Tanaka (in a comment here) has kindly translated (from Japanese to English) an article by Isaku Okabe (a popular Japanese military critic) in the J-Ships February 2018 issue. J-Ships is a popular Japanese maritime magazine.
Isaku Okabe's article concerns the Soryu Mk.2's improved, more stealthy, snorting/snorkeling performance. The information on the Soryu Mk.2 performance is based on Submarine Matters' articles written by Anonymous and Pete ( here, here and here and especially here, here and here ) .
Tanaka's Translation [with some further Pete translation] is:
"THE INCREASING CAPABILITY OF STEALTH CRUISING THANKS TO THE LONGER UNDERWATER DURATION".
"There are some estimations of performance comparison between [the current] Soryu class [Mk. 1] and [submarine number] 27SS [see TABLE below] in a blog [Submarine Matters] written by a foreigner [ :) ] who is familiar with submarine matters.
In the blog, 27SS is called "Soryu Mk.2" and its maximum period of continuous [fully submerged] cruising at a speed of 4 knots is estimated to be 7~9 days compared to that of Soryu's 3~3.5days.
The blog says the general period of continuous [Soryu Mk.2] fully submerged cruising will increase to 6~8 days though the current Soryu class can cruise only 1~1.5 days.
The so called "Soryu Mk.2" will be able to conduct secret patrols without snorting for a much longer time. In regard to cruising at a speed of 18 knots, "Soryu Mk.2" will be able to do it continuously for 3~4 hours which is 3~4 times longer than current Soryu's.
The time required for charging batteries for the current Soryu Mk. 1 is estimated to be 5~10 hours, whereas the "Soryu Mk.2" needs just 1~2 hours, which makes the latter much more stealthy.
Supposing the mission period is 60 days, the "Soryu Mk.2" [needs to snort] 8~10 times compared to 40~60 times for the Soryu Mk.1. Snorting [with loud diesels running] reduces stealthiness - so a submarine needs to move out of its operational area to be safe.
[Lithium-ion Batteries (LIBs)] can reduce the number and length of snorting times which increases the stealthy operational time. This results in much more efficient use of submarines.
It goes without saying that these are estimations by a foreigner [ but kindly provided by Anonymous ] and no one knows if they are correct or not. But at least they can be good indicators to infer the progress of submarines using LIBs [rather than shorter operating Lead-acid Batteries (LABs)] .
Converting from [the Soryu Mk.1's] AIP + LABs to [the Soryu Mk.2's] LIBs is not as simple as just changing the type of batteries. Many parts of the submarine need to be modified such as whole power system and safety management system for the realistic and safe use of LIBs.
The 11th [27SS] and 12th [28SS] Soryu class submarines, which correspond to what the foreigner calls "Soryu Mk.2", will undergo major battery-electrical system conversions but not other major changes. Soryu Mk.2's hulls, weapons, sensors and control systems remain almost the same as current Soryu class." [The author, Okabe, did not mention the major change to the more powerful, storm tolerant, snorkel system. Maybe that will be introduced on the Soryu Mk.3?].
TABLE - SORYU & Oyashio Program as at January 25, 2018
Isaku Okabe's article concerns the Soryu Mk.2's improved, more stealthy, snorting/snorkeling performance. The information on the Soryu Mk.2 performance is based on Submarine Matters' articles written by Anonymous and Pete ( here, here and here and especially here, here and here ) .
Tanaka's Translation [with some further Pete translation] is:
"THE INCREASING CAPABILITY OF STEALTH CRUISING THANKS TO THE LONGER UNDERWATER DURATION".
"There are some estimations of performance comparison between [the current] Soryu class [Mk. 1] and [submarine number] 27SS [see TABLE below] in a blog [Submarine Matters] written by a foreigner [ :) ] who is familiar with submarine matters.
In the blog, 27SS is called "Soryu Mk.2" and its maximum period of continuous [fully submerged] cruising at a speed of 4 knots is estimated to be 7~9 days compared to that of Soryu's 3~3.5days.
The blog says the general period of continuous [Soryu Mk.2] fully submerged cruising will increase to 6~8 days though the current Soryu class can cruise only 1~1.5 days.
The so called "Soryu Mk.2" will be able to conduct secret patrols without snorting for a much longer time. In regard to cruising at a speed of 18 knots, "Soryu Mk.2" will be able to do it continuously for 3~4 hours which is 3~4 times longer than current Soryu's.
The time required for charging batteries for the current Soryu Mk. 1 is estimated to be 5~10 hours, whereas the "Soryu Mk.2" needs just 1~2 hours, which makes the latter much more stealthy.
Supposing the mission period is 60 days, the "Soryu Mk.2" [needs to snort] 8~10 times compared to 40~60 times for the Soryu Mk.1. Snorting [with loud diesels running] reduces stealthiness - so a submarine needs to move out of its operational area to be safe.
[Lithium-ion Batteries (LIBs)] can reduce the number and length of snorting times which increases the stealthy operational time. This results in much more efficient use of submarines.
It goes without saying that these are estimations by a foreigner [ but kindly provided by Anonymous ] and no one knows if they are correct or not. But at least they can be good indicators to infer the progress of submarines using LIBs [rather than shorter operating Lead-acid Batteries (LABs)] .
Converting from [the Soryu Mk.1's] AIP + LABs to [the Soryu Mk.2's] LIBs is not as simple as just changing the type of batteries. Many parts of the submarine need to be modified such as whole power system and safety management system for the realistic and safe use of LIBs.
The 11th [27SS] and 12th [28SS] Soryu class submarines, which correspond to what the foreigner calls "Soryu Mk.2", will undergo major battery-electrical system conversions but not other major changes. Soryu Mk.2's hulls, weapons, sensors and control systems remain almost the same as current Soryu class." [The author, Okabe, did not mention the major change to the more powerful, storm tolerant, snorkel system. Maybe that will be introduced on the Soryu Mk.3?].
TABLE - SORYU & Oyashio Program as at January 25, 2018
SS No. | Build No Name | Pennant No. | MoF approved amount ¥ Billions FY | LABs, LIBs, AIP | Laid Down | Laun -ched | Commi ssioned | Built By |
5SS Oyashio | 8105 Oyashio | SS-590/ TS3608 | ¥52.2B FY1993 | LABs only | Jan 1994 | Oct 1996 | Mar 1998 | KHI |
6SS-15SS Oyashios 10 subs | 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 Mk 1 | 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 | 8125 Shoryu | SS-510 | LABs + AIP | 2014 | 6 Nov 2017 | Mar 2019? | KHI | |
27SS First Soryu Mk 2 | 8126 | SS-511 | LIBs only | 2015 | 2018? | Mar 2020 | MHI | |
28SS Second Soryu Mark 2 | 8127 | SS-512 | ¥63.6B FY2016 | LIBs only | 2016? | 2018? | Mar 2021? | KHI |
29SS First Soryu Mk 3 (1) (3) | 8128 | ? | ¥76B FY2017 | LIBs only | ? | ? | 2023? | MHI? |
30SS Second Soryu Mk 3 (2) | 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.
---Tanaka, Anonymous and Pete