Purely a personal view, I have had reservations myself about the AUKUS "optimal pathway" since it was announced in March 2023. From a cost and risk perspective it does not look optimal. It is very complicated, and places huge loads on the future RAN if any step fails, while assuming future governments will continue to fund it heavily. I support the idea of the RAN getting SSNs, but I perceive we are doing it in a slow and risky way.
My first concern is that we are getting both Virginia and SSN AUKUS SSNs, requiring the RAN to maintain two different classes of SSN, built by different supply chains. This is a huge challenge. It means different spare parts, equipment, maintenance procedures, safety protocols, crew training, maintenance staff training, training facilities (e.g. simulators). We should have picked one and stuck to it.
If the main objective was to maintain USN Virginias in Australia, we should have sought to build or buy Virginias. I don't understand why this could not have been done similar to the F35 program, with Australian firms contributing components to US Virginia production, perhaps building modules at ASC for final assembly in the USA, then getting some of the resulting SSNs. Setting out to learn all about Virginias, then switching to building the product of a different industry, seems risky and wasteful to me. Now that we know the USA is continuing with Virginia Block VI construction well into the 2040s, I don't see a reason we could not do the same. The design risk would be eliminated.
My second concern is with the design of SSN AUKUS in UK. In an operational sense, it is not clear to me that the RN and RAN's operational requirements will be the same. I doubt we need an ice -strengthened fin for example. We need something designed to operate optimally in warmer waters. It is much larger and probably more expensive, to accomodate the PWR 3 reactor. I question whether the RAN has internal technical experts that can meaningfully contribute to the design process. Few countries do.
I also question why we need 8 SSNs? That seemed to be part of the original Morrison announcement without any Navy analysis to back it up. UK and France only have 7 and 6 SSNs respectively. There is provision for Australia to first get 3 to 5 Virginias under AUKUS. If the RAN ended up with "just" 6 Virginias, I suspect that would be perfectly adequate, allowing a squadron of 3 on each coast. That force would easily be equivalent in capability to the previously proposed 12 Attack Class SSKs, with far greater range and additional capabilities via VLS tubes.