Use of Rail-Gun/up-coming tech on surface vessels?

[localhost127]

I have not seen very many articles on the subject as of late, so feel free to correct...but it seems from what I remember, the issue in regards to rail-gun technology was about utilizing the weapon/tech on surface vessels, and what power plant would be able to supply the necessary power.

What I thought of right away, and what I have not seen reported on yet (or maybe I just have not seen it), but wouldn't these weapons be much more useful as anit-ship weapons? e.g., land/coastal based? especially in tight coastal aeras/seas, etc? or even if they are ship-based, wouldn't the primary topic of discussion be ship-to-ship warfare, instead of ship-to-land?

any opionions on this, or why I haven't heard this aspect discussed before?

 

[S400]

Powerplant type is obvious

I have not seen very many articles on the subject as of late, so feel free to correct...but it seems from what I remember, the issue in regards to rail-gun technology was about utilizing the weapon/tech on surface vessels, and what power plant would be able to supply the necessary power.

What I thought of right away, and what I have not seen reported on yet (or maybe I just have not seen it), but wouldn't these weapons be much more useful as anit-ship weapons? e.g., land/coastal based? especially in tight coastal aeras/seas, etc? or even if they are ship-based, wouldn't the primary topic of discussion be ship-to-ship warfare, instead of ship-to-land?

any opionions on this, or why I haven't heard this aspect discussed before?

Nuclear powered vessels are the obvious choice for rail gun systems.

 

[localhost127]

Nuclear powered vessels are the obvious choice for rail gun systems.

well, obviously. but even that solution yields new questions as to whether one reactor is enough to power the vessel's onboard systems, as well as being able to support such a weapon.

my question wasn't meant to veer off into the ongoing issues regarding making such a weapon possible to use on a ship, but more whether the direction this weapon could be used should be land or ship based. it seems that all of the attention i have seen/read over the past few years has been about using a rail-gun on a surface vessel to attack land based targets. it seems obvious to me that this weapon would be much more prime to take on the big tasks such as being a land (or surface based) anti-ship weapon..or even worse, anti carrier weapon.

imagine sneaking such a weapon to a coast or just outside of port where a carrier may be anchored

 

[S400]

imagine sneaking such a weapon to a coast or just outside of port where a carrier may be anchored

I don't believe they would be any easier to 'sneak' around than other, more traditional terrestrial anti-shipping weapons. Add to that their rather limited range and it would not be hard to maintain a safe, off shore distance. Carriers effective range is well beyond the reach of the rail guns under development.

I think we've seen that ships in port are subject to much less exotic weapons systems (read dinghies that go boom).

 

[eckherl]

BAE should have a proto type system in place for the U.S Navy by the year 2011, thats the date promised at the current time. Due to the size of the capacitors that are needed a ship mounted system is more realistic. Big capacitors will fit in a ship versus that they cannot be safely installed on a land based mobile platform(tank). Heres a really cool U.S Navy propaganda photo of the ultimate vision for this type of system, if I am wrong please correct me but isn`t the U.S Navy also wanting to go to all electric ships sometime in the future.

 

[Grim901]

As a land based system It seems there are more applications for it in the role of conventional artillery and if it can ever be shrunken down to scale, MBT weapons, rather than coastal artillery. Missiles provide much more potential in that field in terms of range, mobility and accuracy.

As for the anti ship role, I think the same argument applies. Against moving targets the idea of conventional gun type weapons, no matter how powerful, appears to have given way to the much more flexible missile systems. Gun type systems seems to be used more now against static positions and for (some) shore bombardment.

It may be that a rail type weapon would have more applications if combined with the new guided munitions we see emerging, but they always seem to strike me as a missile substitute, a slightly cheaper alternative to keep artillery potent.

 

[Misguided Fool]

I don't believe they would be any easier to 'sneak' around than other, more traditional terrestrial anti-shipping weapons. Add to that their rather limited range and it would not be hard to maintain a safe, off shore distance. Carriers effective range is well beyond the reach of the rail guns under development.

I think we've seen that ships in port are subject to much less exotic weapons systems (read dinghies that go boom).

Just correcting your "limited range" remark:

http://www.popularmechanics.com/technology/military_law/4231461.html

And more specifically :

While the 32-MJ LRG should start firing soon, it could take another 13 years for a 64-megajoule system to be built and deployed on a ship. The Marines, in particular, are interested in the potential for rail guns to deliver supporting fire from up to 220 miles away—around 10 times further than standard ship-mounted cannons—with rounds landing more quickly and with less advance warning than a volley of Tomahawk cruise missiles.

I don't think 220 miles is short by any measure, considering it is just a gun, with much much much cheaper ammunition than a million dollar tomahawk. Obviously tomahawks will still have their uses, but this system can easily fill the gap between the harpoon range and the tomahawk range, and can replace cruise missiles in the surface bombaring role (upto 220km inland, assuming a ship is can go right next to a coast, which is usually not possible

Also, as it's not guided, it can't be affected by jamming, and its speed of Mach 8 will make interception ... difficult. Add to that its immense speed and the ridiculous kinetic energy, it's unlikely to miss and if it does, it might end up causing some awesome waterworks .

 

[localhost127]

Just correcting your "limited range" remark:

http://www.popularmechanics.com/technology/military_law/4231461.html

And more specifically :

I don't think 220 miles is short by any measure, considering it is just a gun, with much much much cheaper ammunition than a million dollar tomahawk. Obviously tomahawks will still have their uses, but this system can easily fill the gap between the harpoon range and the tomahawk range, and can replace cruise missiles in the surface bombaring role (upto 220km inland, assuming a ship is can go right next to a coast, which is usually not possible

Also, as it's not guided, it can't be affected by jamming, and its speed of Mach 8 will make interception ... difficult. Add to that its immense speed and the ridiculous kinetic energy, it's unlikely to miss and if it does, it might end up causing some awesome waterworks .

i just have a hard time understanding how they will manage firing direction tolerances with such a small projectile, reaching accurate distances 220km away. e.g., a ship bouncing back and forth from waves...how on earth could you implement a gyro/balancing system that would be so finely tuned to the disruptions/movements of a ship, that you could launch a projectile to those kinds of distances without a high measurement of error on the trajectory?

 

[onslaught]

i just have a hard time understanding how they will manage firing direction tolerances with such a small projectile, reaching accurate distances 220km away. e.g., a ship bouncing back and forth from waves...how on earth could you implement a gyro/balancing system that would be so finely tuned to the disruptions/movements of a ship, that you could launch a projectile to those kinds of distances without a high measurement of error on the trajectory?

Correct me if I'm wrong but wouldn't the sheer speed of the projectile minimize the effects of of a rocking ship, along with a gyro? The instant the projectile leaves the barrel of the railgun (maybe I should say rails), it isn't affected by the movement of the ship which moves the the rails. The longer the time between when the firing button is pushed to when the projectile leaves the rail, the more the projectile trajectory is affected. Since the projectile is moving so fast through the railgun, the ship's rocking doesn't have that much time to change the trajectory of the projectile. The gyro should be able to handle any minor deviations from there.

 

[localhost127]

Correct me if I'm wrong but wouldn't the sheer speed of the projectile minimize the effects of of a rocking ship, along with a gyro? The instant the projectile leaves the barrel of the railgun (maybe I should say rails), it isn't affected by the movement of the ship which moves the the rails. The longer the time between when the firing button is pushed to when the projectile leaves the rail, the more the projectile trajectory is affected. Since the projectile is moving so fast through the railgun, the ship's rocking doesn't have that much time to change the trajectory of the projectile. The gyro should be able to handle any minor deviations from there.

correct. but more inline with tolerances of the launch platform. at that speed/trajectory, a (lame estimate) 0.05mm difference in launch platform slope could be a final launch difference between a 190km and 200km; a 10km variance. that could have devastating effects with regards to collateral damage/innocents from a non-accurate launch.

i will probably have to read up on this topic elsewhere, but my question is just how are they planning on getting the launch tolerances so tight / little error...where a tiny error in slope or launch velocity will have drastic outputs on the trajectory? add all of this to a moving launch platform, and the room for error increases.

these are just basic questions from someone who doesn't truely understand all aspects; which is why i'm throwing the questions out there.

and how on earth could you accurately target something 200km away with an unguided, ballistic trajectory shot? would GPS of the launch platform be able to have the fine granularity of known position (launch position) to be able to determine the correct direction to launch towards target? the tolerances would have to be so fine...shooting something over the horizon like that (unguided) must have so many technical obstacles to overcome.

 

[Quagmires Suck]

Correct me if I'm wrong but at upwards of 200 km wouldn't the curvature of the earth come into effect? I'm pretty sure you can't see an object the height of a ship at that distance if you are on even (sea) level with any type of optics because of the curvature. Also is there any possibility of making this a space-based weapon since that would solve most aiming/colaterral damage problems. Perhaps it could be nuclear or solar powered.

 

[localhost127]

Correct me if I'm wrong but at upwards of 200 km wouldn't the curvature of the earth come into effect? I'm pretty sure you can't see an object the height of a ship at that distance if you are on even (sea) level with any type of optics because of the curvature. Also is there any possibility of making this a space-based weapon since that would solve most aiming/colaterral damage problems. Perhaps it could be nuclear or solar powered.

getting a reactor into space isn't good for PR/dangers if launch vehicle explodes before or after reaching orbit

the batteries/capacitors for such a weapon would likely be very massive (and very heavy), making a space-based weapon too expensive to be feasible

and yes, that was the whole point of my discussion/questions (related to curvature of the earth; unguided ballistic trajectory)

 

[Alatien]

If I may toss in my 5 c.

The problem of guidance is the same as for ballistic missile. Most of the missiles have a very short burn time, and aim at having short "impulsive" burn to minimize gravity losses. So the powered flight is very short. This makes these missiles similar to artillery that they are powered only during initial "impulsive shot" - either rocket propellant or gun charge.

So aiming and guiding a railgun round would be similar to guiding a ballistic missile - not a significant issue. Sure, the round would need guidance, navigation and control (GNC) system, and probably some aerodynamic surfaces, but it has been done before. The accuracy could be similar to that of Excalibur XM982 with CEP ~ 10m.

Curvature of the Earth would not affect the flight/accuracy, except for target aquisition and communication with the ship. But that what satellites and UAVs are for.

What I see as a big pro compared to missiles (Harpoon, Exotec, BrahMos) is that railguns allow higher salvo density (multiple rounds simultaneous impact), and higher attack speed (Mach 6). This reduces effectivness of CIWS, which already have problems dealing with individual Mach 2+ missiles.

Regards

 

[S400]

Just correcting your "limited range" remark:

I believe you misunderstood which systems I was comparing the railgun's range to. We were talking about anti-shipping weapons, not weapons on ships. You should think more in terms of anti-shipping missiles, etc. 220 miles can be considered limited range with regards to those systems.

 

[Firn]

So aiming and guiding a railgun round would be similar to guiding a ballistic missile - not a significant issue. Sure, the round would need guidance, navigation and control (GNC) system, and probably some aerodynamic surfaces, but it has been done before. The accuracy could be similar to that of Excalibur XM982 with CEP ~ 10m.

A good post. I wonder how the taxing the immense acceleration of a projectile in a Railgun is on the various components. Perhaps the greatest challange for the Excalibur XM982 was to overcome the g-forces generated in the firing process. Overall it is clear that only a guided system can achieve the acceptable degree of accuracy needed for certain missions for such huge ranges as 150km or more. I guess that the potential for extremely long-ranged artillery (400km +) is there when one is able to integrate appropriate aerodynamic surfaces and possibly additional rocket propulsion. We will see.

 

[Alatien]

A good post. I wonder how the taxing the immense acceleration of a projectile in a Railgun is on the various components. Perhaps the greatest challange for the Excalibur XM982 was to overcome the g-forces generated in the firing process. Overall it is clear that only a guided system can achieve the acceptable degree of accuracy needed for certain missions for such huge ranges as 150km or more. I guess that the potential for extremely long-ranged artillery (400km +) is there when one is able to integrate appropriate aerodynamic surfaces and possibly additional rocket propulsion. We will see.

High g forces are indeed a problem, but the revolution in solid state components has really helped here. Solid state memory, optical gyros (both already implemented on many spacecraft), and patch antennas make things like Excalibur possible.

What is challenging is terminal targeting. Excalibur relies on GPS for targeting which is ok for hitting ground coordinates, but not moving targets. Its OK in most applications, but still at long range Excalibur has a flight time of about 1 minute, and a lot can happen in 1 minute.

Its even more challenging for railgun in ship-to-ship combat. At range of 350 km (~200 miles) the flight time will be around 5 minutes. This means that targeting GPS coordinates is useless, as a typical ship will move 3 km during that time. Updating target coordinates via satellite or UAV is possible, but not practical from jamming and other EW perspective.

My bet would be that the rounds could be targeted with IR or passive EM (like anti radiation missiles). Both sensors can be miniaturized (easier than radar/lidar) but both sensors have limitations. Especially since the round will heat up a lot, possibly blinding its own IR seeker, and passive EM seeker is useless against "silent" target. Its an interesting topic.

Regards

 

[Misguided Fool]

Based on pure conjecture:

Let's assume the barrel is 30 metres long. A projectile travelling at mach 6 would travel at 2 041.74 m / s. So it would cover 30 metres in 0.014693349789885098004643098533604 seconds. If the ship/barrel moved 5 metres in 1 second (say, waves), that would be a difference of 0.073466748949425490023215492665 metres. That's a difference of 5 metres in one second causing a difference of 7 centimetres. 5 metres per second is 18 kilometers per hour. How many ships rock around at 18 kmph?

I think in the worst storms (i have no specialist knowledge about this, so once again, pure conjecture) the ship's guns don't move at more than 5-10 kmph.

Just finishing off the above calculations. If the round were to be shot for 200km, a difference of 7 centimetres at firing would give an inaccuracy of 14 kilometres. I think at 200km, no artillery gunner would complain.

However, don't take those numbers blindly. I'm prone to mistake :. Check them yourself!

 

[gardnerdesign]

I am surprised none has thought about the potential defencive roles that a railgun could preform. It seems to me it would make an excellent AAA or CIWS far superior than any missile based or chemicaly propelled gun systems.

The rail gun would be far more economical in this role. Instead of one gun and a massive power pack (generator(s) and capacitor banks) coupled with a single turret capable of bombarding a target with several rounds, a defencive system would utilize a few guns attached to phalanx like mounts and a much smaller power pack. The power pack reduction can be explained by the need to only launch 2 or 3 rounds per incoming target.

The capabilities of the rail gun make it perfect for intercepting a wide range of targets from slow high flying aircraft to low flying supersonic even hypersonic missiles. long range targets such as aircraft would be targeted by the main air defence radar wile the phalanx mounts would allow for targets that are extremly time critical such as sea skimming missiles and ballistic missiles to be intercepted.

The system could also utilize various calibers for example some mounts would countain larger caliber rounds for long range targets or targets that utilize a highly irradic trajectory, these rounds would contain terminal sensors such as passive infrared (wich due to the short flight time involved in intercepting would not blind themselves) and control serfices to maintain a high probubility of intercept at long range. Smaller caliber guns would act more like the traditional CIWS and would be unguided. due to their reduced weight and greater projectile to rail length ratio would conserve alot more charge in the capacitor banks to fire higher volumes of fire.

essentially mixing the theater air defence and point defence roles into a single system. If you realy want to get futuristic you could even use a vertically aimed railgun with a sustainer rocket engine and infrared terminal guidence to engage mid course balistic missiles and even low level satillites. You could potentialy fire multiple rounds at one target for far less cost as a single SM-3 or THAAD (or intercept multiple targets with one projectile per target for an even further decrease in interception costs).

 

[Firn]

A highly interesting post

High g forces are indeed a problem, but the revolution in solid state components has really helped here. Solid state memory, optical gyros (both already implemented on many spacecraft), and patch antennas make things like Excalibur possible.

While I know that the g forces on space crafts are high I wonder how they compare to the g forces in an railgun. Given the principles of construction one could "soften" the acceleration of the projectile by increasing the "barrel", the lenght on which the projectile gets accelerated.

What is challenging is terminal targeting. Excalibur relies on GPS for targeting which is ok for hitting ground coordinates, but not moving targets. Its OK in most applications, but still at long range Excalibur has a flight time of about 1 minute, and a lot can happen in 1 minute.


Its even more challenging for railgun in ship-to-ship combat. At range of 350 km (~200 miles) the flight time will be around 5 minutes. This means that targeting GPS coordinates is useless, as a typical ship will move 3 km during that time. Updating target coordinates via satellite or UAV is possible, but not practical from jamming and other EW perspective.


My bet would be that the rounds could be targeted with IR or passive EM (like anti radiation missiles). Both sensors can be miniaturized (easier than radar/lidar) but both sensors have limitations. Especially since the round will heat up a lot, possibly blinding its own IR seeker, and passive EM seeker is useless against "silent" target. Its an interesting topic.

Hm sums up a lot of problems quite well.

AA-missiles travel also at high speeds, partly above Mach 3. They seem to have manage the heat-up. Of course the relationship between the speed and heat-up is not a linear one, I guess that it is closely related to the and speed and the specific resistence of the medium in which it travels. So also a big difference between a target at sea level and in the space.

I wonder if not a good use of a railgun against large ships at very long ranges would be to "soft-lauch" a heavy guided projectile/rocket with the HE-warhead needed to combat such a target. Let assume that this railgun it is capable to "softly" accelerate a 300kg rocket to a velocity of roughly 1500 m/s. For an very long shot of 600+ km it would propel the rocket high up into the atmosphere. Only a relative small amount of propellant and possible aerodynamic surfaces would be needed to further greatly lenghten the reach of such an "artillery".

Good post also by you, gardnerdesign.

 

[swampfox]

Another Popmech Article...

Also is there any possibility of making this a space-based weapon since that would solve most aiming/colaterral damage problems. Perhaps it could be nuclear or solar powered.

I think it was another article in Popular Mechanics that they suggested putting 25 foot steel rods up on a satellite. Supposedly the sheer velocity they accrued while entering the atmosphere did away with the need for any propulsion or warhead. You just had to be right above your target when you fired.