On the DAC/Rank/Information tab of the f5 Class Design window, there's a list field titled:
Eligible additional classes if this is primary class for a shipyard
This is empty for all of my ship designs but seems like it ought to contain other sufficiently similar ship designs. Is this a list that gets populated automatically within a certan tolerance, or is there something I have to do manually?
For example, my Geosurvey and Gravsurvey ship designs are exactly equal in tonnage and carry identical components except as follows:
Geosurvey: 3x Ion Engine + 3x Geological Survey Sensors
Gravsurvey:4x Ion Engine + 2x Gravitational Survey Sensors
. . . and these engines and sensors all have the same tonnage and crew requirements. Seems pretty interchangeable to me! But neither ship is listed as an alternate build option for the other. Is there a way for me to make that happen?