October 5, 2020

Electrical Propulsion Costs: Soryu Mk IIs & New "3,000t" Class

Following “Soryu and New Japanese Submarine Class Table” of September 30, 2020 Anonymous, on October 4, 2020, advised [with some word changes by Pete for improved English]:

The price of new SLH LIBs for Soryu Mk II (27SS Oryu, 28SS Toryu) and the New “3,000ton” Class submarine (8.6 B yen for 29SS, 8.4 B yen for 30SS) are nearly same suggesting the following.

First, the unit price of a LIB module is 8.75 million yen (hence 8.4 Billion yen for 960 modules) nearly three times as expensive as a corresponding 3 million yen LAB module. The LIB modules are significantly cheaper than previously expected [1].

Second, a New Class (3,000t) submarine will be equipped with the same amount of LIBs as a Soryu Mk II [2, 3, 4].

[1] Prices of 480 LABs and AIP (consisting of 4 Stirling generators (excluding LOx tanks)) in Soryu Mk Is are 1.5 and 1.3 Billion Yen respectively. So this totals 2.8 Billion Yen. Although, including LOx tanks may make the total 4 Billion Yen.

The cost of 960 LIBs for Soryu Mk II and New “3,000t” Class submarines are 8.6 and 8.4 Billion Yen respectively). 

Anyway, the cost of LIBs (8.4 or 8.6 Billion Yen) are three times more expensive than the total cost (2.8 Billion Yen) of LABs and AIPs for Soryu Mk Is. As mechanical output of one AIP is 75kW, we can understand how expensive Stirling AIP is. 

[2] Maximum power output for Oryu, a Soryu Mk II is reduced to 4,200kW from 6,000kW for a Soryu Mk I suggesting maximum speed of 18knots for Oryu down from 20knots for a Soryu Mk I [8knot/20knot)^3*6000kW=4200kW].

I doubt a Soryu Mk I can efficiently achieve a maximum speed of 20knots as this may cause problems such as permanent damage to the propulsion system. Therefore, a reduction of maximum speed to 18knots in a Soryu Mk II, is a more realistic speed to avoid permanent damage to the propulsion system.

[3] Judging from the direction of Japanese Ministry of Defense (MoD) R&D for submarine, the undetected performances (including quietness and maximum silent speed) have improved for Soryu Mk IIs and the New “3,000t” Class submarines. 


Anonymous drew Pete's attention to the cutaway diagram (above) Soryu Mk II, specifically 28SS Toryu, (but also applying to 27SS Oryu) submarine with a label "Lithium-ion batteries" pointing to the double deck LIBs arrangement that Anonymous and wispwood2344 described. (Diagram published at http://blog.livedoor.jp/wispywood2344/archives/54964300.html with wispywood244 providing annotations & "Reference: JMSDF via [January 2020 edition] "SHIPS OF THE WORLD vol.915 p.93")
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[4] In the Soryu Mk II [like 28SS Toryu in diagram above] an additional 240 LIBs are loaded in a double deck manner in place of the large AIP LOx tank that would have been in a Soryu Mk I [16SS to 26SS]. The double deck manner arrangement of 960 LIBs total in Soryu Mk IIs raises the center of gravity. The unequal vertical arrangement (3 x 240 LIBs in 3 bottom decks and 240 LIBs in a middle/double deck) of LIBs is an unstable arrangement and increases stray magnetic fields. The optimal arrangement of LIBs, in terms of positional stability and minimal stray magnetic fields, would be an all bottom arrangement. This all bottom arrangement may be applied for the New "3,000t" Class submarine.

By Anonymous (with word changes by Pete for improved English/clarity).

2 comments:

Anonymous said...

Hi Pete

(Before correction 1)
[1] Cost of underwater electricity supply system (LIBs) of a Soryu Mk II and a New “3,000t” Class submarine is nearly twice as expensive as [the 5 Billion Yen price?] of a Soryu Mk I's (LABs and AIP). In a Soryu Mk I the price of 480 LABs [totals around 1.5 Billion Yen?] and the prices of 4 Stirling AIP engines and the LOx tank is also added.

(After correction 1)
[1] As prices of 480 LABs and 4 Starling generators (excluding LOx tanks) in Soryu MKI are 1.5 and 1.3 Billion Yen, respectively, cost of LIBs for Soryu MKII and “3000t” Class submarine (8.6&8.4 Billion Yen) is three expensive than total cost of LABs and AIPs (4 Billion Yen) for Soryu MKI. As mechanical output of one AIP is 75kW, we understand how Starling AIP is expensive.

(Before correction 2)
[4]In the Soryu Mk II, based on the previous AIP sectional loading structure, additional LIBs are loaded in a double deck manner (in section 10 above diagram) in place of the large LOx tank that would have been in the Soryu Mk I. This LIB arrangement also provides an improved center of gravity. In contrast, the New “3,000t” Class submarine may have an optimal arrangement of LIBs all on the bottom with a newly developed non-AIP sectional structure.

(After correction 2)
[4] In the Soryu Mk II, based on the previous AIP sectional loading structure, additional LIBs are loaded in a double deck manner (in section 10 above diagram) in place of the large LOx tank that would have been in the Soryu Mk I. The double deck manner arrangement of LIBs in Soryu MKII raises position of gravity center and unequal vertical arrangement (3 x 240 LIBs at 3 bottom decks and 240 LIBs at a middle deck) of LIBs providing unstable position and increased stray magnetic field, respectively. Optimal arrangement of LIBs in terms of positional stability and minimal stray magnetic field is all bottom manner on the keel. This arrangement may be applied for 3000t Class submarine.

Regards

Pete said...

Hi Anonymous

Thanks very much for your October 5, 2020 at 6:15 PM.

I have altered the text accordingly with word changes for clearer English, where appropriate.

Regards

Pete