On the occasion there would be ghost ships captained either by greedy captains of merchant ships or greedy explorers/conquistadors who hunted for gold.
the whole theme for these ghost ships is greed and that these humans are being punished for their greed. Said humans becoming ghosts or undead beings.
These vessels can either be seen sailing alone or work together as fleets. These ships also attack ports or ships that cross their paths. If they run into another ghost ship, they battle each other but are unable to damage or sink one another.
They move unnaturally fast as well as against the wind. Their armaments, such as cannons have been greatly enhanced by the magic or curse that clings to them and they have special cannonballs that although they dont damage the victim ship, can bring on a whole series of impediments onto the victim ship,