I can see both sides of it. We need to keep US shipyards busy, because we are always going to need ships for the Navy/Coast Guard/Etc., and we don't want to outsource that. But...we also like to believe in capitalism and the free market. We'd like to have mulitiple domestic ship yards bid on navy ships....but how many ship yards can stay busy without the US Gov't force feeding them jobs ?
Same issues as other manufacturing and other businesses when you talk about free market. Employment laws and tax laws are not comparable. The cruise industry is the prime example with Carnival paying virtually no income taxes and their employees not subject to US labor or tax laws or health regulations. The primary reason you see yacht owners using flags of convenience is to save money on the crew.
Building the ships isn't the big issue. It's operating and staffing of the ships.