Ai-chase (Ship goal) Causes the specified ship to chase and attack the specified target. Takes 2 arguments... 1: Name of ship to chase. 2: Goal priority (number between 0 and 89).
With very few exceptions, Ai-chase should not be used for capital ship combat. Due to the restricted capital ship AI and their limited maneouverability, they almost inevitably end up doing a 'circle of death' around each other, often interfering with their own firing arcs, other parts of the mission and just generally looking bad. For much better control of capital ship encounters, use waypoints to bring them to the desired locations.