“Bunker,” the Fuel for the Giant Engines in Large Cargo Ships

The world grapples with the emissions.

By MC01, a frequent commenter on WOLF STREET:

When pricing a container shipment, we are sometimes told rates have gone up because “bunker oil” has increased in price or that the delivery will take a few extra days because shipowners ordered their skippers to slow down to save “bunker oil.”

But what is this “bunker oil”?

The term “bunker oil” defines all types of fuel used by the shipping industry and generally speaking can be split in two categories: distillates and residuals.

Distillates are produced during fractional distillation of crude oil and generally are very close in viscosity to diesel #2, the mainstay fuel in trucking and agriculture, but slighter denser.

Residuals are produced from the thick sludge left over at the bottom of the refinery’s fractionating column and are only a step or two removed from bitumen, the stuff used to pave roads: the most widespread types of residual bunker available have densities ranging from 500 to 700cSt at room temperature. For comparison, the densest types of diesel fuel have a viscosity  of under 35cSt at room temperature. This means that this type of bunker has to be pre-heated before it can be pumped into the fuel system.

There are also several blends of distillates and residuals, or of various residuals, whose viscosity ranges from 300 to 400 cSt, which are sold to provide a cheap alternative to straight diesel fuel while at the same time helping to meet environmental legislation.

Pollution by maritime vessels is regulated worldwide by the International Convention for the Prevention of Pollution from Ships (MARPOL), first ratified in 1973, and regularly amended over the years, the last time in 2013.

The MARPOL protocol legislates all aspects of ship-related pollution, from emission levels to how waste from the ship latrines should be processed and disposed of (not a joke when modern cruise ships are involved).

Emissions in particular have long focused on sulfur oxides. As with all fossil fuels, the trend has long been towards lower and lower sulfur content. But instead of focusing on emissions themselves, the MARPOL protocol legislates the limit of sulfur in bunker oil, and in such bizarre fashion it deserves a mention.

While there exists an ISO standard for bunker oil (ISO:8217, last revised in 2017), it’s not considered binding by MARPOL, which instead relies on the International Maritime Organization (IMO) to sample bunker oil sold in several locations worldwide and coming up with a “worldwide average” which is just that. Presently the limit for this “worldwide average” is 4.5% sulfur content.

This helps explain why worldwide consumption of residual fuels (as defined by the US Department of Energy) has been steadily declining after peaking in 1991. Latest data put daily worldwide consumption at 8.3 million barrels per day, down 4 million barrels per day from the 1991 peak.

When the MARPOL protocol relating to sulfur content was being discussed, several countries expressed concerns about its standards not being strict enough. To appease them, the concept of Environmental Control Areas (ECA’s) was introduced. ECA’s are areas coinciding with the territorial waters of EU member countries, Norway, Iceland and the United States (plus US dependencies in the Caribbean) where ships must use low-sulfur fuel, meaning bunker oil with less than 1% sulfur content.

In addition, the Chinese government has unilaterally created three ECA’s: One around Hong Kong and the Pearl River Delta, one around the estuary of the Yangtze River, and one largely coinciding with the Bohai Gulf. These three ECA’s include seven of the ten busiest ports worldwide.

Starting in 2000, ships sailing through these ECA’s have to comply with another set of emission rules collectively known as Regulation 13, which limit air polluting nitrogen oxides (NOx) emissions.

Regulation 13 is divided in three Tiers: Tier I, for ships built starting January 1, 2000, Tier II for ships built starting January 1, 2011, and Tier III for ships built starting January 1, 2016.

Each Tier is further divided in categories according to engine rotation speed. Low speed engines, the kind used in the large commercial vessels, have deceptively high limits: for example Tier III defines the NOx limit for engines up to 129 rpm as 3.4g/kWh while engines in the 130-1,999 rpm class have an emission limit of 2.4g/kWh.

However these low speed engines tend to run on much “dirtier” (meaning with a high organic nitrogen content) fuels than high speed ones for economic considerations, meaning they require even more work from engine manufacturers to provide engines the shipping industry can use worldwide.

Stricter environmental legislation around the world is only part of the increasingly more challenging environment these engine manufacturers have to deal with. There are only three that make the giant low-speed two-stroke diesel engines used in the largest container ships, bulk carriers, and tankers: MAN SE of Germany, Mitsubishi Heavy Industries of Japan, and Wärtsilä of Finland. Read…  The Engines of the Largest Container Ships in the World, and Challenges their Manufacturers Face

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  56 comments for ““Bunker,” the Fuel for the Giant Engines in Large Cargo Ships

  1. hendrik1730 says:

    The article speaks about “density” where cSt is given as a property of the fuel. cSt ( centiStokes ) is a unit of VISCOSITY, not density.

    • Sinbad says:

      Exactly, one of my jobs was to measure the viscosity of lubricating oil used in diesel engines, to check for dilution caused by the diesel fuel.

      The co called residuals are used almost exclusively in steam engines, and so are pretty rare these days.
      Virtually all modern freighters use diesel engines, and the fuel is very like the fuel used in diesel cars and trucks.

      The efficiencies of a large freighter engine are much higher than the engines used in trucks, so I find the fuss about the pollution caused by shipping a bit strange, when there are so many diesel cars and trucks on the roads.

      There was a move here in Australia to power diesel trucks using compressed natural gas(CNG), which is a much cleaner fuel. but the Government stepped in and taxed the fuel so highly that it was no longer viable.

      • Bruce says:

        We have CNG buses here trying to get rid of them they cost to much to run

      • Wolf Richter says:

        Sinbad, you were wrong in your last comment about the use of bunker, and we corrected you then…


        And you’re still wrong because you haven’t read our comments with those corrections. You think that these large container ships use the same fuel that Navy ships use, but that’s patently wrong.

        • d says:


          No real fuel consumption or emissions per hour/day, even as averages which I was hoping for.

        • d says:

          But in comments

          ” Using data supplied by Maersk, the daily fuel consumption of a Triple-E container carrier works out to 82,120 kg, or a tad over 82 metric tons.”

          with no emission data.

        • Sinbad says:

          OK I checked, you are right, I was wrong.

        • baldski says:

          Wolf: you are so right. Shipping companies cannot afford “Navy Special” fuel oil. The Navy wants one fuel for all their vessels no matter how they are powered. Hence, “Navy Special”. Steam turbines, diesel engines, gas turbines are supposed to use the same fuel oil. It gets hairy with gas turbines due to vanadium content in residual fuels. Vanadium pentoxide is highly corrosive to turbine blades at the high operating temperatures of gas turbines.

        • Caliban says:

          The above article:

          “Latest data put daily worldwide consumption at 8,320 barrel per day, down 4,000 barrels per day from the 1991 peak.”

          Should be:

          “Latest data put daily worldwide consumption at 8,320,000 barrel per day, down 4,000,000 barrels per day from the 1991 peak.”

          Per: http://www.usaee.org/usaee2014/submissions/OnlineProceedings/Implications%20of%20RFO%20Phase%20Out-Ramberg&VanVactor.pdf

        • Wolf Richter says:

          Thanks. Fixed.

      • Ambrose Bierce says:

        In the US CNG is a special subsidy to transportation, prices were driven low by the Feds ZIRP policies while no public access to CNG was promoted. If I search all CNG stations in my area there are quite a few including one less than a mile away, but they are not PUBLIC. The reasons for this one can speculate, to help promote public transportation, to subsidize public services like trash pickup, and school buses. The previous admin also wanted to push development of EVs. Its relatively easy to convert a gasoline engine, and small personal compressors are available. Consumers are being screwed just in a different way.

    • Wolf Richter says:


      Thanks. I made the correction.

    • Caliban says:

      Measured Sulfur Dioxide (SO2) emissions from Kilauea ranged between ~50 to ~1350 metric tons per day between the years 1979-1997*. Kilauea is just one of 32 volcanoes that were known** to be active last week. I can see limiting ship engine SO2 emissions close to coastal regions. But, as far as worldwide effects on atmospheric SO2 concentrations
      I think that the volcanoes might have the upper hand.

      **there are many volcanoes underneath the sea and Antarctic ice caps (~100 active volcanoes known to be underneath the western Antarctic ice cap) that are difficult to monitor.

      • Wolf Richter says:


        Yeah, but we can’t do anything about volcanoes. We can do something about man-made emissions.

        • d says:

          2 dozen or so big ones active at once would be good. It would with all the soot and ash emmissions make a “Nuclear Winter” which might be enough to generate a mini ice age and save the planet from human induced global warming.

      • Gandalf says:

        The main reason to lower sulfur content in fossil fuels was that the sulfur dioxide was turning into acid rain and destroying forests and damaging crops and farmland in the U.S. and Europe. This was already becoming an issue in the 1980s.

        Once rules were put into place to reduce sulfur levels and sulfur dioxide emissions, the acid rain started to improve, and the damage to forests and crops improved.

        Sulfur dioxide is also a greenhouse gas, but the push to reduce sulfur levels started in the late 1980s and 1990s, before global warming was being discussed, and it was because of acid rain.

  2. ScottS71 says:

    Interesting atrticle. If we looked at this ships stats that you mentioned in your last article:

    “Maersk’s Triple-E container ships – the largest container ships in the world with a capacity of over 18,000 twenty-foot-container equivalent units (TEU) – are powered by two MAN two-stroke diesels, each driving its own propeller. Each engine has eight cylinders with an 800 mm bore. The engines are designed to deliver their maximum efficiency at 73 rpm. Their combined power of 59,000 kW allows the monster-ship to cruise at 16 knots.”

    Can you tell us consumption and fule cost per hour to run? and maybe the sums on this ship going from Shanghai and LA? Probably not a quick reply maybe another post. Anyhow thanks for the article :)

    • ScottS71 says:

      this ship could hold about 2.78mil, microwaves (box size 0.3*0.25*0.25m =0.0187m3 per box). in 18,000 20ft containers.

      • ScottS71 says:

        Admittedly thats a small miccrowave. Double box size and cut quantity by 1/2 to get largish more common sized moicromave. Still a boat load of microwaves :)

    • MC01 says:

      Using data supplied by Maersk, the daily fuel consumption of a Triple-E container carrier works out to 82,120 kg, or a tad over 82 metric tons.

      Bunker oil prices vary wildly worldwide and have different dynamics: for example right now a metric ton of IFO380 (a benchmark blend of residuals and distillates) is US $450 in Singapore, $470 in Long Beach but $420 in Houston and $430 in Rotterdam.
      So using Singapore prices, a Triple-E costs about $36,900 per day in fuel alone when under steam.

      Mind the Triple-E’s were designed from the ground up for the Europe-Asia trade. Not only that, but when Maersk and Daewoo settled on the design there was no container port in the US that could harbor the Triple-E’s. Since then Long Beach has been upgraded and can handle container carriers 18,000TEU or more, but Maersk has expressed no interest in bringing them to the US, which is a pretty crowded trade already.

      • Dan Romig says:

        Thank you MC01.

        I am surprised that Maersk runs a Triple-E on 82 metric tons per day.

        Assuming these twin engine MAN powered ships are burning 3,422 kg of fuel per hour at an efficiency of 175 g/kWh, that would be just under 20,000 kW output.

        I would have guessed that these ships would run at two thirds of available power output when they’re on their journeys, but is it really at one third? This lower output would certainly be less stressful on the engines.

        • Mean Chicken says:

          FWIW, stress (bore wear mainly?) is a big deal on these. Quite an elaborate rod design has helped.

          Surely they can burn different fuel while at sea, the 3 mile rule in effect? But I’m not sure, just guessing.

        • MC01 says:

          According to the MAN literature I have in front of me now, the Specific Fuel Oil Consumption (SFOC) was calculated at the following conditions:

          Ambient air pressure: 1,000 millibar
          Ambient air temperature: 25°C
          Cooling water temperature: 25°C
          Fuel calorific value (minimum): 42,700kJ/kg

          As the same literature warns: “Although the engine will develop the power specified to tropical ambient conditions, SFOC varies with ambient conditions fuel oil lower calorific values. For calculations of these changes see [redacted].”

          As I was trained as a chemist, not as an engineer, I will gliss over the enormous number of variables regarding parameters such as hull and propeller fouling and get to my field.
          Each 1% variation in the fuel oil calorific value corresponds to a 1% loss in SFOC. Among the many parameters each 1°C increase in scavenge air coolant temperature results in a 0.06% loss in SFOC.
          On top of this the shaft generator “eats” quite a lot of power, especially when the ship needs to run one thousand or more climate controlled containers (“reefers”). Each 20ft reefer needs up to 6kW while 40ft can eat almost twice as much (11kW).
          There are all sorts of diagrams to decide how to generate this electrical power: generally a combination of Waste Heat Recovery (WHR), oil-fired generators and shaft generators is used with power generation “spread around” according to needs. For example a ship with a fouled hull and sailing in heavy weather will rely far more on WHR and oil-fired generators and considerably less on shaft generators.

          No need to tell every last drop of fuel counts, quite literally.

    • Caliban says:

      This is data on the ship Evergreen Ever Luna:

      The 333.5 meter long Evergreen container ship Ever Lunar, at 100,400 deadweight tons, can carry 8,200 TEU’s (20-foot equivalent containers) or 90,000 gross tons of cargo. It’s 9-cylinder 18,000 liter, 68,640 Mega-Watt Diesel engine is about 55% efficient. It can carry those containers 55,000 nautical miles before refueling.

  3. Scott says:

    That’s not the only reason why bunker oil consumption has gone down. Heavy fuel oil was also used to heat large apartment buildings, college campuses, hospitals and factories, as well as for power generation. This usage has declined due to increasing environmental regulations, cost and even outright bans. As a result, there is decreasing availability in certain markets, which further incentivizes movements towards other fuels.

  4. GSH says:

    No idea what the thermal efficiency of these monster engines is but for recreational diesel boats the back of the envelope figure is 1 gallon per hour for every 20 hp (15kW) actually used propelling the boat. Using this figure the Maersk ship would burn between 3000-4000 gallon/hour depending on engine load.

    • Gibbon1 says:

      I think the thermal efficiency is around 45-50%. Probably depending how you want to calculate it.

  5. Drango says:

    I read that if the shipping industry were a country, it would be the sixth biggest polluter in the world. Yet another reason to stop the US from being the dumping ground for the world’s excess capacity.

  6. Gunthet says:

    Compared to cars those emission standards are a joke. Sulphur content is at least hundred times higher then in diesel from the gas station and particles are not regulated. For nitrous oxides is some limit but it seems high compared to car diesel. The next pollutant are particles that could come fr two sources here. Unburnt fuel generates soot and impurities from the crude oil that accumulate in the residue can contain whatever, say vanadium for example.

    Somehow the emission standards differ extremely between land and water.
    A similar absurd situation exists with river ships and their engines. The German city of Xanten has almlst no car traffic dowmtown but a river with plenty of commercial riveroats closeby. Pollution is ( relatively) off the charts but nobody cares.

    • Robert_D says:

      It seems that nobody cares. Yet many do.

      Comments that I make here regarding pollution gain little traction, and often attract outright opposition.

      On top of which, liquid fuels pumped out of the ground are a diminishing resource, and such monster vessels, along with the American penchant for monster-sized personal vehicles to carry 1 or 2 people — is wasting a resource {CHEAP oil} that will never be available again.

      We humans are wasting a valuable resource and fouling our own nest too. And pollution from China, not just her sea-going vessels pollutes America too. For evidence, research the prevalence of fallout from the Roman mines in Spain — that can be seen from cores from Greenland and Arctic ice sheets at the height of Roman economic prowess. Lead from the Roman mines blanketed the world with lead. LEAD !

      We won’t learn.



      • ScottS71 says:

        interesting. If the worlds winds blow west, and lead is heavy, how could Roman products, land in iceland? Maybe the glacier sheet had lead in it when it carved up the world, maybe? Im just asking as I dont know. but seems odd. I do agree with the overall agrument. We need to implement/convince consumers, all consumers, to pay more to save our planet… which should read, save mankind, the planet will be here for a long time (BBC QUOTE). which is intersting.. Why save the planet over save mankind.. the planet is innocent, man kind kills it… easy to sell this, i guess.

        • ScottS71 says:

          sorry, east.. the world winds blow east…

        • Robert_D says:

          From your post : “Maybe the glacier sheet had lead in it when it carved up the world, maybe?”

          The scientists can date the layers in the ice-cores drilled from the ice sheets, TO THE EXACT YEAR (as an analogy think tree rings in two-thousand year old trees). They have become that good. It is clear that the lead and other mining-byproducts — wafted to the Arctic circle environs — as a result of hundreds of thousands of Roman slaves working the Roman mines.

          Imagine that, vanquished people who were enslaved to work the Roman mines, and who typically expired due to the work — also covered the entire world with harmful pollution — at the height of Roman economic, and thus military, power. Sound familiar ?

    • Mean Chicken says:

      Refiners don’t extract most all of the vanadium?

      • Gunther says:

        Mean Chicken,
        I don’t know. I remember this from a material sciennce lecture long time ago.
        The point there was corrosion, not residuals of refining.
        Depending of the amount and other circumstances it may make sense to extract the vanadium. If the residues of destillation are sold as bunker fuel with next to no pollution limitations whatever dirt may stay in the fuel unless it damages the engine.

      • MC01 says:

        Careful because here you are threading in my territory and I may bore you to death.

        Generally speaking there are only a very few crude oils from which vanadium recovery is feasible outside of very small scale, experimental or test production.
        The most vanadium-rich crudes are those from Venezuela and, until 2013 there were a couple of refineries in Europe (one in Germany and the other in The Netherlands) which recovered vanadium from oil residues but it was nigh on insignificant production and it has since ceased, especially given that dealing with PDVSA these days is not exactly easy and that vanadium prodcution worldwide has exploded (see below).
        More vanadium can be recovered from ashes from oil and coal fired power plants but the recycling industry concentrates on reprocessing the spent catalyzers from petrochemical complexes. I think the latter’s the source of most if not all the vanadium obtained “from crude oil” these days.

        Vanadium has long been obtained chiefly from titano-ferrous magnetites and worldwide production is completely dominated by just three countries: China (don’t tell me you didn’t see that coming), South Africa and Russia.
        China has some of the richest vanadium-bearing magnetites in the world and supplements them by extraction from, drum roll please, Australian magnetites.
        The US and Canada are an extremely distant fourth and fifth respectedly and the bulk of their production is a byproduct from the processing of uraniferous sandstones.

        Hope this helped you and not bored you.

    • Flying monkey says:

      I live in Germany and was in Xanten twice this year. Pedestrian zones with no cars are common place in most European cities. It makes shopping in those districts much safer for pedestrians and there is less congestion. I would be first inclined to say it has less to do with exhaust gases than promoting a safe, stress free zone. It promotes gathering downtown because the communal atmosphere is good.

      A good read would be James H. Kunstler “The geography of no-where”. It basically details the fall of the American city center due to the automobile.

      They don’t even allow bicycles at certain times of the day in Xanten.

      “Seit 5. November 2015b dürfen Radfahrer in der Zeit von 20,00 Uhr bis 08,00 durch die Fußgängerzone radeln, ohne eine Ordnungswidrigkeitsanzeige zu riskieren. “

  7. Emre says:

    I don’t have a wide knowledge about the technical side of this topic, and wondered how does the trend of running ultra large container ships with LNG correspond to this discussion.

    Also IMO regulations effective as of 2020 to limit Sulphur content to 0.5% will totally change the landscape of shipping.

    • MC01 says:

      The use of LNG as a maritime fuel is a complicated and, how can I put this, politically charged topic.

      The first two commercial LNG-powered container ships, the Marlin Class owned by Totem Ocean Trailer Express (TOTE), were built using a $320+ million loan guarantee from the Maritime Administration (MARAD) by General Dynamics in San Diego. However, and here’s the funny thing, the two ships were wholly designed by Daewoo of Korea, and the propulsion system was designed by a MAN/Doosan joint venture and built in Korea, as were many subassemblies and systems. The onboard gas storage facility was designed and built by Cryostar in France.
      In short there are strong suspicions General Dynamics was involved merely to access the generous loan guarantees MARAD offers under the Jones Act and its amendments.

      These engines, like all LNG maritime engines, are dual fuel, meaning they can run on either “straight” bunker or a combination of LNG and bunker in different modes. These modes use different fuel percentages and can be varied according to fuel prices.

      These engines, whose technology derives from work done jointly by MAN and TEPCO (the irony!) in the early 90’s for power generation, were originally conceived for LNG carriers, with Qatargas being not merely the first customer but a strong believer in this technology.
      LNG carriers have the huge advantage over other vessels of the ready availability not merely of large quantities of LNG but also of the onboard facilities to prepare LNG for being injected in the cylinders.
      By contrast other vessels require not just the installation of large enough LNG tanks and their ancillaries, but also the installation of riliquefaction units and compressors.

      LNG would not be attractive outside of LNG carriers if it weren’t for emission controls but it’s just one of the many ways possible to achieve them: separate tanks for ultra-low-sulfur fuel to be used when sailing through ECA’s and/or dry scrubbing are just two other solutions to reduce sulfur emissions.

  8. John says:

    Cargo ship is the most efficient means of transportation.Railroads are not even close.

    There is a comprehensive article in Wikipedia:

    Energy efficiency in transport


    Ton x mile / gallon.

    Starting with lowly pedestrians and all the way up to Emma Maersk-largest container ship in the world.

    Them damn pedestrians are real jerks-who more than anything else contribute to global warming.While pointing accusatory fingers at majestic ocean-going ships.

    Hopefully US Congress will make walking and jogging a federal criminal offence.

    • Lune says:

      Hmm. That Wikipedia article states the efficiency of a large cruise ship is between 13-17 passenger miles per gallon. OTOH, walking provides 360 miles per gallon, and biking is 700-4.7k miles per gallon depending on aerodynamics of the bike.

      So looks like walking still beats the water. Plus our fuel is renewable, sustainable biofuel, rather than fossil fuels. And we’re rather clean burning except for some methane emissions :)

      • John says:


        There is a difference between passenger mile per gallon and ton × mile per gallon.

        But soon this difference disappears.We’ll see pedestrians,joggers and bikers with 1 metric ton ( 2200lbs) bodies.Obesity appears to be a general order of the day.

    • dave jr says:

      My thoughts exactly. If emissions were calculated on a per ton – mile basis, these container ships are very clean. Yet we have to listen to dopes complain as they haul their fat butts to the mall to pick up a 60″ flat screen they bought from Korea.

      • Mean Chicken says:

        Makes perfect sense to me, hypocrites prevail with their misinformation. For instance, Elon Musk would rather blow money launching an electric car to space as opposed to cleaning up tons of plastic waste from an ocean somewhere.

        • d says:

          Elton musk understand something very few others do and is trying to do something about it.

          “We had better find another planet to live on, as we are swiftly destroying this one”

          Unknown Arms dealer.

  9. raxadian says:

    This was interesting.

    I wonder how much does this realy affect electronic prices?

  10. steve brassey says:

    Wolf, why do you allow Jim Rickards to be seen on your site?

  11. John says:

    I just remembered an old painting from my mother’s art book:

    Barge haulers on Volga (1870)


    That’s what I call energy-efficient,zero-emissions maritime transportation !!!

    Russians probably never heard about obesity epidemics which ravages the West.

    Barge hauling beats stationary bikes,jogging,Atkins diet and other such exercises in futility.

    • RD Blakeslee says:

      In my microcosm, “Shank’s mare” is used as transportation to hunt for cows hiding their calves. My microecosystem works this way: The grass is first generation solar dividend, it grows using photosnthesis. Second generation solar dividend are the cows: They eat the grass. Third solar dividend goes to me. I eat the cows.

      I could construct pyramid graphs of the complications, I suppose. For example, trees are second generation solar dividends, like grass. They offer third generation serving as fuel for cooking my cows.


      • davejr says:

        Strange isn’t it. That the 2nd generation (cows) don’t wage war on the 1st generation (grass). They consume as needed, but don’t advocate getting rid of that which supports them. Damn smart cows.

    • MC01 says:

      Have you seen Blackadder the Third? Do you remember that episode where, due to being pretty much bankrupt, Blackadder decides to become a highwayman and has to find himself a suitable “mount”, a problem he solves in his typical fashion?
      Same thing here.

  12. Flying monkey says:

    Bosch Homburg (commercial Diesel injector lead plant) is developing a marine natural gas injector. For marine applications the engine would get switched over to natural gas from bunker oil once the ship gets close to the harbor or with a certain pollution zone since Nat. gas burns cleaner.

    • MC01 says:

      All LNG-fueled marine engines already are duel fuel, see my reply to “Emre” above.
      The technology is actually nothing new but was pioneered by a joint venture between MAN of Germany and TEPCO of Japan in the 90’s and originally developed in its present form for Qatargas LNG carriers.
      Two-stroke diesels actually cannot run on “straight” LNG: they still need the oil in the bunker to lubricate the cylinder walls and for auxiliary cooling. If you have ever seen a seized chainsaw or brushcutter that’s what lack of lubrication will do to a two stroke… on a much much larger and far more expensive scale.

      Generally speaking LNG-engines presently in service never run under 3% of “pilot oil”, a technical term to indicate bunker oil when used in combination with LNG.
      However, and here is the amazing thing, there are several “modes” available to these engines: a fixed LNG/pilot oil mixture is just one of them. Many engine modes “switch” between this mixture and bunker in either cycles or bursts over the course of several minutes.

      And it is all already here.

      • Night train says:

        Partially correct. Large 2 stroke slow speeds use a second set of injectors, which inject a certain BN oil into the walls to neautrilize and lubricate. It is not pre mixed as this would lead to a whole wealth of issues.

  13. unit472 says:

    Very interesting and informative threads on ships. I hope Wolf Street does more like them.

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