A gunboat squadron is like a gnat in comparison to the larger ships-of-the-line. Nevertheless, they have a useful place in the fleet. A gunboat would typically have only a single mast with square-rigged sails, mounting between one and three fixed cannons.
Fleets of all navies kept gunboats on hand. They could be useful in shallower waters, as with only a single mounted cannon, they were able to manoeuvre relatively easily where a large ship could not. If this cannon was a 32-pounder it could still prove dangerous to larger vessels. For instance, a frigate could easily destroy a single gunboat with a single broadside hit. But if deployed in large numbers, the frigate would struggle to deal with every gunboat before sustaining heavy damage itself. The extremely cheap cost and relative time is taken to build these gunboats could prove a tremendous advantage.
Gunboats were crucial to Napoleon's notion for the planned invasion of England in 1804, whilst the US Navy's policy between 1803 and 1812 focussed its Navy around the concept - this was to prove ineffectual against the British Blockade in the war of 1812.
In the Game
In Black Seas, Gunboat squadrons are tiny vessels. This means that they are extremely difficult to hit, but are vulnerable to collisions from larger vessels, particularly if that vessel was travelling at speed. They mount only a single light cannon and are too small to allow for upgrades - their relative evasiveness, however, means that they will be difficult to deal with in battle.