2nd Response to WahooDaddy - Australia need be passive on Taiwan's Defence

On 7/28/2025 12:53 PM WahooDaddy commented in red. My responses are in black:

Working as a coalition, with the Aussies and JMSDF and other regional partners, what d'you think the subsurface warfare scene would be like in the South and East China Seas?

Quite complicated - see my previous article for Maps and the US-Western allies'  IUSS. Many naval coalitions have a history of inefficiency in terms of interoperability (communication including language, standard procedures, common weapons and ammunition). See the weak and poorly coordinated American-British-Dutch-Australian (ABDA) Command easily destroyed by one country, the Empire of Japan, in early 1942.

Without full US involvement, with its internationally dominant submarine force and its full access to the IUSS undersea sensor network, regional countries with significant submarine forces (Japan, South Korea, Australia, Vietnam, Singapore, Taiwan (in about 5 years) and others) would be too weak to face the PRC Navy. 

This is considering the PRC has SSNs, large forces of conventional submarines, anti-submarine: surface vessels; UAVs; UUVs; satellites; large maritime patrol and carrier aircraft and land based missile torpedoes. 

The PRC likely has built up its own "IUSS" (weaponised with smart mines and submarines)  with many undersea arrays in the open, straits and narrows of the East China and South China seas. The islands the PRC has seized in the South China Sea present excellent platforms for criss-crossing undersea arrays.

Do RAN/JMSDF subs have the endurance to stick it out against the PLAN? If the balloon went up with the PRC invading Taiwan, would the RAN/JMSDF hang back, or try to support kicking the PLAN back from their ops in the Taiwan Strait?

No, the RAN has long transit distances, northwards, from its submarine base at Fleet Base West, south of Perth. Also other Australian bases are very distant for our slow diesel powered ships and subs to help Taiwan. The RAN would have trouble (our subs running out of fuel and food) discretely patrolling for PRC subs and surface ships passing through the Malacca Straits. So the RAN has to operate south of those straits. 

RAN Collins subs running their diesels, probably make them too noisy in the South China Sea against an enemy like the PRC. Japanese subs (all shorter range) cannot patrol much further south than the Luzon Strait, though when using air independent power (AIP) they are at least quieter. Singapore's force of 4 to 6 conventional subs (with AIP) are best placed to quietly shadow the PRC's conventional subs, but are very unlikely to attack them.

If the PRC invaded Taiwan the RAN, with a destroyer and frigate, moving as fast as the slow (15 knot cruise speed) supply ship probably would be too late and weak to  take on PRC forces. For speed and discrete movement Australia needs SSNs to be relevant in a PRC war against Taiwan. We are unlikely to have fully manned Australian SSNs until the late 2040s.

Japan is already better placed in seas south to Taiwan. But again, without US involvement all the allies would hang back because the PRC navy is too powerful in ship numbers, nuclear propulsion, emerging full sized aircraft carriers and long range anti-ship (and maybe sub) missiles. 

The picture would become considerably more complex if Russia and North Korea coordinated actions with China. Such as North Korea bombing or invading South Korea and Russia embarking on other territorial objectives in Putin's playbook.

I'm trying to look at it from a non-US perspective. I appreciate your thoughts and feedback!

No worries :) We'll talk off-line about what you're doing with these views.

Cheers Pete