I don't see how any of what you posted indicates lack of flexibility. Fuel economy is not even an argument. By nature GT is less fuel efficient, but I have already mentioned that. On the other hand, you have a limited space and a certain tonnage and speed requirement. If two diesels and two GT's cannot satisfy this requirement in the space available, you build a ship using COGAG, despite the cost in fuel efficiency.
You really need to lay off the caffeine! The article in my post which the link points to indicates the lack of flexibility of the current 4 GT configuration used in the Arleigh Burkes and why a move towards Hybrid Electric Drive (an IEP) is desirable to overcome them.
Navies all over the world use COGAG in their destroyers. So where's the fire?
No they don't Royal Navy has never used a COGAG arrangement in any of the 29 Gas turbined powered destroyers built since the war. In fact the only COGAG ships in the RN were the 4 Type 22 batch III frigates and 3 Invincible class CVS. There is no fire just if you starting from scratch you might go with something that's current and not ape what folks did 20 years ago!
Perhaps, the Royal Navy knows nothing about ships and Rolls Royce nothing about marine gas turbines.
The day you can point out a destroyer to me that is the size of the Queen Mary 2 is the day its Warsila diesels will have any relevance in a discussion about destroyers. Until then it is meaningless to compare the diesels used in a 149,000 ton ship to the ones used on a 7,000 ton ship. The 052C uses diesels that put out 5MW. Its GT's put out 28MW. So as I said, the diesels are in fact wimpy compared to the GT's.
Iver Huitfeldt class AAW frigate 6,645 tonnes full load, Four MTU 8000 20V M70 diesel engines, 8,2 MW each (BTW they make more powerful ones!), top speed 28 knots I don't think it's engine rooms are any bigger or smaller than any other ship of a similar size and it's not about what power you can generate it's about how you can move a ship through water at speed, reliably under fire.
Again, the argument has been about whether Chinese shipbuilding industry is capable of building ships with engines using CODAG arrangements, not whether you personally think CODAG is "complicated". Can you provide evidence either way?
No that's not the argument, the argument was "is propulsion the thing that's limiting the size of Chinese vessels?". I am simply stating what I believe all the views I express in this forum are personal and my own if you're claiming to speak on behalf of someone else maybe you should declare that interest other wise it's just YOU don't agree with my viewpoint and there's no need to be so uncivil about it.