Your Nations Warships, MKII

[Gallia-]

The supersonic missile will be detected on radar and infrared before the subsonic missile.

A warship can easily track a supersonic target flying in a straight line and compute a firing solution. This is not a problem because computers are good at math, and can do trigonometry quite a bit faster than I can (which is to say, do it at all).

What it has problems with are pseudorandom evasive maneuvering, which significantly enhances the survivability of the subsonic AShM in the terminal engagement (horizon) to a significant degree. The subsonic AShM being superior to the supersonic in all other important aspects (mass, range, cost, low altitude flight regime) means it is superior overall, even if certain areas are not as impressive. Speed is not the most important aspect of an anti-shipping missile, and is in fact highly detrimental, all other things equal.

[The Technocratic Syndicalists]

The supersonic missile will be detected on radar and infrared before the subsonic missile.

infra-red yes, radar not necessarily. Supersonic AShMs are usually larger and thus will have a larger RCS but an objects speed is not relevant to its RCS.

A warship can easily track a supersonic target flying in a straight line and compute a firing solution. This is not a problem because computers are good at math, and can do trigonometry quite a bit faster than I can (which is to say, do it at all).

Who said the supersonic AShM was flying in a straight line?

What it has problems with are pseudorandom evasive maneuvering, which significantly enhances the survivability of the subsonic AShM in the terminal engagement (horizon) to a significant degree. The subsonic AShM being superior to the supersonic in all other important aspects (mass, range, cost, low altitude flight regime) means it is superior overall, even if certain areas are not as impressive. Speed is not the most important aspect of an anti-shipping missile, and is in fact highly detrimental, all other things equal.

Again, there's no reason a supersonic AShM wouldn't be capable of pseudorandom evasive maneuvering. Supersonic AShMs also almost universally have longer ranges although this is most likely due to their larger size and thus larger fuel capacity. The harpoon has a range of 124 km, the exocet up to 180km, and the naval strike missile up to 290km. For comparison the p-800 has a range of 600km and the p-700 625 km. Subsonic land attack missiles like the tomahawk have longer ranges but aren't really used as AshM's, at least not since the TASM was cancelled.

Low altitude flight regime is also a moot point. The BrahMos is capable of sea-skimming as low as 3-4 meters above the surface as can the p-700 and p-800.

low weight isn't necessary an advantage. Bigger missiles can carry bigger warheads and more powerful navigation equipment.

You're left with cost which is really the only real advantage a subsonic missile has over a supersonic one.

[Velkanika]

That's true, but when the modern surface Navy has been fighting enemies who's best anti-ship assets are ground based, it makes sense that they'd make targeting that their priority. Hence why the average Arleigh Burke-class cruises around with about 50 Tomahawks.

I don't see how that is relevant.

The Burke isn't quite disposable, per se, but it's more so than a Ticonderoga. That, and the fact there are literally 3x as many as Ticos, is the only reason it does what it does.

Take a look at the typical weapon mix on both the Arleigh Burke-class and Ticonderoga-class. The Ticos are armed almost entirely with SAMs in their Mk-41s with about a dozen SUBROCs thrown in. The Burkes on the other hand are usually armed with Tomahawks and Evolved Sea Sparrows, and rely on the Ticonderogas or nearby aircraft for long range air defense.

As for supersonic AShMs supersonic or hypersonic missiles can't go that fast at sea level and maintain much in the way of range, so pretty much all of them follow a ballistic flight path. That means that the defenders can start tracking the incoming weapons almost as soon as they're launched and start taking shots at them from maximum range. Sea skimming supersonic or hypersonic missiles don't have it much better as their exhaust/surface skin would be more than hot enough to emit a detectable radar signal, plus rocket exhaust is radar opaque so the defender could again see them from well over the horizon. This means that the defender would have at least two or three minutes to engage incoming missiles. On the other hand, an incoming harpoon attacking a Ticonderoga would be detected by the ship's AN/SPY-1 no sooner than about 90 seconds out. More time to engage means more chances to intercept the threat.

[The Technocratic Syndicalists]

As for supersonic AShMs supersonic or hypersonic missiles can't go that fast at sea level and maintain much in the way of range, so pretty much all of them follow a ballistic flight path. That means that the defenders can start tracking the incoming weapons almost as soon as they're launched and start taking shots at them from maximum range. Sea skimming supersonic or hypersonic missiles don't have it much better as their exhaust/surface skin would be more than hot enough to emit a detectable radar signal, plus rocket exhaust is radar opaque so the defender could again see them from well over the horizon. This means that the defender would have at least two or three minutes to engage incoming missiles. On the other hand, an incoming harpoon attacking a Ticonderoga would be detected by the ship's AN/SPY-1 no sooner than about 90 seconds out. More time to engage means more chances to intercept the threat.

The p-1000 for reference has a range of 500km when following a sea-skimming trajectory of 25 meters or lower. The p-800 and BrahMos use similar technology and thus most likely have similar performance.

[We-a Are-a Very-a Close-a To Italia]

Our Aircraft Carrier Is The Victor Emmanuel Class
Crew 1451 men
Aircrew 1203 men
C4I staff 140 men
Marines 325 men
Sea endurance Unlimited
Length 244 m
Beam 39 m
Draught 8.7 m
Flight deck length 232.6 m
Flight deck width 34.5 m
Hangar deck length 134 m
Displacement, standard 72 290 tonnes
Displacement, full load 77 100 tonnes
Propulsion and speed
Speed over 28 knots
Nuclear reactor 2x
Aircraft
70 Aircraft
Armament
Missiles 2 x A43 Sylver VLS for 32 Aster-15 surface-to-air missiles
Artillery 2 x Oto Melara 76-mm Super Rapid guns, 3 x Oerlikon Contraves KBA 25-mm anti-aircraft guns

[Protestant England and Germany]

On a Ballistic Missile Submarine, what is the best place for Torpedo tubes?

[Gallia-]

The Ticos are armed almost entirely with SAMs in their Mk-41s with about a dozen SUBROCs thrown in.

They are not.

Ticonderogas have probably fired more Tomahawk missiles in anger than any other warship class afloat.

As for supersonic AShMs supersonic or hypersonic missiles can't go that fast at sea level and maintain much in the way of range, so pretty much all of them follow a ballistic flight path. That means that the defenders can start tracking the incoming weapons almost as soon as they're launched and start taking shots at them from maximum range. Sea skimming supersonic or hypersonic missiles don't have it much better as their exhaust/surface skin would be more than hot enough to emit a detectable radar signal, plus rocket exhaust is radar opaque so the defender could again see them from well over the horizon. This means that the defender would have at least two or three minutes to engage incoming missiles. On the other hand, an incoming harpoon attacking a Ticonderoga would be detected by the ship's AN/SPY-1 no sooner than about 90 seconds out. More time to engage means more chances to intercept the threat.

The biggest problem is that mass correlates with cost, development time, magazine size, and use platforms. Subsonic missiles can easily reach 400 km with something slightly larger than a Harpoon missile, doubling that range can be done with something between a Tomahawk and Harpoon missile in size, easily carried by fighter aircraft or warships. To reach 400 km with a supersonic missile requires something roughly the size of P-700. 800 kilometers with a supersonic system requires a weapon the size of P-800 if you want a warhead comparable to Harpoon. For larger warheads, you start needing tremendous loft altitudes (upper stratosphere) to keep fuel requirements down, and mass soars past 4-5 tonnes pretty quickly.

P-270 and Harpoon are comparable weapon systems in range and warhead size. P-270 has a terminal speed approaching Mach 3. Harpoon has a terminal speed somewhere around Mach 0.8. P-270's warhead is 320 kg, Harpoon's warhead is 220 kg. Both have ranges of about 120 km. Harpoon weighs 700 kilograms. P-270 weighs 4,500 kg, or about 6.5 times greater mass than Harpoon.

On a Ballistic Missile Submarine, what is the best place for Torpedo tubes?

Behind the sonar sphere.

[Protestant England and Germany]

The Ticos are armed almost entirely with SAMs in their Mk-41s with about a dozen SUBROCs thrown in.

They are not.

Ticonderogas have probably fired more Tomahawk missiles in anger than any other warship class afloat.

As for supersonic AShMs supersonic or hypersonic missiles can't go that fast at sea level and maintain much in the way of range, so pretty much all of them follow a ballistic flight path. That means that the defenders can start tracking the incoming weapons almost as soon as they're launched and start taking shots at them from maximum range. Sea skimming supersonic or hypersonic missiles don't have it much better as their exhaust/surface skin would be more than hot enough to emit a detectable radar signal, plus rocket exhaust is radar opaque so the defender could again see them from well over the horizon. This means that the defender would have at least two or three minutes to engage incoming missiles. On the other hand, an incoming harpoon attacking a Ticonderoga would be detected by the ship's AN/SPY-1 no sooner than about 90 seconds out. More time to engage means more chances to intercept the threat.

The biggest problem is that mass correlates with cost, development time, magazine size, and use platforms. Subsonic missiles can easily reach 400 km with something slightly larger than a Harpoon missile, doubling that range can be done with something between a Tomahawk and Harpoon missile in size, easily carried by fighter aircraft or warships. To reach 400 km with a supersonic missile requires something roughly the size of P-700. 800 kilometers with a supersonic system requires a weapon the size of P-800 if you want a warhead comparable to Harpoon. For larger warheads, you start needing tremendous loft altitudes (upper stratosphere) to keep fuel requirements down, and mass soars past 4-5 tonnes pretty quickly.

P-270 and Harpoon are comparable weapon systems in range and warhead size. P-270 has a terminal speed approaching Mach 3. Harpoon has a terminal speed somewhere around Mach 0.8. P-270's warhead is 320 kg, Harpoon's warhead is 220 kg. Both have ranges of about 120 km. Harpoon weighs 700 kilograms. P-270 weighs 4,500 kg, or about 6.5 times greater mass than Harpoon.

On a Ballistic Missile Submarine, what is the best place for Torpedo tubes?

Behind the sonar sphere.

Where would a good site for Submarine based Ballistic Missiles?

[The Technocratic Syndicalists]

The biggest problem is that mass correlates with cost, development time, magazine size, and use platforms. Subsonic missiles can easily reach 400 km with something slightly larger than a Harpoon missile, doubling that range can be done with something between a Tomahawk and Harpoon missile in size, easily carried by fighter aircraft or warships. To reach 400 km with a supersonic missile requires something roughly the size of P-700. 800 kilometers with a supersonic system requires a weapon the size of P-800 if you want a warhead comparable to Harpoon. For larger warheads, you start needing tremendous loft altitudes (upper stratosphere) to keep fuel requirements down, and mass soars past 4-5 tonnes pretty quickly.

P-270 and Harpoon are comparable weapon systems in range and warhead size. P-270 has a terminal speed approaching Mach 3. Harpoon has a terminal speed somewhere around Mach 0.8. P-270's warhead is 320 kg, Harpoon's warhead is 220 kg. Both have ranges of about 120 km. Harpoon weighs 700 kilograms. P-270 weighs 4,500 kg, or about 6.5 times greater mass than Harpoon.

Greater mass combined with greater speed means more kinetic energy which means more destruction which (besides the faster time to target and increased difficulty of interception) is the whole point of a supersonic AShM. For a small target like a corvette or a destroyer a small subsonic missile like a harpoon or exocet is more than adequate for the job. The reason the US or other western navies don't use supersonic AShMs is because they don't need them. US ships like the tico and arleigh burke are intended to escort carriers and provide anti-air and anti-sub capability while the carrier's air wing deals with surface threats. For the Russians if the cold war had gone hot they would have had to face US carrier groups which is why they invested in things such as supersonic AShMs and kirov class cruisers.

Speaking of the kirov, I find it a very fascinating ship. It's been hampered by collapses of the Soviet and later Russian economy and is a victim of the incompetent military bureaucracy in Moscow, yet it's extreme armament suggests it has the potential to be a devastatingly effective surface combatant.

[Gallia-]

The biggest problem is that mass correlates with cost, development time, magazine size, and use platforms. Subsonic missiles can easily reach 400 km with something slightly larger than a Harpoon missile, doubling that range can be done with something between a Tomahawk and Harpoon missile in size, easily carried by fighter aircraft or warships. To reach 400 km with a supersonic missile requires something roughly the size of P-700. 800 kilometers with a supersonic system requires a weapon the size of P-800 if you want a warhead comparable to Harpoon. For larger warheads, you start needing tremendous loft altitudes (upper stratosphere) to keep fuel requirements down, and mass soars past 4-5 tonnes pretty quickly.

P-270 and Harpoon are comparable weapon systems in range and warhead size. P-270 has a terminal speed approaching Mach 3. Harpoon has a terminal speed somewhere around Mach 0.8. P-270's warhead is 320 kg, Harpoon's warhead is 220 kg. Both have ranges of about 120 km. Harpoon weighs 700 kilograms. P-270 weighs 4,500 kg, or about 6.5 times greater mass than Harpoon.

Greater mass combined with greater speed means more kinetic energy which means more destruction which (besides the faster time to target and increased difficulty of interception) is the whole point of a supersonic AShM. For a small target like a corvette or a destroyer a small subsonic missile like a harpoon or exocet is more than adequate for the job. The reason the US or other western navies don't use supersonic AShMs is because they don't need them. US ships like the tico and arleigh burke are intended to escort carriers and provide anti-air and anti-sub capability while the carrier's air wing deals with surface threats. For the Russians if the cold war had gone hot they would have had to face US carrier groups which is why they invested in things such as supersonic AShMs and kirov class cruisers.

Speaking of the kirov, I find it a very fascinating ship. It's been hampered by collapses of the Soviet and later Russian economy and is a victim of the incompetent military bureaucracy in Moscow, yet it's extreme armament suggests it has the potential to be a devastatingly effective surface combatant.

Kinetic energy is irrelevant, AShM use chemical energy to defeat surface targets. Specifically fire. Greater mass means less platforms can use the weapon, it costs more money, it is generally less effective per unit of weight carried, and it has a smaller missile magazine. These are all highly relevant.

A US CVBG would defeat any Russian SAG pretty handily. What CVBGs feared were Soviet hunter-killers, SSGN, and Bear/Badger regiments. Supersonic AShM were invested by the USSR because their systems had tremendous range, which is one reason you would want a supersonic missile: to close range gaps rapidly and avoid "wasting" target tracks. Sort of irrelevant if you have near real time OTH targeting though, which is why the US Navy's LRASM is subsonic, but the USSR didn't have that. First pass engagement is fairly important since snaking AShM are rather vulnerable to not hitting their intended target.

e: Kirov was probably hampered because it's a sub chaser.

[Velkanika]

As for supersonic AShMs supersonic or hypersonic missiles can't go that fast at sea level and maintain much in the way of range, so pretty much all of them follow a ballistic flight path. That means that the defenders can start tracking the incoming weapons almost as soon as they're launched and start taking shots at them from maximum range. Sea skimming supersonic or hypersonic missiles don't have it much better as their exhaust/surface skin would be more than hot enough to emit a detectable radar signal, plus rocket exhaust is radar opaque so the defender could again see them from well over the horizon. This means that the defender would have at least two or three minutes to engage incoming missiles. On the other hand, an incoming harpoon attacking a Ticonderoga would be detected by the ship's AN/SPY-1 no sooner than about 90 seconds out. More time to engage means more chances to intercept the threat.

The p-1000 for reference has a range of 500km when following a sea-skimming trajectory of 25 meters or lower. The p-800 and BrahMos use similar technology and thus most likely have similar performance.

Got me there, but it's pretty easy to find something going 1,600 knots at sea level. The thermal signature alone would show up on radar long before you'd get a skin return. Engaging it on the other hand would be interesting.

Greater mass combined with greater speed means more kinetic energy which means more destruction which (besides the faster time to target and increased difficulty of interception) is the whole point of a supersonic AShM. For a small target like a corvette or a destroyer a small subsonic missile like a harpoon or exocet is more than adequate for the job. The reason the US or other western navies don't use supersonic AShMs is because they don't need them. US ships like the tico and arleigh burke are intended to escort carriers and provide anti-air and anti-sub capability while the carrier's air wing deals with surface threats. For the Russians if the cold war had gone hot they would have had to face US carrier groups which is why they invested in things such as supersonic AShMs and kirov class cruisers.

Speaking of the kirov, I find it a very fascinating ship. It's been hampered by collapses of the Soviet and later Russian economy and is a victim of the incompetent military bureaucracy in Moscow, yet it's extreme armament suggests it has the potential to be a devastatingly effective surface combatant.

I agree with Galla's points, so I snipped his out.

Kinetic energy doesn't actually matter a whole lot against anything larger than a Corvette. Frigates and other large surface combatants are tough enough that getting hit with what is functionally a small aircraft traveling at Mach 2.5 won't cripple them outright unless it hits something vital. Missiles need every bit of explosive power they have got in order to do much more then punch a hole the same diameter as the missile in the hull and send flaming shrapnel and remaining fuel through the compartments immediately in front of the impact site along their direction of travel. A 5-inch shell from WWI would do more damage than an inert SS-N-12.

[The Akasha Colony]

Greater mass combined with greater speed means more kinetic energy which means more destruction which (besides the faster time to target and increased difficulty of interception) is the whole point of a supersonic AShM. For a small target like a corvette or a destroyer a small subsonic missile like a harpoon or exocet is more than adequate for the job. The reason the US or other western navies don't use supersonic AShMs is because they don't need them. US ships like the tico and arleigh burke are intended to escort carriers and provide anti-air and anti-sub capability while the carrier's air wing deals with surface threats. For the Russians if the cold war had gone hot they would have had to face US carrier groups which is why they invested in things such as supersonic AShMs and kirov class cruisers.

Speaking of the kirov, I find it a very fascinating ship. It's been hampered by collapses of the Soviet and later Russian economy and is a victim of the incompetent military bureaucracy in Moscow, yet it's extreme armament suggests it has the potential to be a devastatingly effective surface combatant.

Kinetic energy is irrelevant. Ships are actually very resistant to impacts, they don't do much to them at all. What kills a ship is an uncontrolled fire, one that the ship's crew cannot handle. This forces them to abandon ship and either scuttle it or leave it until the fire hits the magazines or some such. Either way, the ship is lost. The best way to cause this is through the delivery of a significant quantity of explosives. Ideally multiple strikes, since as we've seen in the Falklands and Operation Praying Mantis, even frigates can be remarkably difficult to sink.

Who said the supersonic AShM was flying in a straight line?

To make it maneuverable means encountering a form of the death spiral. Now it needs to be structurally reinforced and given more powerful actuators for the control surfaces. This adds more weight and size so now you need more fuel and a more powerful engine to meet the same speed/range goals. But because it's heavier you now need a more reinforced frame...

Again, there's no reason a supersonic AShM wouldn't be capable of pseudorandom evasive maneuvering. Supersonic AShMs also almost universally have longer ranges although this is most likely due to their larger size and thus larger fuel capacity. The harpoon has a range of 124 km, the exocet up to 180km, and the naval strike missile up to 290km. For comparison the p-800 has a range of 600km and the p-700 625 km. Subsonic land attack missiles like the tomahawk have longer ranges but aren't really used as AshM's, at least not since the TASM was cancelled.

At the same time, the development of TASM and LRASM have clearly demonstrated that there is nothing inherent to the supersonic platform that gives it superior range or payload. For the same range, a subsonic missile will be substantially smaller and lighter than a supersonic one. The same thing can be said of speed. Keeping mass constant, a missile traveling at Mach 2 can expect to only have a quarter of the range of a missile traveling at Mach 0.8. This is rather concerning.

Low altitude flight regime is also a moot point. The BrahMos is capable of sea-skimming as low as 3-4 meters above the surface as can the p-700 and p-800.

And how fast are they at that altitude? How much does their range diminish in that flight pattern? These ranges are anemic compared to the ranges modern cruise missiles like Tomahawk and JASSM are capable of at subsonic speeds.

low weight isn't necessary an advantage. Bigger missiles can carry bigger warheads and more powerful navigation equipment.

Low weight is a huge advantage. Any reasonable carrier aircraft can fire a Harpoon. Which cannot be said of P-800 or BrahMos. The lighter weight gives the smaller missile a much wider variety of launch platforms, and larger platforms to field the lighter missile in very formidable numbers. Harpoons can be vertically launched from a standard VLS, allowing ships to easily be armed with additional quantities if ship-to-ship engagements are expected. But big AShMs that require custom launchers take up valuable space and limit the ship's flexibility. It also directly affects cost, which is a very important parameter.

It should also be clarified that carrying a larger warhead is not a benefit of a supersonic missile. Current supersonic AShMs have been designed to have larger warheads, but this is not a matter inherent to their nature as supersonic missiles, but instead a matter of simply being larger to begin with. Consider in any event that BrahMos, P-800, and Harpoon all have roughly the same warhead weight, but Harpoon has a much better payload fraction than either of these two. Both P-800 and BrahMos are under 1/10, while Harpoon is 1/3.

You're left with cost which is really the only real advantage a subsonic missile has over a supersonic one.

Except that we're not.

The only notable advantage that a supersonic missile has is terminal survivability. In all other aspects, ceteris paribus, subsonic missiles are superior. And that's the key thing to consider. You are comparing missiles in the 3,000+ kg range to one that is not even 3/4 of a tonne. Yes, when your missile weighs 10,000 kg you can make it go really far and really fast and have a big warhead. Because at that point it's basically a plane already.

But when controlling for other factors, subsonic missiles pull ahead. When you compare two missiles of the same weight and size, the subsonic one will have longer range. It will have a higher payload fraction. Its minor shortcomings in the survivability department can be easily overcome by simply using more missiles coordinated for time-on-target strikes.

[The Technocratic Syndicalists]

Kinetic energy is irrelevant. Ships are actually very resistant to impacts, they don't do much to them at all. What kills a ship is an uncontrolled fire, one that the ship's crew cannot handle. This forces them to abandon ship and either scuttle it or leave it until the fire hits the magazines or some such. Either way, the ship is lost. The best way to cause this is through the delivery of a significant quantity of explosives. Ideally multiple strikes, since as we've seen in the Falklands and Operation Praying Mantis, even frigates can be remarkably difficult to sink.

I wouldn't be so sure about that. Most AShM's use semi-armor piercing warheads that don't explode on impact, rather they have a delayed fuse that causes them to explode when they're inside the ship for more damage. In this case the ship is damaged by two actions, firstly the kinetic energy of the missile hitting it, and secondly the explosive going off inside it. The kinetic impact of the missile hitting the hull or deck is likely to be significant. Depending where it hits the force would likely ripple out throughout the hull and cause secondary damage in a large area surrounding the impact point . Furthermore when the warhead explodes missile fragments, already traveling at supersonic speeds, will be further accelerated by the explosion and cause damage throughout the interior of the ship.

To make it maneuverable means encountering a form of the death spiral. Now it needs to be structurally reinforced and given more powerful actuators for the control surfaces. This adds more weight and size so now you need more fuel and a more powerful engine to meet the same speed/range goals. But because it's heavier you now need a more reinforced frame...

That's true of subsonic AShMs as well. My point is that a subsonic missile is not inherently more maneuverable (in the sense of maximum g force it can pull) than a supersonic one.

At the same time, the development of TASM and LRASM have clearly demonstrated that there is nothing inherent to the supersonic platform that gives it superior range or payload. For the same range, a subsonic missile will be substantially smaller and lighter than a supersonic one. The same thing can be said of speed. Keeping mass constant, a missile traveling at Mach 2 can expect to only have a quarter of the range of a missile traveling at Mach 0.8. This is rather concerning.

Except that a subsonic missile has a much lower practical range limit. Being slower, it takes them much longer to get within seeker range of their target. You inevitably reach a time threshold where the targeted ship can now cover a large enough distance and you end up with a situation where your subsonic missile has to scan an impossibly large area and can't find its' target. This isn't a problem when you''re attacking a stationary target on land but poses considerable problem when you're trying to hit an enemy ship at a few hundred kilometers. With a supersonic missile time to target is extremely short so the ship you're firing at can't cover much ground before the the missile is within seeker range of it.

And how fast are they at that altitude? How much does their range diminish in that flight pattern? These ranges are anemic compared to the ranges modern cruise missiles like Tomahawk and JASSM are capable of at subsonic speeds.

the P-1000 can fly at a sea skimming altitude of less than 25 meters at mach 2 and has a range of 500 km. The brahmos can cruise at 5m altitude at mach 2 and has a range of over 300km.

Low weight is a huge advantage. Any reasonable carrier aircraft can fire a Harpoon. Which cannot be said of P-800 or BrahMos. The lighter weight gives the smaller missile a much wider variety of launch platforms, and larger platforms to field the lighter missile in very formidable numbers. Harpoons can be vertically launched from a standard VLS, allowing ships to easily be armed with additional quantities if ship-to-ship engagements are expected. But big AShMs that require custom launchers take up valuable space and limit the ship's flexibility. It also directly affects cost, which is a very important parameter.

the harpoon is incompatible with the mk. 41 VLS. The harpoon has to be launched from it's own launching system.

It should also be clarified that carrying a larger warhead is not a benefit of a supersonic missile. Current supersonic AShMs have been designed to have larger warheads, but this is not a matter inherent to their nature as supersonic missiles, but instead a matter of simply being larger to begin with. Consider in any event that BrahMos, P-800, and Harpoon all have roughly the same warhead weight, but Harpoon has a much better payload fraction than either of these two. Both P-800 and BrahMos are under 1/10, while Harpoon is 1/3.

I said a larger warhead was an advantage of a heavier missile, not a supersonic one.

Except that we're not.

The only notable advantage that a supersonic missile has is terminal survivability. In all other aspects, ceteris paribus, subsonic missiles are superior. And that's the key thing to consider. You are comparing missiles in the 3,000+ kg range to one that is not even 3/4 of a tonne. Yes, when your missile weighs 10,000 kg you can make it go really far and really fast and have a big warhead. Because at that point it's basically a plane already.

But when controlling for other factors, subsonic missiles pull ahead. When you compare two missiles of the same weight and size, the subsonic one will have longer range. It will have a higher payload fraction. Its minor shortcomings in the survivability department can be easily overcome by simply using more missiles coordinated for time-on-target strikes.

I'd say that's a pretty huge advantage considering a missile is pretty useless if it doesn't hit it's target.

It's like the difference between a b-1 and a b-52. Sure the b-52 has a higher payload fraction and is lighter and has a longer range, but that's all useless if it gets shot down on the way to its target.

[Fin Dovah Junaar]

The Kingdom of Vadena has begun construction of a new class of ship designed to sail the waves of the cold sea in a much greater capacity than any previous design, more dependent on sails than earlier designs.

[Gallia-]

The range is a good point, except subsonic missiles have practical ranges in excess of 150-200 km which is sufficient for most naval actions. Supersonic missiles are theoretically useful, but are being replaced by OTH targeting and datalinks in the US Navy, so as long as Triton has eyes-on a CV or something it can be hit within any reasonable range.

Something like LRASM would take about an hour to run out of fuel at cruise speed, so even in the unreasonable even that a CV is chugging for 30 knots in an hour, there is only a difference of ~60 km between detection location and real location, or less.

For a weapon with two-way datalink, this is negligible.

You're forgetting that P-1000 also weights 5 tonnes, or ignoring that deliberately. Brahmos is half that. Brahmos appears to shave mass by having a small warhead, smaller than Harpoon! P-1000 has half the range of LRASM, a warhead the same size, and weighs five times as much.

Also, a supersonic missile is not more likely to hit its target than a subsonic one. In fact it is probably less likely, assuming the target has adequate radar or IR countermeasures, where the seeker has less time to discriminate the target and the decoy. A subsonic weapon may accidentally hit its target after the ship passes through its own chaff cloud, and generally has more time and space to engage and maneuver than a supersonic weapon due to its slower closing speed.

Speed is not a huge advantage in avoiding counterfire. Computers are very good at trigonometry and can readily calculate the path of a closing supersonic or subsonic target that is not maneuvering, and destroy it. You would require a weapon so fast that it closes within the time the warship's computer is able to bring ordnance to bear, or the crew has no time to react to give the computer permission to fire. This would require velocities in excess of Mach 3 or even hypersonic weapons, in all likelihood.

AShM do not rely on speed anyway, they rely on pseudorandom maneuvering to make it hard for the computer to predict which direction the weapon will go. A computer with one cannon under its control can easily plot the course of a rocket, but they can't predict the future perfectly. A maneuvering weapon will be difficult for a CIWS to adequately engage (this is why SeaRAM exists), and is generally superior to simply blasting through the radar screen hoping you aren't shot at. Supersonic missiles, having higher relative velocity to the ship means it has less time and space to maneuver, although I don't think this is tremendous since the important thing when jinking is just moving in unexpected directions, not how many or how far.

All told, while a subsonic AShM has a greater chance to be intercepted, it is likely to be fielded in greater numbers, procured for less money, and have larger magazines for a given tonnage and volume. Systems like P-1000, P-800, and naval Brahmos cannot be carried by aircraft, require larger warships and missiles to achieve comparable standoff ranges, and are fielded in smaller numbers and lesser magazines without a necessarily equal or greater increase in overall killing power.

While it's amusing to think that superheavy missiles like those on Slava or Kirov are somehow better than a few box launchers with Harpoon and Tomahawk missiles, it's probably not true since the latter can be carried by more warships, in bigger numbers, and fired from many various multipurpose platforms working in synchronization.

A Soviet SAG or CVBG might be using four or five different types of heavy, supersonic standoff anti-shipping missile deployed from surface ships and submarines. A Western CVBG will have one, perhaps two, with many more missiles carried and many available platforms to use them in larger numbers.

[The Kievan People]

the P-1000 can fly at a sea skimming altitude of less than 25 meters at mach 2 and has a range of 500 km. The brahmos can cruise at 5m altitude at mach 2 and has a range of over 300km.

1. The minimum altitude of the P-1000 is 40 meters. This is not quite sea skimming.
2. The P-1000 only enters low altitude in the terminal phase. During the approach phase one missile flies at high altitude (~10km) to find the target and the rest of the group fly at "medium" altitude (~3km). This was designed specifically to defeat the Aegis/Standard missile. But the Standard Missile can be now be cued by an AWACs over the horizon, negating the advantage.
3. The maximum range of the P-1000 is only 700km. 500km range for a low altitude flight all the way is implausible.

Brahmos only has 120km range in a lo-lo trajectory. Given it's size this basically would restrict it to submarine delivery against a warship with air cover.

The most capable Russian supersonic AShM is probably the KH-31AD. Unlike giga-Brahmos it is well sized for carriage on a Flanker of Fulcrum. It is also exceptionally agile.

[The Akasha Colony]

I wouldn't be so sure about that. Most AShM's use semi-armor piercing warheads that don't explode on impact, rather they have a delayed fuse that causes them to explode when they're inside the ship for more damage. In this case the ship is damaged by two actions, firstly the kinetic energy of the missile hitting it, and secondly the explosive going off inside it. The kinetic impact of the missile hitting the hull or deck is likely to be significant. Depending where it hits the force would likely ripple out throughout the hull and cause secondary damage in a large area surrounding the impact point . Furthermore when the warhead explodes missile fragments, already traveling at supersonic speeds, will be further accelerated by the explosion and cause damage throughout the interior of the ship.

The kinetic impact won't do anything. So what, you've punched a hole in the target. Who cares? Ships can stay afloat with a lot of holes, as centuries of combat has proven. The force might knock a few things off the walls and cause bending in parts of the hull, but it won't cause any noteworthy damage on its own unless you get lucky and hit the VLS or the bridge or something.

The explosion is the dangerous part, and given that the warhead will have a detonation velocity of somewhere around 9,000 m/s, the "extra" velocity won't be a significant component at all. The real damage is going to be caused by the warhead design, and the larger warheads available to a subsonic missile (of comparable size to a supersonic one) will be more useful than a minor improvement to fragment speed.

That's true of subsonic AShMs as well. My point is that a subsonic missile is not inherently more maneuverable (in the sense of maximum g force it can pull) than a supersonic one.

True, but a subsonic missile will sustain lower g forces for a given turn rate.

Except that a subsonic missile has a much lower practical range limit. Being slower, it takes them much longer to get within seeker range of their target. You inevitably reach a time threshold where the targeted ship can now cover a large enough distance and you end up with a situation where your subsonic missile has to scan an impossibly large area and can't find its' target. This isn't a problem when you''re attacking a stationary target on land but poses considerable problem when you're trying to hit an enemy ship at a few hundred kilometers. With a supersonic missile time to target is extremely short so the ship you're firing at can't cover much ground before the the missile is within seeker range of it.

If you can provide accurate mid-course guidance and reliably eliminate targeting error, then this drawback evaporates. If you cannot, your engagement range is significantly hampered by the lack of targeting data anyway. If you can provide a datalink, then Tomahawk-like ranges become possible, but a supersonic missile capable of this range would be enormous.

the harpoon is incompatible with the mk. 41 VLS. The harpoon has to be launched from it's own launching system.

VLS capability is one that Boeing has proposed to the Navy. Harpoon easily fits into the launch cylinder (and even a torpedo tube), unlike P-700. The Navy didn't want it since all of their ships already have the box launchers, but VLS launch is a requirement or design capability for upcoming platforms like LRASM and JSM. Even the Harpoon's box launchers take up a trivial amount of space compared to P-700.

vs.

I said a larger warhead was an advantage of a heavier missile, not a supersonic one.

Which is irrelevant when the question is whether supersonic or subsonic AShMs are superior. Ceteris paribus a larger missile of otherwise similar capabilities will carry a heavier warhead, but a subsonic missile will carry a proportionately much heavier warhead than a supersonic missile.

I'd say that's a pretty huge advantage considering a missile is pretty useless if it doesn't hit it's target.

It's like the difference between a b-1 and a b-52. Sure the b-52 has a higher payload fraction and is lighter and has a longer range, but that's all useless if it gets shot down on the way to its target.

Except that the difference in survivability between the B-1 and B-52 isn't actually that large. The primary defense mechanism for both is the same, and coincidentally the same for warships too: electronic countermeasures. It certainly isn't speed; the B-1 won't be outrunning or out maneuvering missiles or fighters.

In fact, the terminal survivability advantage of a supersonic AShM needs to be further qualified: it is more survivable against gun-based CIWS but less survivable against missile-based CIWS. The former is true because it is harder to target and will close the distance through the gun-based CIWS' range extremely quickly. But even a supersonic AShM lacks the maneuverability to evade an agile, guided interceptor missile like RAM or ESSM, whose engagement range is over ten kilometers, giving plenty of time for engagement. And with the enormous infrared and radar signature such a large AShM would emit, detection and engagement at very long ranges would be easy.

This minor advantage can be overcome, as Galla mentioned, by simply using more cheap, subsonic AShMs. For the weight of one BrahMos, you could carry four Harpoons. Which not only deliver over four times the explosive payload but would be harder to reliably decoy and defeat as a whole. This advantage only gets larger when you compare it to even heavier missiles.

[Polar Svalbard]

Rail gun frigate, would that be better than an anti-ship, ship born weapon

[Connori Pilgrims]

Rail gun frigate, would that be better than an anti-ship, ship born weapon

No.

Flat no.

Railguns are not being proposed as anti-ship weapons. Anti-missile and land-attack yes, but not anti-ship.

[The Kievan People]

Care to elaborate?

The missile is already better than a guns. The guns make the CIWS footprint much larger without really adding much. If the first shot doesn't kill it, just fire another missile.

You also doubled up the fire control radar for some reason?

[The Technocratic Syndicalists]

What about a missile like the p-900 alfa (SS-N-27) that cruises at subsonic speed but has a supersonic terminal stage? Doesn't it have the advantage of both systems?

The p-900 has a launch weight of 2,600 kg, range of 270 km, and has a 300 kg warhead. It cruises at mach 0.8 for the first 200 km with a sea-skimming trajectory and then 70 km away from the target activates its rocket booster and sprints at mach 2.9 toward its target.

[The Akasha Colony]

What about a missile like the p-900 alfa (SS-N-27) that cruises at subsonic speed but has a supersonic terminal stage? Doesn't it have the advantage of both systems?

The p-900 has a launch weight of 2,600 kg, range of 270 km, and has a 300 kg warhead. It cruises at mach 0.8 for the first 200 km with a sea-skimming trajectory and then 70 km away from the target activates its rocket booster and sprints at mach 2.9 toward its target.

No. Not really. Let's run through the components individually:

-Consider that it is still twice as heavy as LRASM, but has a smaller warhead and shorter range. So it is still size-inefficient compared to a purely subsonic missile.

-From a cost perspective, you still need to develop a missile capable of Mach 2.9 and include a separate rocket booster for that stage. This reduces the payload fraction further and adds weight and complexity. So it will cost far more than a subsonic missile with a simple turbojet. It will likely cost at least as much as a regular supersonic missile, if not more because it now needs two motors and will be operating at two different speeds (which needs to be taken into consideration when developing the aerodynamics of the missile itself).

-Spending most of its time at subsonic speeds, it does not accrue the reduced flight time benefit of an entirely supersonic missile.

-It is still just as vulnerable to interception as a regular supersonic missile, thus missile CIWS will have a field day.

So in the end, rather than having the "benefits" of both, you get the drawbacks of both: a missile that is as big and expensive as a fully supersonic one with the short range and light warhead weight of a subsonic missile, and without the flight time advantages of a supersonic AShM. You get the improved protection against gun CIWS but this isn't even a particularly large threat. ECM is the biggest threat, against which this missile has no advantage, followed by missile-based CIWS.

[The Technocratic Syndicalists]

Isn't a subsonic missile still vulnerable to being shot down by gun based CIWS and by any SAM or missile CIWS with active homing?

[Gallia-]

What about a missile like the p-900 alfa (SS-N-27) that cruises at subsonic speed but has a supersonic terminal stage? Doesn't it have the advantage of both systems?

The p-900 has a launch weight of 2,600 kg, range of 270 km, and has a 300 kg warhead. It cruises at mach 0.8 for the first 200 km with a sea-skimming trajectory and then 70 km away from the target activates its rocket booster and sprints at mach 2.9 toward its target.

That's twice the weight of LRASM, which has both a warhead weight and range three times greater.

[Gallia-]

Isn't a subsonic missile still vulnerable to being shot down by gun based CIWS and by any SAM or missile CIWS with active homing?

Anti-shipping missiles jink erratically when engaging targets to avoid CIWS fire.

This is what confounds gun CIWS.

Missiles, being capable of maneuver, are less likely to be thrown off by missile jinking since they can just change direction.