Map A - The map above indicates that China's whole coast is uncomfortably shallow for SSBNs (less than 200 meters (m)) from China's main SSBN Base (Yulin/Sanya on Hainan Island) then north:
- on the edge of the South China Sea
- up through the Taiwan Strait,
- East China Sea
- Yellow and Bohai/Po Hai Seas.
This shallowness makes Chinese submarine (including SSBNs, SSNs and SSKs) movements partly channeled and more predictable for opposing submarines and Western undersea sensor layers. For the sensor map see August 1's, Part One Map C). This makes quietness/discretion all the more important for Chinese SSBN.
In addition to China's shallow coastal water the ability of Chinese SSBNs to break out into the more desirably open Pacific Ocean is corralled by the islands of Japan, Ryuka Islands/Okinawa. Senkaku Islands, Taiwan, Bashi Channel/Luzon Strait, Philippine Islands, then Indonesian Islands (including Borneo) in the South. I'll talk about alternate Chinese territorial actions in Part Five.
Between all of thes islands Japanese and US laid sensors are likely (or definite August 1's, Part One Map C) and act as trip-wires to rapidly indicate Chinese SSBN breakout attempts.
In a shooting (medium to high intensity) war the US and Japan could act quickly to weaponize the undersea sensors, with:
- rising from the seafloor mines-small torpedos (which may have been already laid/laced in the
- MPAs (eg. P-8s, P-1s and P-3 Orions) dropping depth bombs or small torpedos. More rapid B-1
bombers, F/A-18s or F-15s dropping the same.
- SUBROCs (available since the 1960s) and cruise missiles (from Harpoons to Tomahawks and
similar) carrying warheads-torpedos.
Map B - The HQ of each of the Chinese Peoples Liberation Army - Navy (PLAN's) Fleets are indicated, along with ship and submarine numbers in each. China's 4 Yulin-Sanya based SSBNs (South Sea Fleet) are at Hainan Island just south of Zhanjiang HQ. (Map courtesy page 29 of US DoD, Annual Report to Congress - Chinese Military Power 2016 large 7 MB PDF. Pages 25 - 26 itemises all the PLA-N subs)
As reflected on the Chinese PLA-N orbat on Map B China has many SSKs and some SSNs to protect and/or run decoy actions for the SSBNs. The top-cover from Chinese aircraft and missiles (including Chinese SUBROCs, cruise missiles and DF-21Ds (in an ASW role) could also protect Chinese SSBNs as could Chinese surface ships and undersea sensors-mines.
See Map C (below) for all the Asia-Pacific submarine forces. USN subs are not included in part because they can be rapidly redeploy from the US West coast, Hawaii and Indian Ocean patrols.
Opposing Submarine Forces
In peacetime to low intensity confrontation Western submarine forces, on station and/or alerted by SOSUS (plus other sensor) sensors could be directed to tail the Chinese SSBNs. Assuming the Chinese SSBN set out from Hainan or are already in the South China Sea (SCS), Western submarine forces could include:
- about 4 to 10 US SSNs (from Yokosuka Japan, Guam or elsewhere) coming from any direction.
- from north and east about 4 Japanese SSKs (of 16-18 available) from Yokosuka or Kure, Japan or
already on patrol down to the Philippines area.
- from south and west of the SCS subs from 2 more of the US's allies (namely Singapore (4) and
- Indian SSN's may have reason to track Chinese SSBNs as well
- meanwhile South Korea's and others subs from the Japanese Navy might be available for any
Chinese SSBN deployments in the Yellow of East China Seas.
Of course in a confrontation all Western navies in northeast Asia would also be watching out for Russian and North Korean submarine activities.
Map C - (can be made much larger scale here) All the Asia-Pacifics submarine forces (except the USN's). India can be included because Indian sub's (including SSBNs) may need to, or want to, venture into the Pacific to put China's eastern seaboard cities at risk. India's current SSBN (INS Arihant) may eventually mount 1,000 km range K-15s (insufficient to hit much of China from Indian Ocean launch points).
Until India fully develops the long range K-4 SLBM Indian SSBN may need to operate in the Western Pacific if it is to plausibly put China's main cities (on the east coast) at risk.
Part Five - on Chinese geographical strategies will follow later this week.