h a l f b a k e r yYeah, I wish it made more sense too.
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There are a number of entries on the HB for various spaceships
powered by a daisy chain of explosions - usually nuclear but,
sadly, no underwater craft. Therefore, I am putting forward a
suggestion of building a torpedo shape craft with a rocket nozzle
or combustion chamber at the rear into
which small pellets of
sodium are injected.
Sodium, which reacts very enthusiastically with water, is not a
pollutant once it is mixed back with seawater so would there
would be no hydrocarbon byproducts or leakage. I'm not sure of
the energy density of Na compared to petroleum products or
batteries but suspect it would be good enough. This device would
be noisy, inefficient and quite dangerous but could be marginally
viable which has always been good enough for me. I find that low
standards make life easier anyway.
"Create sodium pellets and pour water over them."
Kursk submarine explosion
http://en.wikipedia...ine_Kursk_explosion
Not good [8th of 7, May 10 2012]
VA-111 Shkval
http://en.wikipedia.../wiki/VA-111_Shkval
interesting ... [8th of 7, May 10 2012]
Supercavitation
http://en.wikipedia...iki/Supercavitating
Also interesting. [8th of 7, May 10 2012]
Reactions of sodium and Potassium with Water
http://www.youtube....watch?v=l9z5-mJ8NZk
Maxwell Buchanan is correct of course about K being more reactive the Na [AusCan531, May 11 2012]
Verrry interesting report on dropping alkali metals into water
http://www.theodore...aliBangs/index.html
(And the resultant bangs) [AusCan531, May 11 2012]
[link]
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I think you will find that when sodium reacts with water, the main result is sodium hydroxide (lye). Yes, it dissolves in seawater nicely. But it likely still counts as a pollutant. |
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Is the reaction violent enough? I suppose it might
be of the sodium were finely divided, but I'd
recommend potassium instead. |
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Instead of pellets, the machine could extrude a solid rod of sodium from its rear end. |
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has anyone ever attempted to superheat the water
at the front of the submarine? |
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I recall a vogue for francium on the HB some years ago. |
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// has anyone ever attempted to superheat the water at the front of the submarine? // |
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Those links are indeed interesting [8th]. The claimed
speeds for underwater objects are astonishing. P'raps I
should amend my Sub-m-Orion design to be propelled by a
combustion chamber at the rear, as initially postulated,
but additionally have a small amount of the sodium (or
potassium) extruded out the front to create the super
cavitation effect. |
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I don't think it would exactly have a 'silent running' mode
but it might go like the clappers. |
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In reply to [theircompetitor], most of the effort has
heretofore been spent
on trying to superheat the water in front of, and generally
all around, the other guy's submarine. |
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For which there are two approaches … |
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(a) Arrive so fast that your opponent has no
time to react, deploy countermeasures, or
take evasive action; |
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(b) Arrive slowly, but so quietly and
inconspicuously that your opponent has no
time to react, deploy countermeasures, or
take evasive action. |
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Choose either option (a) or option (b); they
are, by and large, mutually exclusive. |
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Agreed. Although kinetic bombardment from orbit might
qualify as something arriving quickly, quietly and
inconspicuously. |
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One of my favourite sayings is that there is 'good', 'quick'
and 'cheap' - you can pick any two. Especially when I am
quoting on projects. |
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The Kursk suffered a little problem with torpedo
propellant cooking off in the forward torpedo
compartment, didn't it? Peroxide and kerosene, or
similar, went bang and cooked the front off the
sub. |
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The remainder of the crew were trapped in an aft
compartment and a CO2 scrubber set the
atmosphere on fire when it came into contact
with water in the compartment? |
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It's been a while since I read the story. |
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It might be a little difficult to convince the Navy that
carrying a massive block of sodium metal around,
underwater, is a good idea. |
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They do carry nuclear weapons and sundry combustibles underwater. And it wouldn't be a massive block of sodium anyway (just a massive bunch of little pellets of sodium). |
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To be fair, I did say in the post that it would noisy, inefficient and quite dangerous. |
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Sodium hydroxide is indeed nasty, but it would be converted to harmless carbonate/bicarbonate over a few hours or so. |
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Look up liquid metal nuclear reactors for a precedent for carrying significant amounts of sodium metal around underwater. |
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Liquid-metal cooled nuclear reactors |
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And it's actually NaK, a eutectic Sodium-
Potassium alloy. |
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//Sodium hydroxide is indeed nasty, but it would be converted to harmless carbonate/bicarbonate// |
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You lye!
(Sorry, I was just being caustic) |
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//And it's actually NaK, a eutectic Sodium- Potassium alloy// |
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...And I see that anything from 40-90% potassium is liquid at room temperature. Well then, isn't liquid NaK the perfect fuel for this project? If it's being used as a coolant in nuclear reactors, then all of the phase chemistry will be well worked out, compatibility with piping materials, welding, etc. It's allready been done. |
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Hypergolic (with seawater) Liquid fueled torpedo anyone? |
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Thermite is the obvious choice here.
Aluminum and rust are stable and safe for the sub and its sailors.
Reaction is just fine in water environment. |
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