The Indian Navy (IN) is going use a new type of diesel for its ships. According to a statement, the Indian Oil Corporation Limited (IOCL) has developed a NATO-grade diesel oil for use in IN’s ships. This fuel is called the High-Flash High-Speed Diesel IN 512 (HFHSD- IN 512). The fuel was launched in a ceremony presided over by Vice Admiral G.S. Pabby and IOC Director (Research and Development) SSV Ramakumar, along with IOC Director (Refineries) S.M. Vaidya.


The ships will receive fuel refined by IOCL units at Paradip and Haldia. The High-Flash High-Speed Diesel will result in lower pollution, better combustion efficiency and reduced stack emissions (smoke emitted from a ship’s stack). According to the IN-IOCL statement, the fuel meets the MIL DTL 16884 M norm, the universal diesel standard for all ships in NATO navies, and the benchmark across the world.


The MIL DTL 16884 M is also called Naval Distillate Fuel, and is symbolized as the F-76. In the 1970s, the U.S. Navy used a number of different types of fuels for use on board naval ships, submarines, gas turbines, electrical propulsion and smaller aircraft. They even used JP-5, a variation of jet propulsion fuel JP-4, which further complicated logistics. In order to simplify the supply chain, a multipurpose fuel was needed which would, along with being more economical financially, also offer the same levels of performance. This led to the creation of a naval distillate fuel called MIL-F-16884 NDF (Naval Distillate Fuel), and was called NATO F-76 by all NATO allies. F-76, when first used in NATO navies actually had a higher sulfur content than JP-5, and was thicker compared to the fuels used earlier. Over the years, the sulfur and ash content have been reduced, but the fuel is still called F-76 by NATO navies.


The new fuel being adopted by the IN, the High-Flash High-Speed Diesel – IN 512, has been customized keeping the NATO F-76 fuel in mind. Here’s an in-depth look at the High-Flash High-Speed Diesel – IN 512:


1. Since it now conforms to NATO standards, this means that vessels of foreign navies can be fueled by IN ports and other fleet support ships.

2. It has a low pour point, which means that it can now behave normally at low temperatures and can still power marine engines in cold weather.

3. It has the highest cetane number across all marine diesels available

4. The higher the cetane number, the more efficient a diesel engine gets – it’s like the octane number of petrol, the higher the better

5. Most marine diesels have a cetane number approaching 45, which is quite close to that of the HFHSD – IN 512.

6. MIL – DTL- 16884M stipulates a CN of 42.

7. The High-Flash High-Speed Diesel-IN 512 has a high flash point, meaning that it will not ignite on its own unless the optimum combustion temperature is achieved.

8. A ballpark flash point is somewhere around 60 degrees.

9. Diesels with low flash point will auto-ignite, causing vibrations, loud noise and a drastic increase in emissions like smoke and particulate matter (soot).

10. The new diesel has improved cold filter plugging point characteristics, which means it will still operate normally in low temperatures.

11. The MIL-DTL-16884M stipulates a CFFP of -7 degrees Celsius, which by inference is also the CFFP of the new IOC marine diesel.

12. In November 2019, the Indian Oil Corporation had launched a special winter-grade diesel for the Indian Army, which had a low pour-point of -33 degrees Celsius.

13. This was specifically targeted at vehicles operating in Ladakh and the Line of Actual Control (LAC).

14. The IA diesel is also compatible with diesel engines in passenger vehicles, which is why it’s commercially available at IOCL outlets.

15. The winter-grade diesel can operate at -33 degrees Celsius.

16. The Indian Navy does not need to carry out any special modifications in its ships to use HFHSD-IN 512

17. The Indian Oil Corporation has already launched a low-sulfur variant of their bunker oil.

18. This oil will be used for merchant vessels, and conforms to the norms put down by the International Maritime Organization, collectively called Marpol Annex VI, launched in January 2020.

19. As per the circular, ships must use a fuel with not more than 0.5% sulfur content, and if that is not available, shipping companies will have to use alternative fuels like LNG, Methanol.

20. They also have to install exhaust gas cleaning systems to keep emissions in check, and use onshore power supply when berthed.

21. Utilizing a low-sulfur diesel fuel will require a deep-cleaning of combustion chambers of every naval engine/turbine using HFHSD-IN 512, since it’s a Very-Low-Sulfur Fuel Oil (VLSFO) and using a cleaner fuel like the one in question for commercial purposes would require a similar purging process.

22. The Indian Oil HFHSD – IN 512 can be considered a more advanced derivative of the fuel used to conform to the Marpol Annex VI specs.

23. Interestingly, Bharat Petroleum’s product catalog also has a High-Flash High-Speed Diesel, and Hindustan Petroleum also manufactures a similar blend.


Adreesh Ghoshal is an automobile engineer with a deep interest in defence technology. He lives in Mumbai.

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