You might think that the electronics are impossible, but there are in fact home made electronics and cpu. And home made nuclear reactors.
How long would it take 10 persons, working alone, to build the USS Nimitz from scratch?
Heres what I understand;
The Nimitz has about 100,000 tons of steel.
It also has about 10 tons of uranium.
It has about 1,000 tons of copper, gold and other rare metals.
So given all this a historical medieval iron smelter produced, roughly 1 ton of steel or metal per day. That would take (roughly) 1000 years to produce all the steel.
Uranium has a crustal abundance roughly 10000 times less than steel- but is also used less, so the cost should be similar.
Other materials should be about the same cost. Say after these 3 categories we've spent 3000 years.
Then, the assembly. You would assemble some construction equipment first. There are home made vehicles and equipment about the size of a car, so if we have 10 people they should be able to build a roughly 10 ton piece of equipment. This takes roughly a year.
Tower cranes in shipyards are roughly 300 tons, and are the largest piece of equipment. So our 10 tons per year of equipment is 30 years to build this.
Once we have the equipment and materials, it's just a matter of building the ship. David Hahn built a 1kw of reactor in about a month. A 1gw reactor with 10 workers should take a million times more. That's 10,000 years for our team. We could probably reduce that to 1,000 years because of scale.
A construction team requires about 10 people to build a 2,000 sq ft house in 3 months and aircraft carriers are relatively simple to build. So since our carrier is about 1 million square feet that's another 10,000 years of assembly. And its repetitive work which could probably be reduced to 1,000.
And that's it. We've built an aircraft carrier over 5,000 years with 10 people- and could probably automate and do it in less.
Oh and Sam Zeloff makes a transistor in about a few minutes. That means about 1000 years to build a 1b transistor chip.