The Artillery Beam is a Main System, but doesn't benefit from being manned. It fires an uncontrollable beam that is the length of the ship. It does 1 damage per room hit, but it is able to bypass all shields.
More power means faster cool down.
Power Lvl(scrap cost) = Cool down (seconds)
1 = 50
2(30) = 40
3(50) = 30
4(80) = 20