Active Rudder Thrusters (ART)

Azimuth Thruster Engineering, Configurations & Applications

An azimuth thruster is a 360° steerable marine propulsion unit that rotates around its vertical axis to direct thrust in any direction. Unlike a conventional shaft-and-rudder arrangement, an azimuth thruster provides full thrust vectoring, which dramatically improves manoeuvrability, station keeping and bollard pull. MPSI supplies azimuth thruster systems built for continuous heavy-duty operation in harbours, terminals and offshore fields.

MPSI azimuth thrusters are available in Z-drive and L-drive configurations from 150 kW to 3,500 kW, with propeller diameters from 800 mm to 3,200 mm. Standard models such as the MPSI-ZT-2500 are engineered for 45–65 tonne bollard pull ASD and escort tugs, and every unit can be customised to a specific vessel's power, hull geometry and classification requirements.

Each azimuth thruster is manufactured with Klingelnberg bevel gears, a high hydrodynamic thrust nozzle, an integrated lubrication and cooling system, and factory quality assurance before delivery. MPSI supports the full lifecycle — technical selection, well integration, sea trials and spare parts — for tugboats, ferries, workboats and offshore vessels throughout Indonesia and Asia Pacific.

Azimuth thrusters are most commonly specified for ASD (Azimuth Stern Drive) tugs, escort tugs, harbour tugs, passenger and Ro-Ro ferries, offshore supply vessels, dredgers and special-purpose vessels that require precise dynamic positioning. Where a conventional propeller and rudder cannot deliver enough transverse thrust, an azimuth thruster provides the vectored control needed for safe berthing and station keeping.

Bow & Tunnel Thruster Systems: Engineering & Harbour Maneuvering

Bow and tunnel thrusters provide lateral transverse thrust to maneuver vessels safely at low speeds in congested ports, canals, and tight berths. By providing instant transverse control, tunnel thrusters eliminate the need for costly tugboat assistance during routine berthing and unberthing maneuvers.

MPSI engineers electric, diesel, and hydraulic-driven bow tunnel thrusters with power outputs ranging from 50 kW to 2,200 kW, available in Fixed Pitch Propeller (FPP) or Controllable Pitch Propeller (CPP) configurations. Propeller diameters span from 500 mm to 2,800 mm, tailored for minimal acoustic underwater noise and optimal thrust coefficient.

Each bow thruster unit is engineered with high-strength helical bevel gears, anti-cavitation duct contours, resilient mounting isolating vibrations from the vessel accommodation, and full IACS classification compliance (ABS, BV, DNV, CCS, BKI).

Contra-Rotating Propulsion (CRP): Hydrodynamic Fuel Savings & Power

Contra-rotating propulsion (CRP) systems employ two coaxial propellers rotating in opposite directions. The aft propeller recovers rotational energy lost in the propeller slipstream slip from the forward propeller, converting rotational swirl into productive forward axial thrust.

This counter-rotation principle yields between 10% and 15% net hydrodynamic fuel efficiency improvements compared to conventional single-screw arrangements, dramatically lowering operational fuel expenditure (OPEX) and reducing greenhouse emissions.

MPSI supplies contra-rotating propulsion packages from 300 kW to 4,000 kW for passenger ferries, fast utility craft, and coastal supply vessels demanding extended operating ranges and reduced propeller-induced hull vibration.

Custom Fixed Pitch Propellers (FPP): CFD-Optimized Ni-Al-Bronze

Fixed Pitch Propellers (FPP) remain the most dependable, low-maintenance propulsion solution for commercial shipping. MPSI designs and manufactures custom fixed pitch propellers cast from premium Nickel-Aluminium-Bronze (Cu3), delivering superior tensile strength and outstanding resistance to marine seawater cavitation erosion.

Every propeller blade profile is computationally optimized using advanced Computational Fluid Dynamics (CFD) analysis to maximize open-water thrust efficiency, delay cavitation inception, and minimize hull pressure pulses.

Diameters range from 600 mm up to 5,000 mm for diesel engine outputs from 100 kW to 5,000 kW, with ISO 484 Class I and Class S machining tolerances certified under ABS, BV, DNV, and BKI survey.

Deck-Mounted Thruster Units: Self-Contained Barge & Pontoon Propulsion

Deck-mounted thruster units provide a completely self-contained diesel-driven propulsion package for non-propelled barges, pontoons, dredgers, and shallow-water construction vessels without requiring inboard engine room space or below-deck shafting.

Each deck unit integrates a diesel engine, 360-degree steerable Z-drive azimuth thruster, hydraulic elevation tilting mechanism, and local/remote operator controls on a single rigid skid base.

The hydraulic tilt-up feature allows the thruster lower leg to be rotated up out of the water for blade inspection, rope removal, or seal maintenance directly from the deck without needing dry dock or crane vessel assistance.

Rudder Propeller Engineering, Steering Response & Maneuverability

Rudder propellers combine propulsion thrust and directional steering in a single compact mechanical package, eliminating the requirement for conventional separate rudder blades, steering gears, and lengthy shaft lines. By rotating the steerable nozzle propeller around 360 degrees or through optimized steering angles, the unit provides instant, powerful vectored thrust for agile maneuvering in congested waterways and challenging marine environments.

MPSI rudder propeller units are engineered across a power band of 200 kW to 2,000 kW with propeller diameters from 800 mm to 2,500 mm. Built with high-grade alloy bevel gears, precision hydraulic or electric steering drives, and heavy-duty thrust bearings, they provide continuous heavy-duty reliability for harbour tugs, inland cargo vessels, and utility craft.

Each rudder propeller system is manufactured under stringent IACS quality standards, featuring integrated lubrication circulation, hydrodynamic high-efficiency nozzles, and robust sealing systems engineered to withstand silt and shallow-water debris commonly encountered in river and littoral shipping.

Specialized Thruster Systems: Retractable & Dynamic Positioning Engineering

Specialized marine operations demand tailored propulsion and station-keeping solutions beyond conventional fixed drives. MPSI designs and manufactures specialized thruster systems including vertically retractable azimuth thrusters, dynamic positioning (DP-1 and DP-2) auxiliary units, and custom maneuvering packages engineered to tight naval architectural constraints.

Retractable thruster systems provide auxiliary propulsion and precise station keeping during offshore operations, underwater surveying, diving support, and cable laying. When cruising at speed or operating in shallow waters, the thruster leg retracts fully into a dedicated hull well, eliminating hydrodynamic drag and protecting the propulsion unit.

Covering power envelopes from 150 kW to 3,000 kW with propeller diameters from 700 mm to 3,000 mm, MPSI specialized thrusters feature fast-acting hydraulic retraction mechanisms, multi-layer watertight well seals, fail-safe mechanical locking, and seamless integration with leading marine DP control systems.