One of the very first things I research is Sensors I.  That's all you need to enable the survey module.  One you have that, you can stick one on any hull you have available at the time.  Anomolies can be a huge help when in the early game so I try to get a few ships out on auto-survey right away.  They're usually a cargo hull with a couple engines, a survey module, and several basic life support modules.

I'm pretty sure lhughes means the Survey Ship page at https://www.galciv.wikia.com/wiki/Survey_Ship

As far as I can tell, that page does give an accurate description of the 'core ship design' for the free flagship vessel you get at the start of the game. Sensors IV  and hull size seem to be about speed and getting a bit larger scan range w/ low space for the module.

Another thought: lhughes41, are you relying on the automated ship designer? I've barely used it and never noticed whether it would re-create the flagship design when the required techs became available.