, and convoy escort duties. Though too weak to stand their ground in a line of battle action, their perfect balance between power, speed, and maneuverability makes them exceedingly flexible ships.
In Pirates of the Burning Sea, there are six ships known specifically as frigates. They are, in order of size, the 26-gun Cerberus, the 30 gun Stralsund, the 32 gun Raa, the 32-gun Myrmidon, the 34-gun Capricieux, and the high-tech, 34-gun Defiant.