Marine Transmission & Gear Oils

Castrol BioStat 100


Castrol BioStat 100 Environmentally Conscious Marine Transmission Gear Oils


Castrol BioStat 100 contains selected additives ensuring good oxidation stability, good anti-corrosion and anti-wear properties and low aquatic toxicity. The combination of base oils used in BioStat endows it with a very high viscosity index and an extremely low pour point as well as giving excellent compatibility with elastomeric seal materials.

The careful choice of synthetic base oils enables the product to operate in a wide system temperature.


The BioStat range of high-specification stern oils is intended as drop-in replacements for conventional mineral oils in equipment where there is a risk of accidental spillage or leakage and consequential environmental damage.

Castrol BioStat 100 oils are suited for application in stern tubes, reduction gear, thruster, spur, helical and planetary gear units, couplings, and rolling and sliding bearings.

BioStat is miscible with conventional mineral oil-based stern tubes and gear fluids. When changing from mineral oil-based products to BioStat, the system should be drained to ensure that the mineral oil content of the refilled system is less than 5%. This is necessary to ensure that the overall biodegradability is not adversely affected.


Castrol BioStat 100 Lubricant Advantages:

The careful choice of synthetic base oils enables the product to operate in a wide system temperature.

BioStat stern tube/gear fluids combine excellent protection, extended. drain performance and versatility in Offshore operations to provide the following key benefits:-

  • Reduced environmental impact when compared to conventional lubricants – demonstrable benefits in the following key environmental performance criteria:- Superior biodegradation.
  • Significantly reduced bioaccumulation* and toxicity. Enhanced renewability.

*Using OSPAR criteria for assessing bioaccumulation potential. Good oxidation and anti-corrosion.

  • High shear stability.
  • Good thermal stability.
  • Extremely resistant to hydrolysis.
  • Load stage >12 is passed in the FZG test.
  • BioStat passes the FZG micropitting test with high micropitting load-carrying capacity.
  • High viscosity index allows start-ups at low temperatures and provides for a thicker lubricating film at high temperatures for additional anti-wear protection.
  • The majority of the base oil is derived from renewable resources and does not bioaccumulate.
  • Physical properties and hence system operating characteristics are comparable with those of mineral oil-based stern tube and gear fluids.
  • BioStat is compatible with conventional mineral oil-based products. • Environmentally responsible. The ready biodegradability of the product ensures the rapid natural degradation of the product should it enter the aquatic environment.
  • Minimises harm to the environment in the event of an accidental spillage.
  • Superior oxidative and thermal stability provides extended product life, therefore minimising product consumption and waste.
  • Packaging can be reused or recycled at the end of life.
  • Existing equipment can be readily converted to BioStat with minimal risk and few, if any, system changes.


• Keep the container tightly closed and sealed until ready for use. Containers that have been opened must be carefully resealed and kept upright to prevent leakage.
Store away from direct sunlight in a dry, cool and well-ventilated area, away from incompatible materials.

The biodegradability of BioStat was measured in an OECD 306 (seawater) biodegradation test with a result greater than 60%, making it 100% more biodegradable than conventional mineral oils. BioStat is therefore classified as readily biodegradable in the marine environment.

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Castrol Biostat 100 Lubricant Oil

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