BREAKING. URGENT CANBERRA MEETING. WAR?, page-36

There is no word on what type of subs they are except for the propulsion system.

I could guess that the aim is to just get a largely known design into the water quickly to fill a capability gap in the quad.

On the other hand I could throw our 1960s presumptions on what submarines do and how they do it out the window.

I could speculate that the US may concurrently build a joint service facility somewhere in WA or the NT.