The Silly Notion of “Speed Limits for Ships”

Container Ships Article

By Steve Goreham

Originally published in TheT&D.

Occasionally a report appears which claims to be wisdom, but after careful analysis, offers solutions that don’t make much sense. Such a report was issued earlier this month by United Kingdom consulting firm GL Reynolds, titled “The multi-issue mitigation potential of reducing ship speeds.” The report proposes that we can reduce global warming by imposing speed limits on ocean-going ships.

The GL Reynolds report concludes that a 10-20 percent reduction in ship speeds would have a “highly positive potential impact” on carbon dioxide (CO2) emissions and nitrous oxide (NOx) and sulfur oxide (SOx) pollutants. The report also projects that a ship speed reduction may reduce fatal collisions with whales.

The report is actually conservative and recommends that more study is needed. But the BBC and environmental groups now hail the report as a roadmap for international maritime policy.

Matt McGrath, environment correspondent for BBC News, wrote “Cutting the speed of ships has huge benefits for humans, nature and the climate, according to a new report.” John Maggs from Seas at Risk told the BBC, “It’s a massive win, win, win, win.”

According to the International Transport Forum, ships carried 10.7 billion metric tons of freight in 2017, 70 percent of world freight volumes. ITF projects maritime freight volumes to triple from 2015 to 2050.

Like almost all modern transportation, ships emit carbon dioxide when they burn fuel. Ships emitted about 932 million tons of CO2 in 2015, about 2.6 percent of global emissions. When ships move at lower speeds, they consume less fuel and emit less carbon dioxide. A 2017 study by CE Delft estimated that a 20 percent reduction in commercial ship speeds would reduce CO2 emissions by 19 percent, after a required 13 percent increase in the number of ships to provide the same transport work.

In 2017, the value of the world shipping fleet was estimated at $829 billion. Increasing the size of the fleet by 13 percent would cost over $100 billion, plus additional costs to hire and train additional crews.

Today, most global corporations practice cycle time reduction as a key business process. Apple, currently the world’s most valuable company, calls it “reducing time to value.” On-line retailing giant Amazon implemented one-day delivery for many products this year. Footwear and apparel producer Nike announced a goal to reduce supply chain lead times by 83 percent.

Regulations to reduce the speed of ocean-going ships by 20 percent would increase cycle times and costs for the shipping industry. Crews would need to be paid more for longer voyages and each ship would take 20 percent more time to deliver the same cargo. Cycle-times and costs would also increase for Apple, Amazon, Nike, and all freight customers.

Advocates point out that emissions of sulfur oxides and nitrogen oxides can be reduced with slower ship speeds. But international regulations are already in place to reduce SOx emissions by reducing the sulfur content of fuels and to reduce NOx emissions through new diesel engine emission standards.

Collisions with whales have been rising with the growth of the world shipping fleet. National measures such as routing and speed restrictions are now in place in coastal whale migration areas at certain times of the year to reduce collisions. But how will increasing the number of ships by 13 percent reduce the number of whale impacts?

In 1975 during the first oil crisis, the US federal government imposed a National Maximum Highway Speed Limit of 55 mph. Officials estimated that lowering highway speeds would cut national gasoline consumption by over two percent. Later studies showed actual savings to be less than one percent. Today the world is awash with petroleum and the US 55 mph limit no longer exists.

We could certainly run our ships, planes, and vehicles at slower speeds. And if we returned to horse-drawn wagons, vehicle collisions with deer would be eliminated. But does anyone really think this would stop sea levels from rising?

Steve Goreham is a speaker on the environment, business, and public policy and author of the book Outside the Green Box: Rethinking Sustainable Development.

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112 thoughts on “The Silly Notion of “Speed Limits for Ships”

    • Climate dimwits, thanks to our public school systems and the Propaganda Ministry we sometimes refer to as the Mainstream Media, have achieved majority status and will soon be old enough to vote Communism into power in the U.S. once that happens it will be one delusional scheme after another.

    • How do you enforce a speed limit on international waters?

      Oh wait they probably want a special international water police force to go along with there pollution enforcement police 🙂

      • GPS tracking, satellite imagery, time between waypoints, its not really that hard if yu really want to do it. Bit like illegal oil shipments that have always been there, but only tracked and pointed out when it provides some political/strategic advantage

        • Oh good. think this through. A ship gets nailed for speeding going the UK. UK fines the shipping company thousands of pounds. The cost of the fine is added to shipping rates which increases the cost to the manufacturers which pass that cost onto retail outlets. Retail outlet increase the price of items to be sold consumers. Cost of living goes up. Less goods are sold. Less taxes are collected. Government raises taxes to cover short falls. Good plan. LOL

          • You can’t fine it unless the ship was operating under UK maritime flag you have no jurisdiction and worse it’s a civil breach not even a criminal breach. Understand the basics
            https://en.wikipedia.org/wiki/International_waters

            You can’t exercise universal jurisdiction for anything other than a true crime.

            It would get thrown out of your UK courts the same as it would in any country.

          • Simple solution. If a single country starts doing this, then stop shipping directly to that country. Ship to a sane country nearby, and let trucks and trains take the stuff the rest of the way.

    • I can tell you China’s not gonna do it.

      Looking more and more like the real “goal” here is to throw the world into a global depression.

  1. Frequently, reports and ideas appear which claims to be based on science, like the idea that CO2 increases are dangerous to humanity and the planet, but after careful analysis, these ideas offer solutions to a non-existent problem that doesn’t make any sense, even when analysed using the proposer’s data. Slow shipping is yet another.

    • “nicholas tesdorf November 23, 2019 at 2:14 pm
      Frequently, reports and ideas appear which claims to be based on science”

      A good observation here that much of the legitimacy of climate science and its theory of AGW holocaust derives from the use of the words “science” and “scientist” and the assumption that if it is science it has to be correct. Yet we have plenty of evidence of science that turned out to be dead wrong and we don’t have to go back very far in history.

      Just prior to the AGW scare we were put through the ozone scare. Here’s a brief history of that scare in case you have forgotten. (The sinister role of the UN in the climate scare is also seen in the ozone scare that may be its origin)

      https://tambonthongchai.com/2018/08/07/history-of-the-ozone-depletion-scare/

      The key paper in that scare, its only claim to empirical evidence for the Rowland-Molina theory of anthropogenic ozone depletion, was the Farman etal 1985 paper on which Farman himself had later cast some doubt. It’s just plain bad science and more important, it turned out to be all wrong. Please see

      https://tambonthongchai.com/2019/03/12/ozone1966-2015/

  2. The report does not even consider sail ships – the greenest form of transportation. Are the authors really Big Oil shills?

  3. And what about the environmental cost of manufacturing that 13% increase in ships? PLUS, now you have the increased operating costs, extra personnel to operate and maintain. Don’t ships have bilge pumps to remove sea water that leaks in, doesn’t that contain possible petroleum pollutants? That increases water pollution. Then there’s the logistics at the ports, having to coordinate those extra ships. So many unintended consequences to the “Solutions” proposed by these people that know better.

    • The ships that carry bauxite from Cape York to Gladstone, all run at different speeds. The company has worked out what speed for each ship uses the least fuel for the trip, south when loaded & north when empty.

      At one time the refinery was not at full capacity & needed less bauxite. The ships did not run slower, as that would have used more fuel, increasing emissions, they simply anchored off shore for a day at the end of each trip.

      Thank god ship owners are smarter than consultants.

    • Under international treaty bilge water is not pumped over the side but into on-board tanks. These are empty into special treatment plants ashore. Also ship employ a machine called an oily water separator to extracted the oils from the contaminated bilge water. Spent many years fitting anti-tampering devices to this stuff so it was difficult to circumvent.

  4. Yea whales are special and all that, but how can they ignore bird choppers and smokers? 55 mph in 1975? I drove a red datsun 240Z. It went 55 in second gear!

      • I had a ’65 Corvette and a girlfriend that lived 120 miles away. Because gas was expensive and there were times when one could only fill up on alternate days, I invested considerable time and effort trying to determine the optimal speed for the best gas mileage. I concluded that it was about 68 MPH. That gave me confidence that the Detroit engineers knew what they were doing since most states had a 65 MPH speed limit when the car was designed.

        I suspect that the 1% national savings in gas resulted primarily from people opting to not go on long trips because of the time involved getting there at 55 MPH.

        • I live in Germany, drive a Jaguar,,,,at 250 kmh plus on the motorway, and enjoy cars passing me at lightspeed (no speed limit ) according to the internet Germany has the lowest rate per vehicle on the road, of any country in the world!

    • Yes Ron, but Greta needs to know how many whales you hit with this car…

      Actually that is not strictly correct. Greta KNOWS you ran over whales. How Dare You!

    • I got a speeding ticket at 6am on a Sunday morning, the day after the speed limit had been changed from 65mph to 55mph. Me and the Highway Patrolman were the only vehicles on the road that early in the morning, and he was going the opposite direction over the Arkansas river bridge and had to travel about two miles before he could turn around and come after me, but turn around he did, and chased me down and gave me a ticket. I was only going 65mph. He could have cut me some slack, but he didn’t. That’s a dedicated officer.

      That’s something my uncle, an Oklahoma Highway Patrol Officer would do. 🙂 He pulled me over one night and when I walked back to talk to them he wouldn’t talk to me, he made me talk to the other officer with him, because he didn’t want any favoritism to be shown because we were related. And he was serious. Well, about half way. They let me off with a warming that night for rolling through a stop sign without coming to a complete halt.

      When I hear that song that says, “I can’t drive 55!”, I think of that time on the Arkansas river bridge in my little BMW 2002.

  5. “Collisions with whales have been rising with the growth of the world shipping fleet. ”

    Plus the whale population is going up.

    • Yes John, enormously, and sailing boats are having collisions with them these days at speeds below 10 knots from which they often sink.

      So how slow would a ship have to travel to reduce collision rate?

      No matter how you tried to work it, it would be a massive lose, lose, lose, lose!

    • Also, where I have had collisions is from a whale surfacing right under the bows. You don’t hit them, they hit you.

      Speed is not usually a factor.

      • F.LEGHORN in Alabama November 24, 2019 at 8:18 am

        The whales couldn’t hear a sailboat so I suspect more collisions with sailboats than oil tankers.
        ___________________________

        New business segment:

        Whalesong playback gears for sailboats.

  6. ‘More research needed’ – Gill [GL] Reynolds, whom I worked with, possibly looks towards keeping nicely busy as retirement approaches in – perhaps – ten years or so.

    But, as identified, the same amount of goods will need to be moved; if ships are slower, get more of them [or bigger ones, over perhaps the next fifteen years].
    If ‘Time to Value’ becomes more important, might Apple, say, take goods off ships, and put them on airplanes?
    Electric cargo planes are not with us yet.
    And I am not sure when they will be.
    We just need to invent the magic, unicorn-flatulence-capturing, battery.
    Easy-peasy.

    Auto

  7. They’ll have to put the old Burma-Shave signs (of 1960s American roads) up along the shipping lanes, so that a speed trap officer on a Jet-Ski can hide behind it to catch the ships speeding. Having officers sitting out there in mid-ocean would be dangerous and expensive. And think of all the oil/gas mix that will be wasted with them sitting there idling their engines while waiting on speeding ships.

  8. Ships these days are slow enough already.
    The days of trans-Atlantic liners crossing the pond at 33 knots are long gone.

  9. Does anyone know what the CO2 release would be for the construction of those ships?

    Taking everything as claimed it’s still not clear that on net it would be beneficial as you still have to build out the fleet, which has its own environmental impact, as well as increased fleet size as the total shipping volume increases.

    I’ve never seen a total cost of ownership of a cargo ship, but that needs to be added into the reduction and spread over the useful life if the vessel.

  10. “The GL Reynolds report concludes that a 10-20 percent reduction in ship speeds would have a “highly positive potential impact” on carbon dioxide (CO2) emissions and nitrous oxide (NOx) and sulfur oxide (SOx) pollutants. The report also projects that a ship speed reduction may reduce fatal collisions with whales.”

    From the Richard Nixon school of unicorn logic.
    Vehicles engines and gears that provide maximum efficiency at certain speeds.
    Nixon’s declaration removed using the most efficient gearing and engine revolutions from most vehicles.

    Since higher speeds and efficiencies were eliminated by mandatory law, penny wise, dollar foolish fleet managers across the USA purchased smaller engines for their transports. Fielding trucks with undersized engines that found difficulty cruising efficiently at any gear/speed.

    That presidential idiocy spawned personal purchase and massive use of citizen band (CB) radios to track and avoid speed traps.
    Meaning that on highways where the truckers knew where each and every law Officer was located, speeds quickly reached 70 MPH (113 KPH) or faster.

    Desk jockeys applying the same silly logic to ships/boats utterly ignore sea conditions, wind conditions, ship loading, ship’s schedules where delays run into thousands to tens of thousands in costs per day. Besides ignoring what it takes to get a ship/boat on plane and keep it there.

    “The report also projects that a ship speed reduction may reduce fatal collisions with whales.” more wisdom from mumbling fantasies.
    1) assume the ship is to blame.
    2) assume the ship’s speed is to blame.
    3) utterly ignore all of the slow speed collisions.

    That’s a lot like various states blaming drivers, cars, and car speeds for deer running in front of vehicles. Decades later, drivers avoid certain roads because nothing the states have mandated have prevented collisions with deer.

    Next week, these characters will blame bird speeds for their collisions with wind turbine blades… i.e. more specious science based upon assumptions and opinions.

    • “ATheoK November 23, 2019 at 2:57 pm

      Meaning that on highways where the truckers knew where each and every law Officer was located, speeds quickly reached 70 MPH (113 KPH) or faster.”

      At one time in the UK, the AA used to warn you of that.

  11. It must be possible to charge up batteries with wave power and have fuel free shipping.
    It may not be the quickest but it would be the cheapest.
    Wait a bit and technology will solve the problem, if the problem exists.

  12. Another good example of the process whereby a hypothetical/preliminary look at an issue in an academic sense get into the journalists hands and instantly becomes the activist’s roadmap. No further analysis or double-checking, ACTION NOW! is the cry.

  13. Start building clipper ships. That’s the direction the wackos want us to go apparently.
    Speaking of which. This book https://www.amazon.com/Flying-Cloud-Americas-Famous-Clipper/dp/0688167934
    is an excellent read. Fastest clipper ship setting a record for sailing passage from NY to San Francisco going around the horn. A woman navigator who’s husband was the Captain gambled on data concerning currents and winds provided by the Naval Observatory which significantly increased the distance but turned out to cut the time even more and made the passage in a time that was not beaten even by modern racing yachts until 1989. A sailing speed record that stood for 130 years.

    • 89 days, 8 hours to be precise (anchor to anchor). And that was roughly half the time of the slower packet ships the clippers replaced.

      That record has been bested several times, but by purpose-build racing boats. The Flying Cloud was a working cargo ship, carrying paying passengers and cargo. And made of 97% renewable materials!

      Like the Pony Express, the era of the Clipper Ships was ended by railroads, which although they belched fossil fuel emissions got people where they wanted to go in a week instead of three months.

      • The clippers were considered expendable. It was freight and not passenger fares that was the primary commercial driving force for the clippers. Typically one successful passage around the horn would provide a profit for the investors. Every successful passage after the first was pure gravy. Despite the dangers of navigation, especially around the horn, clipper passengers and freight was getting from coast to coast faster and generally safer than other means. Trying to cut the sailing distance by using land transport over the isthmus of Panama was dangerous because of poor infrastructure, unstable politics, bandits, and vector borne and communicable disease. Similar dangers encountered for the much greater distance over land in N. America.

        I am no sailor but have read and seen enough programs about the days of sail to understand just how tough it was and how dangerous it was to sail and labor intensive to maintain those ships.

    • My sweetie grew up across the street from the LA County Fair grounds. There was a drag strip on the grounds (western end) where the “Funny Cars” and the “Top Fuel” raced at least once a year.

      • They still start and end every NHRA Drag Racing season at that dragstrip in Pomona. They just had the finals there last weekend.

  14. If the intent of restricted shipping speeds is to control climate by reducing CO2 in the atmosphere, the proposal should have died on first reading. Fossil fuel emissions don’t add enough to the atmosphere to make any difference. Atmospheric CO2 content does not control atmospheric temperature. These CO2 facts need to be reiterated every time there is an effort to control emissions. All of the unintended consequences aside, the purpose of the effort has no physical basis in the first place.

  15. “And if we returned to horse-drawn wagons, vehicle collisions with deer would be eliminated.”

    I’d like to see data on that. Spooked deer have a tendency to run into the sides of vehicles just as much as they run in front of vehicles.

    A quick search on “deer Amish buggy collisions” yielded quite a few images. Surprising, since the Amish don’t ‘do’ photographs.

      • ???
        We’d still have deer/vehicle collisions if we went back to horse and buggy days, regardless of the motive power of the vehicle. Isn’t a buggy or a wagon a vehicle?

        Now that I think about it, skateboarders might just be able to maneuver adroitly enough to avoid collisions with deer. I’ve never heard tell of a deer/skateboard collision, but then I don’t get out much.

  16. Any displacement hull ship has a natural hull speed that is 1.34 * sqrt of the waterline length. The propulsion system also has a most efficient specific fuel consumption and emissions operating point. These systems are designed together. To run the ship off that optimized point on the low side is no guarantee of anything.

    But the report’s authors don’t seem to do STEM so it’s a simple obvious win win win win win solution.

    • Yep. A bloody big ship is the cheapest, most efficient way of shipping anything. They get something like 1000 ton miles per gallon. link The operators have every interest in decreasing costs. If they could get a lot more ton miles per gallon by going slower, they would.

      There are much bigger fish to fry.

  17. I work for a major oil company. I just cannot imagine the utter absurdity of making a proposal to senior management to increase our contracted tanker fleet by 13% and then make all the other ships sail slower.

    And we have this total numpty Matt McGrath (from the BBC) talking about this is a massive win win win.

    When will this madness end ?

  18. How many “Star Trek: The Next Generation” fans remember that stupid episode where, to save the universe, all star ships had their cruising warp speeds reduced? Years later the producers admitted it was a stupid plot device and, after several episodes, simply eliminated it from future episodes. They went back to, “Warp nine, Mr. Data! Engage! It’s an emergency!”

    • No, it wasn’t reducing warp speed. It was to STOP using warp altogether in that region on space. I took that to be a message to humans about fossil fuels and how bad they were and should not be used.

  19. I could be wrong, but I though these large ocean-going ships already move at an optimal speed, based on tonnage and hull design. Limiting speeds based on some weird notions would only decrease efficiency.

  20. The silly notion is that CO2 has ANYTHING to do with climate. It does NOT. It is an EFFECT of climate change, not the CAUSE of climate change. I learned 60+ years ago that you cannot change climate. Nothing has changed, except now they teach that you CAN change climate (without even trying, by farting), yet no proof has ever been presented to show how it could be done. There are international laws against even TRYING to control climate. Good god, what have we come to?

  21. Why not replace the diesel engines with nuclear reactors like several navies do? If nuclear reactors are safe enough for boats that can be targeted for missiles and torpedoes, surely they can be safe enough for boats not targeted by foreign navies.

    Or why not rig up some kind of tether and sail for ships traveling the direction of the wind. I saw a concept a long time ago where a cargo ship would use an air canon to shoot a sail high into the atmosphere to catch the wind. The sail would then pull the ship so that ship used less fuel. Or maybe ships can go hybrid and use solar panels to supplement the diesel turbines.

    My point is there has to be better ideas than to slow down ships.

  22. Why bother with ships which are already slow ?

    They should instead propose to limit the planes’ speed to 55 mph.
    Particularly for internatioanl / overseas flights.

    • Many years ago, my buddy was flying his old bushplane against a terrible headwind, the traffic on the highway was going faster than he was.

  23. The last I heard many ships have already reduced their speed below their full cruise capability for some economic reason. It was (as I recall) due to over capacity since the financial crisis, 2008

  24. Eeconumpties recommend a 0 knot speed limit. This will save the lives of hundreds of anchovies! “It’s a massive win, win, win, win, win, win, win, win, win, win, win, win, win, win, win, win, win, win, win, win, win, win!”

  25. We can reduce fuel use in ships by building nuclear powered ships. The USA build on such, named USNS Savannah, IIRC. If fuel costs and concern over pollution were the ACTUAL concern, that’s what we’d do. But the eco-freaks just want to destroy the economy and cause as many deaths as possible.

  26. I have a better idea. Bring manufacturing back to the West, and there’ll be no need for so many ships.

    But that will require rolling back many of the BS ‘environmental’ laws which pushed it out. And having reliable power and lots of it.

  27. Better plan. Fit large whale grinders to the front of ships that fed into the fuel tanks.

    Whales are renewable, more or less, and if we accept whales are going to jump in front of ships then at least nothing goes to waste.

    Surely no one can complain about that idea? 🙂

  28. When one lusts for power,they must control EVERYTHING.
    So is seeking to control the world marine trade and step up or a step down, from claiming to control the Climate?

    Shades of Kids in the Hall;’I’m crushing your head…”

  29. Is the CO2 from shipping 2.6% of human-originated emissions or 2.6% of all CO2 emissions including things like rotting trees etc?

  30. Short-sighted thinking. Policy changes like this have many consequences. For example, we bring manufacturing back from over-seas to USA and Europe. MAGA! We can buy more domestic goods instead of imported ones. We can add air cargo and pipelines to natural gas and oil. Chinese will build a railway to Europe.

  31. If a chap, chapess or chapette has oodles of dosh, they could build a “Black Pearl”. Not Captain Jack Sparrow’s but this. https://www.youtube.com/watch?v=k7pCkzz7IWY

    However, the technology is first world & would not be available in any world envisioned by Greta Thunderbird. She is a silly goose who has no chance of laying a golden egg.

  32. “But does anyone really think this would stop sea levels from rising?”
    Well Steve, if we have to put more ships on the oceans this will raise sea levels due to extra weight displacement. I’m sure there must be a satellite that can measure sea level rise in hundredths of a mm.

  33. I read the title and the first thing that comes to my mind is the fact that ships always travel at their economical speed unless they are behind schedule or to avoid collision or any other reason. Economical speed is not the slowest speed possible neither the fastest.

    • Yes. This was all nutted out during the ocean liner wars to win passengers back in the early 20th century. It is also one reason why you see that massive bow “bulge” on modern ships.

  34. Idiocy

    Speed limits would only mean an increase in the number of ships.

    The “green” left’s real objective is to make everyone (but themselves) poorer, and to reduce the population. I say let’s start with them and thereby raise the average level of rational thinking for the species.

  35. Whales.

    How many have been recorded as damaged / injured by ships.

    Are they so stupid that they are unaware of any approaching ships. The massive underwater noise generated by shipping must surely make any whale disappear in the opposite direction.

  36. There is this crazy thing called “calibration engineering” in which engineers “calibrate” ships combustion through the load profile. The majority of ships are running at specific speeds, so the fueling of such ships is “calibrated” based on emissions regulation and then tested in a regulatory capacity to comply with laws. Every change to these regulatory laws requires hundreds of hours of testing and re-certification of these maritime engines, another massive cost that would be passed down to the shipping industry in the purchase of new powertrains and ships. Guess who pays for this, the final customer. The engines are calibrated to have the best emissions they can at specific loads and speeds, thus changing these speeds would almost in all cases result in lowered emissions systems efficiencies and require modifications.

    Get a f’ing job.

  37. 10-20 percent reduction in ship speeds would have a “highly positive potential impact”
    ≠========?
    Nope. Cargo ships create waves which ultimately limit the speed of the ship. The number of waves is determined by speed and waterline length. The speed of the ship is optimized when these waves line up on integral values with the bow and stern.

    As such reducing speed may or may not save fuel.

    • Ships with bulbous bows are designed to be efficient when the bow wave from the bulb cancels the bow wave from the bow by being out of phase. This happens at one particular speed and reduces wave-making drag. If you slow the ship, you lose the fuel saving effect of that.

  38. In business consulting there is a term TCO “Total Cost of Ownership”.
    When investment is evaluated, TCO is calculated to the end of product life cycle – including recycling costs and dismantling etc.
    Proposal to reduce boat speed might be a smart thing to do from pure fuel economy point of view, but he should have presented all the involved costs preferably on a time line. Is TCO recuded or not?
    He is smart to talk about CO2, because if he would talk about fuel cost and vessel construction savings it would sound like dirty capitalism. Instead he takes opportunity to put lipstick on a pig and made it sound like a virtue.
    So my guess is, that cost savings for ship building and operation is behind this. Not CO2.

  39. ” reduce global warming by imposing speed limits on ocean-going ships.” Making ships take longer to reach destinations means burning MORE fuel. Yea, that will “help” the environment. Another pack of maroons self identifies.

    • You’ve hit on a great excuse to try the next time you’re pulled over for speeding, “Sorry officer but I’m low on gas and speeding to get to a station before it runs empty.” (/sarc)

  40. At 100% utilization, if the current number of ships supply X amount of commodity per year at 30 knots, they will supply 1/2 X amount per year at 15 knots requiring twice as many ships.

    This appears to be a wonderful idea for the ship building industry!

    • Few if any merchant ships except small hydrofoil craft travel at 30 knots. It requires massive power. The United States needed 240,000 shp to move 53,000 GRT at 35 knots. And that was a small ship by modern standards.

      And a single Boeing 747 has about four times more capacity measured in passenger-miles per hour.

      • The actual speeds are thoroughly irrelevant to my point, it could have been 4 and 2.

        Not certain how your passenger MPH applies to cargo and what you are comparing it to?

  41. The total world merchant fleet is about 2 billion tons deadweight. A 13% increase would amount to about 250 million tons deadweight.
    To make one ton of steel produces slightly less than 2 ton of CO2.

    Now calculating the amount of steel needed per ton deadweight is not easy, but clearly the amount of CO2 needed just to produce the steel for the additional ships would certainly run into 8 figures, not counting the energy needed to turn that steel into hulls, machinery etc, nor the extra infrastructure needed.

  42. Under international treaty bilge water is not pumped over the side but into on-board tanks. These are empty into special treatment plants ashore. Also ship employ a machine called an oily water separator to extracted the oils from the contaminated bilge water. Spent many years fitting anti-tampering devices to this stuff so it was difficult to circumvent.

  43. OK, I’m late to the party, but, I want to see the math. Maybe slower means fewer emissions, but they are produced for a longer time. Zero sum??

  44. When the ‘Arab oil crisis’ hit in the early seventies, one response was to reduce the standard speed of new-built merchant shipping from 16 knots to 13 knots. This was the cruising speed that a vessel in good condition could reasonably be expected to attain at 85% of MCR (maximum continuous rating) of the main propulsion machinery. The 85% figure had been determined from practical experience to be (roughly) the highest power that could be sustained without suffering excessive wear rates.

    There are several design factors influencing fuel consumption and, as 2hotel9 pointed out above, the extra time taken to complete a slower voyage does take some of the shine off the reduced fuel consumption rate. I believe that, in the late seventies (or early eighties), a study was done on the effect of the reduced speed, and it concluded that the benefits hardly justified the effort. There were some pretty sophisticated energy-saving ideas that looked good and had capital (and ongoing maintenance) costs that would never be recovered over the operational lives of the vessels they adorned.

    Now, of course, we are not saving merely fuel, but the entire planet! It is therefore to be expected that any crackpot, virtue-signalling idea will be given weight far beyond its practical merits. Be prepared for a rerun of the fuel-economy-obsessed seventies.

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