Bad ideas in war

[The Great Zaganza]

In an age of missiles and drones you can always question the point of a railgun.

 

[Andy_Ross]

A Railgun would be an ideal AA weapon.

 

[jimbob]

A Railgun would be an ideal AA weapon.

Exactly,

Especially if you are looking at defending against multiple drones and missiles

 

[catsmate]

Basically, I think the USN has properly stealthy ships but they tend to stay underwater most of the time.

So a surface vessel would have to do something different. The Zumwalt is not in the same position as the F22 compared to its peers.

Subs are generally out of communication with other vessels and can't easily be tied into the modern data network.

I think its odd that the first attempt to build a railgun is as part of the weapons of a ship.
Given its range, a shore battery seems to be far more logical for all kinds of reasons.

What exactly is such a battery for? Even with a range in the low hundreds of kilometres you need a suitable target in that area. Also shore batteries tend to be immobile, unless you;re postulating a return to rail or truck borne heavy artillery?

In an age of missiles and drones you can always question the point of a railgun.

Cost and velocity favour guns. If you look at, say, Ukraine, there are a lot of mortar, gun/howitzer and rocket rounds being fired.

 

[The Great Zaganza]

Ports are absolutely critical for military and economic purposes, and are a primary target in times of war - and many countries have very few, very critical ports. Defences independent of Naval forces would make sense.

 

[jimbob]

Ports are absolutely critical for military and economic purposes, and are a primary target in times of war - and many countries have very few, very critical ports. Defences independent of Naval forces would make sense.

But not large calibre shore guns. If you are defending against ships, you are still trying to hit a manoeuvring target that could track your shells with radar and take avoiding action unless your shells have some type of guidance. (Or shoot them down or a combination)Whereupon it would often be better to go for a far more flexible missile battery with a far longer effective range.

Point defence weapons, that could defend against flying or surface drones and cruise missiles are another questioni.


This wouldn't be the case for a ship performing shore bombardment - as the port cannot move. And there would be plenty of other things that a shop could bombard effectively near the coast

However I'm not sure that the range of the Zumwalt's AGS is sufficient for it to have been that useful especially for the development costs compared to even fairly cheap missiles..

Which is why I said it would have made more sense if there was an effective railgun for it to use. But as there isn't, having more missiles makes more sense to me.

With, say a 200km range such a ship could stand off shore and reach across the Korean Peninsula, and would have a similar range to the silkworm missile.

 

[The Great Zaganza]

You can't intercept railgun shells - that's kinda the whole point. The other is that a railgun has a way, way longer reach than any ship cannon.
A port railgun could be stored away like a nuke in a silo until needed, making it impervious to attacks.

But I guess a better location would be in range of narrow straits, basically controlling access from from 200-400km away.

 

[catsmate]

Ports are absolutely critical for military and economic purposes, and are a primary target in times of war - and many countries have very few, very critical ports. Defences independent of Naval forces would make sense.

So what? Immobile railgun batteries are targets for everything, can't hide and can't move.

You can't intercept railgun shells - that's kinda the whole point.

Of course they can. Anything, even the much vaunted "hypersonic missiles" can be intercepted, especially by developments in lasers.

The other is that a railgun has a way, way longer reach than any ship cannon.

Even compared to a similar railgun on a ship?

A port railgun could be stored away like a nuke in a silo until needed, making it impervious to attacks.

Nothing is "impervious to attacks".

But I guess a better location would be in range of narrow straits, basically controlling access from from 200-400km away.

And again you're relying on one weapon system. One immobile weapon systems.

 

[jimbob]

You can't intercept railgun shells - that's kinda the whole point.

Ships can dodge and quite possibly could intercept railgun shells.

Even at 100 km the shell still has to fall almost a kilometre just to take account of the curvature of the earth and assuming the round was flying at 2.5 km per second at launch (so Mach 7) you are looking at over 40 seconds flight time.

ETA And you need some way to actually locate the ship in the first place. Presumably from some aerial vehicles, that would, if they are in line of sight to the ship, potentially vulnerable to lasers, or maybe even the shipborne railgun

 

[Andy_Ross]

You can't intercept railgun shells - that's kinda the whole point. The other is that a railgun has a way, way longer reach than any ship cannon.
A port railgun could be stored away like a nuke in a silo until needed, making it impervious to attacks.

But I guess a better location would be in range of narrow straits, basically controlling access from from 200-400km away.

At short range of up to a few thousand meters maybe not but at 100km what would be the flight time?

As for fixed sites, just put the guns on ships and move them to where they are needed.

Even containerise them and move them by road.

 

[jimbob]

As for fixed sites, just put the guns on ships and move them to where they are needed.

Even containerise them and move them by road.

I don't think that would work because of the power requirements. A ship has far more scope for GBFO generators compared to a measley 40 tonne lorry..

Containerised missiles, however are a different question.

 

[catsmate]

At short range of up to a few thousand meters maybe not but at 100km what would be the flight time?

As for fixed sites, just put the guns on ships and move them to where they are needed.

Even containerise them and move them by road.

Assuming launch at 2.5km/s, around sixty seconds, quick calculation.

 

[catsmate]

I don't think that would work because of the power requirements. A ship has far more scope for GBFO generators compared to a measley 40 tonne lorry..

Containerised missiles, however are a different question.

Plenty of options for hiding missiles in containers.

 

[jimbob]

Plenty of options for hiding missiles in containers.

Indeed. Some have even been shown at arms fairs

 

[jimbob]

Plenty of options for hiding missiles in containers.

Also there's the question of recoil. A 50kg shell launched at 2.5km/second is far easier to handle in a turret massing several hundred tonnes in a ship of several thousand tonnes compared to a vehicle massing several tens of tonnes, whilst rockets and missiles can have almost* no recoil.

I'm guessing friction could end up giving a small analogue of recoil in the direction of launch as opposed to against it

 

[Andy_Ross]

I don't think that would work because of the power requirements. A ship has far more scope for GBFO generators compared to a measley 40 tonne lorry..

Containerised missiles, however are a different question.

You would use several vehicles just like a mobile missile battery.
Gun on one vehicle, targeting on another and a generator. or two.

 

[Andy_Ross]

Assuming launch at 2.5km/s, around sixty seconds, quick calculation.

plenty of time to acquire by a ship and for it to take evasive action.
Also as the projectile is not powered it will be losing velocity as soon as it leaves the gun.

 

[Andy_Ross]

Also there's the question of recoil. A 50kg shell launched at 2.5km/second is far easier to handle in a turret massing several hundred tonnes in a ship of several thousand tonnes compared to a vehicle massing several tens of tonnes, whilst rockets and missiles can have almost* no recoil.

I'm guessing friction could end up giving a small analogue of recoil in the direction of launch as opposed to against it

What recoil do you think a rail gun has?

 

[jimbob]

What recoil do you think a rail gun has?

Massive, but I'm sure a ship can deal with that. After all, if we're talking about a 50kg shell at Mach 7 (under 2500m/s) it's less than 5x the recoil of a BL 6-inch Mk XXIII naval gun if I'm reading Wikipedia for the muzzle velocity correctly.

But that's not the same as trying to deal with it in a lorry.

​

 

[Andy_Ross]

Recoil isn't the same as conventional artillery. The main forces are not opposite the direction of the projectile but at 90 degrees and try to push the rails apart.
At the present time a set of rails is only good for a few shots before heat, stress and friction degrade them to a point where they need to be replaced.