I'm conceptualizing this notion in the context of CT (because CT is what I know), but the formulation works just as well for other editions of Traveller (I presume).
It always felt a little bit ... hinky ... that type A and B starports had "no meaningful upper limits" placed on the hull sizes that they could construct in CT.
- LBB2 limited craft to 5000 tons because that was the limit of the design system.
- LBB5 limited craft to 1,000,000 tons because that was the limit of the design system ... although computer model tech level requirements effectively put an upper limit on hull sizes via a kind of back door.
But other than that ... it's basically "build anything, anywhere" with no meaningful guidance regarding the "limits" of shipyard construction capabilities, other than tech level (via backdoor methodology, and sometimes not even that!).
What I propose is:
- Worlds with Population: 0-6 (Non-industrial trade code), USP hull sizes are limited to the UWP population code.
- Population: 2 world can construct up to Hull Size: 2 (200-299 tons) craft.
- Worlds with Population: 7-A that are not Industrialized, USP hull sizes are limited to UWP tech level code.
- Tech Level: C world can construct up to Hull Size: C (3000-3999 tons) craft.
- Worlds with the Industrialized trade code are limited to Hull Size: Y (1,000,000 tons)
Point being that only the highest population Industrialized worlds are capable of constructing Big Ship Universe stuff (20k ton cruisers up through 500k ton dreadnoughts and the like). Meanwhile, on the lower end, there is a better grasp on the construction capacities of non-industrial shipyards limited to Small Ship Universe stuff that will mostly be classified as ACS.
With such a guideline in place, if I want to know "how big of a starship" a location such as
Paya/
Aramis/
Spinward Marches is capable of constructing, I can simply look at the UWP (A655241-9) and note that although the mainworld has a type A starport, the Population: 2 will limit the construction capability there to Hull Size: 2 (200-299 tons) and TL=9 ... so if I want to build something 300+ tons in size, I'm going to need to take my business someplace other than Paya to get the job done.
For ACS market segments, this then gives a reasonable sliding scale for the expectations of "what can be built where" on the low end, while simultaneously emphasizing the importance of industrialized worlds (especially the higher tech industrialized ones!) on the upper end of the BCS.
So using the Spinward Marches as an example of how this plays out ... Glisten, Rhylanor, Mora and Trin all have type A starports and TL=F ... but only Glisten, Mora and Trin are industrialized worlds, Rhylanor is not.
So even though Rhylanor can build TL=F starships, the shipyard facilities at Rhylanor would be limited to a maximum Hull Size: F (6000-6999 tons), which is still "plenty" of any LBB2 design and most commercial shipping designs but doesn't reach all the way up really big LBB5 stuff.
However, any "big iron" Imperial Navy construction of cruisers up through dreadnoughts would have to come from Glisten, Mora or Trin as industrialized TL=F shipyards within the Spinward Marches sector.
Such a distinction in limitations then helps give ... added texture ... to the kinds of market segments that various type A/B starports can support when it comes to construction capacity, along with a better idea of the relative importance of industrialized worlds in the web of interstellar trade and military services.
Thoughts?
If enough people support this idea, I'll cross-post this into the House Rules forum for preservation ... but right now I'm more interested in knowing what people think.