January 25, 2018

Translation of Japanese J-Ships Article which uses Submarine Matters Articles

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 ( herehere and here and especially herehere 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 belowin 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 MattersLABs = 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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Tanaka, Anonymous and Pete

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