Bad ideas in war

[theprestige]

As far as I can tell, railguns seem to be in search of a niche between close range and cruise missile/mrbm range. The obvious advantages are:

1. A smaller, faster projectile that is harder to track, target and intercept; and
2. A much higher ammo capacity, meaning longer/more engagements before needing to retire and reload.

It seems like the applications should be other surface combatants that have been detected at long range, and land targets where shore defenses are either weak or nonexistent. In principle, it should be a lot cheaper to park a battlecruiser off the coast of Yemen, and rail Houthi positions ashore, instead of expending cruise missiles on them.

It also makes it safer to bombard important Chinese coastal facilities. The gun can be fired from much further away than current naval guns. It carries a lot more ammunition than can fit into missile magazines. And the platform itself is much harder to pick up on radar. Similar advantages are apparent for target rich environments such as a Chinese amphibious assault on Taiwan, where you'd have a lot of stuff worth shooting. China is also likely to have very heavy air defenses, which would tend to reduce the value of a carrier-based bombardment strategy.

That said, railguns kind of look like one of those highly desirable techs, like fusion power, that will always be just around the corner. It's obvious that the US isn't there yet.

The "better than nothing" alternative gun, the one with the really expensive ammunition, is the real problem child, in my opinion. It's basically just a bigger naval gun, with smarter shells. Ground-launched glide bombs, basically. While I think "smartillery" is the way of the future, I'm not sure a bigger naval gun is the quantum leap forward in capability we're looking for. I suspect we're better off continuing to make incremental improvements in carrier-based bombardment, supplemented by missiles, until we hit upon the Next Big Thing.

 

[Andy_Ross]

The Royal Navy was considering Battleships with 20" guns before the Washington Treaty and British manufacturing had the capability.
Making bigger conventional guns isn't hard.

 

[Jack by the hedge]

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.

While I haven't thought about the internal forces trying to pull a rail gun to pieces, I'm very sure the total momentum of the gun and projectile will be conserved, so the gun will be hurled backwards as forcefully as the projectile is hurled forwards.

 

[theprestige]

The Royal Navy was considering Battleships with 20" guns before the Washington Treaty and British manufacturing had the capability.
Making bigger conventional guns isn't hard.

Nobody said it was hard. But bigger conventional guns really don't seem to be the meta, at the moment. The trend in surface combat seems to be towards smaller guns with smarter shells, leaving more room for larger gun magazines and/or more room for missiles.

 

[Andy_Ross]

While I haven't thought about the internal forces trying to pull a rail gun to pieces, I'm very sure the total momentum of the gun and projectile will be conserved, so the gun will be hurled backwards as forcefully as the projectile is hurled forwards.

No, that's the point, some of it is directed at right angles to the length of the rail.

 

[Andy_Ross]

Nobody said it was hard. But bigger conventional guns really don't seem to be the meta, at the moment. The trend in surface combat seems to be towards smaller guns with smarter shells, leaving more room for larger gun magazines and/or more room for missiles.

I agree, the point of battleship guns was to penetrate the armour of other battleships.

 

[jimbob]

While I haven't thought about the internal forces trying to pull a rail gun to pieces, I'm very sure the total momentum of the gun and projectile will be conserved, so the gun will be hurled backwards as forcefully as the projectile is hurled forwards.

Andy is correct about the magnetic repulsive forces trying to push the rails apart - which again would lead to the requirement for a bulkier gun and indeed the life is a problem. I agree that railguns don't seem to be practical yet, but all the features would suggest that they would make most sense in large warships

The Royal Navy was considering Battleships with 20" guns before the Washington Treaty and British manufacturing had the capability.
Making bigger conventional guns isn't hard.

But you are still limited to probably under Mach 3 with a gun powered by conventional explosives. Maybe you can get more with some fancy explosives technology but controlling those is probably harder than electrical switching for a linear motor in a railgun.

As far as I can tell, railguns seem to be in search of a niche between close range and cruise missile/mrbm range. The obvious advantages are:

1. A smaller, faster projectile that is harder to track, target and intercept; and
2. A much higher ammo capacity, meaning longer/more engagements before needing to retire and reload.

It seems like the applications should be other surface combatants that have been detected at long range, and land targets where shore defenses are either weak or nonexistent. In principle, it should be a lot cheaper to park a battlecruiser off the coast of Yemen, and rail Houthi positions ashore, instead of expending cruise missiles on them.

It also makes it safer to bombard important Chinese coastal facilities. The gun can be fired from much further away than current naval guns. It carries a lot more ammunition than can fit into missile magazines. And the platform itself is much harder to pick up on radar. Similar advantages are apparent for target rich environments such as a Chinese amphibious assault on Taiwan, where you'd have a lot of stuff worth shooting. China is also likely to have very heavy air defenses, which would tend to reduce the value of a carrier-based bombardment strategy.

That said, railguns kind of look like one of those highly desirable techs, like fusion power, that will always be just around the corner. It's obvious that the US isn't there yet.

The "better than nothing" alternative gun, the one with the really expensive ammunition, is the real problem child, in my opinion. It's basically just a bigger naval gun, with smarter shells. Ground-launched glide bombs, basically. While I think "smartillery" is the way of the future, I'm not sure a bigger naval gun is the quantum leap forward in capability we're looking for. I suspect we're better off continuing to make incremental improvements in carrier-based bombardment, supplemented by missiles, until we hit upon the Next Big Thing.

Agree with pretty much all of this, except possibly the utility against moving surface targets at long range, where I suspect they wouldn't be that useful compared to missiles.

 

[jimbob]

No, that's the point, some of it is directed at right angles to the length of the rail.

Yes but that is in addition to the recoil of the shell. The rails pushing each other apart don't actually add to the recoil as such as each rail is its partner's recoil mass

 

[jimbob]

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.

Of course the AGS of the Zumwalt got round any concerns about barrel life by having the number of shells as the limiting factor.

 

[theprestige]

Of course the AGS of the Zumwalt got round any concerns about barrel life by having the number of shells as the limiting factor.

The AGS was not a railgun. It was the "better than nothing" conventional naval gun they wanted to adopt after they realized the railgun tech wasn't ready yet. The number of shells was limited because the AGS was a much larger caliber than existing naval guns, meaning larger shells and therefore fewer shells per magazine.

Also, because the Z class never went into service, neither did the AGS. This meant that they couldn't leverage economies of scale in the production of these high-advanced smart shells. This in turn meant that the price per shell for the prototypes was extremely high. This led to the canard that the shells were an obscenely expensive waste of money. It's the same thing with the F-35 being cheaper per unit than the F-22. It's not tha that the F-22 was overpriced, it's that we ended up not making very many of them - for very good reasons.

 

[catsmate]

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

Well yess, sort-of. The acceleration cycle of an emag launcher is less 'jerky' (in the sense of fourth order derivative) than a conventional CPR launcher so the stresses of recoil are less, and the 'barrel' of an emag weapon doesn't have to be as structurally strong as one containing a violent deflagration.
Current 155mm weapons can launch a 45kg at >900m/s.

Wrt rockets (and ramjets) burning propellent outside of the containment of a barrel is far less efficient.

 

[catsmate]

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.

And, as recent events have shown, you don't need to destroy a missile or projectile to render it ineffective, just deflect it slightly.

 

[catsmate]

The Royal Navy was considering Battleships with 20" guns before the Washington Treaty and British manufacturing had the capability.
Making bigger conventional guns isn't hard.

Logistics!!
Improving 155mm (and 203mm) shells is probably a better route.

 

[catsmate]

I'd also like to point out that the Swedes are already pushing 155mm ramjet test shells to well over 100km with plans for 150km. Perhaps the US Navy should (again) ask the Swedes for assistance?
Or (worse) ask the US Army, who's working with Nammo, to help....

 

[theprestige]

I'd also like to point out that the Swedes are already pushing 155mm ramjet test shells to well over 100km with plans for 150km. Perhaps the US Navy should (again) ask the Swedes for assistance?
Or (worse) ask the US Army, who's working with Nammo, to help....

Why? The USN already has domestic contractors working on the same things.

 

[jimbob]

Well yess, sort-of. The acceleration cycle of an emag launcher is less 'jerky' (in the sense of fourth order derivative) than a conventional CPR launcher so the stresses of recoil are less,

d⁴x/dt⁴?

I sort of assumed a deflagration would give a rapid change in acceleration but I guess it wouldn't be linear.

Whereas one could easily time the current through every section of a railgun.

 

[jimbob]

The AGS was not a railgun. It was the "better than nothing" conventional naval gun they wanted to adopt after they realized the railgun tech wasn't ready yet. The number of shells was limited because the AGS was a much larger caliber than existing naval guns, meaning larger shells and therefore fewer shells per magazine.

Also, because the Z class never went into service, neither did the AGS. This meant that they couldn't leverage economies of scale in the production of these high-advanced smart shells. This in turn meant that the price per shell for the prototypes was extremely high. This led to the canard that the shells were an obscenely expensive waste of money. It's the same thing with the F-35 being cheaper per unit than the F-22. It's not tha that the F-22 was overpriced, it's that we ended up not making very many of them - for very good reasons.

Yes, we're violently agreeing, I think.

My point is that the F22 had a role in a way that the Zumwalt didn't (even if I think the YF23 looked more potentially impressive and maybe closer to what the 6th generation fighters seem to be shaping up to)

 

[jimbob]

This video suggests that the Japanese idea of having magnesium* "thermite" shells for any guns equivalent to a destroyer's main armament and up might have been a bit of a mistake.


TLDW, starting very hot fires that can't** be extinguished by water or CO2


*Not sure if it is a thermite reaction or just magnesium in there, hence the quotation marks.


** I guess that water could still cool it and work that way, but a lot of hydrogen and oxygen would still be produced in that case.

 

[catsmate]

d⁴x/dt⁴?

I sort of assumed a deflagration would give a rapid change in acceleration but I guess it wouldn't be linear.

Whereas one could easily time the current through every section of a railgun.

Exactly. And you can do fancy stuff with spin, especially with a projectile with the ability to change trajectory.

 

[catsmate]

This video suggests that the Japanese idea of having magnesium* "thermite" shells for any guns equivalent to a destroyer's main armament and up might have been a bit of a mistake.


TLDW, starting very hot fires that can't** be extinguished by water or CO2


*Not sure if it is a thermite reaction or just magnesium in there, hence the quotation marks.


** I guess that water could still cool it and work that way, but a lot of hydrogen and oxygen would still be produced in that case.

It's not true 'thermite', i.e. the Goldschmidt reaction, but barium nitrate and magnesium, plus some rubber. The Tirpitz also used such shells.
They were generally ineffective.

 

[Andy_Ross]

Musashi was 'really' sunk by overwhelming forces and firepower.

There's always a bunch of fanatics that are convinced that their favourite Japanese or German battleship was si superior to anything the Americans or British gad it was impossible for them to be sunk by enemy action and something else has to explain it.

In reality neither Musashi or Bismarck were particularly well designed ships.
Yamato and Musashi were just big. Bismarck and Tirpitz weren't even particularly huge and had many flaws and inefficiencies.

Their biggest mistakes and problems were that they were always going to come up against superior American or RN forces and be destroyed.

It's all very well having a couple of big ships but the Allies haf several dozen.

 

[jimbob]

It's not true 'thermite', i.e. the Goldschmidt reaction, but barium nitrate and magnesium, plus some rubber. The Tirpitz also used such shells.
They were generally ineffective.

Thanks, and is the "thermite" used by bomber command also similar or was that actually the classic thermite reaction?

Musashi was 'really' sunk by overwhelming forces and firepower.

There's always a bunch of fanatics that are convinced that their favourite Japanese or German battleship was si superior to anything the Americans or British gad it was impossible for them to be sunk by enemy action and something else has to explain it.

In reality neither Musashi or Bismarck were particularly well designed ships.
Yamato and Musashi were just big. Bismarck and Tirpitz weren't even particularly huge and had many flaws and inefficiencies.

Their biggest mistakes and problems were that they were always going to come up against superior American or RN forces and be destroyed.

It's all very well having a couple of big ships but the Allies haf several dozen.

Yes, this video was more on the immediate cause. It's certainly consistent with your wider point. It's s almost certain that Lee was undercounting his hits from Washington. He claimed 9 hits. A Japanese officer counted 23 hits on it and at least one has been confirmed in the same place as he said and 14 hits have been counted on the rear of the wreck. The bow is lost, which convincingly is attributed to Washington's gunnery. And if the shells waiting for loading into the turrets can be ignited relatively easily by incoming shellfire that's not very good.

There are apparently reports from Washington of Musashi glowing red, which would be explained by a massive magnesium fire.

And loading up with so called thermite shells isn't very good if you're likely to face battleships

 

[catsmate]

Thanks, and is the "thermite" used by bomber command also similar or was that actually the classic thermite reaction?

Generally the bombs were based on the German incendiaries developed during WW1 and used thermite (metallic aluminium and iron oxide powders mixed as pellets or homogeneously) inside a magnesium/aluminium alloy ('Elektron') casing. The metal casing was sometimes replaced by other materials when magnesium was scarce. Noses were generally steel or iron.
The USAAF used similar (often UK) designs.

If you're interested I have a UKGov document on the various designs stored somewhere.

 

[jimbob]

Generally the bombs were based on the German incendiaries developed during WW1 and used thermite (metallic aluminium and iron oxide powders mixed as pellets or homogeneously) inside a magnesium/aluminium alloy ('Elektron') casing. The metal casing was sometimes replaced by other materials when magnesium was scarce. Noses were generally steel or iron.
The USAAF used similar (often UK) designs.

If you're interested I have a UKGov document on the various designs stored somewhere.

Thanks. You've answered my questions.

 

[Andy_Ross]

I think the whole thermite shells thing is bollox to be honest.
Propellant charges have far more energy and potential to do damage.

 

[jimbob]

I think the whole thermite shells thing is bollox to be honest.
Propellant charges have far more energy and potential to do damage.

Wouldn't they burn/explode far more quickly though?

 

[Trebuchet]

Thanks, and is the "thermite" used by bomber command also similar or was that actually the classic thermite reaction?




Yes, this video was more on the immediate cause. It's certainly consistent with your wider point. It's s almost certain that Lee was undercounting his hits from Washington. He claimed 9 hits. A Japanese officer counted 23 hits on it and at least one has been confirmed in the same place as he said and 14 hits have been counted on the rear of the wreck. The bow is lost, which convincingly is attributed to Washington's gunnery. And if the shells waiting for loading into the turrets can be ignited relatively easily by incoming shellfire that's not very good.

There are apparently reports from Washington of Musashi glowing red, which would be explained by a massive magnesium fire.

And loading up with so called thermite shells isn't very good if you're likely to face battleships

You appear to be thinking of Kirishima, not Musashi. Musashi was sunk by air attack only.
Perhaps the biggest contribution of the Type 3 shells to the loss of Kirishima was that her guns were loaded with them instead of AP when she encountered the American ships.

ETA: Posted before I started the video, which does indeed start by talking about Kirishima. So the confusion is understandable. And I now see you made my second point for me!

ETAA: Did Ryan just mistitle that whole video? Only a few minutes in....

 

[catsmate]

I think the whole thermite shells thing is bollox to be honest.
Propellant charges have far more energy and potential to do damage.

For AA or general bombardment? Yeah, they're specialised ordnance.

 

[jimbob]

For AA or general bombardment? Yeah, they're specialised ordnance.

For messing up your own ship.

I'd guess that they do it differently [ETA propellent charges probably would do their damage almost instantly, and the ship would do a Hood. Not sit on the surface for hours, crippled and reportedly glowing red until sinking]

Did Ryan just mistitle that whole video? Only a few minutes in....

Ah, that would make more sense

 

[Andy_Ross]

Drachinifel covers the loss of the Kirishima and her sister ship the Hiei and the reason for their mistaken use of general purpose shells in his videos on the Guadalcanal battles.



Video on the Kongo class

 

[Andy_Ross]

By coincidence Drach answers a question on the San-shiki shells in this week's Q&A video at 45 minutes(timestamps in video description)

 

[jimbob]

The Trump class seems ideally suited to this thread

 

[lobosrul5]

The Trump class seems ideally suited to this thread

ETA: not sure whats wrong with the format I put the yt video in. But clicking on it works. Anyways, its the always entertaining LazerPigs take on it.

Edited by jimbob: 

Yt tag isn't needed anymore, just paste the link

The bottom line is, its way way too expensive to justify like an extra 30% VLS tubes over an Arleigh Burke. The rail gun *might* eventually be a good idea, but really it needs a nuclear propulsion plant to make that work. Theres also the problem that its likely the only shipyard that can build them is Newport News, and that means giving up building a carrier.

Its a dumb vanity project that will never get built. We needed the FFG(X).[/Edit]

 

[jimbob]

ETA: not sure whats wrong with the format I put the yt video in. But clicking on it works. Anyways, its the always entertaining LazerPigs take on it.

Edited by jimbob: 

Yt tag isn't needed anymore, just paste the link

The bottom line is, its way way too expensive to justify like an extra 30% VLS tubes over an Arleigh Burke. The rail gun *might* eventually be a good idea, but really it needs a nuclear propulsion plant to make that work. Theres also the problem that its likely the only shipyard that can build them is Newport News, and that means giving up building a carrier.

Its a dumb vanity project that will never get built. We needed the FFG(X).[/Edit]

Yup. And perun, with his professional defence procurement head pointed those out as well as the opportunity cost for not building probably 3 Arleigh Burkes for the same displacement and probably less cost. Or even two DDG(X) for less displacement. And about 25 years further down the design path.

As well as the actual mission. A couple of unproven technologies for weapon systems, but which would inherently have both high power and high energy requirements and both of which are fairly short range - lasers restricted to line of sight and railguns to maybe 100 miles if you are lucky, along with a weapon with planned global reach. Is it a long range sniper, or a close-in brawler?

Still, I guess that it's an achievement to make the worst part of the program not the reliance on 2-3 independently-unproven technologies in the same vessel, but its impact on the rest of the navy, and what it's actually for.


Video below

 

[sackett]

But Donnie's remembering the Maine!

 

[Wudang]

I'm waiting for the announcement that Trump Dockyards will be awarded a $100B contract to build the new batleships.

 

[Andy_Ross]

Drachinifel released a video on the subject last week

 

[Wudang]

CT time : why would someone suspected to be a puppet of Putin want to divert US military resources from proven combat capability to outdated ideas?

 

[Mojo]

The Trump class seems ideally suited to this thread

Donnie seems ideally suited to this thread.

 

[Mojo]

CT time : why would someone suspected to be a puppet of Putin want to divert US military resources from proven combat capability to outdated ideas?

Because he saw something about a battleship in an old movie.