Any ship will have lubrication needs beyond that of the engine. There is the transmission system itself, multiple pumps and compressors, valves in piping systems for fuel, water and more. Engine lubrication is a subject in itself, but all of the other mechanical systems will also need lubrication and things such as crane wires and lifeboat falls will need to be kept supple and protected against corrosion using greases. Many machines will have unique requirements and in such cases there are normally special formulations provided by the leading lubricant manufacturers.
Many machine oils and greases are labelled as ‘general purpose’ but this should not be taken to mean that they are suitable for all purposes and in some instances very specific properties are needed. The wrong choice of lubricant can mean the failure of essential systems and this is frequently found to be the main or contributory cause of accidents.
It may be thought that the most demanding application for lubricants is in the engine where high temperatures will be experienced but exterior uses are probably even more so. Winches and cranes as well as underwater equipment will experience very wide operational temperature ranges. For some ships, there will be times when such equipment is exposed to sub-zero temperatures and others when it could be exposed to hot tropical sun. Wind, rain frost and snow will also affect performance. It is however important for the ship that the equipment operates at all these extremes so the choice of appropriate products is something thought must be given to.
Closely allied to lubricants are the hydraulic fluids that can be found in cranes, winches, pumps and many other items of machinery and equipment such as watertight doors, cargo hatches and ro-ro ramps and lifts.
Environmental factors for consideration
Most lubricants and fluids are used in closed applications but in deck machinery and in equipment such as controllable pitch propellers, podded propulsion systems, stern tube seals thrusters and steering gear there is a high risk that they can leak into the waters the ship is operating in. For regulatory purposes such as MARPOL or under local law, any escape into the environment of these products will be considered as an act of pollution and the operator is therefore at risk of prosecution.
Leaks from deck machinery should be dealt with as soon as is practically possible and especially before arrival into port where rain could cause the spill to be washed overboard.
If the leak is of hydraulic fluid and did not result from an accidental spill, there is a high possibility that the system is compromised. The risk of pollution is therefore not the only problem as the system itself may fail resulting in an inoperable winch or a hatch cover that cannot be opened or closed. Failure to lubricate systems is also a cause in many PSC detentions especially if the system is one considered an essential safety device. Seized dampers and air pipe covers are notorious in this regard as are seized valves in many different systems.
The pollution risk from deck machinery and stern tube seals can be reduced by making use of biodegradable lubricants. Such products are generally made from vegetable- or animal-sourced material. Biodegradable products are still in their infancy as far as marine lubricants go, as it was only in 2002 that Vickers Oils became the first company to make biodegradable lubricants commercially available to the global marine market.
In addition to improving environmental credentials, the opportunity to reduce operating costs is just as important to the marine industry as any other business. The use of biodegradable lubricants is one way that vessel operators can achieve cost saving benefits if their makers’ claims as to performance are true.