18: 38: 34
The ability to use an open bay and exterior production capability is unique to the Shipyard IV, generally making it a primary target during a raid. Given the obviousness of the Shipyard IV being a high priority target, the designers realized that to lightly arm such a station could prove disastrous. As a result the station itself is well shielded, heavily armed, and quite capable of defending against even some capital ships without as much need for the picket fighters traditionally used for station defense. Nevertheless, few are willing to leave such valuable assets without dedicated protection from combat ships or defense stations.
Because of the high cost of building even a single Shipyard IV, these ship producing behemoths are a rare sight in the Galaxy. With lower costs and the ability to produce most ships, the Shipyard IV's smaller cousins are far more common in the ship building industry.