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Hydrox Sterntube Oils
What are the Hydrox sterntube oils?
A lower viscosity grade, approximately SAE30, designed for normal/regular running in the sterntube where its use will provide insurance against the effects of any slight or persistent water ingress, but will also protect the sterntube in the event of any sudden water contamination caused by damage to the seal.
Both Hydrox grades are designed for use as sterntube lubricants in their own right though Hydrox 21 in particular is frequently used mixed with existing sterntube oils due to its ability to help in emergency situations.
The Hydrox grades are generally compatible with the oils commonly used for sterntube lubrication and whilst compatibility cannot be agreed without specific laboratory testing, problems have never been encountered in practice over many years world-wide use. The oils can therefore be readily introduced by addition to the existing oil.
If it is not possible to completely change the sterntube system to the Hydrox oils then as much of the Hydrox should be added to the system as possible to obtain maximum benefits. A minimum of 50% oil change over is normally recommended.
To introduce Hydrox into a sterntube we recommended draining the main header tank of the existing oil, fill the header tank with Hydrox and then circulate the oil through the system. This process can be repeated as necessary and the header tank topped up with Hydrox as required. Where a separate oilfeed to the aft seal is present, this should also be filled with Hydrox. Further information
Stocks of Hydrox 550 and Hydrox 21 are available world-wide.
The ability of Hydrox emulsions to protect the stern shaft and bearings in the presence of water is recognised by some of the major classification societies, e.g. Lloyds, DNV.
Further information regarding the properties, use and availability of the Hydrox oils is available at: www.vickers-oil.com.
- Designed and formulated specifically to meet the requirements of oil lubricated sterntube bearings, providing excellent anti-wear properties under boundary and hydrodynamic conditions and excellent corrosion protection properties.
- The oils are fluid and designed to be suitable for use in modern circulatory oilfeed systems and are formulated to have good compatibility with rubber lip seals, being approved for use by the major seal manufacturers.
- The Hydrox oils absorb any water entering the sterntube, reducing the potential for problems associated with free water in the sterntube. The oils form an emulsion with water that maintains a very high level of lubrication and corrosion protection. The emulsions formed have excellent stability therefore free water is not released, ensuring corrosion protection and lubrication even after prolonged standing.
- The oils will absorb very high amounts of water. The maximum water content recommended for normal sterntube lubrication is 20% although the oil will actually absorb much higher amounts than this. When a water content of 20% is reached we recommend draining some of the emulsion and replenishing with fresh oil.
A lower viscosity grade, approximately SAE30, designed for normal/regular running in the sterntube where its use will provide insurance against the effects of any slight or persistent water ingress, but will also protect the sterntube in the event of any sudden water contamination caused by damage to the seal.
- Hydrox 550 emulsions remain fluid even with high water content in the oil, ensuring free circulation of the oil.
- Hydrox 550 is suitable for use as a combined sterntube/hydraulic oil and therefore is suitable for use with many controllable pitch propeller systems.
- A higher viscosity version, approximately SAE 50, with the same water absorbing, lubrication and corrosion properties as Hydrox 550.
- Proven in practice to be very effective in reducing the rate of sterntube oil leakage from a damaged or worn aft seal. A leakage reduction of 70% or greater is commonly reported where Hydrox 21 has been introduced.
Both Hydrox grades are designed for use as sterntube lubricants in their own right though Hydrox 21 in particular is frequently used mixed with existing sterntube oils due to its ability to help in emergency situations.
The Hydrox grades are generally compatible with the oils commonly used for sterntube lubrication and whilst compatibility cannot be agreed without specific laboratory testing, problems have never been encountered in practice over many years world-wide use. The oils can therefore be readily introduced by addition to the existing oil.
If it is not possible to completely change the sterntube system to the Hydrox oils then as much of the Hydrox should be added to the system as possible to obtain maximum benefits. A minimum of 50% oil change over is normally recommended.
To introduce Hydrox into a sterntube we recommended draining the main header tank of the existing oil, fill the header tank with Hydrox and then circulate the oil through the system. This process can be repeated as necessary and the header tank topped up with Hydrox as required. Where a separate oilfeed to the aft seal is present, this should also be filled with Hydrox. Further information
Stocks of Hydrox 550 and Hydrox 21 are available world-wide.
The ability of Hydrox emulsions to protect the stern shaft and bearings in the presence of water is recognised by some of the major classification societies, e.g. Lloyds, DNV.
Further information regarding the properties, use and availability of the Hydrox oils is available at: www.vickers-oil.com.
