Everyone loves a nukulaar boat. They are so.... well.....
- expensive as a weapons system;
- life limited by reactor age and fatigue;
- so much easier to track than an SSK;
OTOH, they have
- excellent global reach (both time on mission and range) ;
- speed to vacate a datum;
- kerb appeal.
So we are proposing spending multi buckets of pubic purse to get... an ornament?
Submarines are a force multiplier in any form, but numbers count. Any sub can have a bad day, by accident or by design, I would prefer to see a single casualty not knocking out the national capability. ( I prefer those that don't hurt people either, having been onboard a sub that blew a raw water feed in the AMS at 400', subs get busy fast, and without warning).
Over the service life, the nukular boat is going to run around 3 to 4 or more in cost per boat over a conventional SSK. The task of the submarine is to interdict by implied or actual threat as a prime capability, and to provide ISR and SOF support as needed, while giving a screening to friendly naval forces from... other boats. I'm a generation out of the current boats, but follow them nevertheless, including having worked on some design items.
The USA and the UK can do well to have interoperable technologies for C3I, and weapon systems, and gain the benefit of a large SSK fleet operated by a dedicated group. Submariners are different, really, really really different. In the colonies, in the bad old days, politely, mufti was the dress of the day, and occasionally, the dress of the day was the "dress" of the day. The spirit of the sub fleet is different. The size of the RAN fleet has needed a major ramp up from what it has, and getting the oddities that go into subs in numbers is a challenge, but at least they aren't dry. AUS is a maritime nation, a fact that the successive govt seem to have been remarkably ill informed on. It is time that the RAN advocated what they need for both surface, literal and blue water, and sub surface capability.
AIP systems still provide a capability that is cost effective, durable and has unique capability that the UK still retains in small parts, and that has been lost to the USN.
For my money, go with AIP, a goodly size boat with extensive munitions flexibility, expand the numbers, for the same money of the project, and review the latest FFG proposals, as they appear to be staggeringly expensive for limited capability, being just wrong sized. Today, the bigness of the flag that can be carried is not a major factor except on parades, what is needed is capable weapon systems, an adequate range, good sea keeping, and modest direct and indirect costs. Overall, having a fleet of 4 or 5 surface skimmers is not a fleet, it is a bathtub distraction.
RAN has had mixed history with the support ships, but there too, the problem of having 3 subs, 4 FFGs, and 1 fleet oiler/support ship is, that the wheels come off with one bang on the side of the support
target. Ship. HMAS HIT ME.... A maritime nation needs to be able to protect its borders. That takes surface, sub surface and air assets to be done effectively. Right now, the UK and the ADF are lean on ASW/surface strike capability, and that leads back to maybe the RQ systems and even the B21 start to make a sort of sense. The B21 is effectively a capital asset, it's a brave OOD that sets out a frag for a B21 to go save the neck of the CPL and LT that are in deep doo doo in the land of far far away....
Notwithstanding that the most recent tiffs that the ADF have had were characterised as being..... well..... desert, and not an obvious location for using subs, frigates or carriers etc.... the one thing that Ukraine has reminded all is that what you see is what you get, conflict will come along at its own sweet inappropriate time, and whatever is in the tool kit at that time is what gets to be used.