Something that actually resulted in productive shipyards would be much better than what we have that results in shipyards that don't produce much, which is still likely better than no shipyards outside of those producing naval vessels and domestic ferries (although, those would probably be imported too, if that were legal; technically that's prohibited under a different act)

It also strikes me that the percentages mentioned in the article are very high. 75% US crew? 75% US owned? 100% US built? Revising the statute to operators needing 55% of their domestic fleet being US built, and requiring 55% US ownership, and a 55% US crew should be more than sufficient. Give tax incentives for newer, more efficient craft both to the manufacturer and the buyer.

The US uses a lot of military power for non-combat purposes. We move supplies for natural and humanitarian disasters. We have water purification ships, hospital ships, and generator ships. We transport weapons systems as cargo, and even those ships themselves could be mostly protected by a surrounding fleet. If we could get a design made that's fitting for heavy movers suitable for both military and civilian use the US government's purchases could bolster domestic shippers' orders.

One even more unusual option since it's a national security concern is the US government could buy large numbers of newer, more efficient craft and lease them on affordable terms (or lease to own even) to cargo companies.