Culverins are good versus artillery, and ships.
The culverin is a light artillery piece that is very effective against enemy artillery and ships. It is not very effective against anything else, but makes up for this fact by being exceptional at it's two primary functions. It deals more damage versus ships than the Light Cannon and at slightly better range, while it doesn't match the Mortar or Morutaru on range it is far more accurate against a moving ship.
They have longer range than most artillery and do bonus damage vs. artillery and ships, though unless an opponent is building cannons or a strong navy they have little use in a match. Some strategists may want to keep a few around just in case of a ship or artillery attack, while others would consider it a waste of resources to build a unit which doesn't counter anything currently in play.
Due to their sizeable range, culverins can adequately defend a shoreline from most ships as they beat all of them on range except Monitors and Ironclads. Ships using Offshore Support or European Cannons will not have greater range than a culverin, they come up 1 point short of matching it's range. When combined with the even higher anti-ship range of outposts and town centers built near the water and walls along the shore (preventing troops from being unloaded), the player will be safe inside their turtle shell until Monitors are able to be produced by the enemy.
Spanish unction cardEdit
Fully upgraded culverins being influenced by the Spanish Unction aura will very rapidly (1-2 shots, 456 damage versus artillery) destroy any artillery which lack comparable or superior tech advantages. These culverins are also capable of inflicting 1710 damage to ships in a single shot, this can make it extremely difficult to successfully land an invasion force directly on Spain's doorstep, even when transporting troops in a high hit point vessel.