Hull autorepair equipment is only available to very large ships

[sturnclaw]

After the equipment rewrite, the existing hull autorepair equipment was assigned to size-4 hull slot. This is rather suboptimal, as it creates a tradeoff between atmospheric shielding for the hull or the ability to attempt to repair combat damage.

At minimum, multiple size classes of hull autorepair should be created to restore the ability of medium and larger ships to access this feature.