April 25, 2017

Submarine Matter's expectation of an Ohio class SSGN now confirmed

On April 13, 2017 Submarine Matters published an article, US & Japanese ABM - BMD forces slowly approaching North Korea, which stated:


"Submarine-wise one SSN or two (with Tomahawk land attack missiles) would normally accompany the Carl Vinson Group. To enhance the option of a first or second strike of Tomahawk SLCMs onto NK targets a US Ohio SSGN might also be on hand in the region. Submarine fired Tomahawks all have the advantage of a greater element of surprise because they can emerge from unexpected undersea launch points."
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This suspicion was confirmed 11 days later on April 24-25, 2017 when Fox News reported

"The USS Michigan, a nuclear powered Ohio class submarine will pull into the South Korean port of Busan for a hull check in the coming hours, military sources confirmed Monday to Fox News...The USS Michigan is one of four Ohio-class guided-missile submarines, originally designed to launch nuclear missiles, that were converted between 2003 and 2007 to be able to fire Tomahawk cruise missiles....The USS Florida (SSGN 728) was converted in August 2003, the USS Michigan (SSGN 727) in October 2004, the USS Ohio (SSGN 726) in December 2005, and the USS Georgia (SSGN 729) in December 2007."


A US Ohio class SSGN is very large (around 17,000 tons (surfaced) and 19,000 tons (submerged)). Its size can be judged from how small the crew look standing on the hull.
Can astute readers spot the (non-Asia Pacific) location?
---

Pete

Japan & US - No submarine building Unions? But the Most Efficient?

I’ve been doing a bit of research on Japanese shipbuilding, relevant union organisations and an estimation of the Japanese and US submarine building industries.

Japan’s peak union body is the Japanese Trade Union Confederation, or RENGO, with 6.82 million members. It formed in 1989. Japan has a large ship and submarine building industry. A shipbuilding union, the All Japan Shipbuilding and Engineering Union (ZENZOSEN KIKAI), was an affiliate with 1,192 members. But I am advised that the All Japan Shipbuilding and Engineering Union was dissolved on September 9, 2016.

I suspect that many Japanese white-collar and blue-collar shipbuilding workers may be in other unions that don’t carry the “shipbuilding” title. Or perhaps the traditional view of Japanese workers being very longterm, in the same industry and company, still applies?

Japan has built submarines almost uninterrupted since 1906. That interruption occurring 1945-1957 when Japan was devastated by bombs and a US submarine blockade.

Japan has two large submarine building companies:
-  the conglomerate Mitsubishi Heavy Industries (MHI) (see MHI submarine website), and
-  Kawasaki Shipbuilding Corporation (KSC)See Kawasaki submarine website.

I am guessing the submarine building workforces of MHI and KSC are around 1,000 each (2,000 total). Perhaps the Japanese Ministry of Defense and ATLA (a sub example) have 1,000 staff total dedicated to submarine research, contracts, production and availability?

They form a submarine building duopoly in the port city of Kobe, with each company continuous building one submarine every two years with launches occurring alternatly and rigidly every October to December. For the on-time, on-budget, schedule see the SORYU-Oyashio TABLE.

Along with the US Japan might be the most efficient submarine builder in the world. This comes from:
1.  duopoly conditions (a government can always favour the competing company)
2.  continuous build (Japan building one SSK every year and the US building 1 to 2 SSNs)
3.  long runs of submarines with relatively few changes eg. few differences between the 10 Soryu
     Mk. 1s (see TABLE) and between the first 39! Los Angeles SSNs, and
4,  only building subs for one customer (US or Japanese) in their own navies.

Or perhaps other counties are more efficient by other measures such as:
-  country A achieving greater economies of scale, through production for foreigners, than A's 
   domestic demand can provide, or
-  raising foreign exchange through sales to foreign customers.

It takes the large, rich US economy to build an SSN or two each year (and eventually one Columbia class SSBN as well). The USSR used to churn out nuclear submarines at that rate but this was a major contributor to the ruination of its economy. China still cannot afford it or is dissatisfied with its SSNs' quality, prefering to mass produce SSKs instead.

A Japanese Soryu submarine being launched, with much fanfare, in Kobe.

---


A Virginia class SSN under construction at Huntington Ingalls Industries Inc - Newport News. Note the propulsor about a mile back, in the distance :)
---

Pete

April 20, 2017

Submarine electricity discharge & generation using combinations of Diesels, LIBs, LABs & AIP

Following last week's articles (here, here and here) Anonymous continues representation of electricity discharge and generation using combinations of Lithium-ion Batteries (LIBs), Lead-acid Batteries (LABs) and Air Independent Propulsion (AIP). An extra variable is use of Diesels on full or half power.

Tables 1 and 2 present extra comparative information.


Figure 4 (below) is the output of diesel generators for model submarines:

Diesels in LIBs-sub operate once every two-days (no operation on Day 2) using diesel on full power.
(a) LIBs + new diesel generator (GE), Power of new Diesel increases to 125% compare to old Diesel. This is noting LIBs require (or benefit from) more powerful Diesels.
(b) LIBs + full power Diesel, 

C-rate of LABs is 0.2C. Output of each Diesel is 2 and 4M in half and full power, respectively.
(c) LABs + half power Diesel + AIP. In AIP operation. LABs are not discharged.
(d) LABs + half power Diesel, Operation cycle of LABs-sub is once a day. 

Grey represents no generation using Diesel; 
Green represents Diesel generation; 
Purple represents AIP generation; 

Lower axis Figure 4 represents electricity discharge and generation according to which team of the 3-watch crew roster are on duty. Where:
- Red represents team 1;
- Yellow represents team 2; 

- Blue represents team 3;  

Figure 4 
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4


Snorkeling/Diesel

(a)  LIBs+new Diesel (day 1 of 2 days)

















2
Discharge





Discharge to day 3, 20:00






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(b) LIBs +full power Diesel (day 1 of 2 days)







Snorkeling/Diesel







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Discharge
Discharge to day 3, 20:00







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(c) LABs + half power Diesel + AIP (every day)





























2
Discharge
Snorkeling/Diesel

Discharge

AIP mode (240kW)

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(d)LABs + half power Diesel (every day)































2
Discharge
Snorkeling/Diesel
Discharge
Snorkeling
/Diesel
Discharge

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time
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01

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Table 1 - Performances of models
Model
Indiscretion ratio, IR [1] %
Submerge at max speed [2] h
Capacity of battery
MW
Output of Diesel [3]
MW
Rotation of Diesel
rpm
C-rate
Current
status
Limit [4]
LIBs + new Diesel
5.2
10
50
5
1200
0.1
1
LIBs + full power Diesel
6.3
10
50
4
1200
0.08
1
LABs + half power Diesel AIP
8.3
1
10
2
600
0.2
0.4
LABs + half power Diesel
12.5
1
10
2
600
0.2
0.4
[1] LIBs, IR=operation time (green)/48 x 100; LABs, IR= green/24 x100.
[2] Max speed is 18 knots; Energy consumptions are 4.5 and 40.5MW for LABs and LIBs, 
respectively.
[3] Data is total output of 2 Diesels. Model sub is equipped with 2 Diesels operating 
simultaneously.
[4] C-rate of LIBs is general data. Value of LABs is for high speed charge/discharge rate.


“C” means one Coulomb. C-rate is the inverse of charging time in hours. An empty
  battery with a C-rate of 0.5 just needs 2 hours to be recharged completely.


Table 2 -  Important factors
Term
Discussion
LAB
LIB
C-rate
As C-rate of LAB is small (0.1C, 0.2C) and capacity is low, C-rate dominates charge/discharge rate. Higher C-rate (0.4, 0.5C) is possible, but, it shortens life of LAB. Half power of Diesel can satisfy C-rate of 0.2C.
Dominative
-
Output of Diesel
As C-rate of LIB is large (0.5C, 1C) and capacity is high, output of Diesel  dominates charge/discharge rate. To get low indiscretion ratio, output of Diesel needs to be increased. In Fig.4 (a), C-rate is only 0.1C. Higher rotation of Diesel or increase of Diesels is possible measure, but it increases noise or vibration.
-
Dominative
Snorkel capacity
To realize high performance of LIBs, an improvement of the Diesel will be conducted within framework of snorkel system capacity to effectively discharge exhaust gases.

To achieve C-rate of 1 for LIBs is difficult (max. two- or three-fold increases?), C-rate of 1 is difficult to achieve (max 02-0.3?).
-
Dominative
Propulsion motor
To achieve high speed performance by LIBs, improvement of propulsion motor is required.
-
Important
Conclusion
To realize high performance submarine equipped with LIBs, comprehensive improvement of power system including Diesel, snorkel system and propulsion motors as well as development of LIBs are required.
Also, improvement and establishment of peripheral technologies including safety system and further reduction of noise/vibration are needed.

Anonymous