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Using Foam inside the hulls of warships.

  1. Dec 3, 2014 #1
    I thought that instead of having compartments filled with air, why not have compartments that were totally filled with foam, permanently preventing water from filling them up? The entire hull beneath the water would simply be foam. An ultrathin metal cubic mesh could stop parts of foam from leaking out around impact/damage locations.
     
  2. jcsd
  3. Dec 3, 2014 #2
    When you say foam, can you be more specific? Interesting idea! Cost could be an issue?
     
  4. Dec 3, 2014 #3

    Bystander

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    What's the useful military purpose of hauling around a lot of foam-filled space? You might want to look at some of the stories/anecdotes about "Q-ships" in WW II.
     
  5. Dec 3, 2014 #4

    Astronuc

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    Adding to what Bystander mentioned, foam would occupy useable space. Living quarters are below deck, as is machinery, fuel, ammunition/missiles, etc. An impact (think armour piercing) would penetrate the hull, and the explosion would push away the foam. Bulk heads provide structure/support/stability to the hull.

    It might work for certain types of small craft.
     
  6. Dec 3, 2014 #5

    SteamKing

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    Recreational craft manufactured and sold in the US and other countries are already mandated to maintain flotation even when they are swamped. Many craft use foam to exclude water from flooding empty space in the hull, which might lead to the vessel sinking.

    On a large commercial vessel or warship, the space below deck is dedicated to carrying fuel, ballast, cargo, machinery, etc. If the vessel is carrying around a large amount of empty space which can't be used to store something or otherwise be occupied, then the arrangement has not been properly designed, and the vessel is larger than it should be.
     
  7. Dec 3, 2014 #6

    nsaspook

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    To add with what the others have said it's also pretty hard to repair damage to structural bulkheads, piping or electrical systems in a room filled with foam and at least on the ships I was on we had stuff (food, weapons,extra equipment) crammed into every possible space when ready to deploy. It's not gimmicks that save warships.

    Here's an old VHS video of a LPH class ship that was hit by a mine in DS and the types of shoring needed to keep it going.
     
  8. Dec 12, 2014 #7
    Foam can expand to fill and solidify a space. That's a hazard when you happen to occupy the space, but when a boat is pierced, I reckon all's fair to save what you have.
    Speaking of saving ships, does anyone remember the US U-boat that caught fire awhile back? The fire was due to a criminal act, but the point that got me was why? Why are we making boats and ships that are so flammable? The aerospace people have been successful at controlling flammables, but it seems the Navy isn't as successful.
     
  9. Dec 13, 2014 #8

    SteamKing

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    The USN doesn't operate 'U-boats'. You have them confused with the submarines operated by the German navy.

    The fire was due to a criminal act, as you yourself stated. If criminals can't start a fire with stuff on hand, they'll bring something which can burn.

    http://www.cnn.com/2013/08/07/us/navy-submarine-lost/

    The worker who set the fires admitted to using alcohol wipes from a trash can to set one fire. The fire which apparently did the most damage was set in a crew berthing space.

    The problem with fighting a fire inside a submarine is that access cannot be easily obtained to bring in the necessary equipment. Once the fire has raged for a period of time, vital equipment inside is damaged and requires replacement. This is usually very expensive.

    It's not clear what you mean here. Every time a plane crashes, a huge fire usually breaks out from all the fuel which was spilled.

    Navy ships usually carry things that blow up, around which it is not recommended that you start a fire. It's the nature of operating a naval vessel.
     
  10. Dec 13, 2014 #9

    DaveC426913

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    Closed-cell styrofoam is solid and buoyant. My sailboat has enough embedded behind bulkheads to keep it from sinking even when swamped to the gunwales.

    The $65,536 question is: how much volume of a military ship do you need to fill with foam to keep it afloat? It does NOT have to be the whole below-waterline volume.
     
  11. Dec 13, 2014 #10

    Bystander

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    ... as stated, plus, is the increased target cross-section offset by the flotation?
     
  12. Dec 13, 2014 #11

    SteamKing

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    If you've got space enough to spare to put foam in, your navy ship is already too big (and too expensive).

    Below decks, naval vessels are not designed with large empty spaces which could be foamed. If the space isn't devoted to housing the propulsion or steering machinery, it's used to store food, fuel, or ammunition.

    Unlike sailboats and other small commercial/recreational craft, naval vessels are subdivided internally with watertight bulkheads and decks, and the compartments formed by these subdivisions can be closed off in the event of damage to prevent progressive flooding into other, undamaged spaces. In a modestly sized naval vessel, this means dozens of compartments; in a large vessel like an aircraft carrier, possibly several hundred compartments.

    Naval designers already assume that ships and submarines can get damaged in battle and plan accordingly.
     
  13. Dec 13, 2014 #12
    Regarding fire on the sub (call it what you will), why would the crew quarters have flammable material given the difficulty of fighting fires in such confined spaces? Silicon compounds can be substituted for natural rubber and materials can be treated with bromide compounds to discourage flammability.

    It rather much reminds me of the 80's when the Soviets suffered most of their house fires from televisions. Due to a few common sense measures by UL laboratories, such failures were rare in the US.

    Aerospace has made great strides in lower-flammability hydraulic fluids and avoiding the spread of fire through the use of metallic fuel lines, and remotely controlled foam injectors.
     
  14. Dec 13, 2014 #13

    DaveC426913

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    Yes, but it's a question of compromise.

    Your assertion is that minimizing the linear dimensions of the craft is of so high priority that it prohibits this safety device. That's fine, as long as that is the priority that outweighs all others. (But if it were the only priority, no ships would be more than 10 feet long. :) Clearly, some priorities such as crew, fuel and weapons take precedence over minimizing size.)

    No ship has size as such a high priority that they don't include room for such things as life jackets for all crew, lifeboats, etc.

    They are as big as they need to be, to do what they need to do.

    And yet they do still sink, taking lives with them.


    I'm not suggesting the OP has an efficient idea, I'm simply suggesting that it could be done if it were considered a priority.
     
    Last edited: Dec 13, 2014
  15. Dec 13, 2014 #14

    SteamKing

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    In case you haven't noticed, vessels are three-dimensional structures. If you make a vessel longer than it has to be, usually it also has to get wider, deeper, or both, in order to maintain stability and to provide the additional volume inside the hull to accommodate the excess structure or fuel it takes in order for the vessel to function.

    And more than that, it's also a question of money. It takes money to build a ship, especially a navy ship, and it takes a lot of money to supply it, crew it, operate it, and maintain it throughout its service life. The amount of money available to do these things is shrinking, not only for the navy, but for the other services as well.

    No one is saying that.

    You don't store life jackets and survival craft inside the ship. These items work best when they can be accessed by the crew as they are going over the side.

    This sounds like Stuart Smalley.

    I'm not aware of any losses of USN vessels lately.

    There are a lot of things which could be done, if they were considered a priority. You could paint the exterior of naval vessels a bright, Pepto-Bismol pink instead of that dreary gray color, if that were a priority. Alas, it's not.
     
  16. Dec 13, 2014 #15

    nsaspook

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    My experience with shipboard fires was that it rarely happens in crew quarters because the people there would stop the fire before it got out of control. The largest non-engine room fire I was involved with started in a storage room for cleaning materials deep in a hold from an electrical short. We cleared the storage spaces around the fire to isolate it from more fuel and then pumped sea water into those spaces to stop the heat from from starting new fires. Being able to selectively flood spaces and then pump them dry below the water line is an important part of shipboard fire-fighting and damage control. Having large spaces with foam would limit that ability.
     
  17. Dec 13, 2014 #16

    SteamKing

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    At the time of the fire aboard the USS Miami, the vessel was docked at Portsmouth Naval Shipyard in Maine. The sub was undergoing an extended maintenance period while at the SY, so it's not clear how many crew were aboard while the SY workers were going about their tasks. That a SY worker, for whatever reason, was able to set one fire, let alone two, shows a shocking lapse in security at the SY. Apparently, the fire set in the crew berthing space was fueled by rags used for cleaning purposes, but details about the incidents are not clear.

    http://en.wikipedia.org/wiki/USS_Miami_(SSN-755)

    http://www.navytimes.com/story/military/2014/11/13/submarine-miami-investigation-fire/18966773/

    It's still not clear what this fire has to do with putting foam inside a ship.
     
  18. Dec 13, 2014 #17

    Bystander

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    If the Geneva and Hague accords/conventions, and international law were modified and universally recognized to bind all parties to the outcome of "nerf fights," there might be an argument that foam and bubble wrap aboard warships would serve some military purpose. It's not the case at present, has never been in the past, and ain't likely to be so in the future.
     
  19. Dec 13, 2014 #18

    Doug Huffman

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    About the Miami, just so. In an extended yard period neither crewing nor conditions are anything like normal I was Plank Owner on the last ship build at PNS and we had - ahhh - difficulties. Rickover's toy, the NR-1 had a significant fire.

    The quality of yard workers varies considerably, from Rickover's hand picked minions to an old cleaner, that I remember with some fondness, called 'Apple'. We had a shore power connection fail, explode and burn, about ten feet from the maneuvering-control room, where I as Shutdown Maneuvering Area Watch had my hands full while old Apple stood in the door way pointing and babbling.
     
  20. Dec 13, 2014 #19

    DaveC426913

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    Not sure why you feel the need to state the obvious and be sarcastic about it. Is there anything I said that would cause you to think I don't know basic 3D geometry?

    Also obvious. Beside the point.

    I think you are arguing a different point. I think you are arguing why they choose other ways to operate a ship - which I don't disagree with. I am simply arguing that the OP's idea is technically feasible and based merely on what the ship builders might decide.

    You seem to be arguing reasons why they might eschew an ostensible safety feature in favour of a smaller ship. I am pointing out that a ship must be made large enough to include its safety features. The ones the engineers decide are warranted.


    (If I were to respond in kind, I would say 'in case you hadn't noticed...') It doesn't matter where you store them. They add weight, and take up room, making for a larger ship than would exist without them.

    You seem to feel there is only a single answer to the OP's question. In fact, there are many ways to answer it.

    Because you are not the person that decides the priorities that go into a ship, you must allow for decisions different from the ones you think are best.

    I have drawn attention to real world examples, demonstrating inarguably that,
    a] it is technically feasible to do so
    b] it is considered warranted under the right conditions
    c] it actually works.

    You're spending too much time on sarcasm and not enough to building a meritous argument.

    'Painting it a colour' is not what a priority is. Why it should be a colour (say, 'we need it camouflaged '- or - 'to be seen at a distance') is the thing that gets prioritized.


    Please try to be less sarcastic. Sarcasm is an attempt to move a discussion to an emotional place, and that suggests you are not comfortable with your arguments to let them stand on their own merits. It's also bad for the board. We're not the only ones reading this.
     
    Last edited: Dec 13, 2014
  21. Dec 13, 2014 #20

    SteamKing

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    No one has said that it wasn't feasible.

    It's not desirable for naval vessels, which is a different matter altogether.
    These conditions have not been established for naval vessels, or even large commercial vessels. See the various comments above.

    No one is saying it doesn't work. If it didn't, foam would not be acceptable for use in providing the requisite reserve flotation for swamped recreational craft.
     
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