Modern Ship's Engines


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Micheal Napier

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Hi All

I was just wondering if on modern ships, if as much space was taken up by the engine rooms etc, as it did on the Olympic class liners and other ship of that time?

Thank you
Mike
 
Jul 9, 2000
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Not really. On warships, the engineering plant can take up to a third of the hull's length, but that includes auxilaries as well. For Merchent marine vessels, it depends mostly on what the vessel is designed for. A large tanker will have it's plant located aft and it takes up a reletively small volumn of the hull. Also, bear in mind that increasing numbers of merchent marine vessels have diesel engines which is nowhere near as space intensive as a steam plant with it's boilers and assocciated equipment. Also a helluva lot more fuel efficient too, and nowhere near as tricky to operate.

Cordially,
Michael H. Standart
 

Erik Wood

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I would have to agree with Mike on that one. On modern cruise ships that actual plant that runs the ship is usually about 2 to 3 decks high and only maybe a fith or at most a fourth of ship itself. Diesel is the way things are these days. Most ships will have 4 to 6 diesel engines with up to 8 generators. Alot more room is used to stow food and extra.

Erik
 
Dec 29, 2000
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Well, some words to think about, from a steam engine passionist.
First a link:
Swiss Steam Engine Manufacturer for modern steam engines.

Many people watch the old ship, and find, that the engines were large, less powerfull and need hundret hands for maintainace and operation.
So Titanic as Olypmic engines did realy not need much space, what need the space were the 'auxillaries', as boilers, coal bunkers, feedwater tanks and mainanace space. even the engines were large, because oparting with low presures and thus need more space than today constructions.

But a good planned and constructed steam engine can still today easy compete with the gasoline or diesel engines, biuld in mordern ships, and as shown at the link above: First ships were 'rebuild' steamers...
What made the steam engine to abandon? Well, it was the size, the difficulty to operate, the many people to stoke the boilers and the bad enery biliance...
But things changed: Modern power plants changed only their engines, from the recipoking engines to steam tubrines, and still todeay the steam turbine is commonly found in power plants, if not propelled by wind, water or solar radiation.
Well, and that changed again ships propulsion units: Okay, not much 'not-naval-ships' have a nuclear power plant, but many marine ships, especially large vessels, like carriers or special ships, like submarines operate with nuclear power as standart engine. Here we find again the steam engine: The reactor heats up the cooling liquid in the 'hot' area, which will pass a heat exchange unit: Only a 'small' drum, compared to old boilers, but much more efficient. here water is evaporated and send from there to the main engine, commonly a multiple pressure steam turbine. The exaust steam is, as in Titanic or Olympic, given to the condensator, were it is brought back into water, feed again into the heat exchange unit, and then the circle starts again. Many of there power plants are in operation still today. Those propulsion plants have following advantages: If the pressure in the steam circle is kept high, the water temperature can bee keep above 100°C without evaporation, making the use of heat very efficient. Also the boiler has been changed, because nuclar power plants often use a special cooling liquid instead of water, having a better heat absorbtion, so making the heat form the boiler and to the water more efficient use.
Also: Feedwater reseve is today less, because the closed steam circle has less need for additional feedwater, as the closed circle on past times.
But consider: Which passenger would be lucky to stay on a nuclear power plant? None, I knew.
So if we like to consider steam engines in modern passenger lines, we must first look a the boiler. Today boilers use usually diesel or gasoline to produce the heat, so why isn't it better to operate a diesel or gasline engine, instead of 'boiling water'...
First: Heat is the magic word. Modern passenger ships have a large demand for heat. Heat is used to make the cabins comfortable, heat powers the air condition, heat is used for the refridgeration rooms, heat powers the temperature of the all-deamnded swimming pools.
So we need heat at a passenger liner. And many lines have special heationg units, only producing steam for the heat demand. Fuel is 'wasted' just for this demand. A modern ships boiler can deliver both: Steam for the auxillary as for the engines as well.
Second: Diesel engines and gasoline engines have a 'short-Flame-way' so fuel is never copletely burned, so allways some fuel is 'wasted'. Modern boiler have 'long-flame-ways' so all fuel can be burned and the amount of air need for this procedure can be exaclty adjusted, so not as in gasoline engines were air for burning fuel is often too less.
Thrid: A modern boiler can be finely adjusted to the demanded power, so if the engine hewades to a port, and less power is need, often the burned can be nearly completely shut down, because the steam reseve in the boiler is enough for the remaining manoeuvers, so fuel will be not wasted anymore.

Three point for a steam propulsion, but what about the real steam enigne. Here the gasolien and diesel engines have advantages. If you use a boiler, just for the ships heat demand, I can switch it on and off as required, without any guess for the engine itself. Also, modern steam turbines propelling the propeller shaft having the disadavantage, not relay to be able to act in a areas of rounds per minute very economical. In high speed rounds often the steam pressure must be very high, so the boiler must run full power, without that the turbine will be able to use up all the delivered pressure, which must be than 'crushed' in the condensator. Not very economicaly and very fuel wasting.
Next an low round the turbine tends to instead rounds, which is very destructive for bearings, the shaft as the propeller itself, as the turbine will waste steam because the pressure isn't that much required, so the last turbine wheel will even tend to higher vibrations, which is same: Destructive. So a turbine is only effective, when a ship runs long distance a one speed. Gasoline and diesel engines have a broad range of available rounds with a avarage good power output, so require not such a gear or electrical power transmission like turbine propelled ships.

And this is the main reason: We have good boilers today, but mostly the turbine is to complex to act economical in a passenger or short-distance freighter. Turbines are comonly today used to propel a generator, so giving the engeriy to the ship, but a small electic engine will propel the propellers of the ship, very uneconomical and not need, if a more 'flexible' engine is used, like gasoline or diesel engines. So here we can turn on and off the boiler for heat, and can power with a small auxilary steam turbine the auxially generator, but the gasoline engines will propel the propeller shaft and the main generators for electricity.

So what do we need? Maybe the men a DLM had an idea. The small passanger paddle-wheel ship Montreux was rebuild an steam power. A modern boilder was build, and a modern, mainainace-less engine was constructed. So the diesel engine of the montreux was dismounted and the steam power plant was build in. It was quite larger, of course, but it was less fuel consuming and produced less exaust, but was same flexible in engine power output.
Today it seems posible to construct large, fast running recipoking steam engines, fully capsuled as diesel and gasoline engines, so called steam-motors. These maintainanceless engines have the posibility to propel a ship, as modern diesel or gasoline engines can do. but having the advantages of the old steam recipoking engines, of a flexible steam consumption, quick direktion chance ability and direkt access to the main shaft.
Combinated with a modern force-flow boiler the ship is able to support heat to auxillary stations from the main engine room as well as for the main steam engines, without having the need of extra boilers or extra manoeuver engines. this will make an engine compact, maintainanceless and maybe a posibility for further ships. Also the engine power as the boiler power can be fine adjusted to the demand of power of the ship just in time, so less fuel will be wasted as the fuel will be burned much better, resulting in spare of fuel and less exhaust.

But none will try to do it, because steam engines are considered 'old', 'powerwasting' and 'maintainance-eating'.... The DLM has shown these these facts are not proof, so maybe we must think in a different view, to Titanics and Olipics power plant, which was still at their time modern, but was apruplty stopped in development after diesel and gasoline engines were found. With the know-how of today maybe the steam engines can have a new breakthru, if someone will give them the chance to proof these facts.
In railways in switzerland modern steam engines have expeted the diesel trains, as on a paddle-wheeler too.

So I wrote this, just to give you an different view to steam engines and the steam power, if we compare them with diesel or gasoline engines.
 
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I'm not quite sure I follow you on this one. A steam engine, by it's very nature is external combustion...or in the case of a nuclear plant, externally heated, which involves the use of extra machinary and space, and the time needed to heat up all that water from a cold start doesn't really go away. An internal combustion engine vis a vis a marine diesel avoids all of that, and is just as flexible in power settings, and doesn't take up as much space. What's more, you can literally start up at the touch of a button or switch.

Maybe I'm missing something here, so if somebody can spell it out in detail, I'd love to hear it.

Cordially,
Michael H. Standart
 
Jul 9, 2000
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Actually, the post looked more like advertising to me. Frankly, no matter how compact the engines can be made, you still need so many BTU's to heat up a given volumn of water to a given temperature, and you can only get so much work out of it. That invloves time and a lot of energy. The problems of thermodynamics just don't conveniently get lost when you want them to.

Cordially,
Michael H. Standart
 
Dec 29, 2000
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No, modern diesel engines need also a 'preheating' time. In not-naval engines, which also must power auxillary heat supplies, like heating units or air condition units need a heating of the cooling water and the main oil for approximately 30 minutes, or till water and oil have the right temperature to start the engine.
Modern boiler have a preheating time to, but as you said: Extra space is need. But modern ships do not have only a diesel... Look at the auxillary heat units reqired, for air condition and heating supply. There are often large boilers, away form the engine, but still present.
Well, and you can try following: The oil in the main diesel is at 25°C, how good will it lubricate the diesel if you push the start button without preheating. It will be sticky and slimy, so the piston rings and the stroke box will be not good lubricated, resulting in less pressure and fuel wasting. This means more exhaust and loose of efficincy.
As I said: Modern steam engins are consideres like a dinosauer.
And terms: I have my diesel, and I can switch it on and off as I like will not match anymore.
Today, with the correct equipment it is possible to start a thermical power plant of 160 MW in less than 5 hours form a complete cold after a great boiler revision. So sir, I cannot agree. Even a diesel has a time to 'wake-up', because here are also the point of thermodynamic: What about if you do not preveat the bunkers, to get the diesel in the right fluidity? What about auxillary heat units, can you switch tham on and off like a coffea machine? No, Sir, you can't.
An auxillary emergency electricity power plant propelled by a 300 PS MTU diesel requires, after overhaul about 1 hour till oil and diesel are in the condition to start the engine without damage, only for preheating. It is not just pushing a button! No, Sir.
as larger the diesel gets, as longer often preheating must come, just to set the engine into the condition to make it start without any damage.
Setting large diesel engines in march is often not less difficult than to move on a steam engine, just one point is different: collegue computer not makes the engine check up, and waits for the treshold signals, till the push at start would work!
Same one can do today with a steam engine, but: Then we can get rid of the auxillary heat plants, because in the stomic of the ship we have a complete thermical power plant, with the posibility to power all the ships demand of energy.

Or wehy do modern power plants still have boilers? Why do skyscrapers do need steam in winter and summer time, so that modern power plants often have a more steam output than electricity?

No Sir, I cannot agree. Even those large tankers were often not propelled by Diesels, because less efficient, the use steam to propel the turbine to the main shaft... The diesel is then just the manoeuver engine.

No Sir, with such arguments I cannot agree!
 
Jul 9, 2000
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Steffen, I spent twenty years in the Navy on five different ships, only two of which were steamships (And one of those had two nuclear reactors to get things going!) Both of these vessels required several hours to go from "cold iron" to "Ready to answer all bells." On the two LSDs I was stationed on, we had four Colt-Pielstik PC2.5V diesels for main propulsion, and four auxilary diesels to generate electricity. Whenever we needed them, we just fired them up and away we went. I recall an auxilary boiler to provide steam for the big kettles in the galley onlyand small hot water heaters in the heads which were heated electrically.

Steam may be useful for heating, but on neither of the LSDs did we have that. Heating was electric. As for airconditioning, no way is steam used for that.

On the matter of large tankers and most other ships in merchent marines, diesels have been replacing steam for some time and will continue to do so. The costs which you assert do not exist are in fact there and just don't go away. The shipping lines would switch back to steam in a cold second if it could be made to operate more cheaply and efficiently. As they have to be mindful of the bottom line, they can hardly do otherwise.

Diesel fuel BTW, does not require preheating.

You are quite free to disagree if you want of course. But bear in mind we have quite a few of the technically inclined around here as well as sailors like myself and Captain Erik Wood who know the score from first hand experience in the real world. Be careful what you assert. If you're wrong, the refutation won't be long in coming.

Cordially,
Michael H. Standart
 

Erik Wood

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The main reasons for replacement of steam circle around it's lack of reliability. If you get one boiler contaminated then the others will follow before you can stop and you will end up like the QE2 and Norway. I have several times come to the side of the Norway who had lost steam pressure do to some problem or another. I have had the pleasure to drive about (a very rough estimation) 15 different steam driven ships. I know engineers that worked on the Queen Mary in her pre war service.

Steam is a fairly unpredicitable and in the passenger business that cost millions an hour. Especially when the ship is late and loaded.

Most of the older ships on the great lakes are still steam operated and done so without much problem. However, they are small and very "idiot proof". Costs include replacing pipes on a yearly baisis. Not to mention saltwater (another reason great lake ships have greater success with steam) has a bad habit of corrision in boilers. But that is just guess work.

I am not sure what was said to fire up Mike, as I have not completely read the thread above his. But steam is on the way out, it is to expensive and unpredictable for at least the passenger industry.

Erik
 
Jul 9, 2000
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Oh, I'm not fired up, Erik. This chap has me scratching my head in confusion if anything. There are probably any number of rivet counters, sailors, and engineers lurking here doing the same. Sure would be nice to find out what he means by THERMICAL though.
wink.gif


Cordially,
Michael H. Standart
 
May 8, 2001
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MIKE... You appeared to be ruffled, & I have never seen you ruffled before... :)
My simple question, put in simple terms..(Be easy on me here) Is a diesel ship the same as a diesel vehicle, or a semi truck, and is it the same diesel fuel?(In my case it is diesel #2)
I have a diesel suburban and it has glow plugs to bring up the temperature inside to fire the diesel, and we have to put treatment inside to keep the fuel from congelling. We call it "winterizing the fuel" but that is only when we get into the cold months. I have never had to, or heard of bringing up the temperature of the diesel fuel itself.
I have told you everything as I understand it, (smile) but was curious to the similarities of a ship and its engine, or if it is another "type" and just uses the same fuel. Does this question make sence?
Toddling around here.... barely!
Colleen
 
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Morgan Eric Ford

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Mike wrote: "As for airconditioning, no way is steam used for that."

Mike, I agree with your post except for the above line. Have you ever heard of the absorbtion cycle? This a method by which heat can be used for refridgeration or airconditioning. Propane powered fridges in campers use this principle and it has sometimes been used on a large scale to cool a building. One of the drawbacks is it uses ammonia. Never heard of it being used on a ship though.


Morgan
 
Jul 9, 2000
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Sounds to me like you got it right. As far as I know, the only real difference between a marine diesel and any other is that the engines on a ship are a lot bigger and use sea water circulating through the engine block as the coolant. On the LSDs I served on, the engines were started using compressed air. Beyond that, the basic operating principles are the same.

The fuel used is diesel fuel marine is, as I understand it, pretty highly refined but not that much different from any other grade. Whatever the differences, it hardly requires preheating, altough the heavy fuel oils once used in boilers such as black oil and bunker C did. It was pretty thick stuff and wouldn't flow well, much less vapourise as needed otherwise.

The treatment you mentioned may or may not be a stabilizer which is intended to keep the fuel from decomposing. I could be wrong on this as I don't have a bottle of whatever you use handy.

I didn't think I was riled up, though parsing what I wrote, I think I can see why others would. Perhaps I was a tad irritated. If this is the case, it's because something about Steffen's posts strike me as being a bit hinky.
eh.gif
That website link he provided is basically corperate advertising which was long on claims, but I saw nothing by way of independant studies to support any of them. I like peer reviewed studies and papers. Solid proof in other words which I'll take over corperate adverts any day.
wink.gif


Cordially,
Michael H. Standart
 

Erik Wood

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I think I have heard what Morgan is talking about. They used it on the early (1930's to present) steamships that used to carry passengers. I believe that some of the ore boats on the Great Lakes still use this process. I am very ignorant on it.

Erik
 
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Morgan Eric Ford

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This URL does a better job of explaining the details of the absorbtion cycle then I can. I barely know my way around a freon system!

http://www.broadusa-inc.com/absorb.html

The machine described here uses lithium bromide and water. I think they used ammonia and some sort of chloride originally.

Basically heat is used to force the refrigerant out of solution. This serves the same function as the compressor in a conventional system.


I've been told that big diesel trucks that operate in cold climates have fuel tank heaters. Supposedly, they run lines from the engine cooling system through coils in the fuel tanks. Some poeple mix gasoline with diesel fuel to thin it out a bit for cold climates. DF #2 is the most common diesel but there is also a DF #1 that's made for cold climates.

Read someplace that some marine diesels will operate on thicker grades of fuel oil once they are warm. These engines are supposed to have some sort of a heater arrangment for the thicker fuel. This is done for reasons of economy as the thicker fuels are cheaper. I'll try to run down some references for both of these.

Regards,

Morgan
 
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Morgan Eric Ford

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Here's a URL for a diesel fuel heater. These are probably intended for extreme locations like N.D. or Alaska.

http://www.maesco.com/products/racor/r_dfh_intro/r_dfh_intro.html

"The Merchant Marine Officer's Guide" discusses different engine types. According to this book, slow speed marine diesels are sometimes operated on bunker fuel. the procedure is to use bunker fuel when operating at a constant speed for a long time. When starting and manuevering they switch back to regular diesel. Sounds like bunker fuel can't handle changes in speed as well as regular diesel.

The same book says a large marine diesel can be brought on line in 15 minutes compared to several hours for a boiler/turbine plant. Some of the really big marine diesels turn over at 30 RPM!
 
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