The step structure does not "solve" this problem, it is probably more like an acknowledgement that the VLS may go no further forward, and given the available topside deck space as a result, let's put something useful there, like this structure.
Okay, well I suppose it is a possible configuration... But it largely depends on whether the mock up platform deck is representative of the real ship's deck level at that part of the ship.
(Let's call it the amidships weather deck for ease of reference)
The step structure is not an elevated platform for the purpose of placing masts and radomes. Masts and radomes don't actually need a structure underneath them, just a tall enough mast or mount. These step structures serve some other purpose, whether it's as a radar room, or storage room, or for whatever other purpose. They use available deck space to its potential without incurring excessive cost in topside weight. I think this particular design philosophy is the same for the 052C, 052D, and 055.
Oh I'm not sure, I think it is quite reasonable to say that on the 052C/D, the step platform's reason for being there is to mount the Type 517 radar and radomes. This isn't to say that all radars or radomes "need" a structural base on every ship ever, but it's just the way they've decided to configure it on the 052C/D. Nor is this to suggest that providing a structural or elevated base for the radar and radomes is its only purpose; I expect that within the platform it can do other things like data processing capabilities, and probably some functions which are completely unrelated to the electronics mounted atop it at all.
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But ignoring what I think 052C/Ds platform is for, what do you think it is for?
Because from what I'm reading, are you saying the platform on 052C/D is meant to be indicative of the aft VLS bank's most forward boundary before it may interfere with the engine space (aka thus the platform indicates where the engine space itself may be)?
Also, I don't think the 052c/d has a "step platform".. it's more like a "stand alone island platform".
That particular definition is the only I found which refers to exposure to weather and sea, probably as a consequence of how it used to be with wooden sailing ships where the main deck was usually also the freeboard deck as well as the weather deck. The other ones all refer to a freeboard deck simply being the uppermost deck below which all bulkheads are watertight. This deck is essentially a thoroughfare deck allowing easy access from bow to stern for each watertight section below, which by design do not connect to each other via hatches, meaning people would have to travel up to the freeboard deck in order to go from one watertight section to the next. I know for sure in the Daring class the 2 deck is the freeboard deck. The 055 is constructed similarly, and it makes total sense that its 2 deck is also the freeboard deck.
Yes, that definition I found was the only one which mentions exposure to weather and sea as well; all the other ones seem much more brief and only talk about watertight bulkheads below, like you say.
I'm not sure if it is because the slide I found is BSing, or if the other definitions are incomplete. Because tbh I haven't found many complete resources that talk about this kind of thing (naval architecture), and most sites with the brief description of freeboard seem to be more general in nature.
Still, this is only terminology. Maybe someone like Jeff with some experience in this area might be of some help(?)
Do you have a source for the 2 deck being Daring class's freeboard deck? It's not that I don't believe you, it is more that i haven't come across any clear references for freeboard decks of any naval surface combatant before.