There are surely 6-10 shipyards on the planet that can handle construction of VLCCs and CVN sized ships.
Dean,
Don't confuse
capacity with
capability. Skills are as important as slip sizes.
Only one shipyard on the entire planet builds CVNs and it is in Newport News. Of course the market for CVNs isn't exactly huge either, especially now, but the Soviets never managed to build one even during the height of the Cold War.
Currently the biggest VLCCs are only built in one yard too. Again, the market is small and that yard can meet
current demand. It simply isn't worth the effort for another yard to develop the skills, suppliers, and other bits necessary to crack into the market. The learning curve is steeper than the profit curve, so only one yard is currently in the business.
The container ship construction market is heading the same way too. One yard (or two at the very most) will own the "biggest" market alone, while others handle smaller construction.
The manufacture of large aircraft is in a similar situation. The planet has only
two manufacturers, both of which are essentially subsidized by their respective governments. (Although Airbus is subsidized far more.)
If we see large, bleeding edge manufacturing of ships and aircraft limited to one or two organizations in the Real World, what can we then infer from that about the OTU?
IM VERY HO, we can infer that the OTU's biggest, best, and/or bleeding edge starships, be they warships or merchants, are only built in a small number of locations.
While
HG2 states that warships can be built anywhere regardless of size and TL because the parts can be always shipped in, I'd think that economics must wiegh in sooner or later. Arglebargle IX could very well strain every financial nerve putting together an
Atlantic-class heavy cruiser from some very large kit, but that would be an exception. The vast majority of those heavy cruisers - or large merchantmen or long range survey craft or whatever - would be built by yards who have oriented themselves towards that kind of work.
What I'm trying to say is that the yard "market" should be segmented just as the trade "market" is segmented. Certain yards will be able to do certain things better than certain other yards, and all of them will still be Class A.
Have fun,
Bill