Page 39 - NAVAL FORCES 03/2017

Protection & Mobility

Malcom Phillips
Features
All Electric Ships

An overview why all-electric combat- specifications and a lack of thoroughness and to operate in their most efficient regimes for
ants are more challenging as they de- independence in testing, according to reports more of the time; potential elimination of long
mand higher power densities, greater presented to lawmakers in the UK and the US. shaft lines and their vulnerable penetrations
shock resistance, and higher levels of This should provide valuable lessons for future though watertight compartments; a significant
projects and for the growing number of navies
reduction in the maintenance burden; the abil-
redundancy than other vessels. now looking to develop all-electric warships, ity to distribute generation capacity around the
including the Chinese and Indian services. ship, making it less susceptible to battle dam-
Well-publicised troubles with the Royal Na- Having said that, mostly electric surface age and quicker to restore fighting ability; and
vy’s Type 45 destroyers – though the ships have vessels are already in service with several to provide the juice needed by increasingly
been behaving better following modifications leading navies, but they are large combat sup- powerful radars and emerging directed energy
– remain something of a fly in the ointment for port and combat service support vessels rather weapons.
advocates of all-electric combatants, which is than combatants, and they mostly use electri-
unfortunate because the most significant prob- cal plant derived from commercial shipping. Type 45 Woes
lems have stemmed from prime movers and Electric power is attractive for a number
associated systems, not from the high-tech of reasons including the elimination of large, Before navies commit to what amounts to
electrics. costly and heavy reduction gearboxes; the a revolution in warship propulsion and energy
These problems and difficulties with the ability to decouple engine rotational speeds generation, they will want to be confident that
power systems for the US Navy’s DDG 1000 from propeller shaft speeds that allows pro- it will work safely and reliably. Therefore, it
“Zumwalt” destroyers stem from inadequate pellers, prime movers and auxiliary generators is worth examining what has gone wrong with
the Type 45 and what is being done about it.
The ship’s main engines are a pair of 21MW
Rolls-Royce WR-21 gas turbines, each driving
a two-pole cylindrical rotor generator at up to
3,600rpm. The WR-21s are supplemented by
two Wärtsilä 12V200 diesel generator sets
rated at 2MW each.

Royal Navy Type 45 Malcom Phillips,
destroyer is a regular contributor to NAVAL FORCES with
HMS “Defender.” 25 years of experience as a journalist and writer
(All photos covering aerospace and defence techno logy and
via author) operations.

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