We have significant lateral recruitment from RN in subs, its already 20-30%. Its historical too, for decades. On any boat, any pommy sailor can clique in with a few other pommy sailors and drink warm beer and marmite. RAN culture fits in with RN culture tightly. The queen, is, the same queen. Australia is popular in the UK, moving to Australia has positive stigma. RSL and Submarine associations here even have sub groups for ex-RN sailors, full of those weird talking bastards with wearing their copy cat scaley dolphins they got in the RN.
I presume HMNB Clyde up in Scotland perhaps isn't as scenic as Sterling or platypus.
Relocating from Britain to Australia is already, a popular thing, outside of defence circles. Its a huge lifestyle change, its popular with families etc. People already have family here (and family over there too). We poach a lot of talent from the UK, in a lot of areas. Australia has over 1.3 million UK residents in Australia.
en.wikipedia.org
With the US is pretty hard. People here would know a lot more than I would. But in all the submariner functions, defence expos, Anzac days, I've attended over the decades, I don't think I have ever met one USN sailor that transferred to the RAN to serve on a submarine here. I am sure there are, but compared to poms?
Met some Army, met some air force, (and they usually leave the adf not long after - which is fine) but never a US submariner who transferred into the RAN. Ever. I don't recall anyone talking about anyone either. Maybe seconded, but not transferred for good.
30 extra sailors doesn't sound like much, but crewing 100 and crewing 130 is huge difference. And we are moving up from ~60 odd currently.
And given that it'd probably be easier for personnel to move between the RN & RAN than between either & the USN. A bigger pool of SSNs & hence crews with two-way movement could be advantageous for both countries.
It would be a nicer way for a submariner to see the world if they join the RAN, and could choose to serve, say 1-2 years in the UK out of their service here. Base your self in the UK, see a bit of europe, etc. UK could return the favor.. Happier sailors, improved retention, more crews, etc.
The UK program could do with greater build volumes 8-12 Australian submarines would bring to them. We would be pretty much equal peers in that kind of program. The UK and AU have significant political influence with each other. There is actually greater soverignty putting these two nations together. (he says as a republican).
In the US, Australia would be such a tiny partner. A forgettable line item. In a world of priorities, our priorities would not be theirs. If we wanted them to lower the crew on future designs (to say 60), good luck wrestling the USN with that.