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Naval Engineering 19-20c: Fun with numbers

  1. Jan 2, 2019 #1
    I have been reading the book _Able Seamen: The Lower Decks of the Royal Navy 1850-1939_ by Brian Lavery, Naval Institute Press 2011, and I came across an interesting paragraph regarding engine efficiency (and labor requirements) as steam began to replace sail. I reproduce the relevant paragraph for the enjoyment of those who enjoy their history of engineering leavened with a sprinkling of numbers.

    This is the first paragraph on page 154 of the book.

    "The introduction of the turbine engine with Dreadnought of 1906 did nothing to relive pressure on the stoker. There was a steady increase in fuel efficiency and Dreadnought herself needed only 1.52 pounds of coal to maintain one unit of horsepower for an hour, whereas Royal Sovereign of 1892 had needed 2 pounds. But this was swallowed up in the far greater horsepower needed. Royal Sovereign had 9660 horsepower and would need 19,320 pounds of coal to maintain full speed for an hour. Dreadnought had 27,720 horsepower and would need 37,544 pounds, all of which had to be shifted by the stokers. It was calculated that the whole fleet had 2,687,000 horsepower in 1905, rising to 5,665,000 by 1913, and it was projected to reach 8,328,000 by the following year.(12) The King Edward class, one of the groups of predreadnought battleships, needed 273 able and ordinary seamen compared with 120 stokers. In the battlecruisers of the Invincible class of 1907 the proportions were reversed - 163 seamen and 224 stokers."(13)

    The individual footnotes read as follows:
    (12) National Archives, Adm 116/3151
    (13) National Archives, Adm 116/1014

    Hope someone finds this fun/interesting.

  2. jcsd
  3. Jan 2, 2019 #2


    Staff: Mentor

    Thanks for sharing. It boggles the mind.
  4. Jan 2, 2019 #3


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    Intriguing. Thanks for the excerpt. A current thread in a Physics sub-forum mentions fuel amounts comparing fission and fusion reactors. The contrast with early 20th coal use in Dreadnought-class ships is amazing. Lavery's description of stokers feeding the engines provides a striking example of a weak-link or choke-point in sustained operations. Along with the coal one wonders how much of the crew including berths and food supplies were mainly to move coal from piles into the boilers?
  5. Jan 2, 2019 #4
    @Klystron , that was one of the major staffing crisis of the Royal Navy at the time. More and more stokers had to be recruited, at a higher rate of pay than seamen as it happens, as well as feeding and berthing them, and there was always a manpower shortfall. Stokers were also needed to shift the coal in the bins to keep it evenly trimmed and available at the head of the bin to be shoveled into the boilers, in addition, more stokers were needed to spread and move the coal in the fire boxes, and to crack and knock the clinker. It was an amazingly labor intensive (and filthy) task.

    Also notable is how no matter the gains in efficiency, it is always outpaced by the increased demands for power.

    In addition, as a point of information, the pre-dreadnought, pre-turbine ships used a triple expansion steam engine which was used as late as the second world war in US Victory and Liberty ships.

    Last edited: Jan 2, 2019
  6. Jan 2, 2019 #5


    Staff: Mentor

    I spent a very enjoyable day visiting the USS Texas museum in (where else?) Texas. It was from roughly the same era. You can crawl all over that ship including machinery spaces and living quarters. It was the last US steam powered warship with steam pistons before turbines took over.

    Very eye opening to me was the space and complexity of the life support for so many sailors. Food, water, showers, laundry, sewage, dentistry, medical, the brig, mail, sleeping and personal space, religion, onboard marines as police, and so on. Self-contained city is a good description.
  7. Jan 2, 2019 #6


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    While reading this thread I was struck by how cramped a type VII submarine vividly described by Lothar-Gunther Bucheim in his book Das Boot (The Boat) was for the crew of ~50. Aside from the Captain's tiny alcove, berths seem almost an afterthought to the boat designers. Bunks are bolted on nearly every horizontal interior bulkhead not already covered by machinery. One of only two heads must be used for storing provisions during long patrol voyages. Instead of stokers and coal, the submarine engineers are obsessed with diesel fuel consumption and the competence of the diesel mechanics.

    Last edited: Jan 3, 2019
  8. Jan 2, 2019 #7


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    Rudolph Diesel's early compression ignition engine was designed to use a compressed air blast to inject coal dust into the cylinder. It was not a success, until the coal dust was replaced with vegetable oil.

    You are surprised by that paragraph because we have forgotten the changes that happened a century ago when the availability of liquid fuel started the “oil age”. We have become blind to the community, local economy and environmental implications of liquid fossil fuels.

    Apart from putting all those stokers and fuel teamers out of work, it made war faster, geographically wider and made the stress and destruction of civilisation more complete.

    Liquid fuels subverted the economy by making many things possible that would otherwise not be done, such as the proliferation of privately owned cars and the state funded commuter and highway systems. That destroyed village communities by forming impersonal cities where common people had less value than car parking spaces. Railways and ships are significantly safer solutions.

    We burn huge quantities of fossil fuels for quite unproductive activities. Airlines based in the oil rich nations now compete to fill seats with international tourists. Rather than investing in improvements to their home and work environment, the tourists escape, competing to transfer their behavioural problems to more exotic places.
    You can now fly across the globe in less time than the incubation period of any infectious disease. So long as the health system is restricted to wealthy patrons in affluent countries, pandemics will occur. The availability of cheap liquid fuels threatens you and your community.

    Our utilisation of liquid fuels has distorted our world beyond reason. We are now seeing a quickening environmental and economic reaction to liquid fossil fuels that is encouraging the introduction of renewable energy and electrical systems. How can you encourage those sensible changes to improve your local environment and community values?
  9. Jan 2, 2019 #8


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    Archimedes invented the screw conveyor in around 235BC. It's amazing to me that it or something similar wasn't adapted to solve this problem sooner.

    [edit] This says 1905 is when they started becoming a thing:

    ...and 1923:
    Last edited: Jan 3, 2019
  10. Jan 3, 2019 #9


    Staff: Mentor

    This is a good thread, because the example can be viewed from many viewpoints.

    We could also view this whole topic as an ordinary application of automation, independent of burning and marine applications.

    Later in the 20th century, conveyors moved the coal, pulverizers crushed it into a dust, and fans blew the dust into the furnace to burn. Dust is not a liquid, but it can be treated like a fluid.

    When we debate whether automation creates more jobs than it destroys, even those stokers become part of the equation.

    (Before someone objects, I prefer very broad definitions for the words "automation" and "AI".)
  11. Jan 4, 2019 #10
    Years ago, I stood in the LP cylinder of the Texas. It was just about all I could do to reach from wall to wall, as I recall it.
  12. Jan 5, 2019 #11

    jim hardy

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  13. Jan 7, 2019 #12
    I made this print from a negative I rescued from a dumpster at work many years ago. This is advertising copy from 1917 (I think Power magazine). Note the century-old point of view: "So easy to handle that women operate them."


    Sorry for the glare. I can't imagine why I printed this on glossy; I just took a quick cell-phone photo to get it onto my computer.
  14. Jan 7, 2019 #13
    Mechanical stocker was invented in 1905, just a bit too late to be used on naval vessels in 1906-1907 period. Also, stockers were not only shoveling coal - most of them doubled as mechanics servicing other parts of equipment. After all, periods of required 100% engine power were rather infrequent.
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