Frequently asked questions

What's in the service package?

Everything that is required to change the seals including the precise alignment of the liner.

Can the job be done afloat?

If the ship can be ballasted by the bow so that the shaft is out of the water then the seals can be bonded provided there is no other damage.

How long will the job take?

Three days for a standard forward and aft seal on the one shaft, provided that other dry dock work does not interrupt our work. CPP installations and split liners will take longer.

Can we replace the sealing rings without pulling the shaft?

Yes, by cutting the sealing rings, then vulcanising the rings with the aid of a bonding kit, and special two component adhesive.

Where do our service engineers go?

Worldwide

What am I likely to need to do at the next docking?

Contact Simplex. We will check our service reports and advise what spares are required. For instance, a distance ring may be required, or the liner may need to be machined or a new liner needed.

Why are my seals leaking?

All seals require a small migration of liquid particles under the sealing ring in order to ensure that the ring is lubricated and cooled. Any water is accumulated in the Number Two chamber and transfered back to the 20 litre tank where it can be drained off. A leakage of up to 1% of the shaft diameter is acceptable.

I have 5% oil in the sterntube oil. What should I do?

Excessive leakage may be caused by a large number of factors for example:

• Excessive wear seal lips

• Hard and/or cracked seals

• Broken or damaged seal springs

• Foreign bodies under seal lips (fishing line, sand etc)

• Damage to seal housing

• Seal liners excessively grooved

• Pitting corrosion in liners

• Damaged gasket or 'O' seal on liner (aft seal)

• Damaged 'O' seal between liner and clamp ring (forward seal)

• Excessive eccentricity on liners

• Wrong oil in system (possible corrosive effect on seals)

• Liners machined under minimum permissable size

• Excessive clearance between sterntube bearings and propeller shaft. (Vibration can cause pumping effect of oil or water past seals)

• Damaged housing gaskets