Railgun news

[Omeganian]

Apparently, the Navy is going to soon fire a railgun from one of their destroyers. Commanded by one James Kirk, no less...

http://www.smh.com.au/technology/sci-te ... ljao4.html

There are also news about China doing its own work on the subject.

http://www.popsci.com/an-electromagneti ... ilguns-too

[The Romulan Republic]

Strange looking ship, the Zumwalt. I saw a picture from the back where it basically looked like a grey pyramid sitting on a barge. I like my ships a little more sleek, but of course its how effective it is that really matters.

[Iroscato]

Einhander will be pleased, wherever he is these days.

[LaCroix]

The worst thing is the strange 'crumple' bend near the railing where the bow transitions to the mid. Looks like they did a papercraft and accidentally folded it where they shouldn't. But that's stealth design for you - it sometimes kicks aesthetics in the face. (Along with seawortyness and cost efficiency)

But I'm not quite baffled that the chinese are investing in this, too. US capabilities are in part developed to counter the Chinese bid for Superpower status. If they don't try to keep up, their ambitious goals are out of reach. And by putting that system on a proven hull, they are cutting some corners in that race. Along with the potentioal ability to retrofit the older designs. I'm not sure you could do the same with the american model, easily.

[TimothyC]

Zumwalt class ships don't have railguns. They instead have the Advanced Gun System. The rail gun demonstrator is actually going to be mounted on one of the Joint High Speed Vessels (JHSV).

[Simon_Jester]

Strange looking ship, the Zumwalt. I saw a picture from the back where it basically looked like a grey pyramid sitting on a barge. I like my ships a little more sleek, but of course its how effective it is that really matters.

The biggest question is going to be its performance in bad sea conditions. There's a reason people don't normally build ships shaped like that. I've heard alarming phrases like "snap roll" thrown around.

[SpottedKitty]

Interesting, but I don't see any indication of how big the actual shooty part needs to be. Can it be turret-mounted? I can't see a spinal mount working, aiming the thing would be a less than straightforward job.

As for stability... have we ever seen any of these things out of the water? Maybe there are vanes like on a submarine, or a beefed-up version of the stability system used on big passenger liners.

[Patroklos]

Reserve boyancy is what the Navy is primarily worried about.

[TimothyC]

Interesting, but I don't see any indication of how big the actual shooty part needs to be. Can it be turret-mounted? I can't see a spinal mount working, aiming the thing would be a less than straightforward job.

As for stability... have we ever seen any of these things out of the water? Maybe there are vanes like on a submarine, or a beefed-up version of the stability system used on big passenger liners.

She has an active stabilization system that works (like on a cruise ship), but unfortunately it looks like it might add to the snap roll characteristics.

[Sea Skimmer]

Active stabilizers are supposed to slow down snap rolling, though if you wanted you could sure program them to make the ship roll worse. As long as the ship isn't flooding it should be fine on that. Heeling in a high speed turn will always be heavy.

The really big problem with this hullform are just how much water is going to come over the bow in a storm when it 'wave pierces' and what that's going to mean for stern slamming in which the screws could come out of the water. And how the fore deck equipment is going to stand up to all that water smashing on it.

Interesting, but I don't see any indication of how big the actual shooty part needs to be. Can it be turret-mounted? I can't see a spinal mount working, aiming the thing would be a less than straightforward job.

http://www.onr.navy.mil/en/Conference-E ... asers.ashx

This might help. I had to rename the document to a pdf to get it to view though.

Basically a 20 MJ and a 32 MJ launch energy railgun are being worked on. The 32 MJ is about akin to the KE firepower of the 155mm AGS on DDG-1000 but nothing else. It could go in the same position, but with a very different mount. would be turreted. Railguns produce much less recoil then powder guns, and tend to be shorter (but bulkier and heavier) so turrets are not a major problem for them even at much higher launch energies then this. So big short squat turret is likely. Due to inefficiency and the sabot/armature mass you also need space for a pulsed power supply in the 100 MJ class which you can see in some of those images in the PDF. Its the size of a very small house.

The 20 MJ launch energy gun compares with the 5in guns on most US navy surface warships, but replacing the guns on existing ships is absurdly unlikely to happen. The 20 MJ is plausible though as an eventual weapon for the Flight III Burke destroyer.

JHSV is to be used for the first at sea trials because that way installing the pulsed power supply is simply a matter of parking existing equipment on its large vehicle cargo deck. Some added structure will be welded in to mount the gun proper on the helicopter deck, probably in a turret with limited traverse and elevation.

With a purely ballistic round the 20 MJ should fire to about 50nm and the 32 MJ gun 100-110nm.

[biostem]

All being told, I'm assuming that the main advantage will be that you don't have to keep stockpiles of propellant. Do the rounds deal more damage than a conventional one of the same mass/weight? Can a railgun projectile be launched in a variable trajectory or force, to get over mountains or behind obstacles?

[Patroklos]

The main advantage is it has 10x the range of the current NGFS in the form of the CG/DDG 5".

[Borgholio]

All being told, I'm assuming that the main advantage will be that you don't have to keep stockpiles of propellant. Do the rounds deal more damage than a conventional one of the same mass/weight? Can a railgun projectile be launched in a variable trajectory or force, to get over mountains or behind obstacles?

There are several advantages:

1. Smaller projectiles. Energy for launch is provided by the ship's generators, not a shell casing, bags of powder, or a rocket motor.
2. Safer storage. They can kill by sheer kinetic impact...no need for a warhead that can go off in an accident or in event of an enemy weapon impact.
3. Cheaper than missiles. Anti-ship missiles can run a million dollars, these projectiles cost about 25 grand each.
4. Faster than missiles and normal guns. They can be launched at hypersonic speeds.
5. Longer range than guns. A normal 5" gun has a range out to the horizon. A railgun can go 10 times that far.
6. Harder to intercept. They are smaller and faster than missiles, so harder to shoot down with traditional anti-missile defenses.

[Patroklos]

This isn't for shooting ships. It is a cheaper alternative to Tomahawks though since right now its that or TACAIR unless the targets are within a dozen odd miles of the shore line.

[Sea Skimmer]

All being told, I'm assuming that the main advantage will be that you don't have to keep stockpiles of propellant.

The main advantage is you can obtain muzzle velocities, and thus firing ranges, that basically cause conventional powder guns to self destruct or have such low barrel lives they are not militarily useful/reasonable. No gunpowder is also very useful because its just safer, but on a cost basis it may be no real advantage. In some contexts you may have a major logistical advantage in weight of fuel vs propellent, but this is only likely to be realized in very large weapons or on a warship which already has large generators. On the other hand if you wanted a 155mm SP gun that was a railgun, and could match the muzzle energy and ROF of the best 155mm weapons today, it would need something like an 8000hp engine hooked to a generator. That's not bloody happening, it'd have to be one or two additional vehicles, a gross disadvantage.

This is a reason why you won't see much talk about adapting EM guns to the anti tank role. Such a gun could be built, but the tank couldn't power the damn thing.

Do the rounds deal more damage than a conventional one of the same mass/weight?

At the velocities in question, no. This is actually a considerable problem for present railgun design because the accelerations involved and small size of the projectiles its very hard to give them an effective HE burster. KE Shrapnel rounds are simple and logical, but the damage inflicted per shot will be pretty low. You need an impact speed of around 3km/s for KE to become more powerful then the energy you'd get out of an exploding round, but we simply cannot make high muzzle energy railguns right now that could deliver that kind of performance. Present goals are for around 2.5-2.6km/s muzzle velocities, with rather less upon impact.

No gunpowder + no explosive burster is ideal because then the entire weapon system is non explosive, and even the risk of the fuel for your power supply can be mitigated, the US just tested (yet another) formula for explosion proof fuel (prior types needed 10% water added, unappealing) that works by using a suspended polymer to physically jam together as the molecular and block the propagation of explosions.

But the reality is we just can't make the guns powerful enough to make the pure KE approach an actual destructive advantage. That does not mean it will not be useful.

Can a railgun projectile be launched in a variable trajectory or force, to get over mountains or behind obstacles?

In principle that should be no problem, as you can adjust how much energy you put into the pulse power supply, and also adjust the length of the power pulse, and thus be much more variable then a modular gunpowder charge. However the electrical efficiency of most EM gun designs will drop off badly at anything but the optimal design velocity. Also the actual switchgear needed to control the electrical power has finite limits and costs attached. And if you make the power pulse too weak the gun won't work at all.

However any useful railgun is going to fire guided ammo anyway, and advanced forms (not all have equal ability to actually shift trajectory, just like not all missiles are highly agile) such ammunition can do things we could never accomplish with any ballistic projectile, such as steepening its impact trajectory to be truly vertical for say, the last 5,000ft of altitude before impact. The 155mm Excalibre guided shell can already do this, as can the GMLRS missile. If you don't need guided ammo your firing range is going to be short enough that you probably don't want or need a railgun either; though that might not be strictly true in the self defense anti aircraft role. The trend in the world though is towards a shitload of guided ammo.

[Sea Skimmer]

This isn't for shooting ships. It is a cheaper alternative to Tomahawks though since right now its that or TACAIR unless the targets are within a dozen odd miles of the shore line.

Tomahawk range is up to 900nm, so even a 110nm railgun isn't intruding too much into that!

I'd suggest what this might be viewed as is sort of filling the role land armies now get out of multiple rocket launchers. A way to expand the volume and range of fire over normal tube artillery in a general support role. Warships the world around have been stuck with roughly 5in powder guns for a long time. Nothing much bigger will fit on them without loosing other key systems; you can have a 155mm but it will fire a lot slower reducing its utility in many roles. Such weapons are pretty effective for general purpose mission, and for most of the cold war they compared well or were superior to 155mm howitzers on land and handily superior to 105mm and 122mm weapons. But nothing improved much in naval gun armaments to match all the heavy caliber rocket launchers everyone's armies spammed from the 1970s onward (earlier rockets were generally no greater or much less in range then 155mmm weapons). And making super exotic guided rounds hasn't gone too well.

Now naval rocket launcher weapons were used at sea in specialist vessels in WW2 and a little into the Vietnam War, but they can't really be used by a normal warship because of the shear bulk of all the ammo. And even then range tended to be very low, with very small rockers. On land that bulk is simply absorbed by large numbers of supply trucks roving around, and the only limit on how big the rocket can be is how long the truck can be. You could put something like BM-30 Smerch onto a ship, but it'd end up needing to be a dedicated hull, something like Arsenal Ship, which is an unappealing concept at best.

With a railgun you can get the kind of range armies can get out of really big multiple rocket launchers, and while shot for shot effectiveness might be low you can carry a large number of rounds (on a decent sized ship) because you don't need powder charges. The size of the pulse power supply is fixed, and for large amounts of ammo per barrel will be more compact then a powder magazine would be. Also you can get more shells by helicopter from a supply ship, and won't need powder charges (probably save 50% of time!). So while you still can't match rockets or missiles for shear intensity of fire, you can match them in the long run for weapons on target and generally destroying crap. You just won't be nearly as good at surprise things, like hitting advancing enemy infantry.

So the end result is warships gain a way to compete a lot better with the present and rapidly proliferating technology of land armies general support artillery. Smerch, A-100 and GMLRS are prime examples of the way this field is going, big, aircraft bomb like warhead effects, precision guidance options ect. They aren't just enormously powerful on land, even with unguided or fixed point of impact guidance (INS/GPS) they are huge threats to shipping because of the low time of flight and ability to saturate a large impact area at acceptable cost. And because they are fairly simple basically nothing stops anyone from using them if they capture them ect... most MRL systems remain limited in caliber and in the 50km range of firing distances but that's already uncomfortable, and will change rapidly as aeroballistic missile designs are adapted to yet more and more existing launcher designs and form factors.

[Adam Reynolds]

Why is it that some form of GMLRS hasn't ever been adapted for warships? I seem to recall proposals for such a concept, quadpacked in a VLS tube. Though that would still have the problem that it couldn't match the sustained firepower of land based systems due to the lack of ability to reload at sea*. Which I suppose is the point of railguns. For another version, wasn't there going to be a version of Standard that was supposed to have the same effect. Has anyone considered using INS and data links to allow anti-aircraft missiles to be used in quick reaction strike missions?

How easily would Standard or ESSM hit MLRS rockets? Though they would of course likely have the problem of losing to saturation attacks, even with AEGIS.

* Though this gives me an idea that would likely be insane. Would it be possible to reload VLS tubes by delivering missiles via helicopter directly to the launch tubes? For another slightly saner concept for the same effect, would it be possible to use box launchers similar to Harpoon with more generic loadouts that can be reload as needed in addition to the VLS missiles? Thus you would have a mix of the quick rate of fire of VLS as well as the ability to have a smaller array of missiles that can be reloaded when needed and swapped out in the field depending on the mission. Though this would obviously be significantly more expensive than pure VLS systems.

[Sea Skimmer]

Why is it that some form of GMLRS hasn't ever been adapted for warships?

That was actually a serious program for a short period during the development of GMLRS, around 2000ish. Called POLAR. It would have had an extended booster to make full use of the height of the Mk41 VLS system and quad packed into the cells. Range about 200km. This was not proceeded with because of the volume of fire issue. Functionally POLAR would be awesome if you built Arsenal Ship, but for a normal warship it'd be another way to blowup point targets, not any solution to volume of fire.

Germany was half serious at one point about putting the normal GMLRS and a normal MLRS launcher on a frigate class (this has been proposed in other contexts too) but this was cancelled in the design process due to German peacemongering and generalized decision to make its new frigates look exactly like colonial gunboats. Indeed the formal descriptions are uncanny.

For another version, wasn't there going to be a version of Standard that was supposed to have the same effect.

That was RGm\M-165/SM-4 LASM, they actually test fired several for a demonstration

The original idea was to take the giant USN stockpile of unwanted SM-1 missiles and repurpose them with new guidance. Problem is many US allies still made large scale use of SM-1, and indeed some still do, while SM-1 production ended in the 1980s. So it was realized that 1) the conversion wasn't free and 2) our allies and our Perry class frigates were going to consume the entire SM-1 stockpile anyway.

It was then proposed to use the oldest SM-2 airframes for this, which is what were used in the demonstration, but the program was killed in 2002. Problem is for how big and costly the missile was it actually wouldn't be all that effective. It'd have zero ability to penetrate even unhardened buildings, couldn't hit anything moving and even the actual fragmentation pattern of the AA warhead was not very good for attacking ground targets. Range would almost not have been overwhelmingly greater then POLAR which would have been much cheaper and had a more suitable warhead, and four times as many missiles per silo.

Interestingly a Chinese land based missile launcher, the SY-400, looks EXACTLY like SM-4. Its not clear this weapon was ever fully developed though. They showed it off at arms shows, but like most Chinese weapons they didn't demonstrate anything to show it actually flew or was anything but a serious attempt to fish for money. China still has a lot of stupidly redundant competing state arms companies. The SY-300 seems to be more or less POLAR.

Has anyone considered using INS and data links to allow anti-aircraft missiles to be used in quick reaction strike missions?

Some SAM systems already have such capabilities, and as far back as Nike it was possible to conduct a surface to surface mission with useful accuracy simply using the command guidance to loft the missile on a ballistic trajectory. Several heavy SAMs have been fielded with anti radiation homing heads too, Talos was used in this manner in combat in Vietnam to attack communist CGI radar sites. Patriot has a dedicated anti jammer missile intended to destroy people trying to jam its radar from the ground.

In the end though its a really expensive way to do things. High performance AA missiles are much more expensive then dedicated land attack weapons, sometimes comically so. Surface to surface modes are primarily relevant to jammers, and attacking ships, in the later case simply because a ship is so high value it's worth almost anything to damage.

A number of SSMs like Harpoon now have kits to give them GPS guidance for land attack too. This is kinda relevant to hitting suddenly appearing high value targets like an S-300 site setting up, or Osama Bin Laden but not likely to serve as a general support weapon. Still for smaller warships that only have a 3in gun ect.. it can be an interesting addition.

How easily would Standard or ESSM hit MLRS rockets? Though they would of course likely have the problem of losing to saturation attacks, even with AEGIS.

The unguided MLRS rockets would be real easy targets, but the ship wouldn't have much time to react. The maximum speed is only about 650m/s falling to about 400m/s velocity when it breaks open to dump the CBUs in a maximum range shot. Rockets make big radar targets too. For another comparison, the much bigger Smerch system with its 70km range ballistic rocket has them impact at about 630m/s, I'm not sure on launch velocity but probably in the ~800m/s range. So basically not any faster then supersonic anti ship missiles, but not on the deck.

With GMLRS the ship would have much more total engagement time because the missile lofts so high early in flight, but the missile is maneuvering not purely ballistic, and flies at a positive angle of attack before pitching over to dive on the target. Aeroballistic is the trick to why something that size can go 100km. The large variations in speed, angle (which affects RCS) and flight path, and the ability to program in blind evasion while it does this (at cost in range) make for a much harder target even though its still never going faster then about mach 3 at any point in flight.

Most tactical ballistic missiles are aeroballistic and have been since the 1980s (now some much larger weapons are too), the capabilities of this sort of missile are behind the super high performance demanded out of the PAC-3 interceptor and some other ABM missiles. Of course the main problem remains saturation, and the ship simply depleting its magazines to the point it has to retreat from combat.

[quot]
* Though this gives me an idea that would likely be insane. Would it be possible to reload VLS tubes by delivering missiles via helicopter directly to the launch tubes?[/quote]

No the weapons are too large for that to be realistic on a moving ship. The Mk41 system originally had a reloading crane for each cluster, intended to allow reloading at sea after the missile was brought on deck by conventional side by side underway replenishment. Attempts to actually do so not only failed, they damaged the missiles and apparently in one case nearly caused one to explode. The reloading cranes have been been removed, which frees up the three silos per cluster they took up.

The much earlier 3T series missile launch systems used horizontal missile storage with a strike down elevator, rather then vertical, and actually could realistically be reloaded at sea, though it was seldom done or practiced. If you wanted at sea reloading you'd want that kind of setup.

For another slightly saner concept for the same effect, would it be possible to use box launchers similar to Harpoon with more generic loadouts that can be reload as needed in addition to the VLS missiles? Thus you would have a mix of the quick rate of fire of VLS as well as the ability to have a smaller array of missiles that can be reloaded when needed and swapped out in the field depending on the mission. Though this would obviously be significantly more expensive than pure VLS systems.

Harpoon sized missiles are a little more plausible to handle on deck then an SM-2 scale weapon but it would still not be easy. Ships pitch and roll. These sorts of launchers are often in less then ideal locations for reloading, and anywhere you could put reloads you could probably put more actual launchers too. A more important point is why though. Navies are not awash in huge piles of extra weapons. The USN doesn't have enough serviceable missiles to fill ever Mk41 silo ONCE. Not all ships are in service at the same time anyway, but its no surplus even with that in mind. Thus the interest in low cost high volume of fire weapons and unending attempts to make guided gun rounds.

As far as small missiles go you can pretty much put a Netfires like missile in a box system anywhere you want with manual reloading in good weather, and some Israeli patrol boats already have Spike-LR carried around like that. LCS will be getting launchers for Hellfire in the next few years. Interestingly though high performance anti tank missiles cost about the same as what GMLRS does. All the cost is in the guidance system, pure GPS/INS being far cheaper then laser or radar homing. The rocket motor and airframe costs are minimal.

But given how far along guided shells are coming the need for spamming really small missiles ais limited. They won't have much range with rocket power, and air breathing propulsion makes the cost skyrocket. The USN Hellfires are for attacking small boats, as in 1 LCS vs 40 small boats kind of situations. Land attack isn't even being considered as the radar homing Hellfire is to be used.

ERGM was a failure, a couple other programs were failures, basically because they pushed the state of the art too quickly and had too many problems with shock hardening the guts. We already had guided shells like Copperhead but they were fired at lower velocities, thus less acceleration, and had unexceptional ranges. Now though were overcoming that issue, and the shell for AGS actually works. So does that screw in GPS fuse that can make any 155mm round guided has been fired in combat.

[Patroklos]

This isn't for shooting ships. It is a cheaper alternative to Tomahawks though since right now its that or TACAIR unless the targets are within a dozen odd miles of the shore line.

Tomahawk range is up to 900nm, so even a 110nm railgun isn't intruding too much into that!

Yeah, I guess I should have been more specific. 44% of the worlds population lives withing 150kms of a coast. That means far more than 44% of military targets are in that area. So while we would still need Tomahawks and such for the truly long range strike missions (or airframes) at $1M a pop having a weapon like this rail gun will greatly reduce our reliance on expensive cruise missiles far more than a mere range comparison would suggest. Cruise missiles are also used because its too dangerous to use TACAIR or we don't want any risk or POWs, circumstances where this weapon will also come into play.

Of course you have to take warhead types, loiter times, etc into account. But if we can swap a several thousand dollar rail gun round for a $1M Tomahawk even a 1/5 of the time the savings become readily apparent.

[Pelranius]

Interestingly a Chinese land based missile launcher, the SY-400, looks EXACTLY like SM-4. Its not clear this weapon was ever fully developed though. They showed it off at arms shows, but like most Chinese weapons they didn't demonstrate anything to show it actually flew or was anything but a serious attempt to fish for money. China still has a lot of stupidly redundant competing state arms companies. The SY-300 seems to be more or less POLAR.

Seaskimmer,

China has deployed the SY-400 to some extent (there's a news clip showing it at some PLA artillery unit, on one of those modular MRL trucks, with those Chinese SMERCH derivative/knockoffs also on the MRL truck as well).

Incidentally, how hard would it be to build a mobile land based railgun for long range artillery fire? General Atomics is proposing for their 10 MJ Blitzer railgun to have two truck mounted generators hooked up to the mobile railgun for AD missions. Now the most pressing issue is getting a compact and mobile power source on a heavy truck frame (or some more exotic form of energy storage/generation). The defense contractors I spoke to at a naval technology conference this year was convinced that it could be done, for what that's worth.

PS: I'm the Jeffrey Lin half of Eastern Arsenal.

[biostem]

Interestingly a Chinese land based missile launcher, the SY-400, looks EXACTLY like SM-4. Its not clear this weapon was ever fully developed though. They showed it off at arms shows, but like most Chinese weapons they didn't demonstrate anything to show it actually flew or was anything but a serious attempt to fish for money. China still has a lot of stupidly redundant competing state arms companies. The SY-300 seems to be more or less POLAR.

Seaskimmer,

China has deployed the SY-400 to some extent (there's a news clip showing it at some PLA artillery unit, on one of those modular MRL trucks, with those Chinese SMERCH derivative/knockoffs also on the MRL truck as well).

Incidentally, how hard would it be to build a mobile land based railgun for long range artillery fire? General Atomics is proposing for their 10 MJ Blitzer railgun to have two truck mounted generators hooked up to the mobile railgun for AD missions. Now the most pressing issue is getting a compact and mobile power source on a heavy truck frame (or some more exotic form of energy storage/generation). The defense contractors I spoke to at a naval technology conference this year was convinced that it could be done, for what that's worth.

PS: I'm the Jeffrey Lin half of Eastern Arsenal.

How small can you make a safe fission reactor? They have them in attack subs, which are smaller than the ballistic missile ones, but they're still pretty big vessels... I'm also assuming that you wouldn't need the power output of one meant for a sub, but at the same time, there would be big issues if the reactor were damaged/destroyed/stolen.

[Jub]

How small can you make a safe fission reactor? They have them in attack subs, which are smaller than the ballistic missile ones, but they're still pretty big vessels... I'm also assuming that you wouldn't need the power output of one meant for a sub, but at the same time, there would be big issues if the reactor were damaged/destroyed/stolen.

I don't know about how practical it would be, but some years back a company put forward the idea of a semi-trailer sized fission reactor that could power a small neighborhood. I don't know if that's come along at all, but it seems like something in that range could be feasible.

[Pelranius]

How small can you make a safe fission reactor? They have them in attack subs, which are smaller than the ballistic missile ones, but they're still pretty big vessels... I'm also assuming that you wouldn't need the power output of one meant for a sub, but at the same time, there would be big issues if the reactor were damaged/destroyed/stolen.

I don't know about how practical it would be, but some years back a company put forward the idea of a semi-trailer sized fission reactor that could power a small neighborhood. I don't know if that's come along at all, but it seems like something in that range could be feasible.

Pebble bed reactors could be somewhat safer than current fission designs if you want to go mobile, though I'm not familiar with energy density and the like. Might be lighter too, if you design it right.

[Jub]

Pebble bed reactors could be somewhat safer than current fission designs if you want to go mobile, though I'm not familiar with energy density and the like. Might be lighter too, if you design it right.

True, but I think we're probably both trying to solve the wrong problem. I doubt the issue is generating power, but instead storing it so your weapon can burst fire above its standard ROF if called upon to do so. So better batteries and quick charging capacitors would probably be better bang for your buck than a truck bed sized fission reactor.

Of course, if you have the money to throw at it, both is better and reduces your supply tail considerably.

[Darmalus]

As I recall modern nuclear reactors scale well enough that you could have everything bigger than a rowboat be nuclear. The limit is the number of nuclear operators you can train, as I understand it the Navy is already at the razor edge of what it can support with current standards and recruitment rates.