Japanese Submarine Developments through to 2030, Soryu Table.

Japan relies on continuously building one submarine per year to keep the managers, designers and building workforce continuously employed. This also provides a construction tempo that is now aimed at having 22 submarines at any one time in the Japanese Navy. Design development is also continuous.

About 9 out of 10 years an operational submarine is produced, but about once every 10 years a test submarine (like 21SS) or extensive testing development program, occurs.

21SS

The designation “21SS” is derived from the submarine being laid-down (or at least the project commencing) on the 21st year of the reign of (now former) Japanese Emperor Akihito. Akihito acceded to the throne in 1989.

As can be seen in the SORYU TABLE below 21SS was a test submarine or test program equivalent.

Given 21SS’s 2010 timing Pete believes 21SS signified the concerted beginning of Japan’s 

Lithium-ion Batteries (LIBs) for submarine program. The actual LIBs testbed submarine used may have been Harushio class TSS-3601 (launched as SS-589 in 1995, converted to AIP testbed in 2002, converted to LIBs testbed in 2010, decommissiond in 2017).

27SS

The LIBs development program continues to this day in the shape of 27SS (Japan’s first soon-to-be operational LIBs submarine) launched in 2018 and due to be commissioned this year (see Table below). Also see the Japanese Ministry of Defense (MoD) Acquisition, Technology & Logistics Agency (ATLA) LIBs development activity by scrolling half way down here.

29SS

29SS may likely be the first submarine of a new class following the Soryus. Both Anonymous and wispywood2344 advise 27SS and 28SS are still Soryus. [1] 

The description of Japanese submarine 29SS research/testing below draws from Anonymous's comments on Japanese submarines on February 19 and 21, 2020 

Submarine prototype and tests conducted during MoD budget financial years FY2017-2018 and FY2019-2022 concerned prototype research on submarine hull forms. This was aimed at significantly reducing hydrodynamic noise with the long term aim of permitting Japanese submarines to face ASW threats through the year 2030.

Anonymous believes optimization of hull form research was conducted to reduce noise caused by bubbles, hydrodynamic flow, vibration and by the propulsor – see [2] and [3].

Japanese researchers at ATLA built a [29SS] scale model for various tests conducted in large naval test tank (length 247m, width 12.5m, depth 7m). The findings of this research together with other research findings will influence Japan’s future (post Soryu) submarine design designated 29SS. [Pete comment: 29SS likely also exists as a complex mainframe computer simulation shared between MoD central, its ATLA agency and submarine builders MHI and KHI (see Key to Table below the Table).]

A formal report by the MoD indicates 29SS is being used as a test submarine for various research technologies. 29SS has the same shape and dimensions as the Soryus. Further design modifications will take place in operationally deployed 30SS and 31SS (etc) as is usual in Japan’s yearly continuous build of submarines practice.

[Pete comment: There may be increased blending of the sail. There is some blending of the Soryu sail’s leading edge. Further blending may be not as extreme as depicted in Alfa and Type 212A submarines at Submarine Matters here. There will be ongoing research for quieter diesel engines, improved LIBs and “Improved Snorkel”].

[1] wispywood2344 advises Quarterly PR magazine published by the Kinki-Chubu defense bureau vol.62 (2020 winter). page3. states that "Toryu is the 12th vessel of Soryu class submarine." It was published at in January 2020, ie after the May 1st, 2019 Enthronement of Japan's current Emperor Naruhito.

[2] “Terminology for underwater acoustics – Phenomena (Y0011B)” by Standard for Ministry of Defense (NDS), page 22, terminology number 1561. “Definition of hydrodynamic noise: noise caused by hydrodynamics.”

[3] ibid, page 67, “Classification Table”

Hydrodynamic noise is classified into i) bubble noise (1562, noise caused by generation, vibration or collapse of bubbles underwater), ii) flow noise (1564, noise caused by turbulence flow such as turbulence flow boundary, separating flow and wake), iii) flow induced vibration noise (1568, noise caused by vibration of structure or part of it which is induced by water flow), iv) wave-breaking noise (1569, noise caused by collapse of wave) and v) propulsor noise (1571, noise caused by propulsor*1-2).

*1 Propulsor includes propellers, water jets, etc.

*2 Causes of propulsor noise include cavitation, "wing" [rudder and sail-plane?] vibration by lift fluctuation, local vibration of [rudder] induced by tailing vortex.

Note: Pricing issues will be discussed next week using Anonymous’ comment of February 24, 2020 .This is on the issue of Australia possibly choosing a LIBs Soryu if the current Naval Group Attack class submarine program collapses.

SORYU TABLE. as at February 27, 2020. 

SS No. Diesel Type Motor	Build No Name	Pennant No.	MoF approved amount ¥ Billions FY	LABs, LIBs, AIP	Laid Down	Laun -ched	Commi ssioned	Built By
5SS Oyashio 2 Toshiba motors	8105 Oyashio (mythical currents)	SS-590/ TS3608	¥52.2B FY1993	LABs only	Jan 1994	Oct 1996	Mar 1998	KHI
6SS-15SS Oyashios  10 subs 2 Toshiba motors SMC-7?	8106 -8115 various	SS-591-600	¥52.2B per sub FY1994-FY2003	LABs only	15SS Feb 2004	15SS Nov 2006	15SS Mar 2008	MHI & KHI
16SS Soryu/ Dragon class  Mk I	8116 Sōryū (mythical dragons)	SS-501	¥60B FY2004 all Soryus with Kawasaki  12V25/25SB diesels, see and SMC-8 motor	LABs + AIP	Mar 2005	Dec 2007	Mar 2009	MHI
17SS	8117 Unryū	SS-502	¥58.7B FY2005	LABs + AIP	Mar 2006	Oct 2008	Mar 2010	KHI
18SS	8118 Hakuryū	SS-503	¥56.2 FY2006	LABs + AIP	Feb 2007	Oct 2009	Mar 2011	MHI
19SS	8119 Kenryū	SS-504	¥53B FY2007	LABs + AIP	Mar 2008	Nov 2010	Mar 2012	KHI
20SS	8120 Zuiryū	SS-505	¥51B FY2008	LABs + AIP	Mar 2009	Oct 2011	Mar 2013	MHI
21SS Concept			No 21SS built But was a concept research project on LIBs. 1st LIBs sub launched is 27SS		research in  2010	research	research
22SS	8121 Kokuryū	SS-506	¥52.8B FY2010	LABs + AIP	Jan 2011	Oct 2013	Mar 2015	KHI
23SS	8122 Jinryu	SS-507	¥54.6B FY2011	LABs + AIP	Feb 2012	Oct 2014	7 Mar 2016	MHI
24SS	8123 Sekiryū	SS-508	¥54.7B FY2012	LABs + AIP	15 Mar 2013	2 Nov 2015	13 Mar 2017	KHI
25SS	8124 Seiryū	SS-509	¥53.1B FY2013	LABs + AIP	22 Oct 2013	12 Oct   2016	12 Mar 2018	MHI
26SS	8125 Shoryū	SS-510	¥51.7B FY2014 last SMC-8 motor	LABs + AIP	2014	6 Nov 2017	18 Mar 2019	KHI
27SS Soryu Mk II  due to 1st with LIBs	8126 Oryū 11th Soryu	SS-511	¥64.4B FY2015 12V25/25SB diesel SMC-8B motor Roblin paper US$536mil?	LIBs only (NCA type)	2015	4 Oct 2018	Mar 2020?	MHI
28SS Soryu Mk II	8127 Toryu 12th Soryu	SS-512	¥63.6B FY2016 "2,900t" surfaced	LIBs only	Jan 2017	6 Nov  2019	Mar 2021?	KHI
29SS Not operational. Research project like 21SS 29SS may be the 1st of a New class			¥76B FY2017 Concept research for new features eg. maybe blended fin for noise reduction & better water flow and also new propulsor. New diesels, new snorkel system. 1st all new features sub may be 38SS	LIBs only	2017 research	research	research	MHI assisted by KHI & JMoD
30SS New Class? 12V25/31S SMC-	8028?	SS-513	¥71.5B FY2018	LIBs only	2018?	2020?	2022?	MHI?
31SS New Class ?	8029?	SS-514	¥B? FY2019	LIBs only	2019?	2021?	2023?	KHI?
32SS New Class ?	8030?	SS-515	¥B? FY2020	LIBs only	2020?	2022?	2024?	MHI?
33SS New Class ?	8031?	SS-516	¥B? FY2021	LIBs only	2021?	2023?	2025?	KHI?
34SS New Class ?	8032?	SS-517	¥B? FY2022	LIBs only	2022?	2024?	2026?	MHI?
35SS New Class ?	8033?	SS-518	¥B? FY2023	LIBs only	2023?	2025?	2027?	KHI?
36SS New Class ?	8034?	SS-519	¥B? FY2024	LIBs only	2024?	2026?	2028?	MHI?
37SS New Class ?	8035?	SS-520	¥B? FY2025	LIBs only	2025?	2027?	2029?	KHI?
38SS Soryu Mk III or New Class ?	8036?	SS-521	¥B? FY2026 1st production sub using all Project 29SS features	LIBs only	2026?	2028?	2030?	MHI?

Key to Table: Table information exclusively provided to Submarine Matters. LABs = lead-acid batteries, AIP = air independent propulsion, LIBs = Lithium-ion Batteries. ¥***B = Billion Yen. MHI = Mitsubishi Heavy Industries, KHI = Kawasaki Shipbuilding Corporation of Kawasaki Heavy Industries. 

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Anonymous and Pete