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About SKF Marine

Innovative thinking and expertise

The Simplex brand is part of the SKF Marine product portfolio. SKF Marine has been in the marine industry for more than 70 years, applying innovative thinking and expertise to critical machinery. SKF Marine products and services apply to many areas of a ship, making us a valued system and services engineering partner for designers, builders, operators and system suppliers.

SKF Marine is a specialized provider of products and mechanical services for propulsion shafts and sterntubes. The Simplex shaft components, including sterntube seals, intermediate shaft bearings, thrust bearings as well as complete sterntube solutions and accessories, have set the standard in the market for years.

In addition to shaft components SKF Marine develops, produces and sells stabilizers, couplings, lubrication systems, condition monitoring and condition-based maintenance solutions, bilge water separators, environmental monitoring systems as well as special services.

To find out more about our complete product portfolio, please visit skf-marine.com.

Find more about SKF here.

  • 1948

    Simplex sterntube seal. The world’s first lip seal for oil-lubricated sterntubes

    Still in use today and replacement parts still available

    Simplex white metal sterntube bearing for oil-lubricated sterntubes. Simplex pedestal bearing: plummerblock and tunnel bearing

  • 1953

    Simplex thrust bearing

  • 1960

    Production of retractable fin stabilizers under license

  • 1970

    Simplex rudder stock seal

    Simplex SC-1 seal for oil lubricated sterntubes

  • 1974

    Simplex high load thrust bearing

  • 1984

    Simplex white metal sterntube bearing with active hydrostatics

  • 1985

    Simplex SC-1 seal for water lubricated sterntubes

  • 1992

    Simplex SC-2 seal, new generation of SC-1 seal

  • 1993

    Simplex Airspace non-pollution seal

  • 1998

    Simplan mechanical face seal for water lubricated sterntubes

  • 2001

    Launch of new sealing ring material VitonPOD for all Simplex seal types to facilitate use with sensitive oils, such as hydraulic oil, and biodegradable oils (EALs)

  • 2002

    Simplex FlexiTube complete sterntube solution

  • 2013

    Simplex SC-3 seal, new generation of SC-2 seal

    Simplex SternTube complete sterntube solution

  • 2015

    Simplex Net protector

  • September 2016

    New design intermediate shaft bearing

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Product List

Shaft Components & Services

  • Oil lubricated sterntube seals
  • Combined lubricated sterntube seals
  • Water lubricated sterntube seals
  • Sterntube seal accessoires
  • Net protection
  • Intermediate shaft bearings
  • Thrust bearing
  • Sterntube bush
  • Sterntube solutions
  • Bulkhead seals
  • Rudder stock seals
  • Services

Oil-lubricated sterntube seals

Simplex oil-lubricated sterntube seals are designed for oil-lubricated propeller shaft bearings and have two key purposes – firstly to prevent the leakage of oil into the engine room or water, and secondly to keep water out of the sterntube. These seals comply with industry classification requirements and are type-approved by all major classification societies. As such, they are designed to last for years to come and withstand the following conditions:

High water pressures and high circumferential speeds
Radial and axial shaft displacements
Operating times of 6,000 hours and more per year

Combined lubricated sterntube seals

Simplex combined lubricated sterntube seals are designed for shaft bearings that need to withstand the harshest of conditions. These oil/grease lubricated seals are designed to protect the bearings against sediments and marine growth. They comply with industry classification requirements and are type-approved by all major classification societies.

Water-lubricated sterntube seals

Simplex water-lubricated sterntube seals are designed for open-ended, water-lubricated sterntubes. Under the influence of increasingly strict environmental requirements, this type of lubrication is becoming more and more popular. Water lubrication is by far the most environmentally friendly solution for lubricating propeller shaft bearings and is thus compliant with current legislation such as the VGP 2013 (Vessel General Permit) regulations. The modular design of the water-lubricated sealing system allows servicing work to be carried out very quickly and safely.

Sterntube seal accessories

The requirements for the operation of a ship determine the individual design of our Simplex shaft components. In addition to maximum reliability, safety and efficiency on-board, SKF Marine offers an extensive program of Simplex supporting units for condition monitoring, oil supply, cooling and operation.

In combination with the proven products from SKF Marine, our customers receive complete solutions from a single source for everything related to the shaft assembly.

Net protection

A potential risk posed by fishing nets or lines floating on the surface of the sea is that they can be drawn in by the propeller and become entangled – they can then find their way into the seal and damage the sealing rings.

If a sterntube seal becomes damaged and oil enters the seawater as a result, the ship will not be allowed to continue its journey and must be docked for immediate repair. High docking costs and potential contractual penalties through noncompliance with delivery deadlines can have serious consequences.

Intermediate shaft bearings

The operational efficiency of a machine or plant is determined above all by the quality of the bearings used in all rotating applications. This applies in particular to the line-shafting of ship propulsion plants. The Simplex bearings were developed especially for this purpose as short, plain bearings.

Simplex high-load thrust bearings

The Simplex high-load thrust bearings (HL) are single-collar bearings for absorbing the thrust loads produced by the ship's propeller.
 Other applications, such as with turbines, air blowers, cutter suction dredgers and centrifugal pumps, are also possible. If required, the bearing's internal parts can also be fitted into gearboxes or, by using flange-type casings, onto engines and motors. Of course, the Simplex HL thrust bearings are manufactured in accordance with the rules of all international classification societies.

Simplex sterntube bushes

The Simplex sterntube bushes have been proven over decades of shipboard operation. 

While merchant shipping generally benefits from the standard design of Simplex sterntube bushes - cast-iron/lead-based white metal (GG-20) - the bushes intended for ships subjected to higher stresses, such as icebreakers, are made of nodular cast-iron/tin-based white metal (GGG-40). The intercrystalline bonding of the materials provides the highest possible quality and durability. The length of a bush is determined by the rules of the respective classification society.

Available in different material combinations of bushes and white metal lining
Bushes available up to 2,800 mm in length and with outside diameter of 1,200 mm

Simplex sterntube solutions

The Simplex FlexiTube and SternTube provide customers with precision technology in a complete package solution, including sterntube bushes, patented sealing packages and installation supervision.

For designing a customized sterntube solution, SKF Marine only needs to know the type of hull, the sterntube length and the diameter of the propeller shaft. Thanks to an intelligent module design we are able to deliver customized stern tubes for vessels of all types and sizes.

Bulkhead seals

Where bulkhead openings for shafts need to be sealed to protect adjoining spaces against flooding, Simplex bulkhead seals offer the optimum solution. Our list of references includes sealing solutions for chemical and product tankers as well as for gas tankers and offshore vessels. Our special gas-tight bulkhead seals are also available for explosion hazard areas. The latest generation of Simplex bulkhead seals operates well under the highest shaft speeds and is especially designed for offshore supply vessels with long shafts and multiple bulkhead openings.

Simplex rudder stock seals

Simplex rudder stock seals exclusively seal oscillating rudder stock shafts against oil or water.

For straightforward locations we manufacture easy-to-fit packing glands consisting of split-ring elements. For more awkward locations, for example in the region of the waterline, we offer our Simplex rudder stock seal which matches the Simplex sterntube seal in terms of its design and size availability.

We offer standardized types of rudder stock seals which can be supplied with grease or oil lubrication depending on the customer’s specification. As for all our seals, we also offer customized versions of the rudderstock seal.

Simplex services

We provide support for your ship throughout its life cycle – taking care of it every step of the way with professional planning, regular dockings, emergency servicing and quality spare parts. Our comprehensive service for Simplex shaft components, e.g. sterntube seals, bushes, tunnel bearings and plummer blocks, ensures that your vessel is optimally equipped, maintained and always ready for operation – worldwide and 24/7.

Worldwide service network for maritime customers
Available 24 hours a day, 365 days a year
Direct contact by service email: service@skf-marine.com
Qualified SKF service stations with trained and certified experts
Highly professional staff for efficient service and customer support

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