A wide range of advanced non-nuclear submarines can provide excellent asymmetric defence within 4,000 km of Australia if distributed to ports around the country.

About NINE non-nuclear boats can be bought for the price of ONE Virginia class submarine. Non-nuclear boats are much cheaper to operate.

Japanese Taigei submarines are recommended. Naval Group, TKMS and Hanwha / Hyundai have good options as well.

Available Non-Nuclear Submarines

Non-nuclear boats	Manufacturer	Built	Submerged endurance
TAIGEI	Mitsubishi / Kawasaki	6	4 weeks with Li-S batteries.
Scorpène Evolved	Naval Group	0	80 days with lithium-ion batteries.
Scorpène	Naval Group	13	3 weeks if FC2G fuel cells used (diesel & O2).
Orka class	Naval Group	0	Several days at top speed…probably 3+ weeks at low speed. Li batteries.
Type 212CD	TKMS	0	40 days with PEM fuel cells + Li batteries. (2 being built)
Type218SG	TKMS	4	4-6 weeks with fuel cell & Li batteries
Blekinge A26	Saab	0	3 weeks with Stirling AIP.
KS-III	Hanwha / Hyundai	3	3+ weeks with Li-S batteries. VLS for land attack – which we don’t need.
S-80+	Navantia	2	3+ weeks with bioethanol-powered fuel cells. 16 years to build.

Uncrewed submarines & smart mines

Unlike nuclear submarines, we could easily have hundreds of these that could swarm hostile naval shipping at a comparatively low cost.

Name	Notes
Ghost shark XL-UUV	Currently in the RAN, “dozens” planned
SpearTooth Large UUV	Australian company
Smart mines	In development for the ADF now

Mission

Threaten hostile ships and submarines within 3,000km of Australia from under the sea with torpedoes and mines. (Missiles launched from aircraft and trucks can threaten ships from above.)

Nuclear vs. Taigei: Cost

The fourth Taigei Class submarine cost $US 470 million. Virginia SSN cost about $US 4,500 million ($A7 billion) each.

Nuclear + Collins LOTE	$B	Submerged endurance	Taigei	$B	Submerged endurance
6 x Collins LOTE (full of rust)	5	1 day with lead acid batteries	10 x Taigei non-nuclear submarines	10	~30 days with fuel cells and/or lithium batteries
3 x Virginia Block IV SSN (not available)	21	80 days*
5 x AUKUS SSN	211 (?)	80 days*	–	0
Infrastructure	8			4
Contingency	123		Proven design in production	1
TOTAL	368			15

(* Nuclear subs can operate till the food runs out. Approximate cost in A$ rounded up to nearest billion. Sustainment cost far less for diesel-electric boats.)

Nuclear vs. Taigei: Weapons at Sea

Nuclear + Collins LOTE	Weapons	Total	Taigei	Weapons	Total
6 x Collins LOTE	22	132	10 x Taigei non-nuclear submarines	30	300
3 x Virginia Block IV SSN	37 (Includes 12 in VLS)	111
TOTAL		243			300

• One class to maintain instead of three (Collins, Virginia, AUKUS)
• More weapons at sea in more places for less cost
• AUKUS class vs. alternative number of “Taigei-successor submarines” not included as cost and capabilities are speculative.

Japanese Sōryū & Taigei submarines 

“Japan’s new Taigei class … provide the Japan Maritime Self-Defense Force with some of the most advanced underwater performance of any submarine force in the world.” (US Naval Institute)

Eight Japanese submarines have been built with Lithium-Sulphur batteries to date with each one taking 2.5 years to complete. Lithium-Sulphur batteries appear to be less complex to operate and support than fuel-cell systems. (2 Sōryū + 6 Taigei)

Theoretically multiple boats could be assembled in parallel in various electorates around Australia using imported components. (This would be instead of the 11 Mogami-class frigates Australia is buying from Japan.)

(Note that Tony Abbott wanted to buy Sōryū submarines in 2015 before they started using LI-S batteries.)

Extended Taigei?

Duplicating the crew accommodation section in the above diagram would seem to increase the battery capacity by 25%. As well as improving morale and crew retention submerged range should be increased to well over a month at minimal cost.

AUKUS submarines

The purpose of the AUKUS submarines is to attack the PRC, which has 600+ nuclear warheads in 2025. We have eight cities.

Note also that if nuclear submarines were ever built superpower adversaries would be obliged to destroy them before they could be launched – which would create a Chernobyl-like problem if they were fuelled at the time.

French nuclear submarines

Peter Briggs, president of the Submarine Institute of Australia, has suggested buying the French Suffren Class nuclear submarines instead of the AUKUS SSN. These would probably be very capable but unfortunately take 15 years to complete compared to 2 years for the Taigei and cost 3 to 4 times as much.