Build a modern battleship

[MadRat]

Any kind of directed-energy weapon is limited to line-of-sight, don't forget. If the enemy is below horizon, you can't harm him with microwaves (well, there are probably some unorthodox methods...)

It is still a function of power and distance.

How long until we see coastal towers? No BBG will reach those heights.

 

[EmoBirb]

Any kind of directed-energy weapon is limited to line-of-sight, don't forget. If the enemy is below horizon, you can't harm him with microwaves (well, there are probably some unorthodox methods...)

Not only that, the amount of energy required to make any DEWs viable for offensive purposes over extremely long ranges would have to be immense. We're just now seeing lasers slowly becoming viable for close range self defense, we're still very, very, very far away from 'super lasers' and 'microwave guns'.

 

[Desertfox]

If you need a big gun build a modern monitor, something like a big LCS with an 8" cannon, that can scoot in, fire off a few salvoes and then scoot out. Make it cheap, disposable, and single use.

 

[Cirov]

In a peer fight involving hypersonics where the potential defended footprints possible with weapons like PAC-3 or SM-6 are - due to the intercept geometry challenges - so small as to almost point-defense range, there is some logic to needing your missile-shooter having a good enough sensor suite to at least protect itself.

In any event, since LRHW range is currently bigger than unrefueled CVW strike fighter range for the foreseeable future, there's also an argument that the CVW will be the primary defensive shield of the fleet, with the LRHW or weapons like it being the primary alpha strike, at least in the opening phases against critical targets.

That's worth noting, I hadn't thought of that. I assume offboard targeting is viable? Couldn't you use an Aegis-equipped warship to guide in a missile from whatever platform is most advantageously positioned?

I feel like we have to find a solution that doesn't involve a billion-dollar radar on every single boat in the fleet.

capital ship guns force enough other constraints onto a ship that it's likely they're no longer viable as an offensive weapon, even if we're doing Gerald Bull things to them and launching say 8" extremely low drag shapes out of a 12-16" tube for ludicrous range. What did they call it, "Strategic Long Range Cannon"?

Thing is, once you get past about 25km range, you really do need a terminally-guided cannon projectile. Because a 1mps difference in muzzle velocity will put your point of impact off by over 250m. A 1-mil error in gun azimuth will put you off by (range in km).

Accuracy at long range is a good point, but there are gradations of costs here. A steerable fin and either GPS or a seeker head is one level of cost--the projectile you're proposing is going to need thrust vectoring and glide wings. For evidence, look at LRLAP and look at Excalibur. Both are guided 155mm rounds, but LRLAP cost $500,000 per round delivered and was expected to increase to $800,000-$1,000,000 each. They also never demonstrated the claimed range. Excalibur, on the other hand, reached a peak price of $250,000 each in the early days and is now around $70,000 each. So by increasing the capability of the round from "guided" to "guided and self propelled" we have caused a 2x to 14x price increase, depending on which numbers you take. For a VGAS system, you are talking even more complexity than LRLAP.

Because a ship with LRHW and the AAW flag is getting shot at by high end AShCM and AShBM strikes, plus whatever hypersonics the enemy chooses to throw your way.

Yes, so it will have BMD escorts. I'm in favor of defending warships that need defense, I'm not in favor of giving every warship every capability under the sun.

Ships spend a whole lot of time doing things other than shooting, and having a couple of helicopters is such an advantage for all the other jobs (plus ASW) that the Burke IIs added a 2-ship helo hangar instead of just the lily pad of the Burke Is. Nevermind those little British ASW frigates with hangar space for a pair of Sea Kings!

Yes, helicopters are an advantage for all these other jobs that a missile boat shouldn't be doing! Why does a Burke need ASW helicopters? Design and build a dedicated ASW destroyer/frigate that isn't trying to pull double duty as AAW.

None of this is a satisfactory answer for "why should a dedicated ballistic missile warship waste space on irrelevant capabilities."

The point of naval gunfire support is that the ship is already at the firing position, in the hot zone. Because it takes way too long for a ship to get into position after a call for fire. 30 knots is 30 nautical miles per HOUR, you cannot hide 100nmi off the coast and respond to a call for fire in less than 3 hours.

You need to be waiting so close to the shore that you're scraping barnacles off the hull, and you're going to need to gangster lean the ship to gain a couple more degrees of gun elevation to shoot far enough inland.

What *is* the mission here?

To be honest, as much as I love big guns, I am having a hard time imagining any plausible target or mission set existing that would justify new construction super-large naval guns. The AGS CONOPS, even if it were valid today, does not need super-large guns, since no common land target (AFVs, foxholes, camouflaged berms and trenches for ATGMs/AT guns/howitzers) needs anything bigger than 8" (203mm) HE or cargo - and those are the only target sets that can let one argue the point that you'd rather use naval shells to blow them up rather than more expensive munitions.

Really the only target that might justify super-large ordinance is other capital ships, but then they're the type of target where "spare no expense" already definitely applies and you would be perfectly right to expend expensive large subsonic/supersonic/hypersonic cruise missiles, heavy and superheavy torpedoes, DF-21D/26s and LRHW type missiles.

Even if one accepts the need for super-large naval guns, twelve 18"s is insane, even for the Imperial Japanese who might have considered such a payload for their Super Yamato battleships. Even if you didn't use Yamato/Montana-level passive protection schemes, such a number of heavy guns would likely require greater than 40ktons of ship just to have mounts and a ship that can survive the blast and carry 100rpg, and mass would increase significantly if you want these to be autoloaders. There's also the fire-distribution issue; unless you have a comically long ship with twin or even single mounts you're likely packing four turrets maximum, so you're not engaging more than 2-4 targets at a time.

Do note that the reason for >6 large calibre guns for dreadnought-era combatants was due to need for uniform and sufficient splashes to help estimate range, then to ensure at least one hit against large targets (i.e. other battleships) quickly. This probably does not apply as much now in the era of modern radar and optical fire control.

The primary mission is not NGFS, I did not make that clear. The mission is strike and the warship complements existing cruise missile capabilities.

The Ukrainians and Russians regularly intercept each others' cruise and ballistic missiles at high rates, so China could certainly shoot down very large numbers of subsonic, non-stealthy Tomahawks. Passive surveillance will likely spot the incoming strike package soon after launch and allow interceptors to gather. Tomahawks can be shot down by cheap and numerous heat seeking missiles on their way to target, and gun or missile GBAD will take a toll as well whenever they fly too close. Then they'll suffer further attrition in the terminal phase. Overall, a package of hundreds of missiles might be required to actually impact the target with 50+ missiles.

The enemy has more than one target, and they will be making repairs. You don't hit an air base once, you hit it once per month. If the stockpile count of 4,000 missiles is to be believed, and US production is indeed currently <100 per year, then we'll blow through all of it in very little time--weeks if we really try. Adding more missile production isn't the solution, missiles are just too expensive to engage large numbers of protected, hardened targets. Guns, on the other hand, are much more affordable to feed, and that is the role of a large gun-armed warship.

So I think the mission profile looks something like this:
18" gun battery fires saboted 12" shells. Range of approximately 180km, GPS guided, bursting charge of approximately 80lbs. I'm not an engineer, I'm just loosely basing this on the USNSFA concept described here, but I thought the given bursting charge was optimistic, so I reduced it to the 80 lbs bursting charge of the historical 12" HC Mark 17. If that description is believable, then a saboted shell fired out of an 18" gun should be capable of even longer range or larger payload.

Approach to 180km away from the target (naval base, air field, beachhead, whatever you're destroying that day). Volley the 12 guns as fast as you can. 180km is pretty far, and you have AAW escorts plus SeaRAM and Phalanx to catch incoming, but there's no reason to dilly dally. The Mk7 could manage 2 RPM, I'm going to humbly suggest 1.5 RPM sustained--the barrels might have some level of active cooling or at least improved materials science. A 30-minute bombardment would sling 500 shells per ship. Explosive effects are complex to model, they can't be boiled down to just comparing weight of filler--the crater of a Tomahawk with 250 lbs explosive filler is comparable to or smaller than a 16" HC shell with 150 lbs of filler, because thick shell walls concentrate energy to create a more complete detonation, and I suppose because the kinetic energy plays some kind of role. But, regardless, a 3-ship mission could deliver a lot of effects, seriously damaging the targeted facility. As usual, complicate the repairs by mixing in 200 or so remote mining shells, with ~100 submunitions each.

The value proposition here is cost, so let's look into it.

A 16" HC shell in the 1940s probably cost the equivalent of $70,000 in today's money. That might not be perfectly accurate to say, as the number is just a straight transcription of the cost in 1940 in line with inflation. We've made advances in manufacturing since then, everything has gotten cheaper to make. A modern dumb 155mm shell only costs $1k-$2k, so that would put a 16" shell at 20x the mass and 35x-70x the cost. Curious on others' thoughts, whether anybody has a good source on price, once you get the production lines running and economy of scale benefits. For now, though, let's assume a cost of $70,000 for the basic shell, and similar costs for smaller shells due to increased complexity with the sabot.

GPS-guided Excalibur costs $70,000 and the overwhelming majority of that is going to be the guidance kit. Mounting the same technology on a much larger, roomier shell is going to make it cheaper--estimate $50k for guidance tech, so $120,000 total. Furthermore, precise GPS navigation isn't really needed, we just need to keep the CEP down to 300-500 yards at 180km range, not <5 meters like Excalibur. So guidance is needed until the last 30 miles or so, still pretty high in the ballistic arc, at which point it cuts out to make it jam/spoof resistant.

So this mission would cost $180,000,000 in offensive munitions, the same as ~50 TLAM. It delivers as much explosive filler as 480 TLAM, assuming no interceptions in both cases, but explosive filler isn't the whole equation so the effects would be even more superior for the shells. The interception rate would be much lower for the shells. If guidance kits can keep CEP below 500 meters, the number of hits on an area target like a naval base or airfield would be identical.

The major downside is that the guns have to approach much closer than the missile launchers would. However, that's what navies are for. The mission is going to need escort by many ASW frigates, stealth counter-air to kill enemy recon, attritable drones for counter-recon, Aegis destroyers for terminal defense, and likely 2-3 carriers for air and missile interception. Preparing the battlefield by throwing VLRAAM and CPS at anything that radiates will reduce the enemy's ability to detect the force. The task force should be designed for 30 knots while in the hot zone to further minimize detection chances.

Not the only strike option the USN should have. But it should be one of them.

 

[Desertfox]

You can build some 50k ton monster, or a bunch of cheap LCS with PrSM, which can shoot from twice as far, dont cost a fortune to develop, and are a far less tempting target to the enemy.

 

[Cirov]

If you need a big gun build a modern monitor, something like a big LCS with an 8" cannon, that can scoot in, fire off a few salvoes and then scoot out. Make it cheap, disposable, and single use.

What do you think you need a big gun FOR? Because if the mission is so dangerous and so critical that you're trading a whole ship to land a dozen 8" shells on a target, that sounds like a perfect use case for cruise or ballistic missiles.

You can build some 50k ton monster, or a bunch of cheap LCS with PrSM, which can shoot from twice as far, dont cost a fortune to develop, and are a far less tempting target to the enemy.

Yes, that is a great way to ignore the point entirely. PrSM, like any missile, is costly. Wikipedia claims 200 pounds of explosive filler and a unit cost of "<$3.5 million," so let's assume that means $3 million. If the target can be serviced by 1000 of the semi-guided 12" shells I described above, then you would need 400 PrSM, assuming zero were intercepted, and that the effects of explosive filler translate linearly. $1.2 billion in missiles to wipe out one submarine base. The enemy rebuilds the base in a month or two and never stops operating out of the others. It takes two years to rebuild the expended missile stockpile. Good thing you didn't risk a warship by going into combat, you know, the point of warships.

 

[Scott Kenny]

That's worth noting, I hadn't thought of that. I assume offboard targeting is viable? Couldn't you use an Aegis-equipped warship to guide in a missile from whatever platform is most advantageously positioned?

I feel like we have to find a solution that doesn't involve a billion-dollar radar on every single boat in the fleet.

In theory, yes, Cooperative Engagement Capability works.

In practice, the easiest tracking comes from being right where the target is. Especially when the incoming are hypersonic in speed, like ballistic missiles or hypergliders. Supersonic missiles are somewhat easier to deal with.

Plus, each ship in the fleet having the same radar makes some parts of long-range detection and identification far more challenging. In the old days, you'd be able to say "Oh, that's got a SPY1, that's a Tico or Burke. This other contact has SPS-49 and SPS-48, that's a Nimitz. This third contact has an SPS-40, that's a Spruance." Now, the choice is between SPY1 and SPY6 on Burkes, SPY6 on JFK and Enterprise, plus whenever Ford gets the radar refit. Once the Burke 1 and 2s are out of the fleet the entire radar set is SPY6.

Also, whatever weapons you'd need to be shooting at incoming AShBMs or hypersonics effectively need to be fired from the target. Technically, the launcher needs to be within about 10km, but modern naval separation is well over 10km between ships in the same task group. So at the very least your defensive missiles need to be carried on the battleship. And those defensive missiles are SM3 and/or SM6. (Yes, this means the carriers also need to be carrying SM6s and SM2s, not just ESSMs)

Accuracy at long range is a good point, but there are gradations of costs here. A steerable fin and either GPS or a seeker head is one level of cost--the projectile you're proposing is going to need thrust vectoring and glide wings. For evidence, look at LRLAP and look at Excalibur. Both are guided 155mm rounds, but LRLAP cost $500,000 per round delivered and was expected to increase to $800,000-$1,000,000 each. They also never demonstrated the claimed range. Excalibur, on the other hand, reached a peak price of $250,000 each in the early days and is now around $70,000 each. So by increasing the capability of the round from "guided" to "guided and self propelled" we have caused a 2x to 14x price increase, depending on which numbers you take. For a VGAS system, you are talking even more complexity than LRLAP.

LRLAP would have been roughly 150k each if they were assembled on an assembly line. As is, the 500k+ prices were from being hand-assembled.

But with only 3 ships built there was no reason to build the assembly line for shells. With 30something ships made, just loading the magazines of all the ships would be some 36,000 rounds (assuming 600 rounds per gun, two guns per ship). Plus at least that many more in stockpile.

Yes, so it will have BMD escorts. I'm in favor of defending warships that need defense, I'm not in favor of giving every warship every capability under the sun.

Those escorts would have to be right on the ship, which is a violation of modern dispersal rules.

Again, the easiest tracking of incoming is from the target location, and the ONLY possible engagement geometry is from within 10km of the target location.

Plus, a ship big enough to carry the 69RMA BMD radar is going to be at least 20ktons anyways. So if you can pack the radars onto the battleship, you don't need to build and man another big ship.

Yes, helicopters are an advantage for all these other jobs that a missile boat shouldn't be doing! Why does a Burke need ASW helicopters? Design and build a dedicated ASW destroyer/frigate that isn't trying to pull double duty as AAW.

None of this is a satisfactory answer for "why should a dedicated ballistic missile warship waste space on irrelevant capabilities."

Because those are not irrelevant capabilities. Merely non-combat capabilities.

And ships spend far more time out showing the flag and even doing SAR than they do in combat.

As to the Burkes specifically, they are AAW ships with a secondary ASW capability. The ASW-primary ships were the Spruance class and then supposed to be the Zumwalts. Plus, for fleet management reasons the USN only operated ASW helicopters on anything smaller than a carrier or Amphib. The H-46s were used for heavier sling loads, and those were replaced by Sierra Seahawks on carriers.

The primary mission is not NGFS, I did not make that clear. The mission is strike and the warship complements existing cruise missile capabilities.

[...]

So I think the mission profile looks something like this:
18" gun battery fires saboted 12" shells. Range of approximately 180km, GPS guided, bursting charge of approximately 80lbs. I'm not an engineer, I'm just loosely basing this on the USNSFA concept described here, but I thought the given bursting charge was optimistic, so I reduced it to the 80 lbs bursting charge of the historical 12" HC Mark 17. If that description is believable, then a saboted shell fired out of an 18" gun should be capable of even longer range or larger payload.

Approach to 180km away from the target (naval base, air field, beachhead, whatever you're destroying that day). Volley the 12 guns as fast as you can. 180km is pretty far, and you have AAW escorts plus SeaRAM and Phalanx to catch incoming, but there's no reason to dilly dally. The Mk7 could manage 2 RPM, I'm going to humbly suggest 1.5 RPM sustained--the barrels might have some level of active cooling or at least improved materials science. A 30-minute bombardment would sling 500 shells per ship. Explosive effects are complex to model, they can't be boiled down to just comparing weight of filler--the crater of a Tomahawk with 250 lbs explosive filler is comparable to or smaller than a 16" HC shell with 150 lbs of filler, because thick shell walls concentrate energy to create a more complete detonation, and I suppose because the kinetic energy plays some kind of role. But, regardless, a 3-ship mission could deliver a lot of effects, seriously damaging the targeted facility. As usual, complicate the repairs by mixing in 200 or so remote mining shells, with ~100 submunitions each.

Okay, so it's basically got the same strike mission profile as the Zumwalts. But it's 3-4x the size/cost per ship.

The value proposition here is cost, so let's look into it.

A 16" HC shell in the 1940s probably cost the equivalent of $70,000 in today's money. That might not be perfectly accurate to say, as the number is just a straight transcription of the cost in 1940 in line with inflation. We've made advances in manufacturing since then, everything has gotten cheaper to make. A modern dumb 155mm shell only costs $1k-$2k, so that would put a 16" shell at 20x the mass and 35x-70x the cost. Curious on others' thoughts, whether anybody has a good source on price, once you get the production lines running and economy of scale benefits. For now, though, let's assume a cost of $70,000 for the basic shell, and similar costs for smaller shells due to increased complexity with the sabot.

GPS-guided Excalibur costs $70,000 and the overwhelming majority of that is going to be the guidance kit. Mounting the same technology on a much larger, roomier shell is going to make it cheaper--estimate $50k for guidance tech, so $120,000 total. Furthermore, precise GPS navigation isn't really needed, we just need to keep the CEP down to 300-500 yards at 180km range, not <5 meters like Excalibur. So guidance is needed until the last 30 miles or so, still pretty high in the ballistic arc, at which point it cuts out to make it jam/spoof resistant.

Crud, if you're okay with that level of accuracy, we're talking the M1156 PGK fuze kit or equivalent for the larger shells, not Excalibur. $15k each if the M1156 can actually do the job. Maybe $20k if we need to build a custom fuze kit.

So even cheaper than you were planning.

So this mission would cost $180,000,000 in offensive munitions, the same as ~50 TLAM. It delivers as much explosive filler as 480 TLAM, assuming no interceptions in both cases, but explosive filler isn't the whole equation so the effects would be even more superior for the shells. The interception rate would be much lower for the shells. If guidance kits can keep CEP below 500 meters, the number of hits on an area target like a naval base or airfield would be identical.

The major downside is that the guns have to approach much closer than the missile launchers would. However, that's what navies are for. The mission is going to need escort by many ASW frigates, stealth counter-air to kill enemy recon, attritable drones for counter-recon, Aegis destroyers for terminal defense, and likely 2-3 carriers for air and missile interception. Preparing the battlefield by throwing VLRAAM and CPS at anything that radiates will reduce the enemy's ability to detect the force. The task force should be designed for 30 knots while in the hot zone to further minimize detection chances.

Not the only strike option the USN should have. But it should be one of them.

No. The USN only has 11 carriers in service at present. For normal operations, that means 4 carriers at sea. Wartime? 6-8 carriers in total at sea, the other 3-5 are in refit or battle repairs.

But you are asking for half to a quarter of the entire US carrier force to escort one of these battleships. If you're putting that much air power in the area you should be able to do the mission with the carriers alone.

 

[MadRat]

I think before people try to sell 16-inch battleship guns here, they may want to read through the VGAS thread: https://www.secretprojects.co.uk/threads/vgas-vertical-gun-for-advanced-ships.38947/

What makes sense may not be such a large conventional gun on a battleship. But if you get a lower pressure gun lobbing 7-8 Stormbreakers per minute downrange to a spot 500 km away then my ears perk up.

 

[Desertfox]

What do you think you need a big gun FOR? Because if the mission is so dangerous and so critical that you're trading a whole ship to land a dozen 8" shells on a target, that sounds like a perfect use case for cruise or ballistic missiles.

Yes, that is a great way to ignore the point entirely. PrSM, like any missile, is costly. Wikipedia claims 200 pounds of explosive filler and a unit cost of "<$3.5 million," so let's assume that means $3 million. If the target can be serviced by 1000 of the semi-guided 12" shells I described above, then you would need 400 PrSM, assuming zero were intercepted, and that the effects of explosive filler translate linearly. $1.2 billion in missiles to wipe out one submarine base. The enemy rebuilds the base in a month or two and never stops operating out of the others. It takes two years to rebuild the expended missile stockpile. Good thing you didn't risk a warship by going into combat, you know, the point of warships.

And you are missing the point that to develop your hypothetical battleship would be insanely expensive and losing it would be devastating and you have to get it within ~150km of the target, which means the enemy can use almost everything in their arsenal to hit you, and you are limited to targets near shore.

 

[Scott Kenny]

I think before people try to sell 16-inch battleship guns here, they may want to read through the VGAS thread: https://www.secretprojects.co.uk/threads/vgas-vertical-gun-for-advanced-ships.38947/

What makes sense may not be such a large conventional gun on a battleship. But if you get a lower pressure gun lobbing 7-8 Stormbreakers per minute downrange to a spot 500 km away then my ears perk up.

You mean GLSDB2... Which isn't exactly a gun system.

 

[Brett Davidson]

Any kind of directed-energy weapon is limited to line-of-sight, don't forget. If the enemy is below horizon, you can't harm him with microwaves (well, there are probably some unorthodox methods...)

In The Future of Flight, Myrabo and Ing propose reflecting lasers off one or more remote mirrors. If the beam's not scattered or absorbed by atmosphere, one could strike over the horizon with a high altitude UAV carrying a mirror.

 

[MadRat]

You mean GLSDB2... Which isn't exactly a gun system.

Big guns just are too powerful on modern destroyers until you get to really large ships like the Zumwalts. USS Hull (DD-945), a Forrest Sherman class 2800 ton (4000 tons loaded) destroyer, test fired the 203mm/8" 55-caliber Mark 71 Major Caliber Lightweight Gun (MCLWG) in 1975 to an effective range of 18 miles. Mark 71 was a single gun adaptation of the triple 8's on the Des Moines-class cruisers. The Spruance class was designed with a strengthened bow to accommodate the weight, recoil, and operation of the Mark 71. The USS Hull was not and suffered permanent disfiguration from the tests. For anyone interested, the unclassified test results for MCLWG can be read at: https://www.facebook.com/groups/1216058135233165/permalink/2090896994415937/

In contrast the Zumwalt's 155 mm/6.1-inch and 62-caliber Mark 51 Advanced Gun System (AGS) was able to fire a projectile over 100 miles in a ballistic trajectory. Zumwalt's Mark 51 AGS was only meant for an effective range of 100 miles with about 24 pounds of explosive in a 225 pound projectile. The explosives in the AGS were about 60% more powerful than in the MCLWG, so on par with far bigger guns than the MCLWG. But even Mark 51 are fairly wimpy compared to air-dropped bombs.

The Small Diameter Bomb (SDB), a modest air-dropped weapon in contrast, carries 36 pounds of a more powerful explosive. GLSDB 2 (Ground Launched Small Diameter Bomb Increment II) is another iteration of the 'SDB 2' program (officially GBU-53/B StormBreaker). Once airborne and released it doesn't care much how it got there. If SDB 2 is released above 20,000 feet at its designed maximum speed it can glide to about 80 miles against a fixed target and about 60% of that range against a moving target. It weighs a little over 200 pounds and has a 7" diameter but carries over 100 pounds of explosive. The GLSDB 1 (derived from the GBU-39) reached 33% in extra range over the air launched version.

What I think would be more appropriate than re-birthing giant battleship guns is instead using a recoilless vertical gun, or some 10-inch/255 mm offshoot of something like the Vertical Gun for Advanced Ships (VGAS). This is not meant to fire a flat trajectory, but rather act as a boost-launch to altitude where an attached motor takes it down range prior to release for its final glide. It probably means a minimum range at least beyond 30 or so miles, depending on the slant angle. The 10-inch shells typically carry under 50 pounds of explosives in a 500 pound projectile, so mounting in an SDB 2 payload is a big improvement. It would need some kind of modern sustainer motor, like a ramjet or several akin to what is on the Meteor missile. Your full projectile probably is still around 500 pounds.

Why not use the 8-inch from the MCLWG? GLSDB 2 would not fit properly in a vertical Mark 51, as it needs approximately another full inch in barrel diameter not including clearances for the wings. If a vertical gun was 10-inches/255 mm I would imagine one glide bomb could be launched per shot. If a gun was 16-inch I would imagine that it could actually carry two such weapons if not using a sabot. (It's just barely over 15-inches to fit three 7-inch circles, but you still need room for the wings.) It would be like a MARV'd SSM at that point. (Yes, MARV not MIRV.) The Army fired an 11-inch/280 mm saboted long-range round in a stretched 16"/403 mm 45-caliber Mark 6 gun in 1967, but I see no advantage using a saboted weapon in this application.

In The Future of Flight, Myrabo and Ing propose reflecting lasers off one or more remote mirrors. If the beam's not scattered or absorbed by atmosphere, one could strike over the horizon with a high altitude UAV carrying a mirror.

While it sounds good, a laser is only as effective as the function of power and distance. Scattering of the laser is a different factor that plays a more minor role.

 

[Dilandu]

You mean GLSDB2... Which isn't exactly a gun system.

GLSDB2 could be - at least looking from the size & weight - quad-packed into Mk-41 on ESSM rocket motor. While not optimal, it would likely be much more suited for coastal fire support (as well as other purposes, like engaging unmanned boats) than 127-mm guns or heavier missiles.

 

[Dilandu]

In The Future of Flight, Myrabo and Ing propose reflecting lasers off one or more remote mirrors. If the beam's not scattered or absorbed by atmosphere, one could strike over the horizon with a high altitude UAV carrying a mirror.

Yes, its perfectly workable, but have a problem of having large & relatively costly UAV (it would need to carry a rather complex mirror system of large diameter, after all!) above the horizon - vulnerable for enemy lasers.

 

[CommanderRenHoek]

That's worth noting, I hadn't thought of that. I assume offboard targeting is viable? Couldn't you use an Aegis-equipped warship to guide in a missile from whatever platform is most advantageously positioned?

I feel like we have to find a solution that doesn't involve a billion-dollar radar on every single boat in the fleet.

At the very least you will need onboard sensors good enough to do point defense cueing against hypersonics, which is not cheap anyway. Because of the very high closing speeds, cueing offboard interceptors (or offboard radars cueing onboard interceptors) may be subject to latency even with reliable CEC, when every milisecond counts.

Defense against hypersonics has always been an expensive proposition - see the dedicated SPF thread in the Military section. But that being said, modular and scalable radar concepts like AN/SPY-6 and 7 make it such that you don't need all ships to pack gigantic 69-RMA arrays, but you can make such array sizes for centerpiece combatants/"modern battleships" since carrying such mighty arrays would be one of if not their main raison d'etre. The missile defense fight is probably the only fight I can see where size can still matter.

Yes, helicopters are an advantage for all these other jobs that a missile boat shouldn't be doing! Why does a Burke need ASW helicopters? Design and build a dedicated ASW destroyer/frigate that isn't trying to pull double duty as AAW.

None of this is a satisfactory answer for "why should a dedicated ballistic missile warship waste space on irrelevant capabilities."

Because real world experience seems to indicate that multirole combatants are the most cost-effective use of naval resources, especially in a peacetime/cold war footing.

Experience with overly specialized "one-trick-pony" classes (most particularly with the Royal Navy and to a lesser extent the Soviet Navy) repeatedly show those forces' dissatisfaction with the limitations and constraints posed by over-specialization. As soon as technology and or resources allow, they moved away from specialized types.

Specialization makes most sense when you have a gigantic navy that can spam dedicated AAW/ASW/shooter boats. But no one wants fleets too big nowadays unless war is already underway because manning and maintaining that many (usually small and unupgradable) specialists costs more in the long-term than just having a smaller but more capable (and usually upgradable) multirole fleet. This was the UK's mistake: they went down the overly specialized route while consciously shrinking the Royal Navy.

Only the PRC has the industry and current population to maintain such a force, and even they recognize the value of multirole combatants, AFAIK none of their classes of large combatants are overly specialized to just AAW or ASW, with the only newish specialists being the 022 missile boats which have been apparently passed over for the more capable 056 series corvettes.

The various medium and large USV concepts are desirable since they could be fabricated relatively quickly and might be cheap enough where you can afford to replace them as soon as they're obsolete, but their overspecialization is also why they're seen as supporting enablers for manned combatants rather than anything resembling decisive elements for now.

 

[Brett Davidson]

Yes, its perfectly workable, but have a problem of having large & relatively costly UAV (it would need to carry a rather complex mirror system of large diameter, after all!) above the horizon - vulnerable for enemy lasers.

Good point. And the starting pistol is fired in the Red Queen race. Make the drone stealthy until it unfurls its mirror... nah, too expensive. Make it attributable...

OTOH, being able to call down orbitally deployed resources might be the trick. More networking of distributed assets then?

 

[Dilandu]

Good point. And the starting pistol is fired in the Red Queen race. Make the drone stealthy until it unfurls its mirror... nah, too expensive. Make it attributable...

OTOH, being able to call down orbitally deployed resources might be the trick. More networking of distributed assets then?

My IMHO the general idea to counter laser defenses would be to oversaturate them with large salvoes of shells from multiple automatic quick-firing cannons. While individual shells could be easily destroyed, the massive salvo could overcame defenses - especially if most of the shells are just solid slugs with no explosive (and thus needed to be literally drilled through to be destroyed)

Another possibility would be to use long-range torpedoes - or torpedo-carrying missiles, thst would drop their payload while still below horizon to the enemy. Of course, it would require a rather large torpedo (capable of chasing target from beyond the horizon) and large missile to carry it.

 

[Cirov]

LRLAP would have been roughly 150k each if they were assembled on an assembly line. As is, the 500k+ prices were from being hand-assembled.

But with only 3 ships built there was no reason to build the assembly line for shells. With 30something ships made, just loading the magazines of all the ships would be some 36,000 rounds (assuming 600 rounds per gun, two guns per ship). Plus at least that many more in stockpile.

I would like to see a source on the $150k claim. I don't find it entirely unbelievable, I just haven't seen anything suggesting the price could plausibly come down or why. The only numbers I have seen were high and expected to go much higher. It makes intuitive sense that it would be cost-comparable to a cruise missile, since it is effectively a cruise missile that ALSO has to survive the shock of a 20k G gun launch.

Okay, so it's basically got the same strike mission profile as the Zumwalts. But it's 3-4x the size/cost per ship.

Maybe. I'm not a naval engineer, but steel is cheap and air is free. A 20k ton warship doesn't necessarily cost twice as much as a 10k warship. This would be big, 70k-90k tons to fit the main battery and magazine while not turning into a vulnerable floating bomb, but that doesn't mean 7-9x the cost of a Burke. Certainly an expensive ship.

Perhaps the same mission profile as a Zumwalt, but I don't find it believable that Zumwalt could have carried out that mission. 24 lbs bursting charge each just isn't a lot of explosive. The low CEP means they could probably land the repeat hits needed to take out hardened targets, but only if the hardened target is right where you think it is, and it doesn't help with large area targets. I'm also prepared to doubt the small CEP in the face of powerful peer EW--the Russians were able to pretty effectively disable Excalibur with GPS jamming and spoofing.

Crud, if you're okay with that level of accuracy, we're talking the M1156 PGK fuze kit or equivalent for the larger shells, not Excalibur. $15k each if the M1156 can actually do the job. Maybe $20k if we need to build a custom fuze kit.

So even cheaper than you were planning.

Huh. Good to know, I had missed that one.

No. The USN only has 11 carriers in service at present. For normal operations, that means 4 carriers at sea. Wartime? 6-8 carriers in total at sea, the other 3-5 are in refit or battle repairs.

But you are asking for half to a quarter of the entire US carrier force to escort one of these battleships. If you're putting that much air power in the area you should be able to do the mission with the carriers alone.

Well, I happen to believe that it is foolish to approach the enemy with fewer than 2 carriers set up for combat air patrol. If that isn't true, then the mission I described doesn't need so many carriers. If it IS true, then a carrier-led strike mission would need more carriers anyway, because 2 of them are dedicated purely to local air defense.

Using carrier strike assets to carry out the mission would be difficult and likely would not solve the core problems. F-35C isn't universal in the Navy, so either the strike uses all available stealth assets, taking them away from counter-air missions, or it uses non-stealthy platforms. Stealth platforms could use low-cost cruise missiles/glide bombs with a shorter range, non-stealth would have to use much more expensive cruise missiles. Again assuming the mission requires something like 480 Tomahawk missiles to service, that would be in the area of a hundred planes--fewer if you run them dirty, but that's much more dangerous. So we're talking two carrier air wings of just strike planes, plus another wing or two for counter-air and SEAD, and another one circling the fleet that launched all of this. Since that is all of our carriers, more likely is that you just accept a much smaller strike package, and don't properly service the target the way guns could, while spending more money on munitions and risking very valuable planes on the attack, far from the strike group air defense bubble.

I think before people try to sell 16-inch battleship guns here, they may want to read through the VGAS thread: https://www.secretprojects.co.uk/threads/vgas-vertical-gun-for-advanced-ships.38947/

What makes sense may not be such a large conventional gun on a battleship. But if you get a lower pressure gun lobbing 7-8 Stormbreakers per minute downrange to a spot 500 km away then my ears perk up.

The Small Diameter Bomb (SDB), a modest air-dropped weapon in contrast, carries 36 pounds of a more powerful explosive. GLSDB 2 (Ground Launched Small Diameter Bomb Increment II) is another iteration of the 'SDB 2' program (officially GBU-53/B StormBreaker). Once airborne and released it doesn't care much how it got there. If SDB 2 is released above 20,000 feet at its designed maximum speed it can glide to about 80 miles against a fixed target and about 60% of that range against a moving target. It weighs a little over 200 pounds and has a 7" diameter but carries over 100 pounds of explosive. The GLSDB 1 (derived from the GBU-39) reached 33% in extra range over the air launched version.

What I think would be more appropriate than re-birthing giant battleship guns is instead using a recoilless vertical gun, or some 10-inch/255 mm offshoot of something like the Vertical Gun for Advanced Ships (VGAS). This is not meant to fire a flat trajectory, but rather act as a boost-launch to altitude where an attached motor takes it down range prior to release for its final glide. It probably means a minimum range at least beyond 30 or so miles, depending on the slant angle. The 10-inch shells typically carry under 50 pounds of explosives in a 500 pound projectile, so mounting in an SDB 2 payload is a big improvement. It would need some kind of modern sustainer motor, like a ramjet or several akin to what is on the Meteor missile. Your full projectile probably is still around 500 pounds.

I feel like I'm taking crazy pills here.

The GLSDB/StormBreaker has a much better ratio of explosive filler to overall weight because it can't be fired from a gun. Right? They didn't design gun artillery shells to be heavy just for fun, its because it has to endure a 20,000 G acceleration and not crack up. If you fired a cruise missile out of a gun, it would break. Then you would go back and strengthen it to survive the acceleration, and it would not break but it would also be mostly metal, like shells are.

The vertical gun idea is plausibly interesting as an actual application for rail/coil/any other kind of magnetic accelerator. Slow (500-2,000G) acceleration, essentially just a boost phase for a cruise missile to reduce its size, increase range, or increase payload volume. Even if this technology all pans out, I still think there would be room for a true gun, that doesn't launch guided, easily intercepted, expensive missiles. Maybe not, though, since GLSDB is pretty cost effective.

Because real world experience seems to indicate that multirole combatants are the most cost-effective use of naval resources, especially in a peacetime/cold war footing.

I have to contest this on a few levels.

One, first and foremost, I take some issue with the idea of a "peacetime navy." The purpose of navies is to fight wars. Thirty years ago, right after the Cold War, it made complete sense to build a peacetime, patrol navy. But that time isn't now, any future navy should be built with the distinct possibility of fighting a peer war.

You might not have meant this, but I would also remind everyone that the navy you start a war with is frequently quite similar to the one you end with. The USN in WWII built no battleships during the war--all of them were laid down before hostilities, and the majority of the BBs used were built WELL before the war. The carriers were mostly laid down during the war but were already designed before the war, not counting the CVEs for obvious reasons. So if you design and build a peacetime navy, you probably don't have the luxury of waiting until a war to start designing a wartime navy. You need the industrial capacity lined up and ready to go before the war starts, if not already cranking out the warships you need.

Experience with overly specialized "one-trick-pony" classes (most particularly with the Royal Navy and to a lesser extent the Soviet Navy) repeatedly show those forces' dissatisfaction with the limitations and constraints posed by over-specialization. As soon as technology and or resources allow, they moved away from specialized types.

Specialization makes most sense when you have a gigantic navy that can spam dedicated AAW/ASW/shooter boats. But no one wants fleets too big nowadays unless war is already underway because manning and maintaining that many (usually small and unupgradable) specialists costs more in the long-term than just having a smaller but more capable (and usually upgradable) multirole fleet. This was the UK's mistake: they went down the overly specialized route while consciously shrinking the Royal Navy.

Why should a large, multirole design be more upgradeable? If ASW technology changes, I don't see why a Perry or Spruance could not be updated while a Burke could.

Only the PRC has the industry and current population to maintain such a force, and even they recognize the value of multirole combatants, AFAIK none of their classes of large combatants are overly specialized to just AAW or ASW, with the only newish specialists being the 022 missile boats which have been apparently passed over for the more capable 056 series corvettes.

That's a ridiculous assertion, and I think you've been conditioned to accept repeated failures and shortcomings of the USN as normal. The USN is the biggest navy on the planet by displacement. The US is a maritime power and has been since WWII, if not earlier. It is a matter of will. The USN convinced itself that minimal manning and large, multirole warships was the best way to posture, and that doesn't need to be the case. If the US realigned its industrial priorities and swept out the corruption inherent in a stratified, wealth-inequal society, then no one could challenge their ability to produce large numbers of warships. Or, if they just started buying large numbers of specialized but technologically simple warships, re-energizing the shipbuilding sector and reducing the tendency of private industry to downsize.

The cost is worth it. The purpose of a navy is to fight and win wars at sea. If you don't believe in that mission, then obviously NO cost is worth it and you should not procure a navy. If you DO believe in that mission, then you need to pay for that mission, by building AAW destroyers that don't have to risk their necks playing Russian Roulette with an enemy submarine.

Edited to add: the US committed to generalization of the Navy fairly recently, mind you. This wasn't a lesson learned during the Cold War, it was a result of the Peace Dividend. Perry was my example of a specialized ASW warship that didn't try to act like AAW at the same time.

 

[CommanderRenHoek]

You might not have meant this, but I would also remind everyone that the navy you start a war with is frequently quite similar to the one you end with. The USN in WWII built no battleships during the war--all of them were laid down before hostilities, and the majority of the BBs used were built WELL before the war. The carriers were mostly laid down during the war but were already designed before the war, not counting the CVEs for obvious reasons. So if you design and build a peacetime navy, you probably don't have the luxury of waiting until a war to start designing a wartime navy. You need the industrial capacity lined up and ready to go before the war starts, if not already cranking out the warships you need. Edited to add: the US committed to generalization of the Navy fairly recently, mind you. This wasn't a lesson learned during the Cold War, it was a result of the Peace Dividend. Perry was my example of a specialized ASW warship that didn't try to act like AAW at the same time.

The USN figured this out as well, which is why they planned for mass production of Aegis ships as quickly as possible and kept doing it despite the end of the Cold War. This is precisely because you do mostly fight with the fleet you start with, so may as well build as many of the most producible complex combatant you can since you likely won't have time to build them when the shooting starts. AFAIK, there were no plans for a Perry follow-on and indeed the Knox-class even before the end of the Cold War were not to be replaced.

Why should a large, multirole design be more upgradeable? If ASW technology changes, I don't see why a Perry or Spruance could not be updated while a Burke could.

All things being equal, a larger design has more space for new systems and more allowances for growth, instead of having to fight a shrink-wrapped hull and cutting up compartments to incorporate new features. Its part of why the Iowa battleships - the inspiration for this topic - lasted as long as they did; so long as you didn't go for radical alterations you could pretty much add new stuff as needed (just had to mind the guns' muzzle blast radii and shock).

Spruance was definitely upgradable as a hull; see the numerous mods done to that class's members as well as the production of Ticonderoga and Kidd. However, the US SWAPC allowance standard is something like 10-15% of design displacement, and the Ticonderoga and Kidd more than used up the basic Spruance design's margins, which seem to have contributed to the difficulties in upgrading the Ticonderogas: the Mk 26 equipped ships could not be easily upgraded to take VLS (and per the relevant discussion here in SPF, were expected to only take 88-something cells rather than the 122 of the purpose-built Bunker Hill group), and the VLS ships were costly to upgrade even before accounting for the heavy use during GWOT.

Perry was much less upgradable due to the smaller upgrade allowances; the Australian Adelaide sub-class and the Turkish G-class had to get very creative to get updates like a Mk 41 8-cell launcher. And these upgrades were pushed less because Perry was a perfect hull to keep and more because the navies in question had little choice (the 90s Australian gov't did not want to spend on proper replacements for their Perth-class destroyers, the Turks today because their new frigate programs are still underway).

I have to contest this on a few levels.

One, first and foremost, I take some issue with the idea of a "peacetime navy." The purpose of navies is to fight wars. Thirty years ago, right after the Cold War, it made complete sense to build a peacetime, patrol navy. But that time isn't now, any future navy should be built with the distinct possibility of fighting a peer war.

That's a ridiculous assertion, and I think you've been conditioned to accept repeated failures and shortcomings of the USN as normal. The USN is the biggest navy on the planet by displacement. The US is a maritime power and has been since WWII, if not earlier. It is a matter of will. The USN convinced itself that minimal manning and large, multirole warships was the best way to posture, and that doesn't need to be the case. If the US realigned its industrial priorities and swept out the corruption inherent in a stratified, wealth-inequal society, then no one could challenge their ability to produce large numbers of warships. Or, if they just started buying large numbers of specialized but technologically simple warships, re-energizing the shipbuilding sector and reducing the tendency of private industry to downsize.

The cost is worth it. The purpose of a navy is to fight and win wars at sea. If you don't believe in that mission, then obviously NO cost is worth it and you should not procure a navy. If you DO believe in that mission, then you need to pay for that mission, by building AAW destroyers that don't have to risk their necks playing Russian Roulette with an enemy submarine.

Don't get me wrong, I agree in principle that a navy should be funded and equipped to win its wars. Most democracies (not just the US) find that a hard sell though for a number of reasons, some infuriating (like ideological-geopolitical naivete or crass penny-pinching), others understandable (real domestic problems and competing social and even defense priorities). But how to address that is rapidly leaving the main gist of this topic which is very large surface combatants/modern "battleships".

 

[Dilandu]

The USN in WWII built no battleships during the war--all of them were laid down before hostilities, and the majority of the BBs used were built WELL before the war.

To clarify, USN planned to build additional battleships during the war - initially the Montana-class were planned, then two additional Iowa's were ordered instead (not finished, though).

 

[MadRat]

I feel like I'm taking crazy pills here.

The GLSDB/StormBreaker has a much better ratio of explosive filler to overall weight because it can't be fired from a gun. Right? They didn't design gun artillery shells to be heavy just for fun, its because it has to endure a 20,000 G acceleration and not crack up. If you fired a cruise missile out of a gun, it would break. Then you would go back and strengthen it to survive the acceleration, and it would not break but it would also be mostly metal, like shells are.

The vertical gun idea is plausibly interesting as an actual application for rail/coil/any other kind of magnetic accelerator. Slow (500-2,000G) acceleration, essentially just a boost phase for a cruise missile to reduce its size, increase range, or increase payload volume. Even if this technology all pans out, I still think there would be room for a true gun, that doesn't launch guided, easily intercepted, expensive missiles. Maybe not, though, since GLSDB is pretty cost effective.

Recoilless guns are basically big bazookas. Maybe they could figure out an electromagnetic launcher reaching 680 miles per hour at release. Correct my general math here, but if you could even accelerate an object to 1,000 feet per second (680 mph) in 50 feet it is abput 310 G's. If you lengthen to 100 feet the acceleration is half as many G's. With air resistance that should get someone to 20,000 feet altitude on a slant before losing vertical speed. If you can get a motor going during ascent then by using control surfaces the projectile could bend its path to a level flight without losing all of its initial velocity. The entire flight could be subsonic, and probably stays within GLSDB 2's performance tolerances. The real trick is giving it a way to travel further than a GLSDB by using a pod to carry it downrange before release. And after release you can still travel significantly further with a much smaller RCS and heat signature. Since SDB 2 can survive impacting several feet of concrete, I can only guess it is robust for handling 150 to 300 G launches.

 

[Scott Kenny]

Big guns just are too powerful on modern destroyers until you get to really large ships like the Zumwalts. USS Hull (DD-945), a Forrest Sherman class 2800 ton (4000 tons loaded) destroyer, test fired the 203mm/8" 55-caliber Mark 71 Major Caliber Lightweight Gun (MCLWG) in 1975 to an effective range of 18 miles. Mark 71 was a single gun adaptation of the triple 8's on the Des Moines-class cruisers. The Spruance class was designed with a strengthened bow to accommodate the weight, recoil, and operation of the Mark 71. The USS Hull was not and suffered permanent disfiguration from the tests. For anyone interested, the unclassified test results for MCLWG can be read at: https://www.facebook.com/groups/1216058135233165/permalink/2090896994415937/

Sprucans were also twice the displacement of Hull.

In contrast the Zumwalt's 155 mm/6.1-inch and 62-caliber Mark 51 Advanced Gun System (AGS) was able to fire a projectile over 100 miles in a ballistic trajectory. Zumwalt's Mark 51 AGS was only meant for an effective range of 100 miles with about 24 pounds of explosive in a 225 pound projectile. The explosives in the AGS were about 60% more powerful than in the MCLWG, so on par with far bigger guns than the MCLWG. But even Mark 51 are fairly wimpy compared to air-dropped bombs.

Semiballistic trajectory, the shells had guidance vanes like the M982 Excalibur.

The Small Diameter Bomb (SDB), a modest air-dropped weapon in contrast, carries 36 pounds of a more powerful explosive. GLSDB 2 (Ground Launched Small Diameter Bomb Increment II) is another iteration of the 'SDB 2' program (officially GBU-53/B StormBreaker). Once airborne and released it doesn't care much how it got there. If SDB 2 is released above 20,000 feet at its designed maximum speed it can glide to about 80 miles against a fixed target and about 60% of that range against a moving target. It weighs a little over 200 pounds and has a 7" diameter but carries over 100 pounds of explosive. The GLSDB 1 (derived from the GBU-39) reached 33% in extra range over the air launched version.
[...]
Why not use the 8-inch from the MCLWG? GLSDB 2 would not fit properly in a vertical Mark 51, as it needs approximately another full inch in barrel diameter not including clearances for the wings. If a vertical gun was 10-inches/255 mm I would imagine one glide bomb could be launched per shot. If a gun was 16-inch I would imagine that it could actually carry two such weapons if not using a sabot. (It's just barely over 15-inches to fit three 7-inch circles, but you still need room for the wings.) It would be like a MARV'd SSM at that point. (Yes, MARV not MIRV.) The Army fired an 11-inch/280 mm saboted long-range round in a stretched 16"/403 mm 45-caliber Mark 6 gun in 1967, but I see no advantage using a saboted weapon in this application.

But SDB of either flavor is not designed for cannon launch forces. I suspect that SDB1/GBU-39 would be more tolerant of launch forces, but SDB2/GBU-53 almost certainly will have to lose some explosive filler (And that defeats some of the purpose, as they'd no longer be off the shelf things).

There's a very good reason why the GLSDB uses an MLRS rocket booster. In addition to being roughly 7.5" square for SDB1, so we're talking about needing a 10.5" diameter tube to fit them in. SDB2 is roughly 9.25" corner to corner.

What I think would be more appropriate than re-birthing giant battleship guns is instead using a recoilless vertical gun, or some 10-inch/255 mm offshoot of something like the Vertical Gun for Advanced Ships (VGAS). This is not meant to fire a flat trajectory, but rather act as a boost-launch to altitude where an attached motor takes it down range prior to release for its final glide. It probably means a minimum range at least beyond 30 or so miles, depending on the slant angle. The 10-inch shells typically carry under 50 pounds of explosives in a 500 pound projectile, so mounting in an SDB 2 payload is a big improvement. It would need some kind of modern sustainer motor, like a ramjet or several akin to what is on the Meteor missile. Your full projectile probably is still around 500 pounds.

We've worked out trajectory shaping these days so that an M982 Excalibur can hit a target on the reverse slope of a ridge relative to the gun. Nearly a 180deg change in vector shortly before impact.

Punting a shell straight up and having it come almost straight back down is trivial compared to that.

The USN figured this out as well, which is why they planned for mass production of Aegis ships as quickly as possible and kept doing it despite the end of the Cold War. This is precisely because you do mostly fight with the fleet you start with, so may as well build as many of the most producible complex combatant you can since you likely won't have time to build them when the shooting starts. AFAIK, there were no plans for a Perry follow-on and indeed the Knox-class even before the end of the Cold War were not to be replaced.

Sadly, officially the Perrys were supposed to be replaced by LCS with the ASW modules.

The designers never got the memo about what that meant for hull silencing.

All things being equal, a larger design has more space for new systems and more allowances for growth, instead of having to fight a shrink-wrapped hull and cutting up compartments to incorporate new features. Its part of why the Iowa battleships - the inspiration for this topic - lasted as long as they did; so long as you didn't go for radical alterations you could pretty much add new stuff as needed (just had to mind the guns' muzzle blast radii and shock).

The Iowas didn't actually last all that long in terms of commissioned service.

Iowa herself only had 19 years active service, being first commissioned in 1943, decommissioned in 1949 then recommissioned in 1951, decommissioned a second time in 1958 then recommissioned in 1984, and finally decommissioned for the last time in 1990.

New Jersey was first commissioned in 1943, decommissioned in 1948 then recommissioned in 1950, decommissioned in 1957 then recommissioned in 1968, decommissioned in 1969, recommissioned in 1982, and finally decommissioned for the last time in 1991.

Missouri was commissioned in 1944, decommissioned in 1955 then not recommissioned until 1986, finally decommissioned in 1992.

Wisconsin was commissioned in 1944, decommissioned in 1948 then recommissioned in 1951, decommissioned in 1958 then recommissioned in 1988, and finally decommissioned for the last time in 1991.

But yes, their large total mass available for upgrades helped tremendously in making them viable for the 1980s reactivations. (stripping all the 3"/50s or Bofors 40mm alone saved a huge chunk of mass)

Spruance was definitely upgradable as a hull; see the numerous mods done to that class's members as well as the production of Ticonderoga and Kidd. However, the US SWAPC allowance standard is something like 10-15% of design displacement, and the Ticonderoga and Kidd more than used up the basic Spruance design's margins, which seem to have contributed to the difficulties in upgrading the Ticonderogas: the Mk 26 equipped ships could not be easily upgraded to take VLS (and per the relevant discussion here in SPF, were expected to only take 88-something cells rather than the 122 of the purpose-built Bunker Hill group), and the VLS ships were costly to upgrade even before accounting for the heavy use during GWOT.

Just installing Aegis onto the Spruance hull basically ate all the weight margins.

Perry was much less upgradable due to the smaller upgrade allowances; the Australian Adelaide sub-class and the Turkish G-class had to get very creative to get updates like a Mk 41 8-cell launcher. And these upgrades were pushed less because Perry was a perfect hull to keep and more because the navies in question had little choice (the 90s Australian gov't did not want to spend on proper replacements for their Perth-class destroyers, the Turks today because their new frigate programs are still underway).

Perrys had very little margin left by the end of their design process. They should have had something like 400 tons, IIRC they had less than 200.

 

[Scott Kenny]

Oops, missed this.

I would like to see a source on the $150k claim. I don't find it entirely unbelievable, I just haven't seen anything suggesting the price could plausibly come down or why. The only numbers I have seen were high and expected to go much higher. It makes intuitive sense that it would be cost-comparable to a cruise missile, since it is effectively a cruise missile that ALSO has to survive the shock of a 20k G gun launch.

No, it's literally a rocket-assisted Excalibur shell. One with an absolutely HUGE rocket, the length of the base round. And we're talking at least one order of magnitude greater production numbers than Excalibur, likely two orders of magnitude.

So I went with 50-100% more than Excalibur. (Excalibur only has a US Army buy of about 6000 rounds!)

Also, $150k was the original target price. I find that target not-unreasonable based on Excalibur.

 

[Cirov]

The USN figured this out as well, which is why they planned for mass production of Aegis ships as quickly as possible and kept doing it despite the end of the Cold War. This is precisely because you do mostly fight with the fleet you start with, so may as well build as many of the most producible complex combatant you can since you likely won't have time to build them when the shooting starts. AFAIK, there were no plans for a Perry follow-on and indeed the Knox-class even before the end of the Cold War were not to be replaced.

The problem is when you sacrifice overall ship counts. You might even say that every single Aegis system mounted on a ship costs us a dedicated ASW frigate. If we cut ASW capability off the Burkes and put it into its own ship, we could either have 10 of them WITH Aegis or 20 WITHOUT Aegis. Which is better?

Because we're going to lose ASW frigates to enemy subs. That's a fact of ASW. Better that the aren't also hideously expensive BMD-capable super-ships.

All things being equal, a larger design has more space for new systems and more allowances for growth, instead of having to fight a shrink-wrapped hull and cutting up compartments to incorporate new features. Its part of why the Iowa battleships - the inspiration for this topic - lasted as long as they did; so long as you didn't go for radical alterations you could pretty much add new stuff as needed (just had to mind the guns' muzzle blast radii and shock).

Spruance was definitely upgradable as a hull; see the numerous mods done to that class's members as well as the production of Ticonderoga and Kidd. However, the US SWAPC allowance standard is something like 10-15% of design displacement, and the Ticonderoga and Kidd more than used up the basic Spruance design's margins, which seem to have contributed to the difficulties in upgrading the Ticonderogas: the Mk 26 equipped ships could not be easily upgraded to take VLS (and per the relevant discussion here in SPF, were expected to only take 88-something cells rather than the 122 of the purpose-built Bunker Hill group), and the VLS ships were costly to upgrade even before accounting for the heavy use during GWOT.

Perry was much less upgradable due to the smaller upgrade allowances; the Australian Adelaide sub-class and the Turkish G-class had to get very creative to get updates like a Mk 41 8-cell launcher. And these upgrades were pushed less because Perry was a perfect hull to keep and more because the navies in question had little choice (the 90s Australian gov't did not want to spend on proper replacements for their Perth-class destroyers, the Turks today because their new frigate programs are still underway).

A specialized ship does not imply a ship built with zero margin. More importantly, not every upgrade a navy wants to apply is a good one. Sure, you could say Perry didn't have enough margin because you couldn't fit a SPY-6 and 32-cell VLS onboard. But why should you want to do that? On the other side of the equation, you could say Burke was a great example of having plenty of design margin, because you could easily fit all the AAW equipment you need. But if that meant leaving ASW gear untouched and undervalued, did the ship really have enough margin?

Don't get me wrong, I agree in principle that a navy should be funded and equipped to win its wars. Most democracies (not just the US) find that a hard sell though for a number of reasons, some infuriating (like ideological-geopolitical naivete or crass penny-pinching), others understandable (real domestic problems and competing social and even defense priorities). But how to address that is rapidly leaving the main gist of this topic which is very large surface combatants/modern "battleships".

I agree. Supposing the political will exists, the strategic need for many, specialized warships is clear.

Recoilless guns are basically big bazookas. Maybe they could figure out an electromagnetic launcher reaching 680 miles per hour at release. Correct my general math here, but if you could even accelerate an object to 1,000 feet per second (680 mph) in 50 feet it is abput 310 G's. If you lengthen to 100 feet the acceleration is half as many G's. With air resistance that should get someone to 20,000 feet altitude on a slant before losing vertical speed. If you can get a motor going during ascent then by using control surfaces the projectile could bend its path to a level flight without losing all of its initial velocity. The entire flight could be subsonic, and probably stays within GLSDB 2's performance tolerances. The real trick is giving it a way to travel further than a GLSDB by using a pod to carry it downrange before release. And after release you can still travel significantly further with a much smaller RCS and heat signature. Since SDB 2 can survive impacting several feet of concrete, I can only guess it is robust for handling 150 to 300 G launches.

Right. So if the gun is NOT a magnetic accelerator, since those don't work yet, then recoilless or not, the shock of launch is going to be tens of thousands of Gs. So anything remotely like GLSDB is out, and the projectile needs a heavy shell and shock-hardened everything. Back to 25 lbs of payload for $100,000 if it's a 6" or 8" "gun" with a crazy-intelligent seeker/thrust vectoring rocket, or 150lbs of payload for $100,000 if it's a 12" or 16" shell fired out of a gun that can actually point at the target, with a bare-bones guidance package that accepts some dispersion.

Oops, missed this.

No, it's literally a rocket-assisted Excalibur shell. One with an absolutely HUGE rocket, the length of the base round. And we're talking at least one order of magnitude greater production numbers than Excalibur, likely two orders of magnitude.

So I went with 50-100% more than Excalibur. (Excalibur only has a US Army buy of about 6000 rounds!)

Also, $150k was the original target price. I find that target not-unreasonable based on Excalibur.

I just think the cost would be higher. Rocket assistance is very complex. Hell, rockets are complex, and you're talking about a rocket that is ALSO shock-hardened and miniaturized to fit in an artillery piece. So it's twice the size of Excalibur but it does a MUCH more difficult task, so I think more than twice the cost is reasonable to expect.

Back to the original debate, does this projectile fill the mission requirement? If we accept $150,000 as accurate, that's still the cost for 25 lbs of explosive filler. We saw in Ukraine that Excalibur was actually worse than dumb shells--the enemy could not just jam it and turn it ballistic, but spoof the guidance so that it would actively steer itself away from the target. So the hit rate might not be flawless, and it might not even be very good at all. And that's assuming we can precisely designate a target, in a very hot zone. More likely, the ship will be firing at a hardened area target, and landing hits with >50m CEP. That will take a lot more shells of 155mm than shells of 406mm.

 

[MadRat]

Right. So if the gun is NOT a magnetic accelerator, since those don't work yet, then recoilless or not, the shock of launch is going to be tens of thousands of Gs. So anything remotely like GLSDB is out, and the projectile needs a heavy shell and shock-hardened everything. Back to 25 lbs of payload for $100,000 if it's a 6" or 8" "gun" with a crazy-intelligent seeker/thrust vectoring rocket, or 150lbs of payload for $100,000 if it's a 12" or 16" shell fired out of a gun that can actually point at the target, with a bare-bones guidance package that accepts some dispersion.

I just think the cost would be higher. Rocket assistance is very complex. Hell, rockets are complex, and you're talking about a rocket that is ALSO shock-hardened and miniaturized to fit in an artillery piece. So it's twice the size of Excalibur but it does a MUCH more difficult task, so I think more than twice the cost is reasonable to expect.

Your logic has some flaws.

1. A magnetic accelerator works pretty great actually.
2. About that rocket launch. I already stated acceleration to 1,000 feet per second in 50 feet is 310 G's. Double the distance to 100 feet and it drops to 155 G's. Do you really believe GLSDB is magic and doesn't encounter any stresses from it's rocket launch?
3. Complexity of the system is not an impossible hurdle. GLSDB already does a rocket launch, post-launch cruise under a decellation, then release and separation of the SDB as a submunition.

 

[Cirov]

Your logic has some flaws.

1. A magnetic accelerator works pretty great actually.
2. About that rocket launch. I already stated acceleration to 1,000 feet per second in 50 feet is 310 G's. Double the distance to 100 feet and it drops to 155 G's. Do you really believe GLSDB is magic and doesn't encounter any stresses from it's rocket launch?
3. Complexity of the system is not an impossible hurdle. GLSDB already does a rocket launch, post-launch cruise under a decellation, then release and separation of the SDB as a submunition.

Did you get confused? Might want to read my post again, that's not really what I meant.

 

[Scott Kenny]

The problem is when you sacrifice overall ship counts. You might even say that every single Aegis system mounted on a ship costs us a dedicated ASW frigate. If we cut ASW capability off the Burkes and put it into its own ship, we could either have 10 of them WITH Aegis or 20 WITHOUT Aegis. Which is better?

Because we're going to lose ASW frigates to enemy subs. That's a fact of ASW. Better that the aren't also hideously expensive BMD-capable super-ships.

The primary threat to a surface ship from a sub these days is not the heavyweight torpedo. It's a sub-launched AShCM, like Harpoon, Tomahawk Block V, P-700 Granit, P-800 Oniks, or 3M54 Klub. Worse, Oscars or Yasens are volleying 24-32 of them at a time. Even a US sub is volleying up to 15 of them at you (mixed Tomahawks and Harpoons).

So you need pretty capable AA defenses on your "ASW frigate" or it's nothing but a target. Hence why Constellation had Aegis and SPY6 and was 7000tons.

The floor for minimum capabilities has gone up a long way since the Perry-class was designed, my dude.

Right. So if the gun is NOT a magnetic accelerator, since those don't work yet, then recoilless or not, the shock of launch is going to be tens of thousands of Gs. So anything remotely like GLSDB is out, and the projectile needs a heavy shell and shock-hardened everything. Back to 25 lbs of payload for $100,000 if it's a 6" or 8" "gun" with a crazy-intelligent seeker/thrust vectoring rocket, or 150lbs of payload for $100,000 if it's a 12" or 16" shell fired out of a gun that can actually point at the target, with a bare-bones guidance package that accepts some dispersion.

So use rocket artillery in the style of MLRS.

We've known how to vent a rocket tube's exhaust forward since 1944 (SturmTiger). And so we have a simple tube surrounded by vent tubes as the "barrel" and we get to launching GLSDBs vertically.

I just think the cost would be higher. Rocket assistance is very complex. Hell, rockets are complex, and you're talking about a rocket that is ALSO shock-hardened and miniaturized to fit in an artillery piece. So it's twice the size of Excalibur but it does a MUCH more difficult task, so I think more than twice the cost is reasonable to expect.

Rocket boosted artillery shells are a solved problem. We've had them in active combat service since 1970 (US M549), and the concept goes clear back to 1941.

They're well understood. And heck, the Excalibur is a base-bleed shell, so it's got a tiny rocket motor already. LRLAP is an Excalibur with a full size rocket booster. Actually, I think LRLAP has a sleeker projectile shape as well, but it's still functionally an understood/solved problem. No reason for them to be stupid expensive, we're just using more materials to make LRLAP than Excalibur. Longer rocket casing, more thermal liner, more solid rocket propellant of a type we know how to make.

Back to the original debate, does this projectile fill the mission requirement? If we accept $150,000 as accurate, that's still the cost for 25 lbs of explosive filler. We saw in Ukraine that Excalibur was actually worse than dumb shells--the enemy could not just jam it and turn it ballistic, but spoof the guidance so that it would actively steer itself away from the target. So the hit rate might not be flawless, and it might not even be very good at all. And that's assuming we can precisely designate a target, in a very hot zone. More likely, the ship will be firing at a hardened area target, and landing hits with >50m CEP. That will take a lot more shells of 155mm than shells of 406mm.

So drop the GPS enhancements and go strictly with an IMU. Better, have a weapons mode that is pure IMU with the GPS off for when there is heavy GPS jamming. All the guidance needs to know is where it started from and where it needs to go. Once the gun computer says "here is the expected course you will be flying" and sends it, the shell's IMU is comparing actual position to expected and correcting on the fly.

Yes, it will take more shells of 155mm than of 406mm. We can fire said 155s about 10x faster than the 406s. Equal amounts of boom is 6x 155s per 406.

 

[MadRat]

I think his comment on GLSDB was directed at my post. Instead of a smaller rocket booster I wanted something capable of sustained flight out to several hundred miles. More complex obviously. But the same system could fire the original GLSDB at much shorter ranges. If it was an electromagnetic launcher or not does not matter to me so much.

 

[Scott Kenny]

I think his comment on GLSDB was directed at my post. Instead of a smaller rocket booster I wanted something capable of sustained flight out to several hundred miles. More complex obviously. But the same system could fire the original GLSDB at much shorter ranges. If it was an electromagnetic launcher or not does not matter to me so much.

No fancy launcher required for GL-SDB, it's an MLRS rocket booster with an SDB1 bolted on top. Just leave a way for the rocket exhaust to be vented outside the hull.

 

[MadRat]

No fancy launcher required for GL-SDB, it's an MLRS rocket booster with an SDB1 bolted on top. Just leave a way for the rocket exhaust to be vented outside the hull.

The whole point GLSDB uses a rocket launch kind of makes the idea that SDB cannot take a rocket launch a head scratcher argument. I am not sure why people keep saying it.

 

[DWG]

The primary threat to a surface ship from a sub these days is not the heavyweight torpedo. It's a sub-launched AShCM, like Harpoon, Tomahawk Block V, P-700 Granit, P-800 Oniks, or 3M54 Klub. Worse, Oscars or Yasens are volleying 24-32 of them at a time.

If a Yasen throws 32 missiles at an FFG, it's reduced to using heavyweight torpedoes at whatever the FFG was protecting, or going home. A Project 949AM can potentially do that three times, but there's only, what, two of those operational?

Even a US sub is volleying up to 15 of them at you (mixed Tomahawks and Harpoons).

Only if you deliberately fill the VLS with anti-ship Tomahawks before you sail.

So you need pretty capable AA defenses on your "ASW frigate" or it's nothing but a target.

Target, or guaranteed mission-kill?

 

[Scott Kenny]

If a Yasen throws 32 missiles at an FFG, it's reduced to using heavyweight torpedoes at whatever the FFG was protecting, or going home. A Project 949AM can potentially do that three times, but there's only, what, two of those operational?

Still worst-case threat you need to design around.

Only if you deliberately fill the VLS with anti-ship Tomahawks before you sail.

Isn't the Block V now set up with the unified ground/sea target sensors?

Target, or guaranteed mission-kill?

Well, to me every surface ship is a target. But either way it's done for several months even if not permanently.

 

[Scott Kenny]

The whole point GLSDB uses a rocket launch kind of makes the idea that SDB cannot take a rocket launch a head scratcher argument. I am not sure why people keep saying it.

It certainly can't take a cannon launch, but it doesn't need to.

 

[DWG]

Well, to me every surface ship is a target. But either way it's done for several months even if not permanently.

I'm referring to mission-killing the sub. If it flushes its VLS, which may overwhelm an FFG, then its ability to influence the fight shrinks to torpedo range. It's a near zero-sum result, not a win. On the strategic level it may even be a win for the FFG.

A sub's job is not to kill escorts.

 

[Cirov]

Your logic has some flaws.

1. A magnetic accelerator works pretty great actually.
2. About that rocket launch. I already stated acceleration to 1,000 feet per second in 50 feet is 310 G's. Double the distance to 100 feet and it drops to 155 G's. Do you really believe GLSDB is magic and doesn't encounter any stresses from it's rocket launch?
3. Complexity of the system is not an impossible hurdle. GLSDB already does a rocket launch, post-launch cruise under a decellation, then release and separation of the SDB as a submunition.

So, if you take two quotes from my post that were talking about different things, and seemingly don't read either of them, then yeah, you'll find some flaws in my logic.

1. Sort of. EMALS qualifies and is likely a better starting point--railgun projects tend to focus "low mass, high velocity," which is the opposite of what you want for an assisted rocket launch. But it's far from a solved problem. Rocket artillery is a solved problem, gun artillery is a solved problem--we can build another variation of either of those fairly quickly and easily. Figuring out a magnetic accelerator that sits vertical, is pretty short, and accelerates a 500 pound (ish) object to approx. 300 m/s is a whole set of new engineering problems. Maglev and EMALS throw a much lighter object much slower. How do you hold the projectile? If you use a sled, how do you slow it back down?

But, fair point, I suppose. A slow magnetic accelerator is a lot closer to real than a Mach 8 mega-gun.

2. Yes, I know. I have zero problem with GLSDB incurring 300 or 500 Gs. There's a line somewhere, but I'm not a rocket engineer so I'll just assume the line is around 500 Gs. This is where the reading comprehension comes in, because I said that already. We are talking about launch assist for a projectile very similar to GLSDB, and my entire thesis is that yes, you could draw benefit from an assisted launch, so long as the launch did not involve tens of thousands of Gs. A gun that is not a magnetic accelerator, recoilless or not, will incur thousands of Gs on launch, or it will be a cap gun that imparts no useful velocity. Therefore, either the projectile will not resemble GLSDB and will instead have a cost and payload profile similar to LRLAP, or we will have to invent a working magnetic accelerator first.

3. Completely irrelevant. No idea why you said that. The complexity I was weighing in on has to do with the comparative cost of LRLAP and Excalibur, neither of which remotely resembles GLSDB. Adding a rocket booster to a gun-launched projectile, which GLSDB is not, means designing a rocket motor and fuel system that can survive a 20,000 G launch. I think that process adds more cost to the projectile than some other users seem to think, and that it is not worth it compared to the effectiveness of firing a subcaliber munition, possibly with a gas generator, and with a rudimentary guidance unit.

With regards to the hypothetical GLSDB first-stage accelerator you're talking about, yeah, I think you're right. The complexity would not be a significant cost factor. The rocket booster would undergo a very similar force of acceleration as a normal hot or cold launch, so no trouble there. It might be SAFER: if the booster fails, the projectile is already accelerating towards the ship while moving very quickly away from it. To work optimally, you would just have to add a few seconds of delay so that the booster saves fuel until the initial velocity has been turned into altitude. Each one would still be more costly per payload unit delivered than artillery shells, but there is absolutely a role for cruise and ballistic missiles, and this one would get ahead on the cost curve thanks to the accelerator launch.

If you aren't talking about a gun-launch GLSDB, then my only argument is that gun-launched projectiles are going to be a lot more affordable, and you need that in a war.

 

[MadRat]

Since we are talking literally one of the most expensive warships in history, whatever it lobs needs to be from a large offset/displacement from the target.

 

[Cirov]

The primary threat to a surface ship from a sub these days is not the heavyweight torpedo. It's a sub-launched AShCM, like Harpoon, Tomahawk Block V, P-700 Granit, P-800 Oniks, or 3M54 Klub. Worse, Oscars or Yasens are volleying 24-32 of them at a time. Even a US sub is volleying up to 15 of them at you (mixed Tomahawks and Harpoons).

So you need pretty capable AA defenses on your "ASW frigate" or it's nothing but a target. Hence why Constellation had Aegis and SPY6 and was 7000tons.

The floor for minimum capabilities has gone up a long way since the Perry-class was designed, my dude.

I don't really think there's a mission profile for a sub-hunting FFG that doesn't involve AAW destroyers nearby. Most likely, the FFG is protecting a carrier group, which obviously has plenty of AAW. But even if not, a very good application of force for sub-hunting would be 3-4 ASW + 1 AAW. You need Aegis to defend from opportunistic strikes, but you don't need 5x Aegis.

And I'm pretty sure sub-launched missiles were a thing when Perry was designed.

Rocket boosted artillery shells are a solved problem. We've had them in active combat service since 1970 (US M549), and the concept goes clear back to 1941.

They're well understood. And heck, the Excalibur is a base-bleed shell, so it's got a tiny rocket motor already. LRLAP is an Excalibur with a full size rocket booster. Actually, I think LRLAP has a sleeker projectile shape as well, but it's still functionally an understood/solved problem. No reason for them to be stupid expensive, we're just using more materials to make LRLAP than Excalibur. Longer rocket casing, more thermal liner, more solid rocket propellant of a type we know how to make.

Solved, yes, but still expensive. And come on, you have to realize that a gas generator is WILDLY cheaper than a full-on thrust-vectored rocket motor. There is a world of difference between those two engineering problems. They are both solved, but bicycles and cars are both solved engineering problems, and one is more complex and therefore more expensive.

I'm not trying to shoot down rocket boosting. My big consideration here is cost, because cost correlates inversely with number of effects put on target, at least in this instance. Use a guided, rocket-boosted LRLAP equivalent when you aren't trying to flatten a hardened area target.

So drop the GPS enhancements and go strictly with an IMU. Better, have a weapons mode that is pure IMU with the GPS off for when there is heavy GPS jamming. All the guidance needs to know is where it started from and where it needs to go. Once the gun computer says "here is the expected course you will be flying" and sends it, the shell's IMU is comparing actual position to expected and correcting on the fly.

Yes, it will take more shells of 155mm than of 406mm. We can fire said 155s about 10x faster than the 406s. Equal amounts of boom is 6x 155s per 406.

My point was, GPS guidance up to the last meter of freefall is going to be the most accurate system. Replacing it the way you describe will solve the EW problem but will come at a cost of accuracy. Again, I don't doubt that the problem will be solved, I just point out that it imposes costs.

Equal amounts of explosive filler is 6x 155mm per 406mm. That does NOT mean equal effects. Bigger shells can penetrate better, and they get more "boom" from the same amount of filler by containing the explosion for a more rapid, complete detonation. Maybe LRLAP gets the same efficiency as a bigger shell, I just know that TLAM uses almost twice as much filler as a 16" HC and gets about the same, slightly smaller, effect radius.

Anyway, that aside. If you require 6x the 155mm shells for the same effects on target, since you can't rely on higher accuracy, and you are paying the same or more per shell, then you are going to spend 6x+. Right? Cost per effect on target is the whole thing I think a gun should minimize.

So, your objections are noted, but I think the product of this conversation is that a very large caliber gun firing saboted base-bleed projectiles with minimal guidance is the best form of strike. LRLAP and existing designs of cruise and ballistic missiles are unaffordable. They provide an advantage in range that we don't need.

 

[Explorer121]

If you really want a big cannon on a ship, I think that a single massive spinal cannon may be the way to go. You would have to use maneuvering shells, optionally with their own propulsion, but I think you could get enough range with something like that. Of course, then you have to compare it with the cost-effectiveness of guided missile destroyers/cruisers/battleships, and it ends up being a solution in search of a problem.

 

[Cirov]

If you really want a big cannon on a ship, I think that a single massive spinal cannon may be the way to go. You would have to use maneuvering shells, optionally with their own propulsion, but I think you could get enough range with something like that. Of course, then you have to compare it with the cost-effectiveness of guided missile destroyers/cruisers/battleships, and it ends up being a solution in search of a problem.

Isn't this a refutation of itself?

A spinal gun, oversized for the ship it is on, will have to fire expensive rounds with very complete guidance capabilities--they aren't just mildly adjusting to counteract unexpected forces, they are steering to a completely new trajectory. Changing trajectory like that burns up energy, so they are either going to accept a shorter range or pack rocket boosters like LRLAP. Halfway to a missile, and unlike a missile, the projectile experiences 15-20k Gs on launch, so the payload will be more like 5-10% mass rather than 50% mass like GLSDB.

So you build a ship that only carries 50 shells for its one gun, and each shell costs half as much as a TLAM with 10% of the effect on target and 20% of the range. Why did you do this? It's a complete misdirection of effort. You are trying to make a gun that launches a missile instead of working with the natural advantages of a gun. What problem does this even solve? Guided, rocket assisted rounds for the Army make sense, if you consider that packing 3-5 Excalibur or whatever with every 155mm battery is easier than putting HIMARS all over the front. But what does the Navy need with a gun that isn't as flexible as a missile nor nearly as cheap as a dumb gun?

Put a bunch of big, turreted guns on a ship. Minimal guidance, no rocket assist, sabot and base bleed to get extra range if you need it. The shells come out to 10% of the price of a missile, with 50% the payload and 10-20% the range. It uses the advantages of a gun to fit in its own niche. If the zone is too hot and you can't approach to with 150km, then use cruise/ballistic missiles from further away, that isn't a niche for a gun. Same if the target is landlocked and you can't physically approach close enough. But if the target can be reached with a gun, and it is a hardened target that will need several hundred warheads regardless of accuracy, then a gun is what you need. Not a gun that shoots mini-cruise missiles, not a first-stage booster that launches cheaper cruise missiles. A real gun, that works like a gun. The Army understands this: they didn't retire the Paladins when they invented MLRS, nor when they invented ATACMS, because a missile can't do everything a gun can do. Why is it so incomprehensible that the Navy could apply this same lesson?

Since we are talking literally one of the most expensive warships in history, whatever it lobs needs to be from a large offset/displacement from the target.

I'm not trying to be rude, but what is the point of engaging in conversation if you don't read or respond to the conversation?

My problem with your GLSDB-launcher proposal isn't the range issue, it's that you're still talking about a cruise missile. In particular, a low-speed cruise missile that will be shot down in droves during flight and terminal approach, very vulnerable to enemy superiority fighters and gun-based point defense. Absolutely, a magnetic accelerator for a low-cost cruise missile has value in certain niches, where you desperately need to stay at long range, or if you don't expect serious air defenses.

But it is not remotely the same niche as a gun, so it isn't an alternative to a gun. Magnetic VGAS for large-caliber cruise missiles does something besides what I think a battleship should do. I'm not shooting down your proposal on its own, you just keep insisting it is a better alternative to my proposal for a traditional gun system, so I have to keep saying that they are not in the same niche.

And you are missing the point that to develop your hypothetical battleship would be insanely expensive and losing it would be devastating and you have to get it within ~150km of the target, which means the enemy can use almost everything in their arsenal to hit you, and you are limited to targets near shore.

Was gonna leave this alone, but whatever.

By that logic, why did we develop aircraft carriers at all? Insanely expensive, shorter range than TLAM, devastating if we lose it.

In the example above, I showed my reasoning to believe that a strike of 1,000 shells could have an effect on target roughly similar to 400 PrSM or TLAM. I believe that the actual number of either missile could be 600 or 800, since they are much easier to intercept than tube artillery rounds, and since they are much less efficient with their payload. I also believe that the shells in question could be substantially cheaper than my estimate of $120,000 each. Therefore, I suppose that a strike could either cost approximately $120 million in shells, or $1.5-2 billion in missiles.

So, using shells produces costs savings of $1.4-1.9 billion. That is the cost of a whole ship, per strike. Developing a new warship is certainly costly, but two billion dollars per strike is a big number. 15 strikes in a war, which would be very low, is already the development cost of Zumwalt, a famously expensive warship. Quite obviously, leaning on ridiculously expensive missiles is the unaffordable option.

Getting close isn't a huge problem. The enemy has the range to hit you, but why did we design Aegis if not to protect our warships while they're being shot at? The enemy also can't shoot what it can't see, which is why I suggested a carrier escort. Carrier-based aircraft will create a bubble a couple hundred kilometers in diameter, shooting down drones they spot using passive sensors. Air Force-supplied long-range fighters will use AIM-174B or AMRAAM to shoot down anything foolish enough to radiate. Carrier-based aircraft will also be keeping a sharp eye out for incoming attack, again using passive sensors--if they spot a large missile launch with thermals, they know the jig is up, and everyone in the fleet needs to light up the radar systems and abort. Approaching the enemy is not impossible, and we do ourselves a disservice treating it that way. Furthermore, the shore is where the targets are--10% of the global population lives within 5 km of the coast. Naval bases, a prime target, are self-evidently close to shore.

And again, why bother posting in a conversation if you aren't reading the conversation? Literally nothing in here have I not already said. This isn't a comment section on Instagram, we are all participating in the same long conversation together, it is reasonable to expect people to read it before weighing in. Why else are we on an old school messageboard?

 

[MadRat]

Peak AMRAAM acceleration can be as much as 500 Gs if my math is right. Of course when launched off a moving plane they should be far less.