The Frigate is the largest and strongest ship available to Europeans and Americans. She has several cannons on both sides and can let loose a devastating broadside, but the reload takes very long and she, like the other ships, also can't shoot at targets which are too close to her. This can make her vulnerable to smaller enemy naval units if they attack in larger numbers.
Stationing some fast-firing Carracks with her is a good way to prevent or at least counter this threat.
Some very large and heavily armoured frigates which were rated as 44-gun frigates, but were operationally armed with over 50 large-sized cannons and carronades, have been built in the late 1790s in the United States of America, with the most famous being the USS Constitution, a ship that still exists today. These ships have sometimes been regarded as equal to the ships of the line, and after losses in the War of 1812, the British Royal Navy even ordered that their frigates shall never engage these 'super-frigates' unless there was at least a 2:1 superiority.