The buying a US SSN design versus UK debate continues.
After advocating a UK designed SSN on Submarine Matters, I'm floating a buy US case.
In response to Anonymous's comments of February 11, 2022
There must be some political, legal or commercial impediments to the UK simply using whole US developed reactors. Otherwise the UK wouldn't have spent Billions pounds, from the Valiant class in 1966, using the PWR series.
Also I don't think US SSN builders would be happy for the UK selling a 66% US designed (Combat System + Reactor) SSN to Australia instead of the US selling it to Australia.
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Yes Australia buying a well understood, tested, Virginia Block IV design or Improved Virginia "Block VI?" without the Virginia Payload Module (VPM) might be best.
Although, if ever Australia had (subsequent) SSBN needs then those six large multi-purpose Vertical Payload Tubes (VPTs) in the Block V might come in handy, ballistically...
One thing to avoid might be the USN Submarine Service's version of the SSN(X) concept. It seems that Submarine Service has a SSN(X) from mid-2030s onwards, dream of a return to a much larger/higher specs/EXPENSIVE Seawolf 2.0.
Meanwhile, Congress, the Pentagon and non-Submarine branches of the USN might prefer just a slightly larger/reasonable specs. moderate priced "Improved Virginia" Block "VI" from the mid 2030s onwards.
If the US is only offering a Seawolf 2.0 design then Australia choosing a future UK SSN might be preferable.
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I'm unsure whether buying the French designed nuclear Barracuda was ever an option for Australia. Naval Group has been trickle feeding IP to Brazil so Brazil has/is designing the future Brazilian SSN's reactor from apparent scratch.
Also Australia strengthening the US alliance is vastly more useful than strengthening a French alliance. This is noting France only maintains 2 light frigates in the Pacific and no full time SSN presence or major SSN heavy maintenance facilities.
Another problem with Australia choosing a UK designed SSN is that the Astutes were way over budget and late. This is in contrast to the first Virginias onwards (less than 10% overbudget and just a few months late). See this US Heritage Foundation article. Whether the US's 2 supplier competitive Virginia build system can benefit Australia will remain a medium term mystery.