motors will improve the energy efficiency
of practically any application.
OPERATIONAL ASPECTS
A ship’s hull form and machinery system
design set certain limits and a basis for the
energy efficiency of the ship. The actual
operation of the ship demonstrates the
success of the design. The optimal use
of ship systems requires a man-machine
interface that ensures correct and efficient
use of a ship’s systems. Operating instructions, training and the skill of the crew
are all important factors when guiding
operators in the use of the ship’s systems
in the most efficient way. For example, the
smooth operation of the propulsion power
control levers reduces stress on the power
plant and propulsion power train and also
reduces fuel consumption.
Modern ships sail with the assistance
of an autopilot for the majority of sailing
time on the open sea. Autopilots have
been used for years and the basis for their
design has been to control conventional
rudder ships. Podded propulsion systems
add another aspect to autopilot operations.
Pods and rudders have different steering
characteristics and steering forces as a
function of steering angle, as the theoretical calculation presented in Fig.1 shows.
This difference is not typically considered
when designing the autopilot operation
and algorythms and leads to non-optimal
performance. Podded propulsion units
provide less steering force at small steering
angles compared to conventional rudders.
The use of adaptive autopilots, which are
properly tuned for podded propulsion, has
been shown to reduce steering actions and
stabilize vessel behavior. Avoiding unnecessary steering actions not only saves fuel
but also reduces onboard vibrations and
wear on the steering system.
Optimizing the propulsion system
for fuel efficiency requires a thorough understanding of the interdependencies between systems and cooperation between
the shipowner, shipyard and equipment
suppliers.Our target is to collaborate with
our customers to find new solutions to
design and operate electrical systems in
the most energy efficient way. ■
Azipod® is a registered trademark of ABB Oy.
seatec 2007
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