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Simplex stern tube and marine shaft seal services, shaft couplings, bearings and spare parts

Simplex Engineering provide a highly qualified team available for stern tube seal and shaft seal services worldwide. We are also suppliers of marine spare parts ranging from stern tube, thrust and shaft bearings, to shaft coupling and Simplex rudder stock & bulkhead seals.

Simplex seal services (all brands)

Our team of highly qualified service engineers have many years of experience working on sterntube seals. They are available to work wherever required, world-wide and provide the reassurance that this critical underwater component will be serviced and reinstalled in accordance with the strict tolerances required. If your vessel is unfortunate enough to have a leakage, our engineers are expert in fault finding and are there to advise on how best to rectify the problem.

On request and depending on the conditions in the shipyard, our service engineers can refurbish your sterntube oil so that it can be used again.
Simplex seal services (all brands)
Simplex seal services (all brands)

Simplex Seal Service

Simplex seal services (all brands)

Simplex Seal Service

Simplex sterntube seals

For more than 70 years, the Simplex sterntube seal has led the way in protecting your vessel from water ingress as well as leakages. It still provides the most reliable and cost effective sealing solution for shaft diameters from 80 mm to more than 1 metre irrespective of whether your vessel has a water or an oil lubricated sterntube system. The patented design of the SC3 sealing rings minimises friction, retains lubricity and keeps contaminants out of the system. Special net protection rings and dirt rings are also available.

The Airspace seal is an ideal way to comply with the VGP regulations. It is recognised as a zero leakage seal by the authorities. It allows the use of standard mineral oils. It has the lowest air consumption. It provides the best protection for the sterntube bearings and has a fail-safe switch-over from Airspace operating status to standard seal operation for a guaranteed safe continuation of the journey without any requirement for an emergency stop.

The range includes both lip type and face type seals or a combination of the two according to the application. Special seal designs are available for dredgers, icebreakers, FPSOs, tidal turbines, surface warships and submarines.

There is a well established network of service stations around the world supported by large stocks of parts to ensure a quick and effective response to all your requirements.
Simplex sterntube seals
Simplex sterntube seals

Simplex Sterntube Seals

Simplex sterntube seals

Simplex Sterntube Seals

Shaft couplings

The OK coupling has gained worldwide approval with more than 50,000 units being installed. It is very simple to install and dismantle using hydraulic pressure to achieve an interference fit, whereby two shafts can be joined, and high levels of torque and axial loads can be transferred without the requirement for keyways or taper / thrust rings, and without creating stress points or fretting in operation.  

To install the OK coupling, slide the thin inner sleeve onto the shaft.  This inner sleeve has a tapered outer diameter.  A thick outer sleeve with matching tapered inner surface is fitted onto the inner sleeve. Ordinary mineral oil is injected between the sleeves and a built-in jack drives the outer sleeve up the taper of the inner sleeve.  Once the outer sleeve reaches its final position, an interference fit is created by releasing the hydraulic pressure. Later the coupling can be easily removed by reversing the process.   

The range consists of:

the OKC joins two cylindrical shafts  

the OKF joins a cylindrical shaft to a shaft with a flange

the OKCX has a special carbide friction coating, which allows a 50% greater torque capacity or a smaller, lighter unit. It joins two cylindrical shafts

the OKFX has a special carbide friction coating, which allows a 50% greater torque capacity or a smaller, lighter unit. It joins a cylindrical shaft to a shaft with a flange

The range caters for shaft diameters from 45 mm to 1,000 mm and forces up to 23,630 kNm.  Tailor-made solutions are available as a “supergrip” bolts for rotating flanges.

  • Shaft Couplings

    Shaft couplings

    Shaft Couplings

  • Shaft Couplings

    Shaft couplings

    Shaft Couplings

Net protectors and dirt rings

Tough marine environments can play havoc on an aft seal’s effectiveness – dirt, fishing lines, and nets can all be responsible for mounting maintenance costs. SIMPLEX net protection solutions include three options, used individually or in combination, for protecting the aft seal from damage caused by fishing nets or lines.

  • Simplex net protector ring is a dirt, net and rope protection ring that is fully split and is positioned in front of the first sealing ring
  • Simplex net cutter has stainless steel blades fixed onto the rope guard or propeller
  • Simplex net pick-up is a fully split ring mounted just inside the rope guard to collect any net, line or rope before it reaches the aft seal

Net Protectors and Dirt Rings

Net protectors and dirt rings

Net Protectors and Dirt Rings

Other seals & bearings

Bulkhead seals

We have a special range of seals where there is a risk of flooding through bulkhead openings. These are fitted on a wide range of vessels, such as chemical and product tankers, gas tankers, offshore vessels, naval vessels etc. These can be used in gas-tight applications, as well as in explosion hazard areas.

Rudder stock seals

For simple applications we supply an easy to fit packing gland, but where the seal has to be located near to the waterline, we recommend the Simplex rudder stock seal, which is very similar to the sterntube seal and can be supplied with grease or oil lubrication.

Sterntube bearings

We supply white metal bearings, with backing material made in either GG-20 or GGG-40, for ships which are subject to higher stresses, such as icebeakers. The maximum length is 2,800 mm and the maximum diameter is 1,200 mm. The oil groove can be straight or helical for twin screw vessels.

We also supply the Simplex BlueRun polymer sterntube bearing for water lubricated applications, irrespective of whether they are closed or open systems. A split version is available for those where there is no need to pull the shaft in order to replace the bearing. The maximum shaft diameter is 500 mm.

Complete sterntubes

We supply sterntubes, complete with white metal bearings, with full piping ready to install. The forward mounting point of the sterntube has a sliding fit in order to compensate for any temperature differential between the water and the sterntube in order to avoid the risk of the ship’s hull suffering stress cracking. Alignment of the sterntube is made much easier by the use of epoxy resin, together with the patented sealing package for the resin.

Intermediate shaft bearings

The Simplex intermediate shaft bearings have been specifically designed for propulsion shaft applications with a short length, so they can be precisely aligned without risk of edge loading. The bearings are self-lubricating and the oil pocket design ensures optimised oil distribution, even at slow rotational speeds. The advanced white metal bearing material provides optimal performance, including emergency running.

The bearings are available as pedestal bearings or saddle bearings with sizes up to over one metre.

Sealed bearings are available to ensure continued operation, even if the shaft is flooded.

Thrust bearings

The Simplex high load thrust bearings are single collar bearings for absorbing the thrust loads produced by both controllable and fixed pitch propellers. The bearings come with a remote temperature sensor junction box, so the bearing can be connected to the ship’s central alarm system. If required, the bearing can be installed according to the “safe return to port” regulations.

The thrust pads are of a self-aligning type, and during installation an adjustment screw can be used for precise positioning and alignment.

The housing design offers maximum stiffness and ensures the proper load distribution directly from the thrust collar into the foundation.

The thrust bearings are very robust and reliable and almost maintenance free.

  • Bulkhead seals

    Other seals & bearings

    Bulkhead seals

  • Rudder stock seals

    Other seals & bearings

    Rudder stock seals

  • Sterntube bearings

    Other seals & bearings

    Sterntube bearings

  • Complete sterntubes

    Other seals & bearings

    Complete sterntubes

  • Intermediate shaft bearings

    Other seals & bearings

    Intermediate shaft bearings

  • Thrust bearings

    Other seals & bearings

    Thrust bearings

More solutions

Dorota Wiśniewska
Sales & Service Representative

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