This achievement is relatively easy when compared to the other pinballfx achievements...
First, hit the ball on the right side of the table 3 times. After that the table will say "Siege Tower in Position!"
Then shoot your ball up the right ramp (it will roll across the table to the siege tower). Then pick Mock Warfare from the list and select with the launch button (A button)
You have two catapults that alternate between one with a flashing red light and a solid orange light. Just press the launch button ( A) when the light is flashing red and the ball will shoot to that catapult and launch over to the ship.
Do this two times in a row the achievement will unlock (and probably obscure your view of the Table).
Good luck and happy hunting.