Understanding the different roles of stabilisers, deposit-control additives and biocides gives marine businesses a stronger basis for preventative fuel care.
By Jason Park | Fuel Right Australia
A boat can spend more time waiting for its next outing than burning fuel. That makes the diesel tank a storage system as well as an engine supply, and creates a useful role for additives chosen to suit both jobs.
For marine businesses, the most valuable conversation is about what a treatment is designed to achieve. Protecting stored fuel from oxidation, managing deposits and controlling microbial growth involve different chemistry. Understanding those differences makes it easier to recommend a product, explain its value and use it effectively.
The opportunity is to bring fuel treatment into planned care while the fuel remains serviceable, with a clear purpose for every addition.
Protection begins before performance changes
Preventative treatment gives an owner a reason to act while the boat is running well. The objective may be to preserve fuel during an extended lay-up or help maintain the cleanliness of the fuel system between outings.
Those objectives deserve separate consideration. A product designed for storage stability is being asked to do a different job from one intended to control injector deposits. Some formulations combine functions; others specialise. The useful question is which capabilities are supported for the fuel and equipment being treated.
This also gives the adviser a better starting point than the size of the bottle. A small, concentrated dose can be commercially attractive, provided the formulation delivers the required function at that dose.
Storage stability and cleanliness are different benefits
Antioxidants help interrupt oxidation reactions. In its guidance on marine fuels containing FAME biodiesel, CIMAC describes their use to improve stability and the potential need to replenish antioxidant protection during prolonged storage. That is a preservation role, with treatment selected for the actual fuel blend.
Dispersants serve another purpose: helping manage certain gums and sediments and reduce their tendency to form deposits. CIMAC discusses this separately from oxidation control. Keeping fuel stable and managing deposit formation can be complementary parts of a treatment programme.
Detergent chemistry brings the discussion closer to the injection system. Concawe’s Low Carbon Pathways working plan describes the use of fuel detergents to keep injectors clean and clean up deposits. Its discussion concerns road fuels; it establishes the function of the chemistry rather than proving the performance of a particular marine product.
For a marine recommendation, that distinction is valuable. Evidence of injector cleanliness supports an injector-cleanliness claim. Evidence of storage stability supports a storage claim. A supplier able to explain both clearly makes the product easier to assess.
Microbial control is a specific treatment task
A fuel biocide is selected to control microorganisms. A non-biocidal conditioner may offer useful deposit-management or protective functions, but it has a different role. Keeping those descriptions precise helps owners understand what they are buying.
Concawe’s guidance on handling biodiesel discusses specialist selection of biocides and removal of the resulting biological sludge. The practical benefit comes from combining suitable microbial treatment with the water and deposit management the system needs.
A recent example of additives in planned operation
In September 2025, the Global Centre for Maritime Decarbonisation published Project LOTUS, a six-month trial of a B24 blend containing 24 per cent FAME biodiesel in very low sulphur fuel oil aboard a commercial vessel.
The report records that the vessel’s routine fuel additive was retained throughout the trial to maintain consistency with its baseline operating procedures. Engine and fuel-delivery performance remained satisfactory under the programme.
This was an operational trial of the fuel blend, rather than a comparison of treated and untreated fuel, so the result cannot be attributed to the additive alone. Its relevance is practical: additive use formed part of planned fuel management. For yacht advisers, the transferable principle is to select treatment for a defined role within the vessel’s operating requirements, while recognising that the fuel blend and machinery in this trial differ from yacht diesel systems.
The strongest recommendation explains the mechanism
A useful additive recommendation connects a stated need to a supported function. For a yacht entering storage, ask what evidence supports stability protection in that fuel. For a deposit-control product, ask whether the evidence concerns the tank, injectors or both.
Test conditions matter. Results from one fuel blend, dose or engine application give useful information, but their relevance to the proposed marine use should be explained. A case study adds operational context; a repeatable test helps establish what the formulation does under defined conditions.
Multi-function products can simplify routine treatment when their capabilities match the application. The same discipline applies: identify the relevant functions, confirm compatibility with the installation and follow the specified treatment rate.
That turns technical detail into customer confidence. The owner can understand why a product was chosen and what benefit the service business expects it to provide.
Compare the cost of the treatment programme
Price per bottle tells only part of the commercial story. The more useful starting point is product cost per litre of fuel treated at the specified dose. From there, consider how the product fits the maintenance programme and how its benefit will be reviewed.
A realistic comparison includes treatment frequency, application requirements and any associated filtration or cleaning. Claims about fewer filter changes, fuel savings or longer storage life become more useful when the supplier identifies the conditions and evidence behind them.
For dealers and service businesses, this is an opportunity to offer advice that owners can use: a treatment with a defined purpose, a clear dose and an understandable place in the vessel’s care.
Marine diesel additives earn their place through the job they do. Bringing that conversation forward, while fuel is still performing well, gives preventative treatment its strongest role: helping preserve the conditions that support reliable boating.
About the author
Jason Park is a fuel quality and fuel infrastructure specialist and former chief executive in the Australian fuel-services sector. His experience spans operational leadership, fuel-system maintenance and project delivery, including sampling and testing, contamination management, tank assessment, cleaning and polishing, treatment selection and preventative maintenance. He leads Fuel Right Australia and Valence Fuel and is the distributor of Biobor though out Asia Pacific, helping operators turn fuel-quality findings into practical maintenance and asset-protection decisions.
Further reading: Fuel Right Australia’s guide to preventative diesel fuel treatment
For more information, visit fuelright.com.au
