Ship building.

[xoxoxoBruce]

Yes, keel+ribs+plates went out with sword fighting and knickers. During the Big One, WW II, the need for ships, and lot's of them, prompted US shipyards to build ships in sections, then join the sections together as drydock space became available.

Now big ships are a series of waterproof compartments joined together. Computer simulations verify the desired rigidity/flexibility for rough seas, plus damage control for various types of attacks.

To build that carrier in one spot would take either many, many years, or a labor force so large they'd have to recruit around the empire. Then when you break the champagne bottle and wave bye-bye, what do you do with that huge labor force that resettled into that community? For that matter what happens to the community that expanded to accept the huge, now unemployed, labor force?

[Lamplighter]

Just think about that poor Wheel#1005 in the center that needs to go pee.

[xoxoxoBruce]

No problem wheel #1005, like his bros, has a bladder that will hold probably 90 psi.

[xoxoxoBruce]

The wiki article on building the WW II Liberty ships describes how the US redesigned the UK model, changing construction from riveted to welded plates and a different propulsion system eliminating the need for difficult to build reduction gears.
The welded plates became problematic, but was ironed out in later construction techniques post Liberty program.

The first ships required about 230 days to build (Patrick Henry took 244 days), but the average eventually dropped to 42 days. The record was set by SS Robert E. Peary, which was launched 4 days and 15½ hours after the keel was laid, although this publicity stunt was not repeated: in fact much fitting-out and other work remained to be done after the Peary was launched. The ships were made assembly-line style, from prefabricated sections. In 1943, three Liberty ships were completed daily.