Home' Asia Pacific Defence Reporter : APDR July-August 2015 Contents Asia Pacific Defence Reporter JULY-AUG 2015 43
transit at 8-10 knots.
This is OK when in transit between their Australian
base and possibly 200 nautical miles from their
potential adversary’s location, but in future the
submarine will need to remain deep underwater,
possibly for as long as 20 days, to avoid detection
while carrying out its mission.
According to Graeme Dunk in his ASPI ‘The
Strategist’ blog, “Developments in submarine detection
through deployment of much more sensitive towed
arrays, including large virtual arrays formed by several
warships, and the move to bi-static low frequency
sonar, will dramatically increase sonar array sensitivity
and submarine detection ranges. This will serve to
inhibit a submarine aiming to engage a surface task
group, and either push torpedo engagement ranges
further out or force a reversion to long range anti-
ship missile engagements. Either way, the submarine
engagement dynamic will have changed.”
This is where technologies not available when
the Collins Class were built come in. They offer
the possibility of increasing underwater endurance
by a factor of up to three or four, which reduces
the indiscretion ratio very significantly. However
underwater endurance can be limited by crew
capability considerations as well as fuel and supplies.
Vastly improved submarine detection methods mean
that future submarines will have to be much more silent
when moving, and even when still, deep underwater.
Coming to periscope depth while near an adversary’s
location to recharge batteries by on board diesel
generators which must suck in air and evacuate
exhaust gases, as well as transmit engine noise
underwater, could have fatal consequences.
APDR considers there are three main technologies
virtually certain to form key components to ensure
much less acoustic noise and greater underwater
endurance for Australia’s future submarines.
The first of these is the evolving technology of lithium
ion batteries, now prevalent in virtually every battery
driven consumer device like mobile phones, electrical
tools and golf carts. Considerable R&D is going on at
present to scale-up configurations of them to replace
lead acid accumulators in submarines.
Secondly, underwater electricity generation is now
an established technology using three main methods.
Presently the Japanese use the Kawasaki Kockums
Stirling engine, DCNS use the MESMA system and
TKMS the HDW/Siemens fuel cell configuration.
Thirdly, permanent magnet synchronous motors
offer greatly increased performance for the same
power input, when compared with classic direct
APDR has observed that the usual blanket of
silence has been imposed by Defence during the
CEP on the three contenders. This is how a DCNS
spokesperson explained it “DCNS are committed to
working closely with the Commonwealth of Australia
to provide the most capable conventional submarine
available. At this point it would be a breach of trust
with the Commonwealth to openly discuss the details
of any system they may or may not be considered for
the Future Submarine.” Exactly.
The information in this article is based on
existing revealed submarine design and technology
information for the DCNS Scorpene and Barracuda;
HDW Types 212A, 214 and 214IP; and Japanese
Soryu. It is quite possible that the three contenders
will be discussing more advanced technologies with
Defence during the CEP.
LITHIUM ION BATTERIES
As yet, no operational submarine has been
commissioned with rechargeable lithium ion batteries
(LiB) in place of conventional lead acid accumulators.
Despite the great promise of increased energy density
and the smaller form factor, so more can be fitted
into the same space occupied by classic lead acid
accumulators, submarine developers are proceeding
APDR met and discussed LiB developments
with R&D personnel at HDW in Kiel. They have
been involved in careful design and testing as they
scale up from small numbers of cells to large scale
assemblies. APDR had the opportunity to observe
some of this testing and discovered the precautions
being taken when recharging against overcharge
which can cause thermal runaway, resulting in cell
rupture and the possibility of a fire or explosion.
Effective control systems and the LiB’s chosen
chemistry remove this risk.
Handheld electronics like mobile phones mostly use
LiBs based on lithium cobalt oxide which offers high
energy density, but presents safety risks, especially
when damaged. Electric power tools typically use
lithium iron phosphate, lithium manganese oxide and
lithium nickel manganese cobalt oxide which offer
lower energy density, but longer lives and inherent
Currently most conventional diesel electric submarines like the Collins
Class travel relatively slowly underwater but still have to recharge lead
acid accumulators every few days, by coming up to periscope depth so
that their snorkel can take in air for the diesel generators.
Exercise Bersama Shield 2015 (front to rear) Royal Malaysian Navy ship KD Ganyang
(3504), Royal Australian Navy submarine HMAS Rankin, and Royal Singapore Navy ship
RSS Stalwart (72) in company during Exercise Bersama Shield 2015 (BS15). Credit: CoA
2/07/2015 3:33 pm
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