March 15, 2019

Australia's future Attack class submarine needs 6,000kW electrical output

Australia’s future Naval Group Attack class submarine design which may be 4,500 tonnes (surfaced) may require diesels with a total electrical output of 6,000kW. This is noting that the 6,000kW is not only for propulsion, but also for the “hotel load” (eg. electrical power for combat system electronics and air-conditioning).

After SubMatt’s article of March 5, 2019 on German (MTU or MAN) diesels for the Attack class Anonymous commented with a range of figures to air issues:

To achieve a total 6,000kW electrical output, 6 diesel generators (probably German designed MTU or MAN) are needed [1].

The Attack class design (beam 8.8m) could arrange its 6 x diesel generators in 2 parallel rows of 3 diesel generators [2].

In comparison the length of Japan’s unselected entry (J-SEA1000) for Australia Attack class SEA1000 competition may have involved these measures. J-SEA1000 without AIP but with 4 x higher powered Kawasaki diesel generators would have been 90-92m long. Naval Group’s Attack class design is 97m long so it may possibly have AIP.

In the case of the Attack class with 6,000kW diesel generators, indiscretion ratio (IR), may all point to a performance index of a  submarine is very roughly estimated to be 3% [3], and in the case of non-AIP it may be 4-5%. This is a pretty good performance index.

An MTU 12V4000U83 for submarine (Courtesy Penske Power Systems (Australia and New Zealand website)).
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[1] The MTU V12 4000 U83 (diagram above) has a mechanical output of 1,300kW and electrical output of 1040kW. 

The MAN 12 PA4V200 SMDS (diagram below) has a mechanical output of 1330kW and electrical output of 1064kW.


The MAN 12 PA4V200 SMDS (preceding link is about 5MB PDF) submarine diesel. May be used on Australia's future Attack class and the Netherland's Walrus replacement. 
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[2] Estimated cross section of Attack-class from various pictures: diameter of pressure hull (d) = 8.8m, thickness of hull steel (a) = 0.05m, thickness of sound absorbing rubber (b)= 0.10 m, width of hull stiffener ring (c) = 0.25m, width of diesel (f) = 1.7m, average distance between diesel-diesel or diesel – hull stiffer (Y). Then, Y=(d-2a-2b-2c-3f)/4= (8.8-2x0.05-2x0.1-2x0.25-3x1.7)/4 =0.72m.

As Y=0.4m for Walrus-class (3 x diesel generators  arranged in parallel) and Y=0.5m for SAAB-Damen submarine design (beam 8m, maybe 2,300 tonne surfaced?) (3 x (MTU or MAN(?)) diesel generators arranged in parallel)

The beam of the Australian Collins-class (7.8m) is slightly less than that of SAAB-Damen submarine (8m). I believe diameters of the two submarines are same, and difference in beam is due to position and shape of flank array sonars of the two submarines.

Last year, the Australian Submarine Corporation (ASC) entered into an agreement with SAAB for the provision of a range of services. The experience of ASC with the Collins-class not only supports the A26 Project but also will be useful for design and building of the SAAB-Damen submarine. The future SAAB-Damen submarine design will be based on the existing and reliable submarine (Collins) platform to some extent.

[3] Calculation in the case of 100MW AIP and 6MW GEs
(1) AIP: 100MW
(2) Energy consumption per day ca.6MW =[hotel load (180kW) + propullsion 60kW] x 24 hours
(3) Operation 10 weeks = surveillance 7weeks (ca.50days) + transition 3weeks (ca.20days)
(4) Required battery energy per day for surveillance = Energy consumption per day – energy suppled from AIP = 6MW-100MW/50days = 4MW
(5) Charge period = (4)/electrical output of GEs x 1hour =4MW/6MW x 1hour = 0.67 hours
(6) IR = charge period (hours) / 24 (hours) x100 (%) = 2.8%=0.67/24 x 100 =2.8%


Anonymous
(with some rearranging by Pete)

4 comments:

  1. Trump administration is planning to roll out the "cost+50" program to Japan, ROK and Germany. This will no doubt change the strategic alliance picture in Asia fundamentally.

    https://warontherocks.com/2019/03/cost-plus-50-and-bringing-u-s-troops-home-a-look-at-the-numbers/

    KQN

    ReplyDelete
  2. Thanks KQN

    for http://warontherocks.com/2019/03/cost-plus-50-and-bringing-u-s-troops-home-a-look-at-the-numbers/ on March 15, 2019:

    "The Trump administration wants to make it more expensive for American allies to host U.S. military personnel in their country.

    It reportedly intends to ask allies to drastically increase the amount they pay for hosting U.S. forces, sparking new fears that the United States will eventually withdraw from these countries entirely.

    Under the so-called “cost plus 50” proposal, allies would pay for the full cost of hosting U.S. units, plus a 50 percent premium. Germany and Japan will walk the plank first..."

    PETE COMMENT

    Also this May apply to the 1,100 or so US marines who are temporarily based in Darwin 6 months of each year.

    Trump sure has a way of threatening America's allies. Putin (if the rumours are true) did a good job helping Trump into the White House...

    Weaker US alliances with Japan and South Korea will also make China and North Korea happy.

    Although risking nuclear proliferation in Japan and South Korea may not be a good US policy.

    ReplyDelete
  3. @Pete:

    Definitely likely to irk the countries involved, but the US can't possibly pull out of any of those countries before the next election. The natural tactic of any allied nation will be to stall or placate at least for that long.

    Cheers,
    Josh

    ReplyDelete
  4. Hi Josh

    Yes, the US would likely take longer than the November 2020 Presidential Election to pull out from Germany, Japan or South Korea.

    Also a Japan or South Korea pullout would play into the hands of Trump's main enemy, China.

    Some eventual US withdrawals from Germany and other NATO countries might be more likely - and would also dovetail with Trump's personal friendship with Putin.

    Regards

    Pete

    ReplyDelete

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