PT boats were 70-80 feet in length.
These guys are 200 feet. A whole different class.
What makes something a blue-water vessel in your opinion? To me, a 200 footer is going to be able to sail anywhere in the world in nearly any sea state. And it can fight in 99.5% of those conditions.
Which makes them less than half the size of an OHP-class Frigate.
Oh, it looks like a cute little ship, but not really something a serious Navy would boast about.