Not aukus specificially but Australia and Japan have signed a Reciprocal Access Agreement. First one Japan has signed

https://www.abc.net.au/news/2022-01-...eaty/100741012

This diagram clearly shows the “time on station” advantages of the SSN over the SSK in the areas that RAN submarines are likely to operate. It’s very significant and shows why 8 SSN’s will be more effective than the previous plan for 12 SSK’s.

https://cimg5.ibsrv.net/gimg/pprune....57f86ecee.jpeg

Yes. That graphic certainly explains some of the capability increase.

Can anyone explain why the proposed number to be purchased is at least 8 and not at least 9? I thought there was a long-standing ‘rule of three’ with naval hardware (one available/on station for every three due transit/maintenance/etc).

Surely pushing for at least 9 is a small extra price to pay for an even greater amount of available hulls at any one time? Or does 8 provide for something I don’t know about?

Yes, that’s a valid point. The Collins class always has 2 in heavy maintenance which leaves 2 (sometimes 3) available for deployment with the last one working up to operational status following maintenance.

There have been a number of statements where they talk about a “minimum of 8” SSN’s to be built in Australia, so they are leaving the option open for additional submarines if the political situation warrants it.

I think the Virginia rotations are 6 months deployed, 2 year maintenance. There is also a gap after deployment, where they are looking to use them in the north sea. To run out the time.

Do we not have a closer port than at Perth for accessing those chokepoints or are they all now chinese controlled?

Theres darwin, but due its location and surrounding arafura sea, its always been a non starter for any important combatants. Thats why permanent basing has only been small ships patrol boats and hydro graphic survey. Theres no other ports between darwin and perth. Sorta the same for east coast as well, the ports there are geographically unsuitable being the barrier reef. Same thing no major combatants based out northern QLD porst. Patrol and hydographic out of cairns. Army amphibious and a visit a couple of times a year by adelaide/canberra and choules to townsville.

The waters around the Port of Darwin (Arafura Sea) are shallow and are not suitable for submarine operations. Also, the Northern coastline of Australia experience very large tidal changes which involve different docking requirements. Cyclones also present another issue.

If the US was to begin submarine operations out of Australia, the joint operations would create a case for a resupply/rearming facility to be built at Exmouth (near Learmonth RAAF Base) as this would reduce transit times and get these vessels back on station faster. There is deep water just to the West so it’s more suitable than Darwin. Also, the relative isolation of that area would mean the activities at that facility would not be subject to many prying eyes.

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This is a more comprehensive map showing RAN submarine operating areas than the one I previously posted.

https://cimg6.ibsrv.net/gimg/pprune....2496b225a.jpeg

Is Perth any better in those respects?
Have to say, from a national policy perspective, it sure would make sense to have Perth as a West coast counterpart to all the current East coast infrastructure..

Exmouth was used by the US Navy as a submarine base in WW2 as their Fleet submarines escaped from Manila Bay. It was considered too remote with a lack of infrastructure and had been bombed by the Japanese. Fremantle then became their base for conducting operations through the Indonesian archipelagic choke points and further afield. Incidentally, the USN used submarine tenders in Exmouth initially- are the relevant to the future of the RAN?

Battles of the last Pacific War seem ever so relevant today as the CCP’s influence creeps south. The last of GB’s theatre maps lacks East Coast weight? Considering the Coral Sea and vital lines of communication to the West Coast of the USA.

There’s a sizeable trench out the back of Rottnest island that the subs use for training amongst other things

. https://en.wikipedia.org/wiki/Holy_L...y_at_Holy_Loch

The USN has two 1970’s era submarine tenders forward based in Guam and which are due to be replaced in the mid-late 2020’s. It would be interesting to see if it was feasible to static base them near Learmonth/Exmouth in a cyclone protective harbour. It would be a quick way of providing this capability until more permanent facilities can be constructed.

https://www.navalnews.com/naval-news...-replacements/

"Is Perth any better in those respects?"

Its the sort of backup available on things like electronics companies, machine shops and the availability of skilled people - you're far better off for resources in a city of over 2 million than in one of less than 150,000. Tenders would work I guess but that's another layer of people and expense

The US can have subs or used to in shallow harbors like Pearl Harbor or Subic bay. So why cant we?

Its not the harbor its the water around look at hawaii on depth chart, its a mountain with DEEP water around it. Also cant find any reference to US nuclear subs based out of subic, yes they visit, but basing is a different kettle of fish

As Rattman said, it’s the depth of water around the harbour that is important.

In deep water, the submarine can change depth to sit just above or below temperature inversions to reduce the chances of detection from noise produced by the boat. In shallow water, the submarine captain has fewer evasion choices so enemy ASW assets (including submarines) can focus on the waters around the harbour to pick off submarines entering or leaving.

Trump defence spokesperson questions AUKUS. Claims people in the military and conservative politicians don't want to share the technology.

https://www.skynews.com.au/opinion/c...017b9fe9da228b

Forecast - and probably why the UK were included in the plans….

https://www.pprune.org/military-avia...l#post11124759