This article follows PART ONE, published January 3, 2018.
The Australia’s Future Submarine (future sub) is very large for an SSK. So powerful diesel-generators in the 2MW class are desirable. This should minimise the number of diesel-generators and keep the length and displacement of the submarine within efficient limits.
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The Australia’s Future Submarine (future sub) is very large for an SSK. So powerful diesel-generators in the 2MW class are desirable. This should minimise the number of diesel-generators and keep the length and displacement of the submarine within efficient limits.
The diesel-generator requirements of the future sub remain unknown due to understandable lack of:
- published figures on the future sub's actual snort cruising speed – between 9 and 14 knots
- a final decision on whether the future sub will use existing lead-acid batteries or lithium-ion
batteries (which can benefit from higher charging rates of more powerful diesel-generators)
- whether 4, 5 or 6 diesels fit best in the future sub (eg. can diesel-generators be mounted 2 sets of 3
horizontally across? or 2 sets of 3 fitting into the sub’s circular diameter?)
injection system, and
tanks
This Naval Group Barracuda-Suffren class SSN cutaway (with K15 reactor) unfortunately does not resolve how 4 to 6 diesel-generators could be arranged in Australia's Future Submarine (Cutaway from Naval Group via navyrecognition via Submarine Matters)
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Power requirements are therefore vague, but the future sub will require around 6 to 8MWe of output - noting its 4,500 tonne (surfaced) displacement and also its high hotel load (serving the (usually nuclear submarine) AN/BYG-1 combat system).
Unusually powerful diesels are risky if they have not been tried and tested in submarines for years before Australia accepts them. The Collins at 3,100 tonnes (surfaced) uses 3 Garden Island-Hedemora diesels with a total output of 5.25MW x 0.8 = 4.2MWe. The Hedemoras needed to be unusually high powered for their time, unfortunately meaning they were untried in submarines, unreliable, restricted use and disliked by RAN submariners.
From a December 2017 comment on diesel-generator choices for the future sub - ideally the diesels should be around 2MW:
Approaching 2MW output is the KAWASAKI 12V/25/25SBs at 1.7MW. Two KAWASAKI ((Totalling 3.4MW output) are used in Japan’s (2,900 tonne (surfaced)) large Soryu SSK. So if 4 x 1.7MW (Kawasakis) are used = Total 6.8MW. 6.8 x 0.8 (power factor) = 5,44MWe. Five Kawasakis may be needed to exceed 6MWe, so 5 x 1.7 x 0.8 = 6.8MWe. It is highly unlikely France and/or Australia would select a Japanese diesel.
If the KAWASAKI option is discarded Australia might require 6 diesels of lower power output, of part-known submarine reliability, even if this increases the dimensions of the submarine.
Both MAN12PA4V200SMDS [1] at 1.33MW and MTU12V4000U83 [2] at 1.3MW appear to have the same performance. Whether they have been sufficiently tried and tested on submarines may still be an open question. Although the piston speed of the engine MAN diesel (at 9.1m/s) is lower than that of MTU (11.4m/s). Anonymous advises lower piston speed tends to reduce sound producing vibration.
Calculating 6 x MAN12PA4200SMDSs = 6 x 1.33 x 0.8 = 6.4MWe.
OR
6 x MTU12V4000U83s = 6 x 1.3 x 0.8 = 6.24MWe.
[1] MAN 12 PA4 V 200 SMDS: Bore 200 mm, Stroke 210 mm, Mechanical output 1.33MW at 1300 rpm (=Piston speed 9.1m/s) , Generator output 1.064MW
(see http://www.marine.man.eu/docs/default-source/shopwaredocuments/pa4-sm-smdsfba3ca1740b144429518d4e002fd7d6f.pdf?sfvrsn=3 )
[2] MTU 12V4000U83: Bore 170 mm, Stroke 190 mm, Mechanical output 1.3MW at 1800 rpm (=Piston speed 11.4m/s), Generator output 1.040MW
( see http://www.tognum.com/fileadmin/fm-dam/tognum/press/2011/MTU_Submarine_Charging_Unit_12V_4000.pdf )
[2] MTU 12V4000U83: Bore 170 mm, Stroke 190 mm, Mechanical output 1.3MW at 1800 rpm (=Piston speed 11.4m/s), Generator output 1.040MW
( see http://www.tognum.com/fileadmin/fm-dam/tognum/press/2011/MTU_Submarine_Charging_Unit_12V_4000.pdf )
Naval Group and the Australian Government might decide to publicise what they have chosen to solve these diesel-generator output issues in the next 3 or 4 years.
Anonymous and Pete