A blog dedicated to helping writers and worldbuilders create consistent, plausible Science Fiction.

Friday, 20 May 2016

Battleships of the Future

Naval warfare has been defined by transitions, all triggered by major advances in technology. Steam power, radar, aircraft... all have led to drastic changes.

Today, we are on the verge of another such transition. 





What's next? 
The defining technologies of current naval warfare are the guided missile, the submarine and the jet plane.

The modern guided missile delivers a warhead accurately to the target, without risking a pilot and without requiring external guidance. The latest developments have focused on extending range, reducing time spent within the zone of defensive fire from the target, and evading that fire with techniques such as sea-skimming or high-speed evasive maneuvers.

Aircraft evolved from directly attacking ships with bombs and guns to becoming missile launch platforms. A missile designed to have the speed to penetrate an enemy ships's defenses does not generally have very good range. This means an aircraft, submarine or another ship is required to approach the target, and close the final distance with the missile itself.

As anti-air defenses became more effective, aircraft and the missiles they carried were forced to evolve.

The premier defenses for a ship today are the anti-aircraft missile and the CIWS gun.

The RIM-174 ERAM, a Mach 3.5 air target interceptor
Anti-aircraft missiles allow warships to take down helicopters and jets within range, and force them to drop their anti-ship missiles from as far as 400km away. With a service ceiling of 34000m, it precludes any sort of high-altitude attack alternative. 

The result is that anti-ship missiles have a minimum range to be useful when mounted on aircraft. As a secondary consequence, they have a minimum size that makes it difficult to mount a huge number of them on a single airframe, making overwhelming defenses through saturation more difficult. This is further compounded by the fact that the target ship may be covered by its own aircraft, and the attacking craft must remain agile enough to evade them. 

The now famous Phalanx CIWS, shooting up to 5000 rounds a minute
The last line of defense is the Close-In Weapons Systems such as Oerlikon or Goalkeeper. They rely on interlinked gun systems shooting a hail of bullets into the predicted path of incoming missiles. They can be backed up by anti-missile missiles such as the Aster missile family, which intercept threats at hypersonic velocities. 

Together, they relegated the subsonic cruise missile to the past. Today, anti-ship missiles are required to sea-skim to evade radar for as long as possible, then 'pop-up' and accelerate to supersonic speeds in the final stretch. This is in direct contradiction with their extensive range requirements.

The results these technologies have had on naval warfare over the past 40 years have been varied.

Countries such as the United States have concentrated their power into Aircraft Carrier strike groups, able to launch missile-equipped aircraft anywhere in the world. In turn, they are protected by an entire cort├Ęge of ships dedicated to anti-aircraft, anti-missile and anti-submarine roles. To improve their attack performance, stealth technologies are being developed to give aircraft an undetected-launch capability or alternatively, shoot from closer ranges with faster missiles. 



Others such as Russia have instead developed an entire suite of warships with the capability to launch dozens of missiles at once, from hundreds of kilometers away, to perform a coordinated strike that would overwhelm any carrier group's defenses.

Smaller nations such as the UK or France have given up on the expensive carrier group strategy, and instead focus on more flexible helicopter carriers and stealthy submarines that can bypass the majority of a target's defenses. 

What's coming next?

A leap in missile performance, and the tentative failure of stealth technologies, will define naval warfare for the next few decades.

One technology being integrated into anti-ship capabilities is stealth, either through stealthy missiles or stealthy jet bombers.

The LRASM project promises stealthy missiles that work together to find their target even when satellite guidance is unavailable and to cooperatively evade anti-missile defenses.

Screen capture from Lockheed's simulated attack on Russian destroyers.
Other nations are not gambling on stealth, instead focusing on making anti-ship missiles much, much faster. An example of this is the BrahMos-II, a joint development by India and Russia. When the attacking missile is faster than the bullets sent to shoot it down, and crosses the final 10km in less than 5 seconds, it has a real chance of evading defensive fire. 

A great fear of today's navies is the ballistic anti-ship missile - tactical ballistic missiles accurate enough to hit warships are sea. Being much larger than the regular supersonic cruise missile, they can perform hundred-gee maneuvers at Mach 10+ plus, coming from thousands of kilometers away and attacking from a vector most current anti-missile defenses are not equipped to handle. China apparently has this capability with the DF-26

The ships themselves are evolving into stealthy missile platforms, with anemic guns and a small onboard flight deck for a helicopter.

The Zumwalt-class destroyer, ironically resembling an ironclad, one of the earliest warships.

In a world of rapidly evolving missile capabilities, it becomes more important to deliver massive, rapid missile strikes that overwhelm defenses, than it is to counter the rapidly diminishing role of aircraft. If tactical ballistic missiles become a widespread threat, then the requirement for aircraft to act as intermediaries will be abolished entirely, paving the way for aircraft carriers to be replaced by Missile DD groups and attack submarines.  

This is further compounded by the fact that semi-stealth aircraft such as the F-35 Lightning II were unable to deliver on the promised performance, much less so when trying to handle the requirements for naval variants or effectively defend itself against agile 'old-school' interceptors such as the SU-35 Flanker.

What are the game-changing technologies?

The first is lasers.

There is every reason to expect that in the relatively 'clean' environment of an open sea, and with megawatts of electrical power directly available from a warship's nuclear reactor, that laser technology will become of great importance in naval warfare.

The main advantage to lasers is the increase in effectiveness in defending against missiles.

The future anti-ship missile, in its hypersonic high-g maneuvering variant, is necessarily thin-skinned. This means that lasers will be able pierce them and ignite solid propellant, spill liquid fuels or cut the airframe into an unsustainable shape. At such velocities, even minor imperfections can crush the missile. 

Lasers have a practical zero flight time, meaning they hit the target as soon as it is detected. Unlike a CIWS gun mount that has to predict the missiles trajectory for slower bullets to intersect and intercept it, a laser defense requires no prediction, only tracking.

"We expect that in the future, a missile will not be able to simply outmaneuver a
a highly accurate, high-energy laser beam traveling at the speed of light," Chief of Naval Research Rear Adm. Matthew Klunder said.
Tracking a missile is also easier, since unlike a 5.7 ton CIWS gun mount that has to be skewed to point ahead of the missile, a laser only needs its comparatively lightweight optics to be rotated. 

A CIWS gun system has to be installed for each possible attack vector, while a single laser generator can feed a beam to multiple optical mounts.

With the correct optics and wavelength, a laser can instantly start shooting at a target at the edge of a 20km horizon, while bullets will never reach that far, therefore vastly increasing the defensive perimeter.

Lasers can also extend to denying the defensive perimeter to aircraft. Aircraft are unlikely to be able to retaliate with a destructive beam in return unless there is a major breakthrough in energy production and density.

The second is railguns.

Railguns are not a mature technology, but like lasers, are a near future technology that will enter the battlefield and profoundly change naval warfare. 

Over-the-horizon range is expected to be over 300km
Railguns deliver projectiles at extreme velocities to extreme ranges. The basic projectile is a metallic slug with radio-controlled fins, allowing it to be 'guided' in a sense over the course of its flight. 

At short ranges, it is extremely effective. It can reach the horizon in a matter of seconds, which means it can take down even supersonic aircraft as a very effective AA gun, or throw a cloud of shrapnel in front of an incoming cruise missile before it starts its final sprint. 

At medium ranges, it can replace missiles in the anti-ship role, since the small, solid projectiles cannot be easily shot down with lasers or intercepted with missiles.

At longer ranges, it can serve as artillery. With a rocket motor attached, it can reach an enemy ship from ranges rivaling dedicated anti-ship missiles, and act as ballistic warheads on re-entry (the rocket engine would ignite at the edge of the atmosphere, where air would not impede an increase in velocity from Mach 5 to Mach 10+). Alternatively, it can use the rocket engine to produce thrust-lift and to overcome the drag losses that result from travelling through lower altitudes and with high-g maneuvers. This would allow it to become a hypersonic kinetic-kill projectile that cannot be shot down by lasers.

Rocket-assisted XM1113 artillery shells. 

How will naval warfare evolve?

Railguns will extend the warship's reach to ranges only expected of cruise missiles. However, the addition of laser defenses means that while an anti-ship missile can have even longer range or flight time, it will be shot down in the final stages of its trajectory.

Aircraft will be relegated to smaller and smaller roles - specialized stealth bombers with poor flight performance, or high-performance interceptors. Neither needs to be carried out to sea, so the aircraft carrier as a dominant force will disappear.

Missile destroyers, that would have already replaced them in smaller navies entirely, would quickly be outclassed by railgun-equipped and laser-defended warships. Both can defend themselves from each others' missiles, but the railgun rounds, especially of the sea-skimming, rocket-boosted variant, can penetrate laser defenses much more easily. 

Other changes will be made. Advances in automation will reduce crew sizes drastically. Improvements in computer performance and sensor sensitivity means that radar technologies will remain ahead of stealth for the near future. 

However, many of the modern technologies remain. 

For non-boosted railguns, the only way to increase range is to increase muzzle velocity. An upper limit in energy requirements and airspeed survivable by the projectile will quickly be reached. This is especially aggravating since the majority of a projectile's kinetic energy is lost in the dense lower atmosphere if pushed to velocities much above Mach 7. Rocket-boosted projectile can increase range without requiring higher muzzle velocities, but weigh more.

This means that conventional missiles are required for long-range (500km+) engagements. 

Ballistic missiles, naturally shielded against re-entry heating with ablative materials, are likely to survive laser defenses. This means systems such as the Aegis Ballistic Missile Defense System will still be in use.

The Battleship of the Future 

Incredible concept art from UCL Ship Designs
Like the Zumwalt resembling its ancestor, the significance of the railgun will return naval warfare to a state slightly reminiscent of battleship supremacy.

In WWII, battleship guns could shoot beyond the horizon, and were armored against similar sized projectiles. The ships were built around their armament.

The future battleship also has guns that dominate the sea, and is built around providing the guns the necessary electricity and protection from aerial threats.

In the image above, the 'advanced hullform' is an extension of the bulbous bow concept. The lasers are mounted on top of the masts to extend the laser's horizon. It also has the benefit of shooting down on seas-skimming missiles, and therefore being able to shoot the thinner-skinned sides (and a larger target profile). Automation reduces the crew required, and increases mission endurance.

UAVs and rotorcraft do not need a large flight deck, but can vastly increase mission capability and provide anti-submarine warfare capability.

Here is another concept image of a laser and railgun equipped warship, but with a more conventional hull:

Based on the Type 45 destroyer.

15 comments:

  1. 5000 rounds a minute on the Phalanx, not per second...

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  2. I will post some thoughts when I have time, but I do have one initial question: how might a beam network (terrestrially based, with a link to a powerful energy grid) affect any of this? If it could vapourise rail slugs and badly damage surface warships, might there be room for semi-submersible craft with their own ability to redirect beams from friendly land based laser systems?

    Would you say there is any room at all for submersible craft in the next few centuries?

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    1. Terrestrial-based beam networks are not going to be very long ranged. In the time scales described, megawatt-scale lasers will appear. The necessity of traversing the thickest, most humid layers of the atmosphere means that you cannot use short frequencies either.

      The second problem is actually putting the mirrors near the target. It would require a network of balloons at high altitude that are somehow immune to 200km/h winds, then directed to a loitering drone near the target. All components of the system are very vulnerable to counter-attack.

      What is likely, however, as laser power increases to the point where it can effectively shoot to the horizon, is that each ship is able to launch a small fleet of drones to start taking down missiles in the 20-100km range. They'd form a portable laser network, short-lived but effective over the course of an attack.

      Damaging enemy warships is a whole different level. At such short ranges, lasers will lag behind kinetics in terms of effectiveness for a very long while.

      Submersible craft will gain more and more importance as time goes on. While I cannot seriously predict how things will play out over the course of centuries, I do know that modern technologies are eliminating submarines' weaknesses one by one. They are already so hard to detect that they're bumping into each other. Their endurance can be increased by closed life support systems, until the point where they are surpassed by entirely autonomous drone subs. Supercavitating torpedoes make their attacks as swift as missiles. The fact that they can dive out of the way of missiles makes them invulnerable to developments in hypersonic missiles....

      As time goes on, and space warfare becomes prevalent, their utility increases again. They are mobile, unlike ground bases, and protected against nuclear and orbital strikes. They can rise, launch a surface-to-orbit missile, and dive again before a spaceship can counter-attack with kinetics. Lasers have a very difficult time traversing the atmosphere, and are mostly stopped by the first meter of water, so counter-attack becomes difficult.

      With the sea as a heatsink, and having less stringent requirements, they will likely outlast an invading fleet too!

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    2. Laser webs less useful on earth? Sheesh, I have a lot of research to do!

      At rocketpunk we were somewhat interested in how small/disposable warships might get. I settled on some mothership craft with smaller drone corvettes with them. Me and someone else (Jollyreaper?) speculated on whether a post-scarcity civilisation might create large nuclear sub fleets as now, just in greater numbers (no need for magitech with something so destructive already being available).

      One weakness I am interested in knowing more about is their vulnerability to damage. Would multiple hulls inside each other like with the Typhoon class help?

      My future history has subs dominant for at least 400 years until a hydro-foil gravity shielded frigate gains prominence (shaped change torpedos just get a little too powerful and so going into compressible air is the only way forward)*. Until then though its technological oscillation over the centuries between large 'dreadnought' subs with redundant hulls inside each other, and smaller frigate subs that are a little more manouverable. Might change the preceding rail gun frigates into railgun battleships instead.

      If aircraft carriers are around when battleships shock back into military relevance, it might be amusing to see attempted conversions to battleships, a bit like the Lexington and Saratoga in reverse.

      Lastly, do you have any sources for all your information? I'm trying to brush up on the numbers game but it is proving very difficult due to time constraints (as you saw from my lacklustre articles on naval combat I send you some time ago). there is a lot to improve on and I am trying to get that in gear.


      *That said, I do think a little handwavium is ok, as a nod to a 'realistic' development of civilization on grounds we might not expect or consider fantastical, hence elements of gravity control as the 30th century approaches.

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    3. Laser webs are firmly the domain of science fiction, so there isn't much material to research. However, we can apply current knowledge to conjecture on advantages and disadvantages.

      Surface warships are limited by the minimum size required to safely clear the waves generated by a storm. If they are too small, they will be flooded by such waves. I believe the smallest powerboat to cross the Atlantic was about 20 feet (6.3 meters) so I do not think warships cannot get much smaller than that.

      For submersibles, the minimum size is much smaller, since they only have to counter the force of the currents. Something as small as soda-cans can do that if powered by advanced energy sources, but the problem then becomes finding a use for a craft that small.

      The pressures at crush depth would be a useful benchmark for assessing how resistant a submarine is to external forces. For a Seawold class submarine, this is about 500m/50MPa. This isn't very much, considering that it will be even more vulnerable to uneven pressure. The multiple hulls of the Typhoon class increase survivability through redundancy.

      A dedicated aircraft carrier is unlikely to be able to be converted into a gun-centered battleship. Certain design constraints (such as power requirements, turret mounts, ammunition reserves) would require such an extensive overhaul that they would need to be turned into a completely new ship.

      I can provide sources for most of my 'real world' information, by ca only give you the theory I based my conjecture on for the rest. Numbers are very setting-specific, and in story-writing, can be swept under the rug if you decide to manage scale-ability and balancing instead.

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    4. To be honest I can only imagine an aircraft carrier being converted if laser defences are shown to be unexpectedly effective, as with aircraft during ww2. If you stripped out the elevator and mounted a recoilless weapon (missile launcher, laser cannon) then you could create a large point defence ship. PPersonally I think the real difficulty would be mounting the fire control radars etc depending on how much wiring their require, how specialised and large a fire control computer is, and whether CeC is shown to be effective in the next few years. Other than that you are right- a 'dreadnought Nimitz' is a fantasy.

      I'm not sure a trimaran hull would be useful as the reduce total interior space. Would a set of outriggers be better? With those you'd get a lifting effect and also the benefit of less mass devoted to the effect (not to mention you could just drop them if they get damaged- whipple armour perhaps?).

      Lastly (and this is perhaps the most important question) what armour could defend these craft. If armour isn't useful, the likely-hood of smaller ships that are expendable rises (hence my previous comment).

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    5. A few points of interest here:
      First, it would not be too difficult to design and build a small surface vessel that can't be flooded. In fact, such a small craft was built be a distant relative of mine over 100 years ago. It was called the Brudegget (brude egg), and was designed as a life boat. It is the basis for many lifeboats still in service. It would not be difficult at all to build a drone surface craft using the brudegget design withonly a meter length. The limitations on length are not due to flooding, but due to the useful volume (if you have a crew, you need supplies to support that crew.
      Second, refitting a carrier would not actually be as difficult as you suppose. The real question is why would you want to. Interestingly, the first aircraft carriers were built from refitted destroyer and battleship hulls (notably the Lexington and Saratoga, used in WWII). Refitting in the other direction would not be difficult at all. The hanger deck spaces would easily support the barbets for turrets, and the weapons magazines. Alternatively, they would house missile magazines to supply launchers, or perhaps a giant salvo of VLTs. All that is really required is to remove/convert sections of the flight deck. If you had the VLTs, it is even feasible that you could place them in locations that don't interfere with catapult launches or landings.

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  3. One minor correction: the CIWS is a system that integrates detection and target tracking with a weapons platform, specificly designed for point defense. The weapons platforms are often AA guns, but many support AA missiles (and only AA missiles) as well. The distinction bewteen CIWS and other point defense systems is that it removes the intermediary involvement of humans between the detection and tracking phase and the weapons engage phase.

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    1. I never made the distinction before, thanks. I've always referred to CIWS and point defense interchangeably, and I think it is the case in practise, but I can see how the differences will matter if the data is unreliable or if the political consequences are great.

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    2. Actually, the point I was trying to make is that both guns and missiles are used in point defense, and are both used by CIWS. The "Close-In" aspect of CIWS defines it as a point defense system, so you were not entirely wrong on this point (it is not exactly interchangeable with "point defense" because there are other point defense systems that are not CIWS (for example, although I might be mistaken, Oerlikon is not a CIWS... Oerlikon is a very old model of AAA, but it is ntirely possible that the Oelikon model was adapted for CIWS, so I don't really know if you were right or not).
      Phalanx is the most famous CIWS, but there is another CIWS that uses a SAM version of the Sparrow, usually in a 4x3 launcher. There is also another version of CIWS that uses heavy AAA (not gattling type guns).
      Outside of the point defense aspect, the feature that defines a CIWS is that the detection and tracking systems are directly integrated into the weapons platform.

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    3. I believe the heavy AA guns you refer to are 35mm and 49 cannons with airburst rounds.

      Your last line got me thinking: would next generation warshios be built around their poimt defenses, instead of the other way around? As in, a central mast with millimeter radar on top, and a 360 degree gun and missile platform that can elevate and depress nearly vertically.

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    4. Yes, the 35mm guns are an example.

      No. Point defense systems will always be built around the object being defended. This is because whatever you build around the point defense creates a shadow zone that the point defense can not protect. Also, point defense systems are generally designed to strap-on. This allows the actual number of such systems to be increased or decreased according to need, allowing for multiple targets to be engaged simultaneously. The idea of the tower does not work very well in practice because it makes a nice target that can easily be cut down (no need to hit the weapons turret when you have a nice section of mast to target).
      In peacetime operations, most large vessels mount 4 CIWS. In wartime operations, these would be augmented to as much as 40, on a large vessel. The Iowas typically mounted well over 120 AAAs (Oerlikons and Bofors) during wartime, but reduced this number to about 20 in peacetime, which were replaced by 4 CIWS once the latter were put in service.

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  4. Sorry for the necro reply, but have just discovered this site (and am quite impressed overall).

    While laser and railgun weapons are going to be the premier systems in the near and mid future for military forces (land, sea and air); the idea of tying these to ships or ground systems is dependent on the need for large generators and cooling systems. Realistically, the best possible platforms for these systems is on an airborne platform.

    While you pointed out that balloons, blimps and other aerostats have limitations, they would be useful as low cost sensor platforms to provide a persistent "bubble" around a formation or battlegroup. A UCAV (or more likely a squadron) orbiting overhead with more sensors and weapons (combinations of lasers, railguns electronic warfare systems and missiles) provides the firepower, since they can look down and shoot down on targets from a greater distance. Self defense systems on ships or AFV's would literally be designed against shots taken at "point blank" range (like an infantryman firing an RPG) rather than incoming long range weapons.

    Ships and AFV's protected by such systems "could" provide power to the orbiting UCAV's by beaming microwave energy to them on their patrol orbits, but the UCAV would fire up the on board engines to engage in combat. This provides 24hr coverage without risking the UCAV running out of fuel or energy , and limiting the need for other support like airborne tanker planes. The UCAV has enough on board energy (turbine engines are quite powerful and compact), sensor area (spreading sensors along the wingspan and length of the fuselage provides a distributed array with 50 or more square feet of area) and cooling (using the moving airstream over the radiating surfaces).

    Future warfare on Earth could resemble some of the scenarios discussed about space combat, with ground or surface naval forces primarily existing to conduct up close and personal tasks (PSYOPS Messaging, boarding and inspecting ships) while also acting as spotters and fire controllers for the overhead UCAV squadrons.

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    1. Welcome, welcome. No necroes here, I watch all threads.

      You make some good points, especially with beamed power. Ships might end up being optimized as floating power stations, with all weapons distributed among flying and orbital platforms.

      Near future UCAVs might drop the U, amount a hybrid beamed/turbine power system.

      Under beamed power, they can operate indefinitely, but the range of a microwave phased array power transmitter forces them into a defensive role. To attack, to operate independently or if extra power is requires, it will burn onboard fuel through a turbine.

      On the other hand, more effort might be made into creating stealth blimps, made of materials transparent to Radar...

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