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The Soryu Mk 2 (at 27SS in the Table below) importantly will have:
(A) a modified propulsion motor (designated “SMC-8B”) [1]
(B) accompanied by Lithium-ion Batteries (LIBs). LIBs provide various benefits such as a low
indiscretion ratio (IR) [a lower the ratio of time spent at periscope depth snorting to time completely submerged
(C) flexibility of operation and high speed performance submerged and
(D) 12V25/25SB diesels used in the current Soryu Mk 1 [but uprated? ie. more powerful? for
the] Soryu Mk 2 prior to use of 12V25/31S in Soryu Mk 3.
the] Soryu Mk 2 prior to use of 12V25/31S in Soryu Mk 3.
The newly modified propulsion motor (designated “SMC-8B”) will benefit from the more powerful diesel and the more electrically powerful LIBs quick charging of LIBs in order to achieve flexibility of operation and high speed performance submerged. In Soryu Mk 1, low speed performance is emphasized because of low effective capacity of LABs.
In the Soryu Mk 2, higher speed performance will be emphasized, because of drastically improved LIB and motor capacity. This allows high speed submergence for a much longer period.
In other words, the main objective of the SMC-8B is [being able to maintain maximum silent speed of up to 6 knots (?) for a longer period]. Key factors will be optimized to reduce vibration/noise, in Anonymous's opinion. As result, maximum speed from point to point somewhat changes as shown in [2] and [3]. As even a tiny improvement of maximum speed for only 5 minutes needs higher power, Anonymous does not think such a tiny improvement has meaning in actual operation.
[1] Budget of Japanese Ministry of Defense (MoD)
[1] Budget of Japanese Ministry of Defense (MoD)
Soryu Mk 1s have propulsion motor SMC-8 and Mk 2s have SMC-8B (where the B means first revision) see Table below. The degree of revision can be measured by the first year cost which is cost for new equipment and so on in the first year. In SMC-8B, the first year cost was budgeted suggesting that SMC-8B experienced huge modifications or SMC-8B is actually a new model. So overall the last Soryu Mk 1 (26SS with SMC-8) costs ¥51.7B FY2014 (see Table below) the cost for the first Soryu Mk 2 (27SS) jumps to ¥64.4B FY2015 of which the development and unit costs of the first SMC-8B are a part.
[2] “FY2014 Annual Report on Life Cycle Cost Management”, Equipment
Procurement and Construction Office, Ministry of Defense (MoD), page 78, Tabale 2. The maximum submerged speed of 26SS (Soryu Mk 1 with Lead-acid Batteries (LABs) + AIP) and 27SS (Soryu Mk 2 with LIBs) are both 20 knots.
[3] Using English wikipedia websites - LIBs have a greater average charge and discharge efficiency 80%-90% (see LIB sidebar) compared to LABs with a lower average in the 50%-95% (see LAB sidebar). A Soryu Mk 2 submarine using LIBs, like a Soryu Mk 1 submarine using LABs both will not exceed 20 knots. However while a Soryu Mk 1 can only maintain 20 knots [for around 1 hour?] a Soryu Mk 2 can maintain 20 knots for longer [around 3 hours?]. This means higher speed for a
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 |
8105 Oyashio | SS-590/ TS3608 | ¥52.2B FY1993 | LABs only | Jan 1994 | Oct 1996 | Mar 1998 | KHI | |
6SS-15SS | 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 | 8116 Sōryū | SS-501 | ¥60B FY2004 | 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 |
No 21SS | No 21SS built | |||||||
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 | KHI | |||
25SS | 8124 | SS-509 | ¥53.1B FY2013 | LABs + AIP | 22 Oct 2013 | 12 Oct 2016 | Mar? 2018 | MHI |
26SS end of SMC-8s | 8125 Shoryu | SS-510 | LABs + AIP | 2014 | 6 Nov 2017 | Mar 2019? | KHI | |
27SS First | 8126 | SS-511 | LIBs only | 2015 | 2018? | Mar 2020 | MHI | |
28SS Second | 8127 | SS-512 | ¥63.6B FY2016 | LIBs only | 2016? | 2018? | Mar 2021? | KHI |
29SS First Soryu Mk 3 SMC-?? | 8128 | ? | ¥76B FY2017 | LIBs only | ? | ? | 2023? | MHI? |
30SS Second Soryu Mk 3 | 8029? | ? | ¥71.5B FY2018 | LIBs only | ? | ? | 2024? | KHI? |
Table from 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. On Feb 13 2018 Diesel and Motor types were added.
---Anonymous and Pete