Wärtsilä electric pod & thruster seals

Eliminate abrasives and aggressive shaft movements

Wärtsilä electric pod & thruster seals

The Wärtsilä Airguard and Sternguard seal ranges are suitable options for electric pod and thruster seal applications. The operating environment will influence the choice of sealing solution. These include abrasives, shaft movements and serviceability requirements.

    Wärtsilä Sternguard OLS3 and OLS4
    The Wärtsilä Sternguard is an oil lubricated outboard lip type sealing solution available from shaft sizes ø80to ø1172 mm and can be supplied either partially split or fully split.

    Optional extras include: In water survey wear down gauge, net protection ring, spacer ring, zinc anodes, tungsten carbide coating for the liner, adaptable interfacing and inner rope guard for added protection.
    OLS3ASternguard mk2_661x661
    Sternguard OLS4 with UNNET
    Wärtsilä Airguard seal
    The Wärtsilä Airguard seal is an oil lubricated outboard lip type sealing solution. The seal works with compressed air, which is applied to the void space between the seal rings to reduce the stress and wear. 

    The aft stern tube seal is a multi-barrier lip type seal which contains four seal rings running on a seal liner, to prevent grooving of the shaft. The two seal rings face the stern tube towards the oil, providing an active double security against oil spills. The other two seal rings face towards the seawater to effectively seal against seawater and sediments. 

    The pressurised air in the central void space is dynamically controlled and monitored, based on the variations of the seawater pressure, which keeps the Wärtsilä Airguard system continuously pressured balanced. This results in less pressure and load on the four seal rings, and minimal wear on the liner. The sealing system also is equipped with an air control unit, drain collection unit, oil tank and pump.


    •  Continuously pressure balanced
    •  Four lip seal arrangement running on chromium steel liner.
    •  Continuous air flow. 
    •  Air barrier between oil and seawater.
    •  Additional standby sealing ring.
    •  UNNET fishing line and net protector included as standard.
    •  Balanced, closed oil lubrication and air supply system.
    •  Double spacer option.
    Wärtsilä Electric Pod & Thruster Seals - OLS3A, OLS4A-P

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