Retractable Azimuth Thruster

The Brunvoll Retractable Azimuth Thruster is lowered from the hull for positioning and manoeuvring and retracted when not in use, extending the vessel's operational weather window. Direct power transmission from a vertical top-mounted electric motor removes the need for special shafts, quick-release couplings and gearboxes between prime mover and thruster, improving total efficiency. Afloat service options are available.

Design

• Column-shaped unit installed vertically in the thruster compartment
• Lowered into operating position and retracted into the hull by hydraulically operated lifting equipment
• When retracted, mechanically locked by spring-loaded locking devices; the hull opening is closed by a flush-plate attached to the bottom of the propeller nozzle
• In operating position the unit is locked and pre-loaded by the hydraulic lifting/lowering actuators; azimuth movement is locked by mechanical brakes when not turning
• Stem housing moves through a combined sealing box and bearing housing mounted to the tank top/sea chest integration plate
• Delivered pre-assembled (azimuth arrangement, retracting arrangement and guiding column) on the tank top/sea chest integration plate for easy installation

Underwater unit

• Replaceable propeller blade bearing liners
• Propeller blades replaceable inside the nozzle
• Various propeller blade materials and designs
• Controllable pitch and fixed pitch propeller versions
• Advanced multiple sealing system for the propeller shaft
• Non-polluting sealing solutions for Environmentally Acceptable Lubricants (EAL); limited amounts of EAL required
• Design complies with US EPA Vessel General Permit (VGP)

Technical data

| Model | Propeller diameter (mm) | Power range (kW) |

|---|---|---|

| AR 63 | 1 650 | 500 – 880 |

| AR 74 | 2 100 | 800 – 1 650 |

| AR 80 | 2 100 | 1 000 – 1 500 |

| AR 84 | 2 300 | 1 200 – 2 140 |

| AR 100 | 2 600 | 1 800 – 2 500 |

| AR 105 | 2 900 | 1 200 – 3 040 |

| AR 115 | 2 900 | 2 500 – 3 500 |

Other sizes on request.

Options

• Electric motor starting options: direct on-line (DOL), star-delta (approx. 60% lower in-rush current than DOL), auto-transformer (typically 50–70% motor voltage at start), electronic soft starter, or frequency converter (6-pulse, 12/24-pulse or Active Front End); motor started with propeller in zero pitch position

Applications

Research vessels, coast guard vessels, offshore supply vessels and shuttle tankers, including operation in the North Atlantic; also used for auxiliary and emergency take-home propulsion.