Virginia Class SSN, ugly as sin but highly efficient - the best acquisition possibility for Australia.
The information in his advice is all Open Source. I've seen it elsewhere on the internet in fragments. But I've never seen such consolidated comments with such a good feel for the subject. Below are his comments:
Former US nuke submarine officer said:
"I think it's very desirable that Australia invest in nuclear submarines - if not US, then French or British.
Diesel boats are quiet when running on their batteries or on their AIP systems (air-independent propulsion such as fuel cells). Unfortunately, such subs can only creep at very low speeds -- just a few knots. Traveling from Perth to Darwin might take 2+ weeks using AIP and/or a battery (except the battery doesn't have anywhere near that range).
Diesel subs can stay submerged and run on their diesels using a snorkel, but there are still problems. First, diesel engines are extremely noisy and easy to detect, acoustically. Second, snorkeling exposes a mast to radar, generates smoke, and produces a very visible wake. Third, snorkeling limits the boat's speed to under 10 knots to avoid snorkel mast problems.
Diesel boats are great for countries like Singapore, Sweden, Germany, and Israel that use them close to their own waters to passively "lurk". They're lousy for sending distances of more than a few hundred km.
If it was just about any other country, I'd say buy diesels, but Australia has such long distances to contend with, even in its own coastal waters.
Tellingly, when new diesel boats are sent from the shipyard to faraway customers, they're sometimes shipped in floating drydocks -- it's faster and easier than sending them under their own power.
Much has been made of Australia's lack of a civilian nuclear power industry -- the US didn't have one either when it developed nuclear submarines.
Australia can get its supplier to help it build the domestic infrastructure to maintain these boats.
If the US will sell Australia its Virginia class boats, it's a very good financial risk. That program is very economically stable (unlike so many other defense programs like the F-35). They've been making these boats for a while. You can probably get them under $2 billion each. The maintenance and life cycle costs will also be very predictable.
You've had a hard time retaining your submariners but that's a very fixable problem that the US has dealt with for years.
Finally, if you buy nukes, you probably won't need 12 nukes to get the same coverage as 12 diesels. The diesels would waste much of careers time at sea just creeping to and from their destinations. Nukes would have much more useful time on station.