Okay, a slight rearrangement of production capacities:
After some brief research, I figured the best country to compare a Kingdom to would be Poland: similar GDP, and we also have a shipbuilding industry.
We have three shipyards overall: Gdansk, Gdynia and Szczecin.
Gdansk has three slipways, Gdynia has two drydocks, and Szczecin has three more slipways.
Of course, slipways aren't everything: most ships are actually built on land these days, and only assembled in a drydock or on a slipway.
So we can expect a kingdom to have eight construction docks of various kinds, plus some refurbishment assets. But these slipways are really, really fucking huge, and the FCS is pretty small, so we could safely assume that two FCS-type 15k tonners could easily be built in one such huge slipway.
So, overall, I can assume a Kingdom has the capacity to build 16 FCS-sized ships simultaenously, or roughly 240 thousand tonnes at the same time.
As for how much capacity should a principality have...I honestly don't know. It obviously doesn't scale linearly, so I'm open to input from all concerned nations
I say we ignore the particulars of construction and just assign "DWT capacity" based on this preliminary analysis, even if we get to building huge VLCCs we can just say Shroomania can build one at a time, no matter if it actually has a dock big enough.
Agreed?