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The US Navy Wants More Railguns and Lasers, Less Gunpowder
coondoggie writes Speaking before nearly 3,000 attendees at the Naval Future Force Science and Technology EXPO in Washington, D.C., Chief of Naval Operations Admiral Jonathan Greenert charged his audience to reduce reliance on gunpowder in a wide-ranging speech on the future technological needs of the Navy. "Number one, you've got to get us off gunpowder," said Greenert, noting that Office of Naval Research-supported weapon programs like Laser Weapon System (LaWS) and the electromagnetic railgun are vital to the future force. “Probably the biggest vulnerability of a ship is its magazine—because that’s where all the explosives are." Weapons like LaWS have a virtually unlimited magazine, only constrained by power and cooling capabilities aboard the vessel carrying them. In addition, Greenert noted the added safety for Sailors and Marines that will come from reducing dependency on gunpowder-based munitions.
Lasers are used against aircraft or missiles. The railguns are for naval targets. Smoke is hilariously ineffective against a railgun strike. And it is hard to maintain a smoke screen around a missile or an aircraft.
Keep in mind, anything you could hit with a navel gun is even easier to hit with a rail gun. Currently the velocity of railguns is roughly equivalent to navel guns. However, that speed will climb.
Eventually this speed should surpass escape velocity which means railguns will eventually be able to tag satellites or even launch small hunter-killer kill vehicles to destroy/disable/subvert enemy orbital infrastructure.
The weapons are quite effective. The question in the new era is how to defend against such things so that a battle group is survivable. Between all this and hypersonic missiles carrier groups might be a thing of the past. Large surface fleets might also just be too vulnerable to be useful.
High endurance aircraft that can strike from extreme range and attack submarines with surface strike capability might be the order of the day. A submersible destroyer for example could get in close with heavy weaponry, fire a salvo, and then dive before enemy systems could target and strike it. Such a thing would be vulnerable to enemy attack submarines but then you could just escort it with a flotilla of attack submarines to act as defense. You could even add some drone carriers. Submersible aircraft carriers were built by the Japanese in WW2. Consider what you could do if you gave such a design a nuclear power plant, expanded the size to Nimitz proportions, and replaced the planes entirely with more compact drones.
That is a possible vision of the future.
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War is diplomacy by crude means.
Well, I might have a way, but it only works on a semi spherical planet in a vacuum.
What do we need a large navy for now?
That is what they were saying after WW1 then look what happened. I'm not saying there's a big war round the corner or anything but we need a large decent navy for when we need a large decent navy.
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Compared to what? How is the current paradigm any better? The only advantage of the current paradigm is that we're well adapted for it. We have the largest surface carrier fleet in the world.
However, the British had the largest battleship fleet in the world and what did that get them when the airplane came around?
Call it what you will... the law of this world is adapt or die. If we wish to maintain our military edge then it is in our interest to be realistic about the long term viability of our fleets and adapt strategies as required.
The issue with our current weapons systems is that they are very vulnerable to modern weapons. You could drop a whole carrier fleet fairly easily with a barrage of hypersonic missiles fired from a small number of disposable re-purposed fishing boats. Just strap on the launchers, sync them with orbital spy sat targeting and geo location... and fire. Those things come screaming in faster then bullets... and even the Aegis defense system is reported to be unable to really stop them.
Hit. Hit. Hit. Hit. Hit. Hit. Hit. Hit. Hit. Hit.
And the carrier group is slag heading to the bottom of the ocean. Don't blame me. I'm not the one that invented the machine gun and made infantry charges obsolete. That's just progress.
You have to know the carrier will be obsolete eventually. And when that happens what will take its place?
I gave two options of what I thought was more survivable. The first is just high endurance aircraft capable of traveling very long distances without refueling. That means the carriers if they exist could stay well out of hypersonic missile range. However, the problem with that idea is that carriers would be incapable of traveling within hundreds of miles of the enemy coast simply because it would be too easy to fire a hidden shore battery that destroyed the carrier. The current range of hypersonic missiles is about 50 miles. That is the current critical range. You have to kill from beyond 50 miles. Or more then 5 times the maximum range of WW2 battleship guns. And note, those guns were not accurate at that range. That is how far the range has opened up. It was not long ago that ships had to see each other to engage each other. Today, if you can see the enemy then one side or the other has committed suicide.
Submersible ships are another option. It sounds exotic but it was successfully done during WW2. The only trick would be to give it enough mass to carry enough weaponry to be effective and then to give it a power plant with enough power to give the ship freedom of the seas. If a carrier fleet can submerge and stay submerged for months at a time like our ballistic fleet then they can cruise right within the critical range of these weapons systems, surface, deploy their weaponry, and then submerge before they can be stopped or retaliated against.
This gives such a fleet freedom of the seas as well as the ability to counter the worst enemy weapons so long as the ships can dive fast enough to avoid a strike.
A counter might be cruise torpedoes. We have missiles that fly to a specific destination, then break off the tip which lands in the water... that tip is a self guided homing torpedo. It homes in on enemy sonar and acoustic signatures and attempts to destroy them. These weapons are quite effective against submarines and it allows US destroyers to launch a few of these in various directions. They all splash into the water and seek enemy targets. It is quite difficult to evade all them. And subs really have very few options against enemy torpedoes.
Simply affix that torpedo to a cruise missile giving it a 500 or so mile range.
In addition, you can setup a web of passive listening stations throughout the ocean floor that listen for even the smallest sound anywhere in the sea. If they're all networked then you should be able to passively echo locate any fleet that gets near the net.
Such are arms races.
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What do you mean by "burn through"? When you heat up a gas hot enough to change its state, the next state up is plasma. Plasma is opaque.
Really, lasers seem much easier to defend against than to get to work right... there's so many varied potential defenses for them (ablatives, smoke, chaff, higher thermal conductivity materials, heat sinks, polished surfaces, etc, plus presenting a precisely pinpointable beacon for return fire). And any ambient scatter (and there will be a lot) will be enough to cause permanent blindness for very long distances in all directions, so you run the risk of having your weapon classified as prohibited under the rules of warfare. This might not apply to high altitude planes and missiles which can be several kilometers away from the nearest observer, but still, the balance of difficulty would seem to be in favor of the defender, not the attacker.
"That girl is a witch!" "Yeah, but she's our witch. So cut her the hell down!"
Then how does a man in a fox hole lob a grenade into another fox hole without even poking his head above his own fox hole?
Naval guns don't point directly at their targets. They account for range by pointing UP. This gives the trajectory a curve which more then compensates for the curvature of the Earth. They also account for wind by pointing the guns slightly into the wind to counter the effect of the wind. And then they account for heading by leading the target a bit such that they're aiming for where the enemy will be when the shell arrives rather then where the enemy is right now. Other things are factored... humidity, air pressure, temperature, etc. Factor it all accurately and in real time with a computer and you have a good chance of hitting your target unless it is jinking all over the place.
Currently railguns have about the same muzzle velocity as a WW2 battleship cannon. Which is only because no one has ever gotten a shell to travel faster then that with chemical propellant. There might be some exceptions. I think some of the giant land guns might have had higher muzzle velocities. The germans had a big gun they used against the French and I think there was another one built in the middle east somewhere but it escapes me. Regardless, the weapons were too large to really be practical. They were big white elephants that accomplished very little compared to their cost.
Railguns have the potential to achieve far higher muzzle velocities. Again, you could potentially fire a shot from a destroyer straight up and slap a satellite out of the sky if you got the muzzle velocity up about four or five times what a WW2 battleship could manage. That is a long way to go but it is technically possible. Where as with a chemical propellant you'd need an absurdly long barrel to even try such a thing.
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Compared to chemical propellants? I don't think so.
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According to that firearm efficiency is not incomparable to piston engines, which is not all that surprising as the conversion of heat to motion is not dissimilar. In that case, a .300 rifle achieves about 32% efficiency.
For a fuel powered railgun, you have to first convert the fuel to heat then to motion then to electricity. The top marine diesles give about 51% efficiency, when you're preppared to sacrafice almost anything on the altar of efficiency. The likely efficiency of a naval marine engine is probably more like 40%, in which case you're already quite close to the gun efficiency and you haven't even generated electricity yet.
You've then got the capacitor bank charging, switching losses and finally the conversion of the insane current into motion.
So my guess would be that a rail gun is substantially less efficient than a conventional firearm.
I'm fairly certain the nuclear reactor that powers the guns and the ship won't be that big of a problem. They don't do it on diesel.
Well, that removes a lot of the advantages: nuclear reactors are vastly more expensive, so you've just put the price way up.
Thats why the strengthen the keel ... 40 years ago.
So why are modern torpedos designed to work that way?
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I'd keep going, but I'm just blown away by how you got to +5 on this. You don't seem to know anything at all about you're talking about. You're mixing and matching things in ways that makes them all simply completely false statements.
Touche, my man.
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There's an interesting thing that hitting a target with a high energy inert round often doesn't do a whole lot of damage. There was a case in WWII of some armed merchant cruisers (i.e. cargo ships with a couple of obsolete guns welded on) were mistaken for cruisers by some German raiders. The raiders engaged at long range with AP rounds and scored some direct hits. The AP rounds went all the way through the unarmored ships and out the other side without detonating (they were designed to penetrate a bit into armor and then detonate: the lack of armor caused the warhead to not trigger). The end result was that the ships wound up with some perfectly survivable 15" holes in them and managed to escape.
Good stuff here. I just have to add that this effect is seen throughout the age of gunpowder: unless gunnery hit the enemy magazine, all they were doing was making pinpricks in the opposing fleet. Keegan's Price of Admiralty describes Lord Nelson's fleet and the HMS Dreadnought being involved in these kinds of battles.
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Lasers have over the horizon issues as they can't use ballistic trajectories. You aren't going to take out another ship at 100 miles with a laser, even aside from the thermal blooming issues which would start sapping the energy of the beam at that range in atmosphere.
Lasers work better against ballistic missiles or airplanes because they are much farther above the horizon and can be targeted without worrying about the curvature of the Earth. Even then, they are still more of a defensive weapon under those conditions.
For long range naval gunfire, it's going to be something like a rail gun that would fire projectiles that can follow a curved ballistic path. That or we just use more advanced missiles.
That said, at ranges that you might get small attack craft, a laser might be useful for ship-to-ship, but so would a .50 cal. and it's probably a lot easier to mount a bunch of those than a directed energy weapon at today's tech level.