AZIPOD
BY
SUDEEP SASI
S7 MA
ROLL NO 56
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Introduction – History & Development
An Azipod or podded propulsor to give it its technical name is a propulsion or manoeuvring device that is external to the ship’s hull and houses a propeller powering capability. This definition differentiates them from azimuthing thrusters which have their powering machinery within the hull and usually drive the propellerthrough a system of shafts and gearing.
TYPICAL AZIMUTHING PROPULSOR POD
POD INTERNALS
ARRANGEMENT – POD HOUSING
Slewing ring for a 7.5MW azipod
Electrical Propulsion
PROPULSION SYSTEM DESIGN
INTEGRATED ELECTRICAL POD PROPULSION
DESIGN FLEXIBILITY
Design Benefits
• Smaller casing
• Added cargo volume
• Smaller vessel
• Low weight
• One-lift installation of Azipod
QUEEN MARY II – FITTING OF PODS
Different Makes of Pods
High demand of station-keeping & DP operation
ICE BREAKERS
Significant and rapid load variation – almost
shock loading
High dynamic performance required –tripping
undesirable
High torque at low speed
Typical propulsion power 5 – 55 MW
depending on ice-breaking capability
High manoeuvrability
ICE BREAKERS
Constructional Benefits
Simplified steel structure
No aligning of shafts and bearings
One-lift installation of the Azipod unit
Building time in dry-dock is reduced
Hydrodynamics
Excellent wake field leads to: Improved hydrodynamic efficiency (an 8%improvement was recorded on Elation)
Less cavitation
Reduced propeller induced vibrations
Reduced noise levels
Disadvantages of azipods
High initial capital cost
Substantial cost of repairs
Vessel crew training for new equipment
Technology still needs to be made reliable and more predictable
New ports may include new problems.
The Future?
Continued development of Azipods and other similar systems
More power, greater efficiency, improving reliability, better
hydrodynamics, etc
ABB’s CRP Azipod concept utilises a conventional shafted
propeller with an azipod immediately aft of it
Combines different power sources so if one fails then the
other still provides propulsion
Expected to be more economical for large vessels e.g new
generation large Container ships
CRP
Generally successful propulsion and manoeuvring system
Particularly popular with cruise ship operators
Expect increasing use of azipods on numbers and types of
future vessels
Susceptible to contact damage due to external position
Susceptible to some bearing, electrical and seal problems
Continuing development should reduce early problems
Expensive to repair – specialist repairs by manufacturers
Any failures - very expensive in cancelled cruises
REFERENCES
abb.com
marinelog.com
hightechnologyfinland.com