Let me describe a couple model ships:
The “Glass ship”, a slower-than-light (STL) only ship, with a Very Small Cargo (VSB) bay (250/250). This ship requires a little TI, a little AU, a little LI, a little BRM. It requires a Tiny Crew Quarters (CQT) and a Short-Range Bridge (BRS). Everything on this ship can be made with technicians and lower workforces. Indeed, the SKF and HWP only take 1/5 their workforce in techs. Only the SAR (in the BRM) absolutely requires technicians - and we’ll see this pattern of high-tech electronics again.
The next model upgrades the cargo bay to the Small version (SCB, at 500/500). This should be familiar, we all have two of them. The small cargo bay requires FAL, made in the Advanced Smelter (ASM), a building that starts to take Engineers. (50 techs to 20 eng).
It is also possible to upgrade the fuel tanks to medium and large versions. The medium version takes less TI than the small, though adds iron and time through the ASM; the large takes even more FET. These give absolutely ridiculous volumes of SF at a cost of weight - that makes the SF spent less effective at decreasing the time of flights.
That’s it. That’s all the ships that can be built without scientists. Let’s look at accessories, though, generally made in the SPP. The SPP takes 50 techs, 30 engineers. The Heat Shielding, Whipple Shielding, Radiation Shielding, and G-seats are all available at this point through exotic materials in the Advanced Magic Lab (AML). BER is always a cold planet, and the derivative BE is needed to create TSH, which is needed for BTS->W from always hot planets.
The Drone Hub requires its own Tech/Eng building. Finally, the Stability Support System is unavailable at this technology level.
So, why can’t we build with larger cargo bays? When you look at the MCB (or High-load, the WCB), you only note that it requires AST (3 AL + 1 TI in an ASM). Man, that building was available for the SCB, you say. But to mount it on a ship, your crew now needs a Small Crew Quarters (CQS). A CQS requires a Life Support System (LIS) and a Weak AI (WAI). And then the LIS also requires a WAI. Unfortunately for all of us, the WAI is created in a Software Labs, a scientist-only building. There is no level of Engineer-but-not-Scientist slow-building possible.
The Large Cargo Bay (2000/2000) requires a CQM; the remaining High-Volume (VCB) requires a CQL. Additionally, the size of the SF fuel tank can increase the crew quarters needed.
The Standard STL engine requires an Automated Cooling System, which requires a WAI. Dead. In fact, every other STL and FTL engine requires an ACS, bringing in the scientist dependency.
Bringing in an FTL engine increases the Navagation module to require several steps in the SL. Dead.
The Stability System requires a WAI. Dead.
For your consideration: what if the Standard and Fuel-Saving Engines required a “Basic Cooling System” (and the Automated became an Advanced). The BCS would instead require a Neural Net (prereq to WAI, made in Eng-only Electronics building). The LIS (in the small, medium, and large Crew Quarters) would similarly need to downgrade it’s three (!) WAI - in the AIR, WR, and directly.
This still leaves the idea that we cannot have FTL-capable ships until scientists. I will leave examination of that for another topic.