Shipyards can't find workers for two reasons. First, they pay like shit. I see flyers for PNSY and they start at $17 per hour. That's a nickel higher than min wage in Massacchussets, where people often live and commute up there to work. Why break your back working in cramped spaces when Home Depot will hire you for $20 an hour?
The second problem is that nepotism killed the trades. It's very difficult to get an apprenticeship without knowing someone in the industry. I would say about 75% of the engineering rates I've checked-in are in their young 20s and joined the Navy because they were trying to get into a trade. The Navy offered a way where they could get professional certifications and experience so they could get ahead in life. On the flip side, the amount of people who are doing this after getting a college degree is way down from where it was 10-15 years ago.
Anyway, there are many young adults willing to work in trades. There are very few middle-aged adults willing to train them. Of the half-dozen times I've called a plumber, only once did one show up with an apprentice and it was his son.
I have also checked in some people who were older and realized that the Navy's pay and benefits scale outpaces the trades pretty quickly with significantly less risk to life and limb.
The economists I mentioned that were on the Weekly Show talked about the fact that America's industrial economy is never coming back. There may be merit to moving the needle from manufacturing being ~8% of the economy to 10% of the economy, but they argue that the decrease in the manufacturing production sector for things like automobiles and moving to things like biotechnology and communications technology is the natural progression of macroeconomics in an advanced society.
Of course, Trump is a politician and his sales pitch is a return to the golden ages of the 1950s. The days where mom knew how to add just the right amount of powdered milk to 'stretch' that meatloaf that was made with canned meat. Meanwhile, dad drove his deathtrap of a car with manual everything and no AC that got 15mpg to top out at 60mph in order to work a mind-numbing job at a factory operating a steel press to make the cans for the meatloaf. If the kids manage to be lucky enough not to die in a car crash, then hopefully they can survive the measles.
I can't imagine why we ever moved away from this lifestyle.