Off the coast of Puerto Madryn, this Chinese boat was illegally fishing in Argentina's territorial waters. The coast guard gave chase and the Chinese boat tried to ram the coast guard ship. The coast guard opened fire and sunk the boat. The entire crew was saved by the coast guard and a second Chinese fishing boat.
These Mantilla-class ships have a helicopter pad and a 40mm gun.
Here's a 40mm gun in action. Is it capable of sinking that boat?