A Helpful Guide on the Important Properties of Marine Lubricants

Every industry knows how important lubricants are, specifically in ensuring that the overall processes and operations of the machines run smoothly. They are responsible for lubrication, as well as the cooling of the parts which are operating relative to each other that are causing friction and other sorts of strains on the machinery. Any equipment activity would be impossible without the use of lubricating oil. Especially with ships and other machines relating to the marine industry. It is important to incorporate the right marine lubricants, in order to improve the engine operation, and even reduce the wear down rate of the machine. With this, the maintenance cost of the entire machine can be reduced as well.

Types and Grades of Marine Lubricants

There are different types and grades of marine lubricants that are available for marine equipment — depending upon the working condition, operation, and requirements of the machinery itself. Moreover, when it comes to marine engines, it is very critical to choose the best grade of lube oil since it hinges on the entire engine operation, which affects the overall processes in the industry. Thus, having to choose the correct lubricant with the right properties is critical for successful operations. These lubricants are used as a coolant, to reduce friction, provide cushioning, act as a cleaning agent, protect the components and engine parts against corrosion, and many more.

Marine lubricants hold a variety of properties, helping the machine to run at its optimal state. From its viscosity, alkalinity, carbon residue, to its oiliness, tend to be properties putting a significant impact on the overall well being of the machinery. But then, generally, the different types of lubricants contain properties that depend on their function in a machine. Lubricants for four-stroke engines, for instance, have qualities similar to cylinder lube oil and system oil found in two-stroke marine engines.

Though this is the case, all lubricants still share the same goal. To reduce friction and heat, prevent damage, and prolong the life of engines and machinery. But then, marine lubricants consist of very important properties. These make them ideally appropriate for what they use in boat motors, aboard ships, and in other marine-related areas.


In a general sense, viscosity refers to the ability of the fluid to resist its movement or flow. A measure of internal resistance to flow between liquid layers. It is actually one of the most important lube oil properties needed to determine what type of lube oil to use for the engines and for different machinery based on its physical properties.

Lubricants with lower viscosity levels can easily pass through an area with small clearances. Those with higher levels, on the other hand, cannot. The advantage of those highly viscous fluids is that they are good for boundary lubrication. Thus, the type of lubricant you should be choosing must be an oil which has neither too high or too low viscosity fluids. This is for proper lubrication to take place.

Furthermore, the viscosity of fluids changes with temperature — it reduces when temperature rises, and increases when temperature drops. A lubricant with a lower viscosity index also has a greater change in viscosity when the temperature changes. Those with a high viscosity index have very little change in viscosity when there is a change in temperatures. Thus, a desirable property for lubricating oils.


The alkalinity of marine lubricants plays an important role in marine engines. It is actually one of the most important considerations with the lubricants. When fuel is burned, sulfuric acid is released into the atmosphere, which can cause acidic corrosion. The main lube oil is responsible for piston and liner lubrication in a trunk piston engine or four stroke engine as well. Thus, it comes into direct touch with the combustible fuel. As a result, lubricant oil alkalinity is critical for preventing acidic corrosion.

Particularly in the case of four-stroke and trunk piston engines. The oil lubricates the pistons and the liner, which then come into touch with flammable fuel. In these cases, alkalinity aids in the management of acidic corrosion. A different type and grade of marine lubricant is required for two-stroke engines, on the other hand.

When the fuel burns, sulfur oxides are produced, which combine with the existing water vapor to make sulfuric acid. The lubrication oil’s alkalinity then counteracts these acidic effects. It’s considerably more crucial because lubricating oil carries liner lubrication in four-stroke engines. The sulfur level of the fuel oil determines the alkalinity of the lubricating oil.

Carbon Residue

Another important property of marine lubricants would be their carbon residue. This refers to the tendency of the oil to burn with a carbon residue under constant or increased temperatures. An oil with a high carbon residue level does not burn easily. And even if they actually burn, they can still end up leaving a huge shoot deposit. You can determine the carbon residue of marine lubricants by how gummy or sticky they are in nature. This causes the piston rings to stick within their groves. 


Aside from marine lubricants’ viscosity, alkalinity, and carbon residue, their oiliness is deemed to be an important property as well. The role of lubricants to engines in a general sense is to reduce friction between the two sliding bodies. Thus, lubricating the surface significantly reduces the amount of friction acting between the two surfaces. This will ensure that certain engine parts run smoothly the whole time. This is then achieved mainly because of the property of an oil to stick to a surface.

Oil manufacturers can choose to apply additional additives in the form of anti-wear agents to lube oil. This will further improve the oiliness property while improving their efficiency under boundary lubrication as well. But then, they are certainly dependent on the requirements of the engine parts or machines you will be applying the lubricants on.

Key Takeaway

Viscosity, alkalinity, carbon residue, and oiliness are just a few of many important properties that determine the efficiency of marine lubricants. But then, though these fluids are used to lubricate engine parts and machinery to work in their optimal state, their properties still deteriorate over a period of time. This is because of the addition of impurities that could include unburnt fuel, water, acid, suspended particles, and more. Meaning to say, there still is a limit to which the same oil can be used, and at a certain stage, it will need to be replenished. Which is why proper maintenance of these engines and machinery is still important, apart from the application of several useful marine lubricants. 

Related Articles

Leave a Reply

Your email address will not be published. Required fields are marked *

Back to top button