Well specifically in the carriers case with decks that overhang over the entire Drydock, it’s mighty hard to retrieve equipment or move equipment into the drydock if the cranes can’t access it.
Theres also the block module construction method that I see China use over what the US uses where blocks are lowered seperated in the drydock and then merged together into one. One does need quite a lot of room to perform this procedure.
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This was how Fujian's hull was pieced together.
While ford on the other hand is built in many much smaller pieces
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