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Water and it’s effect on Boilers?

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Was watching a movie and the engineers were telling the Captain they needed to evacuate before the water hit the boilers? And once it did they ended up exploding? I know Hollywood is great at making fictional or overly dramatic things happen, but got me thinking that it seems like I had heard or read something about boilers in era around WWI - WWII have some vulnerabilities. And now the question is driving me crazy oddly enough so decided to ask in Forums since I know some of you would easily know the answers.

So I am wondering if sea water flooding in would actually cause the boilers to explode and why that is? Or if the flooding would simply douse the fires in boilers causing loss of power? Of course either way having flooding in engine room of a ship is never a good thing, well not really a good thing in any part of a ship for that matter.

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Boilers are under a  lot of pressure and have a high temperature. Forcibly cooling them with external water can cause serious damage to them, yes. And if they're so damaged while under high pressure ...

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14 minutes ago, Admiral_Thrawn_1 said:

Was watching a movie and the engineers were telling the Captain they needed to evacuate before the water hit the boilers? And once it did they ended up exploding? I know Hollywood is great at making fictional or overly dramatic things happen, but got me thinking that it seems like I had heard or read something about boilers in era around WWI - WWII have some vulnerabilities. And now the question is driving me crazy oddly enough so decided to ask in Forums since I know some of you would easily know the answers.

So I am wondering if sea water flooding in would actually cause the boilers to explode and why that is? Or if the flooding would simply douse the fires in boilers causing loss of power? Of course either way having flooding in engine room of a ship is never a good thing, well not really a good thing in any part of a ship for that matter.

Well when any hot tank like a pressure  vessel  like a tank or container is hit by a liquid mass that is very cold this causes the container to experience a thermal shock which can damage the container which in turn release its hot gases. Now there are safety blow off valves to blow off excess steam but in a case of a flood the water volume and quick cool down is too rapid and becomes overwhelmed thus resulting in a thermal explosion.  Rule of thumb is that any quick cool down from one temperature extreme to another causes metal to expand or contract usually results in a deformity and crack in the structure.  In this case its steam but if the container contained an explosive material it would be even worse.  

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TLDR:  What @dionkraft said.

 

The longer version:

It takes days for large marine boilers to reach operating temperature and nearly as long for them to cool down.  That's a lot of potential energy stored up there by itself.  Add to that they mostly operated systems in the 5-750psi range and you're adding even more energy to the mix.  Post-war designs would up the ante to 1200psi, engineers would walk around carrying a broomstick in front of themselves if they heard a steam leak.  That way (hopefully) the stick would encounter the super heated steam first and be sliced in two before the engineer.

When a 1000ºF boiler is suddenly doused with 35º to 90ºF seawater the thermal shock is more often than not sufficient to rupture the pressure vessel and explosively release system-pressure steam in to the people spaces.

To answer your question, though, yes.  Fire is dangerous everywhere in a ship.  Flooding is dangerous everywhere too, when in sufficient quantity.  It's dangerous in any quantity in torpedo magazines and around boilers.

It's messy.

-R

Edited by Mister_Rawr
Ninja'd. Feelsbadman. lolwut.gif

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Yeah figured Boilers would get temperamental about seawater that often is quite cold hitting that hot metal. Metal is all too much like glass when exposed to intense heat and cold at the same time, both will fracture or at the very least deform under such conditions.

So what about the ships that had more than one boiler room with bulkheads dividing them? How often would ships be able to to possibly maintain at least partial functionality if one of the boiler rooms exploded? Or would it oftennresult in a chainnof explosions with the first boiler room breaching the next room and then the sequence continuing?

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Another thing I imagine to be painful is the effects on the water itself after making contact. It would obviously evaporate, but since the steam takes more volume than tha liquid (for 100°C the conversion rate is roughly 1:1700) you would also have a lot of hot steam which wants to expand, and would cook anyone who gets hit by it.

That‘s also why the last thing you want to throw into a burning chimney is water. It would literally explode.

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11 minutes ago, Admiral_Thrawn_1 said:

Yeah figured Boilers would get temperamental about seawater that often is quite cold hitting that hot metal. Metal is all too much like glass when exposed to intense heat and cold at the same time, both will fracture or at the very least deform under such conditions.

So what about the ships that had more than one boiler room with bulkheads dividing them? How often would ships be able to to possibly maintain at least partial functionality if one of the boiler rooms exploded? Or would it oftennresult in a chainnof explosions with the first boiler room breaching the next room and then the sequence continuing?

usually the design of the multi boiler ship or any kind of industrial facility that has the same - like a steam electric power plant have valves which can isolate and divert the flow or stop the steam pressure as long as the valves themselves are not damaged. usually they have multiple valves inline in case one fails..the other should work.  

Operators have diagrams showing which valves to close and open to do a certain kind of result.  They must be accurate as if it took six valves to operate and five guys did it right but the sixth guy turned the wrong valve on/off..the result is not good usually....

Edited by dionkraft

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Just a note..whenever there is a fire on some pressure vessel and could possibly rupture fire fighters will use a 'Fog" water nozzle to gradually cool down the pressure vessel so as not to cause damage or explosion. Any straight water hose application will cause a rapid temperature drop ( at that one spot) and cause metal damage which could an  explosion and cause fatalities.  

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21 minutes ago, Admiral_Thrawn_1 said:

So what about the ships that had more than one boiler room with bulkheads dividing them? How often would ships be able to to possibly maintain at least partial functionality if one of the boiler rooms exploded? Or would it often result in a chain of explosions with the first boiler room breaching the next room and then the sequence continuing?

There are many occurrences of ships losing fires at different times, usually caused by a loss of ventilation or interruption of fuel flow.  Usually each shaft has its own dedicated gear set, turbines, boilers and engineering space.  I've never seen a design in which one prime mover can be shifted to a different shaft.  I don't suppose it's impossible, just very impractical.  Most of the time a flooded engineering space would result in the loss of its associated shaft, while the ship could proceed on the one, two or three remaining.

Cascading failures can, did and do occur though.  Usually through compromising a single point of failure in the fuel, ventilation or electrical supply system.

-R

Edited by Mister_Rawr
Devagueifyin' the linguistification.

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11 minutes ago, Mister_Rawr said:

There are many stories of ships losing fires at different times, usually caused by a loss of ventilation or interruption of fuel flow.  Usually each shaft has its own dedicated gear set, turbines, boilers and engineering space.  I've never seen a design in which one prime mover can be shifted to a different shaft.  I don't suppose it's impossible, just very impractical.  Most of the time a flooded engineering space would result in the loss of its associated shaft, while the ship could proceed on the one, two or three remaining.

Cascading failures can, did and do occur though.  Usually through compromising a single point of failure in the fuel, ventilation or electrical supply system.

-R

The situation with any kind of system when you have a system of valves which can divert from pressure vessel to another whether its fuel, ventilation, electricity, pneumatics etc is the redundant plumbing is added as a benefit but also can be a liability as it can be a maintenance burden, ie, leaks in valves and inspection and testing of their safety of operation.   I would imagine the smaller the space the redundancy would be not considered. On the other hand if (space permitting) redundancy would be considered but there is no rule of thumb. its the old cost benefit argument and it could go both ways.  

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49 minutes ago, Mister_Rawr said:

There are many occurrences of ships losing fires at different times, usually caused by a loss of ventilation or interruption of fuel flow.  Usually each shaft has its own dedicated gear set, turbines, boilers and engineering space.  I've never seen a design in which one prime mover can be shifted to a different shaft.  I don't suppose it's impossible, just very impractical.  Most of the time a flooded engineering space would result in the loss of its associated shaft, while the ship could proceed on the one, two or three remaining.

Cascading failures can, did and do occur though.  Usually through compromising a single point of failure in the fuel, ventilation or electrical supply system.

-R

Pretty much. Most WWII ships had at least two boiler rooms and engine rooms. If one was lost, the other could theoretically carry on, though if the engine room goes down that shaft goes down too. However, in case of boiler explosion, the explosion probably did damage, which may shut down everything. Also, if your engineering spaces are flooding your probably not going to need the boilers much longer.

Often if the boiler room was in danger of flooding they'd shut them down and dump steam (depressurize) to avoid that kind of explosion.

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By the time the boiler rooms are flooding, it is probably time to abandon ship.

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One of the Hollywood fallacy's though is that a boiler rupturing (or exploding as they call it) would catastrophically damage the ship like a small nuke going off inside.  Not likely.  Would there be a catastrophic event in the boiler room?  Yes.  Possibly killing anyone in there.  but once there is a limited amount of steam in the relatively small boiler being released into a large engineering space.  It is doubtful the hollywood 'explosion' would reach beyond the bulkheads of that engineering space. 

Significant damage and loss of life.  Yes.  An exploding ship which should be immediately abandoned?  No.  My 2 cents as a former squid.

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31 minutes ago, SeaborneSumo said:

One of the Hollywood fallacy's though is that a boiler rupturing (or exploding as they call it) would catastrophically damage the ship like a small nuke going off inside.  Not likely.  Would there be a catastrophic event in the boiler room?  Yes.  Possibly killing anyone in there.  but once there is a limited amount of steam in the relatively small boiler being released into a large engineering space.  It is doubtful the hollywood 'explosion' would reach beyond the bulkheads of that engineering space. 

Significant damage and loss of life.  Yes.  An exploding ship which should be immediately abandoned?  No.  My 2 cents as a former squid.

As always HOLLYWOOD takes its liberties to make reality not what it is but what Hollywood thinks it should be to fit their scripted movie. Well movies are a form of escape so we can't fault them on that but if you are a technical person who knows how some things work and their result and you see otherwise in a movie..you have to chuckle and laugh as you KNOW that ain't gonna happen..but why spoil it for others who do not know and are entertained eh?  Sometime you have to laugh within ones self....silently...thats what my wife tells me!

Edited by dionkraft
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Hollywood likes the dramatic and Boiler explosions are no exception,there would not be as catastrophic as depicted also depending on the ship sometimes the boiler or engine would actually break free of there mounts if the ship went vertical as it sunk causing extensive damage

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4 hours ago, Admiral_Thrawn_1 said:

Was watching a movie and the engineers were telling the Captain they needed to evacuate before the water hit the boilers? And once it did they ended up exploding? I know Hollywood is great at making fictional or overly dramatic things happen, but got me thinking that it seems like I had heard or read something about boilers in era around WWI - WWII have some vulnerabilities. And now the question is driving me crazy oddly enough so decided to ask in Forums since I know some of you would easily know the answers.

So I am wondering if sea water flooding in would actually cause the boilers to explode and why that is? Or if the flooding would simply douse the fires in boilers causing loss of power? Of course either way having flooding in engine room of a ship is never a good thing, well not really a good thing in any part of a ship for that matter.

Haven't seen the movie, but they tend to take liberties for the sake of theatre, which is fine.  It's entertainment.  Never a good idea to take a movie as a form of education, so it's good that you asked.

There is some validity to the situation you described.  Its a reason why you don't use water to put out a Class D fire (fires involving metals) aboard ship.  Water lines are only used to push these types of fires overboard if possible, otherwise you use a Class D or E extinguisher.  Burning metals, especially magnesium, do not react kindly to rapid temperature changes resulting for immersion or contact with a large amount of water.  It can break up and explode, doing more harm than good, especially to the DC crew fighting the fire.  When you're talking about boilers that are already extremely hot to begin with, burning coal or oil and containing extremely high pressure steam, and packed in a confined space, suddenly coming into contact in cool sea water rushing in makes bad things happen.

Depending on the degree of flooding, if an engineering crew finds themselves in such a situation, it's time to stop what you're doing and gtfo asap.

 

TLDR:  Extremely hot metals + sudden contact with water = BAD

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3 hours ago, Admiral_Thrawn_1 said:

Yeah figured Boilers would get temperamental about seawater that often is quite cold hitting that hot metal. Metal is all too much like glass when exposed to intense heat and cold at the same time, both will fracture or at the very least deform under such conditions.

So what about the ships that had more than one boiler room with bulkheads dividing them? How often would ships be able to to possibly maintain at least partial functionality if one of the boiler rooms exploded? Or would it oftennresult in a chainnof explosions with the first boiler room breaching the next room and then the sequence continuing?

All comes down to a myriad of factors. But for an idea ofthe forces were talking here -

800px-Locomotive_engineering_-_a_practic

A boiler explosion launched that train onto the top of the other. USS Bennington in 1905, were she not quickly beached by a tug, would have sunk due to it opening a hole in the side. While some ship designs and all it'd be less likely, if the initial blast is from an open hole letting seawater in, and is next to another boiler room, if the blast is powerful enough to open another hole in the ship, that breaches the next room, or destroy anything that blocks the rooms such as the bulkhead or, more likely, some kind of watertight door if it exists, could potentially cause a chain reaction that plays out over time. Unlikely it would be a series of rapid explosions though. 

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26 minutes ago, Kuckoo said:

Haven't seen the movie, but they tend to take liberties for the sake of theatre, which is fine.  It's entertainment.  Never a good idea to take a movie as a form of education, so it's good that you asked.

There is some validity to the situation you described.  Its a reason why you don't use water to put out a Class D fire (fires involving metals) aboard ship.  Water lines are only used to push these types of fires overboard if possible, otherwise you use a Class D or E extinguisher.  Burning metals, especially magnesium, do not react kindly to rapid temperature changes resulting for immersion or contact with a large amount of water.  It can break up and explode, doing more harm than good, especially to the DC crew fighting the fire.  When you're talking about boilers that are already extremely hot to begin with, burning coal or oil and containing extremely high pressure steam, and packed in a confined space, suddenly coming into contact in cool sea water rushing in makes bad things happen.

Depending on the degree of flooding, if an engineering crew finds themselves in such a situation, it's time to stop what you're doing and gtfo asap.

 

TLDR:  Extremely hot metals + sudden contact with water = BAD

Lol yeah you can certainly say they took a lot of liberties considering I just watched this since it was on Netflix and thought it would be fun to watch again since it had been quite a while...

5EDC4002-BCD2-45A9-8DD1-10964D8C0ECB.thumb.jpeg.2e5029151d9bcee8759976893c50abf3.jpeg

So yeah would not take the movie seriously, but the part with the boilers did spark my questions in this thread since I have a good memory and it seemed like I had heard boilers on ships had certain vulnerabilities and hazards. The movie simply reminded me since the one shred of realism they apparently did have was the boilers going up when water reached them...

And I am not afraid of asking questions to find answers and well and contemplate info on various subjjesct pretty much 100% of the time that I spend awake. So I enjoy these discussion threads a lot, and knowing we have wide variety of people that come to these forums I knew I would get a lot of answers from people that may have worked with or knew somebody who worked with boilers and save myself possibly hours of research to satisfy my curiosity. Amazing what things can suddenly remind you of questions that you never got the answers to or had not yet even thought to ask, but this one did lol. 

I do enough historical and and scientific studies as part of my hobbies and I knew in theory boilers would react harshly to those temp changes, however there are always variables. So just because metal or glass might usually shatter, deform, fracture, or explode it does not always do so depending on thickness, materials, or the conditions. So as I said felt this would be good thread to get some answers.

 

 

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If it's a catastrophic explosion you're looking for, it would have to be the result of a nuclear reactor meltdown, with the molten fuel rods melting through the ship's hull and reaching the sea water.  Then you've got a massive thermal explosion on your hands.

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In terms of the OP, seawater flooding a boiler is very unlikely to make it explode.  The reason for this is the seawater will have a quenching effect on both the metal and hot water in the boiler.  You can see this from the fact that many ships in both WW 1 and 2 suffered flooding of active boiler rooms and didn't explode.

What causes boiler explosions is they over pressure (the pressure relief valves / system fails to work) or they are ruptured by something like a shell entering the ship and smashing the boiler.  That causes the boiler to "explode."

The Mythbusters show this on a small scale several times where they detonate hot water heaters (low pressure and temperature boilers).

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2 hours ago, Sventex said:

If it's a catastrophic explosion you're looking for, it would have to be the result of a nuclear reactor meltdown, with the molten fuel rods melting through the ship's hull and reaching the sea water.  Then you've got a massive thermal explosion on your hands.

Not going to happen.  The reason is, once the reactor melts down, the geometry of the fuel rods has shifted.  If it is also mixed with non-fuel rod material like control rods or scaffolding to that holds the fuel rods in place, all that has caused criticality to end.  This means you are only dealing with the residual fission products that are decaying and creating a small amount of heat.

Reactors work because they are very carefully designed to have the fuel in a very specific pattern.  Without that pattern being maintained getting fission to occur is very difficult or impossible.  That's why the Nazi reactor shown probably wouldn't have worked:

maxresdefault.jpg

The geometry of the blocks of uranium are irregular in relationship to one and other.  That isn't good for causing regular and steady state fission.

In essence, the whole "China Syndrome" is nothing but a Hollywood myth.  It simply cannot happen.

See...  They did teach me something from all those years in Navy nuclear power... :Smile_amazed:

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15 minutes ago, Murotsu said:

Not going to happen.  The reason is, once the reactor melts down, the geometry of the fuel rods has shifted.  If it is also mixed with non-fuel rod material like control rods or scaffolding to that holds the fuel rods in place, all that has caused criticality to end.  This means you are only dealing with the residual fission products that are decaying and creating a small amount of heat.

Reactors work because they are very carefully designed to have the fuel in a very specific pattern.  Without that pattern being maintained getting fission to occur is very difficult or impossible.  That's why the Nazi reactor shown probably wouldn't have worked:

maxresdefault.jpg

The geometry of the blocks of uranium are irregular in relationship to one and other.  That isn't good for causing regular and steady state fission.

In essence, the whole "China Syndrome" is nothing but a Hollywood myth.  It simply cannot happen.

See...  They did teach me something from all those years in Navy nuclear power... :Smile_amazed:

I recall a substantial steam explosion risk during the Chernobyl disaster.  As wikipedia put it: "A similar concern arose during the Chernobyl disaster: after the reactor was destroyed, a liquid corium mass from the melting core began to breach the concrete floor of the reactor vessel, which was situated above the bubbler pool (a large water reservoir for emergency pumps, also designed to safely contain steam pipe ruptures). The RBMK had no allowance or planning for core meltdowns, and the imminent interaction of the core mass with the bubbler pool would have produced a considerable steam explosion, increasing the spread and magnitude of the radioactive plume. It was therefore necessary to drain the bubbler pool before the corium reached it. However, the initial explosion had broken the control circuitry which allowed the pool to be emptied. Three station workers volunteered to go manually operate the valves necessary to drain this pool, and later images of the corium mass in the pipes of the bubbler pool's basement reinforced the prudence of their actions." - https://en.wikipedia.org/wiki/Nuclear_meltdown#China_syndrome

 

Although I personally do not know the safety procedures of a reactor on a navy vessel.

Edited by Sventex

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9 minutes ago, Sventex said:

I recall a substantial steam explosion risk during the Chernobyl disaster.  As wikipedia put it: "A similar concern arose during the Chernobyl disaster: after the reactor was destroyed, a liquid corium mass from the melting core began to breach the concrete floor of the reactor vessel, which was situated above the bubbler pool (a large water reservoir for emergency pumps, also designed to safely contain steam pipe ruptures). The RBMK had no allowance or planning for core meltdowns, and the imminent interaction of the core mass with the bubbler pool would have produced a considerable steam explosion, increasing the spread and magnitude of the radioactive plume. It was therefore necessary to drain the bubbler pool before the corium reached it. However, the initial explosion had broken the control circuitry which allowed the pool to be emptied. Three station workers volunteered to go manually operate the valves necessary to drain this pool, and later images of the corium mass in the pipes of the bubbler pool's basement reinforced the prudence of their actions." - https://en.wikipedia.org/wiki/Nuclear_meltdown#China_syndrome

 

Although I personally do not know the safety procedures of a reactor on a navy vessel.

Chernobyl was a case that's different here.  The reactor there was a graphite moderated one.  What you had was a reactor design that was in essence a building sized pile of graphite (think charcoal / coal) with holes drilled in it for the fuel, cooling water, and control rods.  The accident happened when the reactor was operating at very low power (a no-no according to their own operations manual) that resulted in a hot spot forming near the bottom of the reactor.  This in essence was a coal fire.

As with any coal fire, as it progressed, it created gas that had nowhere to escape.  That resulted in the explosion that happened.  This in turn ruptured the water cooling system and released steam.  The aftermath has the now destroyed reactor still burning as a coal fire mixed with burning uranium metal and other metals that were in the reactor as part of its design.  Putting out coal fires is very difficult to do.  It also didn't result in the fissile material (uranium) continuing to fission.

All of this is a major reason graphite moderated reactors were not used in commercial practice in the West (except Britain for a short time in the 50's).  They are dangerous, as well as they produce weapons grade plutonium as a biproduct of operation.

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