You are wrong here, look at these pictures, it indoor ship cradle, which have capacity to produce large ships. I think it is prepared for 054Bs, but also possible for 052 series.
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As for the technique problems, I agree with you, but all in all, it is just money problem. If navy get more funding to produce these ships, they must be able to do it.
Jiangnan shipyard takes several year to upgrade to produce carriers, Guangchuan and Huangpu will take less time to prepare for destroyers. I even think they already finished this work, they just need a certificate to start.
It is meant to weld sections of large ships --- bulk freighters, container ships --- you have any idea how these large ship scale in comparison to a 054B? These ships displace several times more, anywhere from 100,000 to 400,000 DWT. A 054B would be considered a tiny ship. There is no way a 054B would be considered a large ship. These facilities are meant to produce huge commercial ships. Check out the massive drydock next to the sheds. The pieces that are made in these sheds are moved to the drydock for final assembly. Do you remember how they were building 003? The smaller pieces were being assembled into larger modules first, before they were moved to the drydock. In other words, this facility was meant to produce ships the other facility can't.
Sure these facilities can produce the warships and they have the space for it --- the drydock there can build a carrier, maybe two 075 size ships side bye side, but let me remind you that is not their original purpose, much like HDZ's new facilities at Changxin were meant to produce high end commercial ships.
These shipyards are primarily born for industry and profit. Warship construction is only a collateral side business.
At this stage, the small shipyards that have produced 056 successfully are better geared for making 054A+ and 054B. Guangzhou Huangpu's old shed for example, can produce two 054X sized frigates side by side. One of the older HDZ's shipyards, where a 054AP is currently being built, that can produce two 054X sized frigates size by side, and its bigger dock can produce one 054X, possibly two, on the side even if two 075 ships are being built there. If this drydock isn't producing 075, you can load four frigates or destroyers there. There are also two shipyards around the Liaoning peninsula that have produced 056 and can produce frigate.
JIangnan's and Dalian's facilities have not changed, they can produce the same output as they have recently. If Dalian is going to produce another carrier, it would be on the dock used for Liaoning and Shandong, which isn't used for destroyers anyway.
Money isn't the problem. Training is. Restructuring the building line. That takes a little time. What takes even more time is your army of technicians needed to fit the ships. The fitting of the ships take longer than it takes to construct them. Money isn't enough, you also need time to train an army of technicians.