Likely Specs of the Future Japanese "Super Soryu" Sub for Australia

The Soryu first of class (No. 501). Japan's design for Australia, will perhaps be temporarily called "Super Soryu" or in the production sequence as "SS29 mod-AUS". (Photo courtesy seaforces).
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This is a work in progress mainly derived from comments by "S" over the last few months. S's information, from what I call the Japanese military-industrial complex, has frequently been unique and inline with other open sources. I will update and fill out details as new information and corrections come in.

There is a firmer Japanese intention to build the future submarines in Australia. See Reuters' excellent article Japan says ready to build all submarines for Canberra in Australia, September 29, 2015.

An excellent article by Mina Pollmann for The Diplomat indicates: "Japan’s Ministry of Defense (MOD) created the 1,800-person strong Acquisition, Technology, and Logistics Agency (ATLA) on October 1 [2015] to deal with many of the practical challenges that remain to implement this new export policy. A staff of 50 within ATLA will be dedicated specifically to arms export promotion….The proposal for submarine technology cooperation between Japan and Australia is a classic case of Japan trying to alleviate its abandonment fears vis-à-vis the U.S. by proving its commitment to “burden-sharing.”" 

I'm under the impression that Japan will likely win. The US probably still wants that. A winner needs to be qualified to receive the mainly US developed combat system which Australia has already announced Australia will use as a "key strategic requirement" (see item c).  See Lockheed Martin Combat System Laboratory that has just opened at Mawson Lakes un Adelaide. If not Japan then probably Germany. 

The internal Japanese name for Australia's submarine class is (as at September 2015) SS29 mod-AUS. See the Soryu Table below. Japan is making a 29SS first for its own Navy. Japan's 29SS will , perhaps be laid down in Kobe, Japan in 2018. 

If Australia accepts that 29SS will be a part-prototype for the 8 to 12 SS29 mod-AUS submarines to be built in Australia then the Australian sub is unlikely to use Air Independent Propulsion (AIP). Australia did not use AIP in the Collins and "no-AIP" was one of the enlightened decisions involving the Collins. AIP involves high cost, heavy weight additions, balance-buoyancy problems and most importantly can be particularly dangerous due mainly to poison and/or explosive gases. However Australia is likely to use Lithium-ion batteries (LIBs) that are becoming the standard high capacity, quickly charged battery type.

On the issue of less than 30 year operational life the preferred Japanese measure seems to be comparing the Japanese sub with German and French subs according to days actually on operational missions. However, I think non-operational time in salt water (which can rust/corrode hulls) at Fleet Base West should also be taken into account.

The hull structure will be partly double and partly single hull instead of the all single hull on the Collins.

The pressure hull will not use Japan's most secret pressure hull steel alloy known as naval steel NS-110. Instead an alloy that is easier to cut and reweld (for major maintenance in Australia) will be used. I would guess that it may have a US scale HY value of HY-120 or HY-130. Countries involved in formulating a new or existing alloy would include Australia, Japan, maybe the US and possibly also Sweden. Given experience with Collins steel Australia has demonstrated it can make submarine steel. Australia making the steel (probably at Wollongong or Newcastle) might be considered part of the 70%-80% of the “Full Australian” build.

SPECIFICATIONS

Length:	90-92 meters [source S comment October 6, 2015 at 10:43 PM]
Beam:	9.1 meters Worked Out (1) below
Draft:	8.5 meters [approx - this is current Soryu measure]
Displacement:	3,600 tons (surfaced) / 4,500-4,600 tons (submerged) [source for all  displacement figures S comment Sept 26, 2015 3:17AM] Worked Out (2) below
Speed/Range:	11,500nm/10kt surfaced, / Worked Out (3) below 8000-9000nm/6.5kt snorkel  and ca. 3000 nm/4kt submerged, 20+ kt max submerged (current Soryu)
Crew:	60 Worked Out (4) below
Operational depth:	900 feet (275 meters) test depth [same as "shallow" official Soryu depth]
Propulsion:	Diesel-Electric using Lithium-ion Batteries (LIBs) 2 Kawasaki 12V25/25SB or more advanced Kawasaki diesel engines Worked Out (5) and (6) below equipped with newly-developed snorkel-generator system - see (6) below 6+ MW [approx] permanent magnet motor [APDR Oct 2015 edition, Vol. 41, No.8, page 44] 4,500 hp surfaced [est extrapolation]/ 8,500 hp submerged [est extrapolation] 1 shaft / 1 propeller
Armament:	6 x 21-inch (533mm) torpedo tubes for 20 Mk 48 torpedoes or sub-launched Harpoon SSM or Tomahawk land attack or mines or UUVs. Note that reports that Soryus could carry "30" heavyweight torpedos/missiles are a confusion of the 10 torpedos/missiles + 20 mines that could be carried (mines being smaller). No VLS.

                                    AN/BYG-1 combat system with compatible sonars + other sensors

                                        

                                    Detachable Dry Deck Shelter for divers, diver delivery vehicle, LDUUV

Miscellaneous            Modications required: include washing machine, fold-down ladies toilet seat,
                                    longer bunks than the current 5 feet 3 inches

How some figures Worked Out (1) to (5) by S in Comments at October 2, 2015 at 2:00 AM

(1)  Beam remains unchanged 9.1m as on current Soryu. Pressure shaping of hull steel plate to cylinder is very difficult process, so lengthening hull is much easier than broadening beam to increase submarine volume.

(2)  Displacement  "Surfaced: weight minus {liquid oxygen & container (120t), Stirling AIP (2-3t)} plus {LIBs(380t), longer hull + additional fuel (240t)} = +500t"

"Submerged: increase in water weight corresponding to volume increase with increase in hull length (+4m) = +300t"

(3)  Speed and range - "According to right sidebar Wikipedia, both surface and snorkel cruising speeds of Collins are 10kt, but these values seem to be introduced as maximum speeds by the RAN. S calculated and estimated amount of diesel fuel to achieve wiki-performance of Collins (11,500nm/10kt surfaced, 9,000nm/10kt snorkel) , and concluded that Collins must carry 800-1000 tons of diesel fuel to achieve 9,000nm/10kt and that it was impossible. Judging from the projected figure/dimension of Collins and from comparison with Soryu. S thinks that Collins cruises 9,000nm at ca.6kt snorkel by using ca.300ton of diesel fuel."

"29SS mod-AUS may achieve 8000-9000nm/6.5kt snorkel and ca. 3000 nm/4kt submerged. Speed of submarine is affected by drag rather than displacement. In 29SS mod-AUS, as frontal projected area and shape are not changed with slight increase in length (+4m=5%), drag does not become worse meaning negligible loss in performance compared to 29SS."

(4)  Number of Crew - Crews of 29SS will reduce to 59-62 by removal of AIP and an increase in automation in the sub. The RAN may adopt the 3 working-shift system instead of the 2 working-shift system. The 2 working-shift system is too tough for long missions [October 6, 2015 at 10:43 PM].

(5)  Improvement in diesel engine for rapid charge of LIBs - "Enhancement of diesel generation will be achieved by simple capacity increase (increase in bore and stroke) in cylinder volume, not by increase in numbers of diesel engine or cylinder. Increase in numbers of diesel engine requires change of arrangement of diesel engine room. V12 engine (12V25/25SB) is best cylinder configuration with ideal balance and least vibration.

The capacity increase in cylinder is dominated by snorkel capacity which may increase to certain extent which is limited by the unchanged dimension and shape of the mast. JMSDF may make an increase in diameter of snorkel and filter efficiency up to 20-25%. I think new V12 engine can improve in performance of 50-100% (12,000-16,000PS) which brings increase in snorkel speed (15-25%)."

(6)  Worked out by wispywood2344 in Comments on October 2, 2015 at 9:39 PM - The 29SS-class must be equipped with "newly-developed" snorkel-generator system, and its diesel engine must not be 12V25/25S variant. Because, TRDI(Technical Research and Development Institute) had concluded that present snorkel-generator system must be outdated in performance in 2020s, and started development of next-generation snorkel-generator system including diesel engine. The main concept is downsizing, increasing power, and reduce noise emission.[see Japanese language PDF]. Note that the first adoption of 12V25/25S series was 28 years ago (lead ship of Harushio-class), and its design is already obsolete. I guess that performance improvement of the diesel engine should be achieved by "expanding boost pressure" and/or "increasing rotating speed". 

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The increase in displacement (surfaced) up from 2,900 tons (for the Soryu) to 3,600 tons for the SS29 mod-AUS, is probably due to the need for extra diesel fuel (for 10,000+ nautical miles range, up from 6,000) and more diesel engine capacity for faster Lithium-ion Battery charging requirements.

SORYU TABLE 
(which provides the context from which the Australian submarine will be developed)

One of the strengths of Japan overseeing the build of the Australian submarine is that the Japanese military-industrial complex (Japanese Ministry of Defence, Navy, KHI and MHI) is very stable but also constantly innovates.

Each of the Soryus (in the table below) is built on the lessons of each previous Soryu. The Soryu as a group have been developed on the basis of the preceding Oyashio class (11 subs, 1998 - present)  and Harushio class (7 subs, 1990 - 2 may be still training/testbeds).

SS No.	Building No.	Pennant No.	Name/Namesake	LAB or LIB & AIP *	Laid Down	Laun -ched	Commi-ssioned	Built By
16SS	8116	SS-501	Sōryū (そうりゅう) / Blue Dragon Soryu Mark 1	LAB + AIP	March 2005	Dec 2007	March 2009	MHI
17SS	8117	SS-502	Unryū (うんりゅう) / Cloud Dragon	LAB + AIP	March 2006	Oct 2008	March 2010	KHI
18SS	8118	SS-503	Hakuryū (はくりゅう) / White Dragon	LAB + AIP	Feb 2007	Oct 2009	March 2011	MHI
19SS	8119	SS-504	Kenryū (けんりゅう) / Sword Dragon	LAB + AIP	March 2008	Nov 2010	March 2012	KHI
20SS	8120	SS-505	Zuiryu (けんりゅう) / Sword Dragon	LAB + AIP	March 2009	Oct 2011	March 2013	MHI
22SS	8122	SS-506	Kokuryū (こくりゅう) / Black Dragon	LAB + AIP	January 2011	Oct 2013	March 2014	KHI
23SS	8123	SS-507	Jinryū (じんりゅう)/ Benevolent Dragon	LAB + AIP	Feb 2012	Nov 2014	March 2016?	MHI
24SS	8124	SS-508	?	LAB + AIP	2013	2015?	2017	KHI
25SS	8125	SS-509	?	LAB + AIP	2014	2016?	2018	MHI
26SS	8126	SS-510	?	LAB + AIP	2015	2017?	2019	KHI
27SS	8127	SS-511	Soryu Mark 2	LIB only	2016?	2018?	2020?	MHI
28SS	8128	SS-512		LIB only	2017?	2019?	2021?	KHI
29SS	8129	SS-513		LIB only	2018?	2020?	2022?	MHI
AUS1			Super Soryu for Australia	LIB only	2022?	2024?	2026?	in Aus

LAB = Lead Acid Battery.

LIB = Lithium-ion Battery,
AIP = Air Independent Propulsion (Swedish-Kockums designed Stirling engine)

I'll add new figures, comments and corrections as they come to hand.

Pete