Wärtsilä Retractable Thrusters

Wärtsilä Retractable Thrusters are available up to 6500 kW. The upper part of the range is covered by the WST-65RU retractable underwater mountable thruster, a thruster of which the outboard part can be exchanged under water to optimize maintenance when docking of the vessel is not possible. Wärtsilä Modular Thrusters (LMT) with a modular and flexible design are the basis for the retractable thrusters up to 4500 kW.

    • Wärtsilä retractable thrusters provide additional thrust capacity for station keeping or use with dynamic positioning (DP) systems. They are applied on a wide range of vessels, including offshore support vessels, offshore construction vessels, and special vessels such as heavy lift vessels.
    • Using a hydraulic retraction system, the thruster can be fully retracted to lower the vessel resistance during transit to or from the operation area. Retraction of the thruster also enables sailing in shallow waters.
    • Wärtsilä retractable thrusters have a vertical retraction system to minimize space requirement in the vessel. Both L-drive and Z-drive options are available to match vessel types having different inboard height availability.

    Example configurations

    Anchor Handling Tug Supply vessel (AHTS)


    ·         1800 kW retractable (bow)

    ·         CP propeller

    ·         Diesel-Electric

    ·         L-drive

    Retractable thruster application 1


    Pipe laying vessel


    ·         5 x 2400 kW retractable

    ·         FP propeller

    ·         Diesel-Electric

    ·         Z-drive

      Wärtsilä retractable thruster application 2
    Key Benefits
    • Fast retraction and deployment
    • Fully retracted during transit; optional hull closing plate
    • High thrust performance
      • 3° tilted Wärtsilä HR Nozzle (LMT type)
      • WTN type nozzle in combination with 8° tilted propeller shaft (WST-RU type)
      • L- and Z-drive options enable integration in a wide range of vessel types and sizes
      • Outboard part exchangeable under water for maintenance or overhaul (WST-65RU)
    Technical Info
    Retractable thruster
    The propellers are designed for bollard pull condition at 100% MCR power level and valid for uni-directional Dynamic Positioning (DP) application. Final selection depends on the chosen classification society. Selections are not valid for classification with iceclass.
    Wärtsilä Retractable thruster range
    Retractable thruster technical info 5

    The Wärtsilä Retractable Underwater Mountable Thruster (WST-RU) has been designed to meet the needs of large offshore vessels (OCVs) as well as semi-submersible rigs and drill ships.

    With the power output of 5500kW it is typically designed for vessels that require thrusters that can be retracted during transit or while entering shallow waters. The thrusters can be mounted or de-mounted while the vessel is afloat. Additionally, the ability to retract and deploy the thruster enables an increased level of operational flexibility.

    The thrusters feature a unique combination of retractable and underwater mountable functionality. The reliability of the thrusters is the result of robust drive line components, including the gears and bearing and the steering system. The thrusters are equipped with Wärtsilä Oceanguard anti-pollution face type seams, primarily due to their extended operating life in the challenging environments where these thrusters will operate and VGP 2013 compliance.

    The eight degree tilted propeller shaft solution is a feature of the Wärtsilä Underwater Mountable Thruster that reduces the interaction between the thrusters and hull significantly, thereby enhancing the dynamic positioning performance of the vessel.

    In combination with Wärtsilä PCMS (Propulsion Condition Monitoring Service) downtime and maintenance costs can be minimized.

    Key benefits:

    • Optimised thrust enabling effective DP operations
    • Retractable
    • Thruster outboard part can be exchanged without dry docking the vessel
    • Use of patented telescopic shaft technology allows the E-motor to remain static
    • Integrated solution provides smallest possible area footprint and overall lighter construction
    • Based on proved recognizable technology and in-house propeller design know-how
    WST-65 RU_1
    WST-65 RU_2

    Related references


    Please fill in the form if you have an enquiry related to THRUSTERS. Fields indicated with an asterisk (*) are required.

    Find your local Wärtsilä office