World's Most Powerful Rail Gun Delivered to US Navy

An anonymous reader writes "The world's most powerful functional rail gun capable of accelerating projectiles up to Mach 8 has been delivered to the Navy. The new rail gun is a 32-megajoule Electro-Magnetic Laboratory Rail Gun. The Navy eventually hopes to have 64-megajoule ship mounted rail guns. 'The lab version doesn't look particularly menacing -- more like a long, belt-fed airport screening device than like a futuristic cannon -- but the system will fire rounds at up to Mach 8, drawing on tremendous amounts of electricity to generate the current for each test shot. That, of course, is the problem with rail guns: Like lasers, they're out of step with modern-day generators and capacitors. Eight and 9-megajoule rail guns have been fired before, but providing 3 million amps of power per shot has been a limitation.'"

Comments

How silly

[JesseL]

An effective military rail gun would need a huge vessel to carry the capacitor bank and a nuclear power station to make a rail gun practical. Where is the Navy going to get something like that?

Oh wait...

Re:How silly

[paganizer]

I'm vaguely remembering a conversation I had when I was in the Navy, but from what I remember, the USS Enterprise was over engineered to have 8 reactors when they knew only 4-6 were really necessary because they had some thoughts of mounting energy weapons. since the Enterprise was drawn up in the late 50's I'm not sure whether to doubt it or not.

Re:How silly

[AKAImBatman]

The Enterprise was the prototype. Plus, Nimtz carriers only have 2 reactors. So it wouldn't surprise me if they overengineered her power supply for the intent purpose of mounting experimental weapons.

That being said, the Nimtz reactors are a bit more advanced than the Enterprise (lessons learned and all that), so that has a lot to do with the reduction in the number of reactors.

Everything beyond that is classified. I could tell you, but then I'd have to shoot you. (Assuming that I already knew and therefore had been shot. :P)

Re:How silly

[ThePeices]

The majority of people here seem to think the rail gun is powered by a huge capacitor bank which takes a long time to charge, or required a nuclear power station to run it in a ship....bollocks.

A Megajoule class railgun is powered by a Compulsator, a type of modified alternator ( compensated for low inductance to provide enormous current pulses )...the rotor is spun up by a large engine, and the rotational energy in the rotor is turned into multiple high current pulses...in earlier test systems ( still megajoule class ), they can fire a burst of 10 shots on one spinup. These things can be scaled to fit in a modern tank, or up to naval gun size.

Re:How silly

[jollyreaper]

As I recall, the ship had eight reactors because that's how many it took to keep the thing moving. They were expensive and Congress wanted the Navy to go back to fuel oil. As I recall, the JFK was conventional. When the Nimitz class came about, the reactor technology had progressed to the point where they could get away with two and the operational costs came down enough that Congress relented. What the Navy really likes about nuclear is that it gives the carriers so much operational flexibility. A modern carrier has fourteen days of combat stores onboard. The reactors also produce the steam to fire the catapults, a very energy-intensive process. I also heard something about some nuke carriers carrying bunker fuel to help keep the destroyers topped off but that seems a bit silly since there are already fleet oilers to perform that task.

Re:How silly

[Anonymous Coward]

The funny thing is that there are other technologies (ram accelerators, combustion light gas guns) that can reach the same velocity but without the burly power requirements. And for a fraction of the cost... And the projectile doesn't turn into plasma on the way out... And the rails don't wear out after five shots... Seriously, what I hear from people in the field is that the railgun people are scamming the government, especially when there is other cheaper tech out there that will solve this problem.

Re:How silly

[Ramble]

They added energy weapons to the Enterprise ages ago, they call them phasers.

Re:How silly

[Shakrai]

I also heard something about some nuke carriers carrying bunker fuel to help keep the destroyers topped off but that seems a bit silly since there are already fleet oilers to perform that task.

Actually, they do, and it's not that foolish when you think about it. Fleet oilers are generally too slow to keep up the battle group and require escorts of their own. The carrier can't entirely replace the fleet oiler but it does add flexibility to the options of the task force commander.

Re:How silly

[zippthorne]

The problem occurs because you have a high current. In order to avoid welding the projectile to the rails, you must contact the rails with non-trivial area, so every projectile slides along the rails with significant contact. Rail repulsion is a separate, but still important, problem.

Arcing actually replaces the abrasion problem with an ablation problem (and a conductivity problem). Unless you mean arcing between the rails themselves, which shouldn't happen, as the solution is the same as the contact-area and general resistance solution: wider, thicker rails.

Re:How silly

[Baddas]

Wait wait, are we talking a simple flesh wound here? Or like, a through and through to the calf? Because it might be worth it. Did it hurt when they shot you?

Re:How silly

[Chris Mattern]

You're already carrying God knows how many gallons of high-test jet fuel--the fuel oil, being considerably less inflammable, isn't adding that much to your fire hazard.

Re:How silly

[DerekLyons]

I suspect that's an urban legend. (Lots of 'em floating around the Navy.) I've never seen anything, anywhere, indicating that the Navy was looking at energy weapons in that time frame.
 
At any rate, the reactor plant of the Enterprise was originally sized on the need to launch full (Vigilante) sized aircraft while steaming at maximum speed. Plus some additional capacity for operational reserve, in case one or more reactors were down, plus a fudge factor for future growth and to cover against concerns about reactor performance. There was also a general concern in the Navy at the time over the profliferation of electronic systems and their increasing demands for power.
 
Since the reactors ended up performing reliably and more-or-less to spec, and big aircraft didn't become common in the fleet - Enterprise ended up considerably overpowered, much more so than follow on CVN's. The follow on CVN's carry fewer reactors partly because of this, and partly because the individual reactors are so much more powerful and specifically designed for carriers. (The A2W reactor used by Enterprise is actually a slightly uprated C1W reactor - originally intended to be used in pairs for cruisers.)
 
In fact, Enterprise ended up with so much excess steam capacity - that (IIRC) half the steam recievers (a sort of capacitor to hold steam for the catapults) she was built with have subsequently been removed. Off-and-on there has been discussion of mothballing a pair of her reactors in place.

Re:How silly

[Alsee]

I also heard something about some nuke carriers carrying bunker fuel to help keep the destroyers topped off but that seems a bit silly

I agree it's silly.
With all that excess reactor power they should just run a really long extension cord to the destroyer.

Hmmmm.... I intended that just as a silly joke, but the more I think about it the more I realize some sort of variation on that concept might actually be viable. Plenty of engineering headaches (probably the main difficulty being ships generally not equipped to power the propeller by electricity) and the hazards of maintaining such close formation... but it would be cool for one ship to be able to power one or two other ships that are either damaged or having fuel worries.

-

Re:How silly

[jollyreaper]

It's interesting how the cost accounting of the modern navy works out. Nuclear power makes sense for carriers and the three classes of subs we operate, SSN, SSBN, and SSGN, but it's never really taken off for surface ships. The last non-carrier nuclear surface boat was the Long Beach, I believe, an escort cruiser.

The whole naming and classification of surface vessels is also weird. Frigate is a name held over from the age of sail. Back then, heavy fighting was done with ships of the line, frigates were used for the free-wheeling missions of escort and raiding and scouting and what have you. Line ships were too important to risk being lost on mundane missions like that. Destroyers were originally called torpedo boat destroyers, ships capable of keeping up with the fleet while screening against torpedo boat attack. A cruiser was not a class but a job description, with frigates operating as cruisers in the age of sail.

By WWII, you had frigates, destroyers, and destroyer escorts operating as small ships working in various roles. Destroyers carried torpedoes to threaten larger ships, 5 inch guns to use against other destroyers and merchantmen, AAA for use against planes and depth charges for subs. The cruiser was intended to be a heavy combatant that could catch anything it could sink and flee from anything that could sink it. You then ended up with all the weird categories of light and heavy cruisers, battle-cruisers, etc. Then you had your battleships, slow sluggers that could not control the range of the fight. Then improvement in propulsion technology created fast battleships that could keep up with the cruisers. Carriers then pissed in everyone's cheerios because the battleship admirals didn't know what to do with them. Concerted air attack could take out a battleship with minimal loss of air crews but the formations the Americans put together towards the end of the Pacific war would have made conventional air attack suicidal for a well-trained and well-provisioned air force, let alone the Japanese. If two US-style fleets faced off, they'd likely run out of planes and pilots before running out of ships, thus forcing the engagement into a gun battle. The rapid development of technology changes everything.

Since the Cold War, the US has dicked around with cruisers and battleships but now the only large surface combatants left are carriers. Even the Aegis cruisers are running on hulls more comparable to destroyers and the arleigh burkes are using the same aegis. With the hitting power of modern anti-ship missiles, it's seen as impossible to armor a ship sufficiently to survive a strike. Then again, US naval thinking is still shaped by the Cold War and the idea that incoming weapons are going to be nuclear so you have to knock them down or else be incinerated, there's no such thing as armoring against a nuke fireball. Since we haven't had a proper naval engagement since WWII, all we're operating under is a bunch of theory that has not been put to the test in a very long time.

Re:How silly

[LeafOnTheWind]

I'm afraid you're misinformed: the USS Enterprise is equipped with a single power generator - a deuterium matter-antimatter power plant. In addition, while the Enterprise does employ a variety of energy weapons, including a full bank of 12 phaser arrays, the primary purpose of the warp core is to provide the energy for warp-speed interstellar travel.

Re:How silly

[navyjeff]

The Big E's reactors were originally designed for destroyers. Since carriers required more steam, they just put in more reactors. Admiral Rickover wanted the whole fleet to go nuclear and, the Enterprise being the first of its kind, just used what was available to get it out the door. Hence, it's a little overpowered and no longer uses all its reactors.

Also, the reactor plants provide steam to the catapults, which are a major power pulse. When running all 4 catapults, it's handy to have some extra juice.

Re:How silly

[Duhavid]

"Everything beyond that is classified. I could tell you, but then I'd have to shoot you."

You have it backwards! Shoot them first, then tell them.

And to optimize this, you can remove the 'nop', and just shoot them.

I mean, telling them and shooting them is not good, unless they
support transactions. ACID and all that.

Re:How silly

[cecil_turtle]

I'm not sure what you mean by "high-test jet fuel", Jet-A and the military equivalent JP-5/JP-8 are pretty much the same as diesel fuel / kerosene / fuel oil - they can all be pretty much interchanged if you're in a jam, and actually the military grade stuff is pretty inflammable (very high flash point).

Re:How silly

[DMUTPeregrine]

But that's the point of the DDX (what this thing will be mounted on): It's all electric. EVERYTHING goes to the dynamos. The engines take from the power grid of the ship. So if you need to fire faster, you can divert power from the engines to the weapons.

Re:How silly

[T-Bone-T]

One less-obvious thing that hasn't been mentioned is the huge distance an attacking force would have to cover just to get to the carrier. You know those pictures of a full carrier group plowing along with the ships right next to each other? They only did that for the picture and spend most of the time at least several miles away from each other.

Re:How silly

[AKAImBatman]

*cough* cole.... *cough*

*cough* harbor... *cough*

Re:How silly

[hcdejong]

With such powerful power source as nuclear reactor is, why don't Navy use hydrogen-powered jets and just produce hydrogen for them from sea water, as needed? That would boost operational autonomy over the top.

Hydrogen is hard to store. You end up either with heavy high-pressure tanks, or with metal hydrides. Both take up much more volume than the equivalent amount of energy in oil-based fuel. It might be possible, but space and weight for carrier aircraft are always at a premium: making them all 50% larger to accomodate hydrogen tanks would halve the number of aircraft on the carrier, which would make the carrier only 30% as effective as it is now.

Also, you'd need a huge plant to keep up with demand.
The A4W used in the Nimitz class can supply some 100 MW.
Hydrogen contains 37 kWh/kg, let's say hydrolysis is 50% efficient so you need 74 kWh to make 1 kg. 100 MW will get you 1351 kg of hydrogen per hour. That's 31 tons per day.

The Nimitz carries about 11,000 metric tons of aviation fuel. Every aircraft takes off with 5-10 tons of fuel on board, you've got 85 aircraft, so you're looking at using (2 sorties *85*7 tons average) ~1200 tons of fuel per day. You need a reactor 40 times as large as the A4W to keep up with demand.

Re:How silly

[aproposofwhat]

If my memory serves there was significant damage to a layer of paint at the point of impact.

Sorry, mate, but that's just sick.

17 crew members died, and another 39 were injured.

The explosion knocked a 40 ft hole in the ship, and your dismissal of it is disgusting.

Re:How silly

[Nefarious Wheel]

Whups memory did fail. In no way do I wish to trivialise the loss of life, nor diminish the honour of those who served. I will now retreat into the land of ohmygod I wish I hadn't posted that.

Re:How silly

[Shakrai]

The Arleigh Burke has a range of 4,400 miles at 20 knots, that would be about 2,000 miles at 30 knots. 70 hours of operation (or three days at top speed) is not much (especially considering they would want to fill as often as possible).

It's often said that amateurs study tactics, while professionals study logistics. Having the carrier carry bunker fuel to top off her escorts provides more logistical flexibility to the battle group commander.

Presumably everybody around here has heard of the attack on Pearl Harbor? Half of the reason that the Japanese had to retreat (instead of conducting more strikes) had to do with the fact that remaining on station any longer would have risked running too low on fuel. They stretched their logistical abilities to the max to conduct that attack and weren't in a position to exploit their advantage any further. (Of course the other half of the reason was Nagumo's caution.... but the logistical situation was surely in the back of his mind...)

Re:How silly

[Guppy06]

"Nuclear power makes sense for carriers and the three classes of subs we operate, SSN, SSBN, and SSGN, but it's never really taken off for surface ships. The last non-carrier nuclear surface boat was the Long Beach, I believe, an escort cruiser."

Different missions.

Submarines are supposed to stay hidden for long periods of time, and they can't do that if they have to pop up ever few days at the local fuel depot. The carriers are supposed to be out there doing the whole power-projection thing, but (again) it's hard to be out there projecting power when your planes spend a few days every month pwning the airspace around Ye Olde Coaling Station. Really, there's nothing interesting going on at Diego Garcia.

As for the not-so-capital capital ships (at least those not tied to a carrier battlegroup), their job is more or less to fly the flag, preferably in places where people can see it, and people have a tendency to live on land. So your frigates and your destroyers have a bit of a diplomatic role to play when they come to a port, disgorging the crew to partake of the local breweries and sex workers, as a way of telling everybody "Yeah, we're still here. And this is our boom stick." And if you're going to be hanging out anyway, why invest in a technology meant to help you avoid doing so? And on top of that, there are people like the Kiwis still squeamish about the whole "nukular" thing.

Once you decide nuclear isn't worth it on these vessels, the only question remaining is whether to pay money to build a whole separate class of nuclear fun-sized ships for escorting the CVNs (and there's only so many), or to pay money to throw a tanker or two into the mix of a battlegroup.

Re:How silly

[Teancum]

Does the United Kingdom's Royal Navy (there is no "British Navy") prepare to re-fight the Falkland Islands War again? If that is the case, there may be something legitimate in terms of having UK ships be able to engage in a naval war on the other side of the world to defend its last remaining colonial outposts. There aren't that many of them (remaining colonies), but on occasion there are challenges both political and militarily to take them away from the UK by other governments. The UK does need to be able to bare its teeth against would-be aggressors and remind people that they are a nuclear power that shouldn't be screwed with.

As a side note, the Falkland Islands Campaign is one of the most recent naval engagements that involved large scale navies and ship to ship combat. I can't begin to count how many lessons were learned by naval engineers on ship design that have been accounted for in newer classes of ships in both the U.S. Navy and the Royal Navy. Capital ships were lost by both the UK (the HMS Sheffield) and Argentina (the ARA General Belgrano).

While naval technology certainly has changed a bit from this era of fighting ships, it wasn't really that long ago and most of the current naval combat doctrines can find significant examples both in support and against those theories in that conflict. It certainly is studied very closely at the U.S. Naval Academy and other naval colleges around the world. Even more recent changes to combat theory really do need to be tested in actual combat conditions before they are confirmed to work... and I'm glad that they haven't really been tested.

As to if the Royal Navy could put up a similar challenge to their territory in some far-flung place at the moment, I'll leave that up to military planners and UK citizens to debate that philosophy.

Fusion Power...here we come

[clonan]

The REAL reason Fusion power will be perfected...so the Generals can fire their fancy guns more than a few times an hour.

Re:Fusion Power...here we come

[kabocox]

The REAL reason Fusion power will be perfected...so the Generals can fire their fancy guns more than a few times an hour.

Non-solar fusion won't produce that much energy any time soon. What we need is serious solar energy collection; I'm talking about solar powered orbital microwave death rays. That's how to properly power your death dealing toys. With a proper number of death rays, you should be able to fry any acre of land on the globe fairly easily. It's assumed that frying the land will kill off all enemy soldiers, peasants, and nature lovers that may be hiding there.

Re:Fusion Power...here we come

[davidsyes]

(I figure someone'll mark me inflammatory, off-topic, or troll or flame-bait, but, what the hell. I'm not a wus or kiss-ass draped in or ass-stuck by flags... And, I'll turn off my bonuses, too...)

Well, whatever the range, speed, or lethality of those "rail guns", they'll only give further justification for asymmetrical warfare and tactics. If I were a government faced with my ships being targeted by such guns, I'd resort to deploying ships with 50 or 100 MT nukes designed to detonate when impacted by high-energy rounds. The USN had then better hit my ships SPOT ON to assure they nukes wouldn't go off.

Sheesh, talk about exacerbating nuclear proliferation. As long as ONE nation has super weapons, no other nation can POSSIBLY feel non-threatened. Doesn't matter whether the US actually USES them. It's their existence and actual deployment that is unnerving to some nations. And, it only justifies nations spending exorbitant sums of public money on otherwise phantom or unjustified war footing.

But, then, it's just a matter of time before technology for rail guns that are "good enough" hit the fleets. Now, other navies will just have to mount axial mounts and state publicly that they'll unleash as many shells as they can if they detect shock waves hurtling at their own datum point. "Shoot at me, I'll shoot indiscriminantly and with great fervor." That would create furor in world bodies, but *might* keep powerful, flag-waving navies "at bay".

Hmm, my SI is fuzzy...

[Anonymous Coward]

Amps of power?

Beowulf?

[iceyone]

Imagine a beowulf cluster of these!

I miss the days of gunpowder

[INeededALogin]

Seriously, how much energy does it take to kill someone.

Re:I miss the days of gunpowder

[JesseL]

The energy required to kill someone is nil.
The energy required to poke a hole in someone is somewhat higher.
The energy required to poke a hole in enemy armor is higher still.

This isn't for killing 'someone', it for poking big holes in things that are very hard.

Re: I miss the days of gunpowder

[Dolda2000]

In all seriousness, the article speaks of ship mounted guns, so I don't really think they are made to kill individuals. I would think that no amount of energy can ever be enough when it comes to sinking warships.

It makes me wonder, though -- they say 32 MJ per shot, but how much energy is in a normal-sized conventional weapon? They also say Mach 8, but how fast are normal rounds fired?

Re:I miss the days of gunpowder

[icebrain]

Probably not with the Apache, but Germany's Stuka dive bombers (Spanish civil war/WWII) had sirens fitted specifically for that reason.

Re:I miss the days of gunpowder

[Monokeros]

That clearly depends on how awesomely you want to kill them.

Re:I miss the days of gunpowder

[KTheorem]

> This isn't for killing 'someone', it for poking big holes in things that are very hard.

If you have that much energy, though, then surely lasers become a more practical alternative?
Lasers can't be shot on a trajectory to hit something 1000 miles away. Nor can they cause much damage outside of where they hit.

Re:I miss the days of gunpowder

[khallow]

Note that they speak of railguns that deliver 32 megajoules of energy. In comparison, the best for continuous lasers is somewhere around 100 kW for a couple of seconds. That's roughly two orders of magnitude lower.

Re:I miss the days of gunpowder

[Guysmiley777]

The Apache's distinct sound comes from the offset blades of it's tail rotor. If you look at them they are not a 90 degree "X", but instead are offset 55/125 degrees to one another. The goal was to try and reduce the "whop-whop" rotor noise that comes from the main/tail rotor interaction to make the aircraft quieter from a distance. The fact that it sounds scary as hell was just an added bonus.

Re: I miss the days of gunpowder

[blagger99]

Mach 1 = Speed of sound. In air, approximately 1,130 feet per second at 21 degrees Centigrade [1]. Mach 8 = 8 x 1,130 ft/s = 9,040 ft/s.

A 7.62mm round has a velocity of 2,756 ft/s [2], approximately Mach 2.4. Energy use is 3,352 J for a bullet weight of 9.50g.

The article doesn't specify, but I imagine the 32MJ rail gun uses projectiles a little larger than 9.5g.

[1] http://en.wikipedia.org/wiki/Speed_of_sound
[2] http://en.wikipedia.org/wiki/7.62x51mm_NATO

Re: I miss the days of gunpowder

[Hal_Porter]

http://www.fredericksburg.com/News/FLS/2007/012007/01172007/251373

The prototype fired at Dahlgren is only an 8-megajoule electromagnetic device, but the one to be used on Navy ships will generate a massive 64 megajoules. Current Navy guns generate about 9 megajoules of muzzle energy. The same article talks about increasing range 'more than tenfold' to 200-250 nautical miles.

This article about proposals for guns on new destroyers for a talks about muzzle velocities of 800-900 metres per second, or about Mach 2.5. Wikipedia says that 1800 mps or about Mach 5 is 'close to the limit achievable with chemical propellants'

So 64MJ and Mach 8 is pretty impressive. It would mean that US ships would have a profound advantage of having ten times the range of their opponents. More to the point if they were attacking a country with not much navy but decent anti ship missiles, they could avoid getting too close to them. Actually this page says

China acquired SS-N-22 launchers and missiles (specifically, the for-export 3M-80E Moskit variant) with its 19992000 purchase of two Sovremenny destroyers from Russia. According to Russia, the Chinese funded the development of the SS-N-22 version for the People's Liberation Army Navy (PLAN), which has the designation 3M-80MBE, and this version differs from earlier versions mainly in that the range is increased beyond 200 km, and these new missiles will be first onboard the second pair Sovremenny class destroyers. It is speculated that the PLAN intends to use it against the carrier battle groups deployed by United States Navy in case of any confrontation with Taiwan. Now the railgun can actually fire 200-250 nautical miles or about 460 km, so US ships could stay well out of range.

Re:I miss the days of gunpowder

[rahvin112]

The Railguns serve a purpose which right now is being filled by EXTREMELY expensive weapons. The cruise missile has a range of about 600 miles, it also moves at a speed that makes them very easy to shoot down. To compensate for this they fly them at extremely low elevation, but they can still be shot down and you can hear them approaching for quite a while before they get there, making it much easier to avoid being hit by one.

The railgun on the other hand currently has a range roughly 1/3rd the distance of a cruise missile and IIRC the 64MJ version has a range around 2/3 the range of a cruise missile. Not only that but the projectile cannot be shot down as no weapon could catch it, nor even if they could (fired head on) would the interceptor be able to stop it as the kinetic energy of the blob of metal would simply disintegrate anything that tried to stop it with almost no deflection of the weapon. Not only that but the railgun offers extremely high energy on impact, far in excess of the 500-2000lb bomb on cruise missiles. I've heard estimates that place the energy release on impact with that of around 15000lbs of TNT, the explosive energy release is huge but the big blob of metal becomes millions of small pieces of metal that fly in every direction along with rocks and dirt moving at ultra high velocities from the impact site. And above all this the railgun projectile is under $500 in comparison to the $1 million dollar tag for the cruise missile.

The railgun essentially allows the USN to toss moderately sized meteorites at enemies. Whenever a naval article comes up everyone likes to talk about how vulnerable the USN is because of Sunburn and other antiship missiles. What they fail to realize is that once the DDX destroyers come online the fleet wouldn't even need to get in sunburn range to absolutely destroy even fortified coastal positions. Take a couple DDX destroyers and the new CDX carriers and you have a fleet that can sit 400 miles off the coast and bombard all the coastal defenses into oblivion before moving further in to bombard the cities and fortifications further in from the coast. The railgun projectiles also have extreme penetration, they can cut through 10's of feet of reinforced concrete with ease, and even underground facilities become susceptible as 10 projectiles could likely cut a massive hole and penetrate buried facilities that could then be followed up with bombs dropped from planes. There is also another advantage, cruise missiles aren't effective against mobile targets because it takes so long for them to get there, at mach 8 the railgun projectiles flight time is extremely small, along with the no advanced warning (no sound preceding impact) gives the projectile a much better chance at hitting mobile targets without having to use manned aircraft.

The USN is also trying to find guidance systems that can survive the G forces in the hope of having some minimal guidance.

Re:I miss the days of gunpowder

[Alsee]

The videogame generation has grown up and become our military and our engineers.
Putting a bullet through someone's chest is the black-and-white-TV of fatality moves.

-

Re:I miss the days of gunpowder

[Anonymous Coward]

I've heard estimates that place the energy release on impact with that of around 15000lbs of TNT

Think about that critically for a second. For all action there is an equal and opposite reaction. In order for this gun to accellerate a projectile to the equivalent energy of 15000 pounds of TNT, assuming no losses, requires an event on the initiating end equivalent to 15000 pounds of TNT. Considering that a 500 pound bomb, which is only half explosives (typically a mix similar to TNT), can do a decent amount of damage to a ship, it becomes obvious whatever project you're referring to must be another project (probably the so-called "rods-from-god" concept).

In fact, the 32 MJ of energy described in the article (I don't know if that's kinetic or electrical) is only the equivalent of about 15 pounds of TNT. This is just barely more than is contained in the 5" inch shells currently fired by the standard deck gun in the US Navy. The key attraction here is the added range.

whatcouldpossiblygowrong

[Anonymous Coward]

I noticed that almost every story today has this tag on it. What could possibly go wrong if you stop using this tag for every article?

Re:whatcouldpossiblygowrong

[stephencrane]

Seriously. This tag is being used way too much. A rail gun is, for all its complexity, a relatively straightforward concept. A story about, oh, releasing genetically-manipulated mosquitoes into the wild really should set the benchmark. Standards, people, standards. We're -geeks-, fer crissakes.

Re:whatcouldpossiblygowrong

[Chris Mattern]

Meh. He's got some cute pictures, but his grasp of military history is teh fail. The French did *not* discount the possibility of the Germans coming through the neutral Low Countries; in fact, they expected it--it was what they'd done last time, after all. That's what did them in. All their decent units were all lined up on the Belgian border and rushed into the Flanders plain to meet the expected oncoming Germans as soon as Belgium was invaded. But the Germans broke through at the pivot point, in the Ardennes, getting behind the Allied forces now in Belgium and then driving west to the sea to bottle them all up quite nicely, including the British (who managed to evacuate out of the pocket from Dunkirk).

Re:whatcouldpossiblygowrong

[Goaway]

It's simply an expression of the closet technophobia that affects so many Slashdotters.

Re:whatcouldpossiblygowrong

[Anonymous Cowpat]

well, a simple mis-application of Fleming's left-hand rule could result in anyone standing directly behind the gun from getting a fairly substantial hole put in them. That could go wrong.

Re:whatcouldpossiblygowrong

[IndustrialComplex]

Of course, I imagine it would also take a hell of a lot of genetically modified mosquitos to scare the cat, too.


I find that one extraordinarily large genetically modified mosquito works as well.

Obligatory

[DeadDecoy]

They need to attach some focal confirmation for when you hit the target:
Headshot!

1.21 gigawatts

[Anonymous Coward]

Let me know when the flux capacitors get fully charged...

To be a bit mercenary about it...

[KublaiKhan]

There is no such thing as overkill. There is only "still firing" and "out of ammo."

Oblig

[MobileTatsu-NJG]

A spokesman for the Iranian Navy was reported as saying ..."Camping faggots!"

Newton

[dorix]

It's also capable of propelling ships in reverse at speeds of up to Mach 3.

Re:Newton

[clarkkent09]

Projectile weight = few pounds. Ship weight = 50,000 tons. I think the ship will win

Re:Newton

[dorix]

Well yeah, but it still makes for a funny mental picture.

Re:Newton

[agent_blue]

Rail guns do not work that way! Good Night!

Re:Newton

[doctor_nation]

Sorry, but everything works that way (unless maybe if you're near the speed of light). I don't care how you do it, but if you shoot something one way, there is an equal and opposite force the other way. Obviously in this case the ship won't notice, but if the rail gun wasn't bolted down I bet it would jump pretty good.

What are they launching again?

[koa]

As far as I can tell- the article mentions nothing about the types of ammunition they fire with this- however upon closer inspection,
  I may have found a clue:

"Installation of the laboratory launcher is currently under way"

Seems like a waste of some perfectly good laboratories!

Re:What are they launching again?

[Anonymous Coward]

That's just a cover-up. The production model is going to launch lavatories, but since that's biological warfare, they can't just call it what it is.

Can it be carried in a backpack?

[ross.w]

and what colour trail did the Navy pick?

I've got Wood

[cthulu_mt]

God, this is why I love being an American.

Bill Gates was heard to comment...

[Anonymous Coward]

No one needs more than a 64-megajoule rail gun.

Space Gun

[Doc Ruby]

Mach 8 is about 9800KPH. Escape velocity from the Earth's surface is 40,320KPH. This gun is already firing at over 24% of escape velocity. A 64Mj gun would be almost 50%; a 132Mj gun would shoot projectiles right into orbit.

I wonder whether coming generations of this gun could shoot unmanned exploration vehicles or satellites out into space. The Pentagon will probably try to use it just to shoot down spacecraft, but instead we could use their budgets to increase space industry and exploration.

Re:Space Gun

[afidel]

The problem with using a railgun to launch anything but raw materials into space is acceleration. If you have to impart enough energy into the object over a track that at a maximum is a couple kilometers long you're going to be impacting too many g's for much of anything to stand up to.

Re:Space Gun

[CodeBuster]

I wonder whether coming generations of this gun could shoot unmanned exploration vehicles or satellites out into space. This has been considered many times over the years and some startups are even working on some pie in the sky concepts, but basically there are two (2) major problems with the gun-type or single energy input launch mechanisms. First, the package being launched has to be hardy enough to survive the massive acceleration G forces and shock of hitting the atmosphere at orbital velocity right from the start (i.e. sea level) which brings up the second point. The package must also be able to survive a trip through the atmosphere, with continuous deceleration due to air resistance, at speeds high enough to approximate orbital velocity once the package reaches the altitude of low earth orbit, all without slowing down too much or burning up along the way (think re-entry in reverse). Neither of these are trivial problems and compared to the ever improving rocket technologies, which allow variable rates of acceleration during the trip into orbit (a huge plus and the reason why almost all launch vehicles are liquid fueled), the unknowns involved in the gun launch mechanism are simply too great to warrant serious attention at this time (although some private startups are having a go at it anyway).

Re:Space Gun

[Cochonou]

Kinetic energy equals mass times speed squared.
Deploying twice the energy should only send the projectile 1.4 (the square root of two) times faster.

Re:Space Gun

[Muirisara]

Um... OK, Doc Ruby on Rail Guns. :P

Re:Wave Motion Gun

[robvs68]

I hope that the Navy's new Rail Gun doesn't require a brief but critical period to charge before firing, and I hope that is does not require all non-essential power systems to be deactivated, leaving the ship powerless and adrift for a short time after firing... (wiki)

Looks nice

[OeLeWaPpErKe]

I wonder how many times this thing can be fired. They need to get 32 megajoules of energy out of the gun, and without the metal that this power passes through melting. That's not an easy thing to do.

Railguns today tend to melt after each shot, leaving one to replace the rails (the biggest, conducting the part of the gun, the bit in contact with the "bullet").

I wonder what the efficiency is. 32 megajoules come in, how many leave in the bullet. (Generally they only get about 2%-5% efficiency).

An alternative, easier and safer, is a coil gun. Here's a nice index of coilguns : World's coilgun arsenal. But like their railgun brothers, they're not very efficient. The very best of them have the bullet speed of a mini handgun, but they're trivial to make, and rely only on batteries and metal.

Re:Looks nice

[whitehatlurker]

Could they not use ceramic rails rather than metal ones? The input efficiency of the gun appears to be 40%. (The 64 MJ weapon needs 16 MW of power firing every ten seconds = 6.4 MW / 16 MW.) Too bad they don't specify the kinetic energy of the projectiles.

Re:Looks nice

[JesseL]

The best bet would probably be to use something like tungsten for the rail surfaces, to minimize the arc vaporization. I doubt you'd get ceramics conductive and physically durable enough to be suitable.

Re:Looks nice

[OeLeWaPpErKe]

The problem is that the rails need to be conductive, as the whole point is to create a conductive path from coil A -> bullet -> coil B. So not only must the rails themselves be of metal, the bullet itself needs to be a relatively large iron mass (because you have magnetic saturation ie, the maximum theoretical speed of the bullet is related to the weight of the bullet you want to fire)

They can't be ceramic, and they can't be tungsten either (you can't get that amount of tungsten anymore, for any price, it's just a bad idea, they say oil will run out soon, well they're right, but a few things, like tungsten have already run out).

Einstein on rail guns

[sakdoctor]

I don't know if World War III will be fought with railguns or belt-fed airport screening devices, but World War IV will be fought with sticks and stones.

Re:Einstein on rail guns

[xleeko]

I don't know if World War III will be fought with railguns or belt-fed airport screening devices, but World War IV will be fought with sticks and stones.

No, no ... you got the quote all wrong.

"World War III will be fought with radioactive Monkey-Snake Hybrids, World War IV will be fought with watermelons and trebuchets, World War V will be fought with intelligent berzerker cheeses, and World War VI will be fought with sticks and stones ... the size of planets!"

Hey, don't knock it

[Sycraft-fu]

We get a lot of cool technologies because the military wants new toys. You can argue about if it should be that way or not, but it is how things go. GPS is a great example. No civilian organization would invest in something that big. Are you crazy? Who would want that? However the cost wasn't a problem for the military and hence we got one of the most amazing navigational aids ever. Even now that the technology has been proven feasible and useful, or rather essential, the military run systems remains the only one. The European civilian governmental version remains snarled up in political battles.

So while you jest, there could be truth in the statement. Fusion is all well and fine, but there's only so much money going to be thrown at it. We have other cheap power sources in terms of commercial use, so not a lot of commercial dollars, and it just isn't sexy or pressing enough to get much government research dollars... However if there's a major military application, well that could get billions easily.

That's one reason I'm not always opposed to defense spending. Though it is very often wasteful and it seems there are better things to do with the money, it does seem to be one way for getting projects that just don't get built otherwise. A great many things come directly from defense research.

The military's been testing rail guns forever

[Phat_Tony]

I had a physics teacher who used to work at Los Alamos who did some consulting for the military on the side. In the late 80's/early 90's, they had him evaluate the results of some rail-gun tests. They were shooting a small ball projectile at tanks. The projectile left a perfectly round smooth bored hole all the way through the tank, wherever it was fired. The military wanted to know if they could use this to disable things (fire through the engine block) without destroying other things (people, electronics, paperwork, whatever) inside.

In evaluating it, they found that the internal air temperature flashed to something really high (like an oven) in the microsecond the ball travelled through, and that the vaporized steel from the first surface of the tank would kill everyone in the compartment.

It brings home what kind of speeds we're talking about here.

I'm waiting until they start listing the speeds of rail guns in terms of [decimal]c. Full of relativistic goodness. Of course, if they're only at Mach 8, they've got a way to go. The X-15 was near mach 7 and the scramjet tests have hit mach 10, and I'm sure those were more massive than the rail gun's projectiles.

Re:The military's been testing rail guns forever

[San-LC]

I remember watching a movie called the Pentagon Wars where they were dramatizing the tests of the M2/M3 Bradley Fighting Vehicle. In it (based on a true story), they tested the aluminum armor plating by launching an anti-tank warhead against it and seeing what would happen inside. They used sheep in the place of humans, and all of the sheep were killed via overheating due to the internal air temperature flaring up.

How long will the barrel be?

[jollyreaper]

Are these things going to be turret-mounted like with battleships or will the rail have to be as long as the ship, requiring the whole vessel to turn to align the weapon?

Re:uh, wrong. please check your math.

[AKAImBatman]

The DDX Destroyer is just the first step in the Navy's futurization of the fleet. The CVNX project intends to modernize carriers in the same way that the DDX Destroyers will be modernized.

Some of the features:

• Better, more powerful reactors (3x increase in available power!)
  
• Stealth
  
• Electromagnetic catapults
  
• Greater automation leading to reduced crew complement
  
• Better survivability in a fight (like that's been a big concern :P)
  
• Advanced arresting gear (no idea what that means)
  
• Dual Band Radar support
  
• "Flexible ship infrastructure" (i.e. We can mount some kewl energy weapons once Congress gives us the green.)
  

Navy Fact File

As I recall, the original list of superweapons was much more impressive. It just got pared back a smidge when Congress balked at the price tag.

RoF vs. KE

[Thelasko]

Keep in mind the relationship between energy and power. Assuming the reactor on a ship can only produce a fixed amount of power there is a trade off between rate of fire and the kinetic energy of the projectile. If the user of said railgun charges the capacitor bank from a 15 amp wall outlet for five minutes the gun will be capable of firing a small projectile at a reasonably high rate of speed. But if the user charges it up over night it can fire a massive projectile at the same speed.

As far as getting the massive amount of power from the capacitor bank to the railgun itself, I am confident that the military has the capital to use some sort of superconducting material to deliver as much power as they need. I think it's likely more difficult to construct a physical "gun" that can handle the "reaction" from the projectile's "action." I suspect the Navy wants to fire very large projectiles at a very high rate of speed and isn't too concerned about how rapidly they fire them.

Vs Light Gas Gun?

[IdeaMan]

I think the jury is still out on whether rail guns or light gas guns will be the next step.

Let me list the current advantages/disadvantages:
Rail Gun:
+ Simple firing mechanism (Two rails, one plug, massive juice)
+Very little muzzle flash
+Very rapid fire (Gatling configuration to spread out heat on rails)
*Acceleration limited by current carrying capability of rails.
- Complex/heavy electrical system (Banks of caps + power supply to charge them)
- Rail wear
-Heavy projectiles increases support structure significantly

Light Gas Gun:
+ Heavy projectiles scales up rather well.
* Medium complexity (More complicated than Gatling mechanism)
* Acceleration limited by maximum chamber pressure.
- Bore wear
- HUMONGOUS muzzle flash (hydrogen combusting)
- Medium rate of fire.

Bottom line: Flechettes: Rail gun; Sub Orbital or ship killer: Light Gas Gun

Currently light gas guns emit a huge fireball out the end of them, which may tend to limit their use for a shoulder fired weapon (anti-tank, anti-air). On the other hand it is a lot easier to store and release obscene amounts of energy in a gas or powder than in electrical form. I would imagine porting the barrel would allow recovery of some of the hydrogen.

One advantage the railgun might have is it might allow different projectile shapes like fins that would be difficult to achieve with a light gas gun.

We should be using light gas guns to ship fuel up to the bottom of a chain of a LEO space elevators.

Amps != Power

[BlueParrot]

Ampere is a measure of current, not power.

To put it this way, the European Spallation Source is a planned particle accelerator which is planned to have a proton-beam current in the range of a few milli-ampere. That is, comparable to the current drawn by your LCD monitor in standby. The catch is that ESS will be using proton energies up to a billion electron volts, thus making the power output of the accelerator comparable to a small nuclear reactor.

You can NOT quote power in terms of ampere without specifying the voltage. Conversely I've generated several thousands of volts using my bare hands and a piece of nylon, but because the current was rather small nobody noticed.

What is even more interesting is the time over which you can sustain a given power output. Over at our physics department we have lasers with power outputs beyond all the worlds nuclear reactors taken together. The pulse doesn't last very long however...

This has been thought of

[Quila]

An article a while ago had a plan for a circular track a few miles wide. The launch vehicle would be magnetically accelerated along the track and on the last trip around be diverted to a straight launch rail for that last bit of acceleration to target. It was still quite a few gees sideways going around, but a lot less than achieving orbital velocity in a short straight acceleration.

Re:This has been thought of

[Doc Ruby]

A circular track could accelerate the payload gradually around a lot of cycles, rather than stress it with high-G acceleration.

What if the payload were also spiraled around its axis that's parallel to the circle, as it's accelerated along that axis. Wouldn't that neutralize the centripetal effect on the payload, so the total acceleration wouldn't damage the contents of the payload?

Of course a little turbulence in the barrel could really wreck things, and humans would get scrambled. But an evacuated barrel at the top of an Andean mountain and magnetic buffers could eliminate friction, both to minimize turbulence and drag in general, popping out at an altitude already much thinner than sealevel and something like 50 miles further from the Earth's center than at Cape Kennedy.

Re:uh, wrong. please check your math.

[Loke the Dog]

Thats what I suspected.

On large ships, other kinds of weapons are preferable.

This will be more like a traditional gunboat, carrying only one primary gun. Also, as it says in the article, the recoil makes it unlikely that this gun will fire many shots in one battle.

I think this will be a bit like a naval sniper, aiming to destroy major vessels command center before its even detected, and then leave the area quickly and let the big ships take over.

So we won't see many ships with this configuration, but in certain situations, it could probably end a battle before it even gets started. That is, as we all know, the best way to win battles.

Watts!

[Roger W Moore]

Eight and 9-megajoule rail guns have been fired before, but providing 3 million amps of power per shot has been a limitation.

I agree. This would be extremely hard to achieve since amp is a unit of current. The problem is not that but rather that in combination with the voltage required to drive it.

Amps/watts

[Cheesey]

Surprised more people haven't commented on this. Ending a summary with "3 million amps of power" is a classic Slashdotism. It would once have provoked many responses pointing out that an amp of power makes as much sense as a gallon of distance. Perhaps we can't be bothered correcting the editors any more.

Re:uh, wrong. please check your math.

[calebt3]

Advanced arresting gear (no idea what that means) If it refers to the carrier, arresting gear is a cable that the fighters try to hook when they land so that they don't go off the edge.

The US military measures the power of it's weapons

[Colin Smith]

By the size of the bits of canvas left after they hit the tents.

Respawn...

[Misch]

The editor who posted this was fragged with the BFG, but respawned this article a few days later.

Interesting Facts

[timias1]

I sat next to one of the directors of the Navy's rail gun program, during a flight to Boston, and I had one of the most interesting talks with him. The projectiles fired experience about 30,000 g's of acceleration, compared with 12,000 g's for a conventional gun. The major problem is that about 20% of the g's are experienced laterally because the projectile bounce when it is traveling down the rails. The projectiles do not contain explosives, because the kinetic energy is enough to do some pretty good damage. The materials problem with the rails was solved a while ago, and they need to survive for about 1000 shots to be comparable to today's guns. They also don't store the energy for very long before firing, because of losses and safety.

Re:uh, wrong. please check your math.

[Shakrai]

I think this will be a bit like a naval sniper, aiming to destroy major vessels command center before its even detected, and then leave the area quickly and let the big ships take over.

Uhh, wouldn't that require a line of sight to the intended target? Naval combat within visual range went out of style after Coral Sea. If you don't need a LOS then it would seem to be that this is a guided projectile and you don't exactly need a railgun for that (see harpoon, exocet, etc, etc).

I would suspect that the Naval interest in rail-gun technology is probably aimed at point-defense (i.e: shooting down incoming anti-ship missiles) more then anything else.

Re:It's all fun and games...

[AKAImBatman]

It's all fun and games until someone decides to make a nuclear-capable artillery shell for this thing.

There are some serious problems to mounting a nuclear munition on this sucker. First off, the weight of the round currently being fired is actually quite small. The weapon would need to be scaled up by many, many fold just to fire the nuclear munition.

Second, no existing type of warhead would survive the shock of launch. A gun-type device would detonate on launch. (NOT good.) An implosion device requires that the plates surrounding the charges that surround the plutonium core be carefully calibrated. A single charge or plate out of place and the bomb will fizzle out. Advanced hydrogen weapons are out as well, as they require an atomic explosion as a trigger. Plus, the cores of hydrogen bombs need to be kept even more precisely in place in relation to the uranium shell of the weapon.

All in all, the only thing you'd accomplish by combining a rail gun with a nuclear warhead is to either blow yourself up or damage your highly-expensive-bomb-that-could-have-been-more-easily-deployed-with-a-super-sonic-missile.

Re:uh, wrong. please check your math.

[baldass_newbie]

I have no idea how an "advanced" arresting gear differs from a "regular" arresting gear. i.e. The navy isn't saying. It's just... advanced.

These go to 11.

Re:uh, wrong. please check your math.

[WaXHeLL]

Increased range, far greater damage potential (because of the extremely high kinetic energies), smaller size of the projectile (because there is no explosive component), etc

It's not a guided projectile, because anything you'd strap to it probably couldn't withstand the high acceleration nor the extremely high electrical and magnetic fields in the launcher.

But if you have a computer to adjust firing angle, firing energy, etc, you can very well make it targeted (by doing the calculation required for it to strike a target XX miles away at XX altitude).

Re:uh, wrong. please check your math.

[KublaiKhan]

Guided projectiles can be shot down or intercepted or confused with chaff or flares or electromagnetic interference. Unguided projectiles, by their very nature, are not subject to being interfered with--and at such high speeds, it's unlikely the target would be able to see it coming. It'd take 2.2 minutesish to go the 220 mile range, so while it may not be very easy to snipe a mobile target, shore emplacements and the like would be sitting ducks.

If I had such a boat, I would use it against shore batteries, harbor fuel tanks, and other such targets--unless it had some -really- good stealth on it, in which case a bit of close-in sniping might work.

Solar power?

[RudeIota]

Might the Department of Defense's recent effort and research to develop a feasible, mobile solar power source be related? The idea was to beam solar light from space using satellites and focus it onto a solar grid of some sort.

I remember it being (potentially) 10 megawatts, which isn't quite enough to power these devices, but with enough R&D...

http://hardware.slashdot.org/article.pl?sid=07/10/14/2129233 http://blog.wired.com/defense/2007/06/post.html And there's always nuclear etc... I'm pretty sure they have a conceived way to power it if they've already gone this far with the plan. :) (heh.. heh..)

How well do Ram accellerators scale?

[LordZardoz]

Disclaimer: I lack the knowledge to have a legitimate informed opinion on this topic.

Ram Accellerators may be cheaper in terms of raw dollars, but I wonder how well they scale relative to Rail guns? Specifically, economies of scale for mass production, and for the mass per projectile.

Once the technology is figured out for Railguns, I suspect the primary cost will be the power generation. The projectiles themselves will probably be very cheap, and be easier to manufacture than those used by a Ram Accellerator. Essentially, it sounds like the complex part of the rail cannon will be the gun, and the complex part of the Ram accellerator will be the projectiles.

Artillery works better when you can get mass quantities of bullets on the cheap.

The power requirements do seem to be the primary problem for the Railguns at the moment though. Are there any known projects using ram accellerators?

END COMMUNICATION

Re:How well do Ram accellerators scale?

[pragma_x]

I think you're on to something there. If you work the kinks out of the technology, such that the gun itself doesn't wear out very fast, then all you need is a lot of electricity.

Add on a few nuke reactors, and/or a nice capacitor bank, and you're suddenly only restricted by how many projectiles you can carry. As you mention, these are going to be simple - basically just metal slugs. There's no more powder or fuel required for the task, which is in sharp contrast to conventional weaponry.

Doesn't actually take long to charge

[MattskEE]

9 Megajoules may be a lot of energy to release in one fast pulse, but it doesn't actually require all that much time or power to charge.

Naval ships have big powerful engines or reactors that are capable of putting out a lot of power. If a measly 100kW (a tiny amount of total energy, equivalent to a 134 horsepower engine) has been budgeted to charge it up between shots, it will take 90 seconds to charge, this is a while, but the power was small. Suppose they increase it by an order of magnitude to 1MW (a carrier can easily generate this, though it may be expensive to design the charging system), then it only takes 9 seconds.

There are a number of other tricks they can use to speed up firing time, such as storing lots of standby energy in battery or fuel cell banks, ready to be drawn quickly to charge up the rail gun. Batteries and fuel cells can't discharge fast enough to fire a rail gun, but they store more energy than capacitors, so they can charge the bank multiple times without increasing the load on the ship's generators at all.

I'm not sure I see the problem here, it is just a matter of proper power engineering. Since this will probably be replacing some of the standard munitions, generation capacity can be increased.

Correction...

[tjstork]

Since the Cold War, the US has dicked around with cruisers and battleships but now the only large surface combatants left are carriers. Even the Aegis cruisers are running on hulls more comparable to destroyers and the arleigh burkes are using the same aegis. With the hitting power of modern anti-ship missiles, it's seen as impossible to armor a ship sufficiently to survive a strike. Then again, US naval thinking is still shaped by the Cold War and the idea that incoming weapons are going to be nuclear so you have to knock them down or else be incinerated, there's no such thing as armoring against a nuke fireball. Since we haven't had a proper naval engagement since WWII, all we're operating under is a bunch of theory that has not been put to the test in a very long time.. 1. Arleigh Burke destroyers are actually pretty big. Let's compare, shall we, a Burke destroyer against, say, an Royal Navy King George V class battleship of World War I.

CategoryArleigh BurkeKing George V>
Displacement9000 tons23,400 tons
Length509 feet598 feet
Beam60 feet89 feet
Propulsion100,000shp31,000shp
Crew320/td>870

So, the Arleigh Burke is nearly as long, has three times the engine power as a World War I era top of the line British Battleship. In terms of firepower, there's really no comparison. If you plopped an Alreigh Burke and a KGV into the same ocean, the Burke is going to have missiles away before the KGV can even make visual contact.

The moral of the story is that you really have to think about what the Navy has evolved into. It's not that there are no more battleships, per se, it is more like every combatant the navy has is a capital ship in its own right.

I must also digress about armor. It's also a bit of a gap to say that American ships aren't armoured. Yes, it is true that American warships do not have thick steel armour belts in the past, but its also true that thick armour belts can't resist modern shaped charges, its also true that they only were really thick at areas of a ship where designers anticipated the firing arcs of other shells would be. Have a look at the now declassified maps of the USS New Jersey's armor belts. You could theoretically program missiles to hit other parts of the ship. Against a range of threats, from bombs to torpedos, or even missiles that can be programmed to hit a ship from any angle, it is simply impossible to provide passive armor protection on all surfaces.

So, what designers do do is local armoring. They might not armour the entire hull, but they'll wrap critical equipment with some kevlar jackets, and that's not too shabby. That does come from combat experience, in a weird way. During vietnam, they did nothing to protect combat aircraft, but, they realized that putting a little bit of armor around a few critical things would save a lot of planes. These things were incorporated, among other things, into the highly successful A-10, which is a very survivable plane, and, to some extent, that sort of thinking has found itself into US Navy ships as well.

Re:uh, wrong. please check your math.

[Shakrai]

But if you have a computer to adjust firing angle, firing energy, etc, you can very well make it targeted (by doing the calculation required for it to strike a target XX miles away at XX altitude).

How do you have a projectile with a 200+ mile range that isn't guided?

Even at Mach 8 there's almost a two minute flight time to reach 200 miles. Ignoring wind, the coriolis effect and everything else that could change the course of your projectile, what happens if the target changes course in that time or takes evasive action? A lot can happen in two minutes.....

Invented by Kristian Birkeland

[iantresman]

I believe it was Kristian Birkeland who invented the first rail gun, or its precursor, capable of firing a 10kg projectile up to 100m/s (Mach 1 is 334m/s). You can read his patent here: http://www.google.com/patents?id=9WNaAAAAEBAJ&dq=Birkeland,+Kristian

He had claimed that he could reach Mach 2, and send a two ton projectile 90-miles, see http://query.nytimes.com/gst/abstract.html?res=9906E0DF1330E733A2575BC0A9639C946397D6CF

A little more on Birkeland's electromagnetic cannon can be found here: http://www.plasma-universe.com/index.php/Kristian_Birkeland#Electromagnetic_cannon