Below The Thunders Of The Upper Deep

Kaiju¹-class submarine battleship

Builders:

  • Ethring Iron and Steam Works
  • Sukórya Graving & Drydocks
  • Telírvess Naval Yards
  • Captal Daëntry Naval District
  • Ambríël Electric Boat Manufactory

Displacement: 72,830 long tons (standard)

Length: 312 m
Beam: 24 m
Draft: 14 m

Propulsion:

  • 2 x Empire Nucleonics, ICC “Fluoride Chowder” high-temperature circulating molten salt reactor, driving
  • 4 x Blackstone Industries, ICC Brayton-cycle gas turbogenerators, powering
  • 4 x Ambríël Electric Boat Manufactory, ICC magnetohydrodynamic impulsors
  • Bow and stern magnetohydrodynamic maneuvering thrusters
  • Bow and stern navigational X-planes

Speed: 36 knots
Range: Unlimited (6 year refueling interval)

Maximum Depth: 1,000 m

Complement: 232 officers and men (including small craft and flag)

Sensors:

  • Hydrodyne Group Mk. 58/1 passive area-awareness conformal sonar
  • Hydrodyne Group Mk. 58/3 active seeking sonar
  • GenTech Alaercíma Prickleback Mk. 4 lateral-line electrodynamic sensor stripes
  • 8 x GenTech Alaercíma Minnow-class reconnaissance/maintenance UUVs
  • Artifice Armaments, ICC CSR-62 combined search radar
  • Imperial Navy Mk. 55 gun director with combined fire control radar
  • Scorched Earth Infosystems Variant 92 electronic warfare suite
  • Optronic periscope incorporating laser satcom and local-area radio
  • GenTech Alaercíma Intersub Communications System (milspec)
  • 4 x low-profile deployment buoy,
    for 12 x Clockwork Souls, ICC NL-R132 Overseer reconnaissance drones

Armament (Primary):

  • 360 x VLS cells for Artifice Armaments, ICC MS-96 Naginata long-range multipurpose missiles
    (4×72 and 2×36 strips of cells)
  • 9 x torpedo tube for Artifice Armaments Mk. 62 Blowfish heavy supercavitating torpedoes
    (6 forward tubes, 3 stern tubes)

Armament (Secondary):

  • 3 x 384mm superheavy mass driver in single triple turret (usable only when surfaced)
  • 8 x Artifice Armaments, ICC Peacebringer rapid-firing point-defense laser (usable only when surfaced)
  • Eye-in-the-Flame Arms, ICC Wub-Wub sonic implosion system, 6 transducers
    (replaces 6 x Artifice Armaments, ICC supercavitating anti-torpedo microtorpedo launchers used on first four boats)
  • 4 x Steelfist Armored Security and Escorts, ICC Thresher-class squidfighters
  • 4 x sonar decoy launchers

Armor:

  • 4″ spinmetal-composite layered outer hull
  • Cosmic Defensive Technologies, ICC internal kinetic barrier hull reinforcement system
  • Multilayered torpedo defense system placing subdivided tanks and batteries behind outer hull
  • Biomimetic internal shock-absorption framework
  • Anechoic tiling

Other:

  • 4 x Serannis Escape Systems, ICC Su60/200 60-man escape capsules
  • 2 x GenTech Alaercíma Pike-class militarized transport minisub
  • Flexible payload/diver deployment module

The design of the Kaiju-class (and indeed the submarine battleship concept overall) was a product of a convergence in designs following the Fifth Oceanic Dominance. It did not escape maritime architects of the era that designs for the first post-Fifth generation of surface battleships had adopted a missile-dominant loadout and a flattened profile which brought them increasingly close to the guided-missile submarine in overall design. An experimental design project, designated RAGING DOLPHIN, was initiated to consider merging the next generation’s BB(X) and SSS(X) designs into the type that would become the BS(X). The Kaiju-class submarine battleship represents the first evolution from that prototype.

As large as any surface battleship, the Kaiju-class hull follows the general flattened ovoid shape common to large submarines. As is the usual case in submarines of its era, the Kaiju lacks a sail, but does have a slight turtleback at the bow, making it resemble a whale in overall shape. This hump houses the scanning periscope, communications and radar masts, for’ard entry hatch and navigation bridge, and at its foremost extent, the retractable fairing concealing the Kaiju‘s single mass driver turret. Its aftward extent houses two of the four emergency escape capsules.

Unlike smaller submarines with a single pressure hull occupying the centerline of the fairwater hull, the Kaiju has six connected pressure hulls. The two largest run down the midline of the submarine, the smaller crew facilities hull (since it is flanked on either side by the forward VLS cells, 2 x 36) stacked directly above the larger, triple-decked, auxiliary machinery/storage hull, which continues both aft (below the aft VLS cells, 4×72) and forward beyond the former to the for’ard torpedo room. Directly behind the for’ard torpedo room, the auxiliary machinery hull encompasses a flexible payload/diver deployment module, whose lower section can be pressurized to make use of a moon pool behind a retractable flush cover. Four of the eight reconnaissance UUVs are stored here.

At the aft extent of the crew facilities hull are the other two emergency escape capsules, immediately preceding twin hatches for the deployment of the drone buoys and a cargo loading hatch giving direct access from the deck to the storage space located in the auxiliary machinery hull.

Above the auxiliary machinery hull at the bow, beneath the turtleback, is the command center hull, containing the Kaiju’s control room, flag bridge, and computer center.

At the stern, a fourth pressure hull serves as the hangar, containing berthing for the minisubs, the squidfighters, and the remaining four recon UUVs, along with the aft torpedo room below, while slightly forward of this are the dedicated port and starboard drive hulls, each containing one of the boat’s reactors, the associated turbogenerators, and machinery associated with the magnetohydrodynamic impulsors, along with (duplicated) maneuvering rooms, either of which can control all power and propulsion-related systems. Both the hangar and the drive hulls share a common access to the aft entry hatch.

Boats of the Kaiju-class are named after legendary sea monsters.


Footnotes:

  1. Best-fit translation.

And A Desert Topping

Laurë Isilvieré-class battlecarrier

Builders:

  • Ethring Iron and Steam Works
  • Sukórya Graving & Drydocks
  • Telírvess Naval Yards

Displacement: 61,620 long tons (standard)

Length: 268m (waterline); 276m (overall)
Beam: 36m
Draft: 12.2m

Propulsion:

  • 4 x Empire Nucleonics, ICC “Neutron Storm” nucleonic boilers (PWR), driving
  • 4 x 2 Blackstone Industries, ICC high-low pressure turbogenerators, powering
  • 4 shafts x 2 Hammerforge Tool Company, ICC heavy-duty electric drive motors

Speed: 36 knots
Range: Unlimited (6 year refueling interval)

Complement: 1,768 officers and men (including air wing and flag)

Sensors:

  • Artifice Armaments, ICC, ASR-40/2a air search radar
  • Artifice Armaments, ICC, SSR-45 surface search radar
  • Hydrodyne Group Mk. 38/1 passive area-awareness sonar
  • Imperial Navy Mk. 45 Gun Director with 4 x fire control radar
  • Scorched Earth Infosystems Variant 32 (Block II) electronic warfare suite
  • Shimana Aerospace flight control and navigation system

Armament (Primary):

  • 6 x 384mm superheavy mass driver, in two triple turrets
    (A & B both forward of primary superstructure; B superfiring from deck 01)
  • 96 x VLS cells for Artifice Armaments, ICC MG-60 Sarissa long-range missiles
    (1 x 72 and 1 x 24 blocks of cells; supports multiple types; land-attack and/or AShM)

Armament (Secondary):

  • 8 x 96mm Imperial Navy Type Nine dual-purpose heavy mass driver, in four twin turrets
    (surrounding the primary superstructure)
  • 6 x Artifice Armaments, ICC Deathray rapid-firing point defense laser
  • 16 x dedicated launchers for Artifice Armaments, ICC MG-34 Spar medium-range AShM
    (arranged 4 x 4)
  • 16 x dedicated launchers for Artifice Armaments, ICC MA-98 Hawkeye medium-range SAM
    (arranged 4 x 4)

Aircraft:

  • “V” dual flight deck aft, single elevator, 2 x electromagnetic catapults
  • 12 x N5-5I Ripper multirole V/STOL attack aircraft
  • 12 x Clockwork Souls, ICC NL-I40 Purity interceptor drones
  • 12 x Clockwork Souls, ICC NL-R36 Spyglass reconnaissance drones

Armor:

  • Belt: 12″ spinmetal
  • Decks: 8″ spinmetal over machinery and magazines
  • Turrets: 9″-18″ spinmetal
  • Conning tower: 12″ spinmetal
  • Secondary systems: 8″ heavy steel plate
  • Elsewhere: 0.5″ heavy steel plate

The Laurë Isilvieré-class battlecarrier was a product of the post-Fourth Oceanic Dominance environment. While the Fourth had proven the supremacy of the BB/CV hybrid battle group over the battleship-centric doctrine of the Second and Third, the post-Dominance environment left the Admiralty confronting a single inescapable fact.

The hybrid battle group, while unparalleled in its strength and flexibility, was also unparalleled in its expense, both to construct and to operate. This was a matter of considerable concern, since the Admiralty was now required to exercise command over a considerably greater area of ocean than had previously been the case, and the events of the Third Dominance had demonstrated the vulnerability of a fleet in being.

While battlecarrier designs had generally been dismissed as inefficient (critics noting quite correctly that a direct medium-range combatant such as a battleship had mission requirements quite contrary to that of a indirect long-range combatant such as an aircraft carrier), studies suggested that combining the functions of the primary vessels of the hybrid battle group, along with a reduced number of escorts, could create a low-intensity battle group suitable for exercising sea control in secondary theaters, enabling the full hybrid battle groups to be reserved for more demanding missions. In this role, their inefficiency would be compensated for by their economy.

Thus the Laurë Isilvieré-class battlecarrier came to be, combining the forward turrets and missile loadout of the Invictus-class battleships with an aft-mounted flight deck and hangar based on those of an escort carrier. Operating in low-intensity battlegroups accompanied by a limited number of escorts (typically a single cruiser, a pair of destroyers, and a pair of attack submarines), they and their successors kept the Imperial Star flying over Eliéra’s oceans until the end of the Consolidation.

Ships of the Laurë Isilivieré-class are named after Imperial Hands, befitting their nature as agents competent in multiple roles.


(Notes for those paying attention:

This is about two generations removed from the Ulricik Bancrach-class destroyer and a little ahead of our state of the art, hence the coilguns and the laser CIWS. Various aspects of its design were inspired by the proposal for the Phase II refit for the Iowa-class battleships, which can give you a general idea of what a Laurë Isilivieré-class might look like – except that, being nuclear, they have no stacks. Also, they wear dazzle camo, because dazzle camo is cool.)

Amphisbaena

Amphisbaena-class battleship

“Half ahe… that way.”

– Capt. Olavi Corel, first captain of Amphisbaena

Displacement: 125,000 long tons

Length: 330 m (at waterline: 316 m)
Beam: 84 m (at waterline: 48 m)
Draft: 12.1 m

Propulsion:

4 x Empire Nucleonics, ICC 64 MW “Fat Salamander” fission reactors
8 x Blackstone Industries, ICC steam turbines and reduction plant
In-house magnetohydrodynamic “inchworm” drive system

Speed: 42 knots (non-sustainable emergency power: 48 knots)
Range: Unlimited; 12 year refueling interval

Complement:

1,672 officers and men
Thinking Machines, ICC “Admiral Aliniv” Command Optimization Thinker

Sensors:

Artifice Armaments, ICC, ASR-24/3 air search radar
Artifice Armaments, ICC, SSR-36 surface search radar
Artifice Shadow Works X-449 imaging lidar
Hydrodyne Technologies, ICC, “Long Ear” sonar suite
Tactical interweave uplink

Armament (Primary):

6 x Artifice Armaments, ICC 22″ “Big Howlin’ Bitch” railgun
6 x triple Artifice Armaments, ICC, 16″ “Little Sister” railgun

Armament (Secondary):

24 x Artifice Armaments, ICC 9″ “Poniard” conventional gun
36 x Firefly Aerospace, ICC “Waterline” anti-ship seeking missile
36 x Firefly Aerospace, ICC “Gentle Touch” target-finding missile
8 x Eye-in-the-Flame Arms, ICC “Pesticide” automated threat protection system

Armor:

Citadel: 24″ layered C-allotrope/alloy composite; equiv. 53″ steel
Main turrets: 18″ layered C-allotrope/alloy composite; equiv. 39″ steel
Elsewhere: 12″ layered C-allotrope/alloy composite; equiv. 26″ steel

Aircraft carried:

16 x Stonesmight Automata, ICC “Tattletale” scout drones
16 x Stonesmight Automata, ICC “Fleshharrower” attack drones

The four Amphisbaena-class battleships were the last fast battleships laid down by the Imperial Navy (note: the “wet” navy of the era, not its space successor), and participated in a number of military actions including the last battles of the Consolidation to take place on Eliéra proper. They are widely considered to represent the pinnacle of the naval architect’s art, and the furthest development of the “wet” battleship as a class.

The design of the Amphisbaena-class, in keeping with the mandate the IN inherited from the Alatian Navy’s Weapons Development Board, was to produce a vessel that would utterly outclass any opponent against which it was set. Thus, the class carries six 22″ railguns – of a model designed to be scaled down for naval use, rather than used as is – in addition to its six triple 16″ railgun turrets and conventional armaments. This same approach led to the inclusion of the eight “Pesticide” automated threat protection systems, capable, once activated, of automatically reducing anything not tagged as friendly approaching within a mile of Amphisbaena, above or below the water, into chaff and charnel.

The final development of this approach was Amphisbaena‘s magnetohydrodynamic “inchworm” drive. While the primary characteristic of this type of drive is its quietness, and thus lower sonar profile, in the case of Amphisbaena, it was selected because its lack of the issues associated with high-performance propellers, coupled with an otherwise oversized power plant, enables Amphisbaena to reach the otherwise unprecedented – for a ship of its displacement – cruising speed of 42 knots.

It also has the advantage of functioning equally well in either direction, and this – combined with the ability to divert water to side outlets at both bow and stern – gave Amphisbaena unparalleled abilities not only to change heading 180° without turning at all, but also to decelerate, to turn in its own length, and to keep station – making it an incredibly stable gun platform.

It is also to this drive that Amphisbaena owes its entirely symmetrical hull profile and superstructure, since the designers felt no need to inflict the notion of a preferred direction on a ship which otherwise would have lacked one. Despite the quotation above, officers and men serving on Amphisbaena-class ships rarely had difficulty telling the bow of the moment from the stern when the ship was under way, but it is nonetheless true that a red-blue color gradient was added to the bridge paintwork after Amphisbaena‘s sea trials to make end from end clear when moored or hove to.

On the Role of the Dreadnought

Just to clear up a few misconceptions that may have crept in:

David Weber, alas, has done me no favors by convincing much of the SF-reading world that the standard interstellar badass is the dreadnought.

And, yes, you may remember me saying “it sure would be nice to build nothing except dreadnoughts [for ships-of-the-plane]” back when we discussed ship types, but what I did not say is that if they did, they wouldn’t be dreadnoughts. They’d be battleships, because the modal ship classes for engaging in big set-piece space battles are always designated as battleships. Says so right in the name. Battle. Ship.

Or, to put it another way, there are a lot fewer dreadnoughts than there are battleships. (And a lot more cruisers than there are battleships, for that matter, because most missions don’t have any major fleet engagements in them. But that’s another story, already told.) This is principally for economic reasons: when you examine the requirements for a ship of the plane, the battleship sits right at the bang/buck sweet spot, so that’s what you build.

A dreadnought (and to an even greater extent, a superdreadnought) has four virtues, which is why they’re built at all:

  1. It benefits in internal space from volume increasing faster than surface area, which makes it a convenient class to carry extra stuff, from complete flagship suites through shipyard-class repair facilities for its cohorts and prisoner-of-war blocks to all that is required for the many, many specialized variants on the books.
  2. It can afford a hell of a lot of extra armoring, so you are significantly less likely to get your admiral shot off and your fleet coordination suffering if you give him a DN to ride around in.
  3. It can mount a Really Big Gun of the kind you’ll rarely need to use, but you might miss if you didn’t have any of in your plane of battle.
  4. It’s bloody terrifying. When naval architects are told to draw up plans for a DN or SD, the unspoken requirement is that it dominate the battlespace like Conan the Barbarian at a convention of preadolescent pacifists: it dreads nothing, and everything dreads it.

So there aren’t all that many in service, relatively speaking. There don’t have to be – say, speaking non-canonically and off the back of the envelope, eight squadrons in the Capital Fleet (mostly in the Sixth Flotilla, which is the IN’s heavy-hitting force), four squadrons in Home Fleet, two for Field Fleet Spinward (which borders on the Seam), and one for each of the other field fleets: say, 228 in total, not counting specialist classes and the reserve.

You can assume at least four times that in BBs.

 

Ships of the Fleet

So, in today’s piece of worldbuilding, have an analysis and explication of the different classes – or the different types, rather – of military starships operated by the Imperial Navy. (The basis for the ternary plot I’m using is, of course, Winchell Chung’s analysis here, so you might want to go read that first if you’re not familiar with the concept, then come back here.)

Types

shipgrid05The chart on the right illustrates the differences between the various types and classes of warship in common use by the Imperial Navy by their P/D/W ratio – i.e., the relative trade-off between propulsion, defenses, and weapons (i.e. offensive armament):

“in common use” should be read as “not counting all the weird-ass specialist ships we build for special cases”; also, it doesn’t include auxiliary vessels (oilers, hospital ships, etc.) since they’re not operated by the IN, but by the Stratarchy of Military Support and Logistics.

Battleships, Dreadnoughts and Superdreadnoughts

“I am an Imperial Mandate-class dreadnought, and you are within a million miles of me. Ergo, you continue to exist solely on my sufferance.”

an early experiment in AI captaincy

Battleships, dreadnoughts, and superdreadnoughts (B, D, S on the chart) are capital or supercapital ships mounting heavy long-range firepower as their primary function.

These types, the ships of the wall, are the kings of the outer engagement envelope, engaging each other with powerful weaponry at ranges of up to two light-minutes, and rarely closing beyond one to two light-seconds range (a zero/zero intercept at this residual range is considered a “set-piece” battle). They are the purest of all naval vessels in function, existing simply to counteract each other in the battlespace of major fleet actions, or to own the volume of space they can dominate if not opposed; the ultimate argument of star navies.

The principal difference between two of the three types is simply mass and volume; doctrinally, the majority of the ships of the wall of any given time should be of battleship classes, with their larger cousins the dreadnoughts providing heavier stiffening formations to the wall and occasional nasty surprises.

Because while it sure would be nice to build nothing except dreadnoughts, even nearly-post-scarcity economics doesn’t stretch to overbuilding everything just in case.

Superdreadnoughts, while sometimes referring to particularly large dreadnought classes, more typically refer to ships falling in the dreadnought type by mass, while using much of their internal volume for specialized systems: typical examples would include the command superdreadnought, the information-warfare superdreadnought, the anti-RKV superdreadnought, and so forth.

Mauler Superdreadnoughts

One example of this listed separately (L on the chart) since its P/D/W ratio moves it well outside the standard range is the mauler superdreadnought. In this case, the specialized systems in question are a very, very large mass driver or laser, with propulsion and defensive systems stripped back to accommodate it.

Mauler superdreadnoughts are not considered ships of the wall, but rather are specialized vessels used to attack specific hardened targets. Since their low speed and weak defenses render them vulnerable “glass cannons”, they are typically operated as part of a task force including close-in point-defense cruisers, and only brought up once opposing fleets and mobile defenses have been cleared away; however, in their specialty role of cracking hardened fixed bases, they’re unequalled.

Hyperdreadnoughts

The “hyperdreadnought” is a peculiarly unique version of the superdreadnought type, of which the Empire fields three, each unique within its class; Invictus, Imperiatrix, and God of War.  In order, they are the home of Admiralty Grand Fleet Operations, the Imperial Couple’s personal flagship, and the literal embodiment of the archai/eikone of war.  Any one of them turning up in the battlespace would have implications that, by and large, no-one wants to think about thinking about.

Battlecruisers and Cruisers

The backbone of the fleet, battlecruisers and cruisers (C on the chart) are middle-weight combatants, more heavily armed than destroyers and frigates, and yet more maneuverable than battleships and larger ships of the wall. Most cruisers also maintain limited AKV facilities. They are perhaps the best balanced (between operational aspects) of any of the Imperial Navy’s standard types. The distinction between cruisers and battlecruisers is simply one of mass and volume, with battlecruisers identifying the significantly larger and heavier classes of the type.

In fleet operations, battlecruisers and cruisers serve as screening elements and operate on the fringes of the close-in battlespace, maneuvering aggressively for advantage. For the most part, however, these middle-weight combatant types are intended for patrol operations and long-endurance “space control” missions, sometimes alone and sometimes in flotillas, as well as serving as the IN’s go-to types for independent missions of almost any type. In areas of heavy patrol activity, cruisers may lead destroyer or frigate flotillas into action.

Cruisers are also the type within which most variation exists, and cruiser classes may wander quite far from the indicated P/D/W ratio. Of particular note here is the point-defense cruiser (“pd” on the chart), the one type which you might see as a ship-of-the-formation, stripped of most of its offensive armament in exchange for point-defense enhanced to the point of augmenting that of other ships, but many other specialized varieties exist: the assault cruiser (optimized for planetary assaults, i.e., heavy on the ship’s troops and capable of launching drop shuttles and drop pods into atmosphere; some of these are aerospace cruisers, which atmospheric interceptors can sortie from before there’s an orbithead established); the diplomatic cruiser (a big stick to transport the softly-speaking); and the interdictor cruiser (specializing in the volume-security mission, which is to say, to chase down, capture and board other starships).  The primary battlecruiser variants are the command battlecruiser (optimized to carry the admiral commanding a CC/BC task force) and the carrier-battlecruiser (which carries AKVs – see below – as well as its internal armament; this is the type of battlecruiser usually found operating alone, due to its significantly enhanced operational envelope and capabilities).

Due to their versatility, the IN maintains a greater tonnage of battlecruisers and cruisers in commission than starships of any other types.

Destroyers and Frigates

Destroyers and frigates (D, F on the chart) are small, fast, maneuverable ships used for screening larger vessels, as escorts, and for patrol work. On their own, their capacity is severely limited, for which reason they typically operate in flotillas assigned together.

As with the above two types, the most obvious difference between destroyers and frigates is their mass and volume. That said, the strict difference between these two types is that while a destroyer may possess very limited broadside armament, due to its limited volume, it does possess it. A frigate, however, possesses no broadside armament; its spaceframe is essentially constructed around its primary gun.

Like cruisers, destroyers and frigates are designed for the “close-in” battlespace – with the understanding that close-in, in space terms, means anything under one light-second of separation. Indeed, these types arguably dominate this battlespace, since they form the majority of the IN’s screening forces, whereas cruisers are largely incidental to “set-piece” naval engagements. In this area, they use their superior maneuverability to both engage each other with wolf-pack tactics and to swarm larger ships at close-in range. Their lesser defensive capabilities than their larger cousins reflects the intention that they should substitute speed and maneuverability, avoiding being hit, for the ability to withstand taking one.

Destroyers and frigates are also intended to serve in escort and patrol roles in relatively safe space, where antipiracy patrol is the main concern (a flotilla of destroyers or frigates is considered an effective counter to a single cruiser-class vessel, which would be a rare high-end encounter under such circumstances); and in small numbers and specialist classes as scouts, avoiding engagement entirely.

Some frigate classes, uniquely among naval vessels, are capable of atmospheric entry and landing. Such frigates occasionally serve an additional role with Imperial Naval Intelligence.

Autonomous Kill Vehicles (AKVs)

AKVs (A on the chart) – autonomous kill vehicles – are extremely smart multi-bus, multi-munition, multi-mission missiles. An AKV is, in effect, a small, stripped-down, AI-piloted starship – capable of much higher acceleration and greater maneuverability than a standard design, albeit with much less endurance – designed to act in multiple roles: as a mobile reconnaissance platform; as a “fighter craft” used to swarm and destroy larger starships from inside their own point-defense zones; or, when it loses all other fighting ability, as a kinetic energy weapon in its own right.

As indicated on the chart, AKVs have essentially no defensive weapons of their own; the intent is that they should substitute their vast advantage in speed and maneuverability for armor and point-defense.

Monitors

A monitor (M on the chart), in essence, is a fixed base – an orbiting station or asteroid base – used for local defense. Their W/D ratio is skewed more towards defense than the ship-of-the-wall types, since unlike those, they lack even minimal maneuverability to avoid incoming fire or to retreat from the battlespace; on the other hand, their lack of concern for acceleration or other propulsive matters means that there is effectively no upper limit on the mass of the weapons or defenses that a monitor can mount, and asteroid-based monitors may make extensive use of the asteroid’s mass as armor and heatsink both.

Carriers

Carriers (V on the chart) are battleship or dreadnought-sized vessels which eschew armament of their own in exchange for carrying a large number of AKVs, along with AKV replenishment supplies, strap-on AKV thruster packs, observation platforms, etc. Since they are not generally maneuverable enough or well enough protected (the massive flight deck of a carrier is essentially a corridor through the armor into the heart of the vessel) to survive heavy attack, they are usually held back from engagements, and as such their designs heavily emphasize point- and local-space defense over additional propulsion.

Assault carriers

Assault carriers – i.e., those carrying dropships rather than AKVs – also fall into this category. The same general operational rules apply; they are held well back from any engagements, and do not move in to the target area until the high orbitals have already been cleared of the enemy.

Starfighters / Scouts

Starfighters (“sf” on the chart) are not manned fighter-class vessels. (The intersecting rules of physics, economics, and tactical effectiveness do not, in the general case, support a fighter-class of spacecraft in direct analogy to fighter aircraft. Rather, such craft can be replaced trivially by an equivalent vessel removing the biosapient pilot, their life support, and the ensuing limitations on maneuverability, acceleration, and computational performance, and replacing them with a computronium block; in effect, converting the spacecraft into an unmanned AKV.)

Rather, starfighters and scouts are essentially mini-carriers, suitable for operation by a very small crew, or even on occasion a single sophont, dedicated to the special operations and reconnaissance roles. They are small, no-frills starships designed to carry a limited, but still useful, number of AKVs or observation probes in exterior clamps. On arrival at their target, the AKVs or probes are then released to carry out the mission, while the starfighter itself serves as a command post, repair and replenishment depot, and coordination node in the tactical ‘mesh.

Couriers

Couriers (“o” on the chart) are simply militarized (in construction standard) versions of the equivalent civilian type. While remaining, for the most part, “all engine”, military couriers add limited defensive and extremely limited offensive capability to give them at least minimal survivability in the event that they must pass through an engagement envelope; doctrine, on the other hand, demands that couriers should avoid engagement at all costs utilizing their superior acceleration and maneuverability to any other warship type.

Trope-a-Day: Standard Sci-Fi Fleet

Standard Sci-Fi Fleet: Well, most of these classes exist – although it is particularly important to realize that the Empire alone fields literally thousands of specialized class vessels that don’t fit neatly into any of these categories, and that to a certain extent, trying to shove everyone’s ship designs into the approximate same paradigm is an exercise in futility…

Ignoring the permanent city-ships, and starting with the military classes, we have, first, the regular fighting-ship classes.  These begin with the frigate and destroyer (including the latter’s stealthy recon variant), small and fast ships used in “wolf-packs” for scouting, escorts, and screening elements, but which don’t themselves have the resilience or firepower to stand up in the wall of battle.

The middleweight combatants, and the most maneuverable/versatile, are the cruisers and battlecruisers, which also serve as screening elements for heavier ships, but are more often seen as the standard patrol and task-force element, often operating in flotillas (a cruiser wing with a battlecruiser or two thrown in for stiffening) or even independently (especially the battlecruisers).  And since this type of operation (power projection, anti-piracy patrol, general keeping the peace of the spacelanes) is the bread-and-butter of the Powers and their naval forces, most navies, the IN included, field more cruisers and battlecruisers than just about any other type of starship.

These are also classes that come with a large number of variants.  Most recognized among the cruiser classes are the assault cruiser (optimized for planetary assaults, i.e., heavy on the ship’s troops and capable of launching drop shuttles and drop pods into atmosphere; some of these are aerospace cruisers, which air fighters can sortie from before there’s an orbithead established); the diplomatic cruiser (a big stick to transport the softly-speaking); the point-defense cruiser (the one type of cruiser you might see in the wall, designed specifically to augment the point-defense of other ships); and the interdictor cruiser (specializing in the volume-security mission, which is to say, to chase down, capture and board other starships).  The primary battlecruiser variants are the command battlecruiser (optimized to carry the admiral commanding a CC/BC task force) and the carrier-battlecruiser (which carries AKVs – see below – as well as its internal armament; this is the type of BC usually found operating alone, due to its significantly enhanced operational envelope and capabilities).

Then we come to the actual ships of the wall, battleships, carriers, and dreadnoughts.  The battleships are the mainstays of the wall, large and slow vessels mounting heavy, long-range firepower for fleet engagements; and the carriers, even larger vessels, carrying an extensive complement of AKVs (autonomous kill vehicles, the missile/attack-drone fighter-interceptor hybrids described under Space Fighter, to swarm and destroy enemy starships at sub-“knife fight” range – i.e., hopefully inside the minimum effective range of their point defenses).  The dreadnoughts are effectively “super-battleships” built on carrier hulls, used in relatively small numbers to stiffen the wall.

Superdreadnoughts are either dreadnought-class vessels built on even larger hull frames, or regular dreadnoughts with only battleship armament, using the extra internal volume to hold specialized systems; common examples are the command superdreadnought which houses the admiral in charge of a large task force or fleet; the information-warfare superdreadnought; the loadout-heavy mauler superdreadnought, the anti-RKV superdreadnought, etc., etc.

At the top end of the regular classes, we have the hyperdreadnought – taking the design principles of the superdreadnought classes even further – of which the Empire fields three, each unique within its class; Invictus, Imperiatrix, and God of War.  In order, they are the home of Admiralty Grand Fleet Operations, the Imperial Couple’s personal flagship, and the literal embodiment of the archai/eikone of war.  Any one of them turning up on the battlefield would have implications that, by and large, no-one wants to think about thinking about.

Less regular military classes include the starfighter, a frigate-sized mini-carrier with four to eight AKVs clamped to its outer hull, used primarily for covert operations and commerce raiding; the fleet carrier, a giant (and not itself offensively armed) lighthugger starship on the lugger model (see below) whose purpose is to ferry naval task forces to systems not connected to the stargate plexus; the fluffships – whose design is implicit in their name – that police systems for debris, ricochets, and misses after battles; and the relativistic kill vehicles for practicing MAD on an interstellar scale with giant lighthugger missiles capable of shattering planets, given a good run-up.

Among civilian ships, there are also various recognizable classes of starship for different purposes:

For freight transport, for example, one can recognize both the immense grapeships (from the appearance of the external cargo pods) or megahaulers, which transport vast amounts of containerized cargo along the largest and most dependable trade routes, and their smaller cousins the haulers, smaller freighters which handle more volatile but still regular traffic everywhere, and are willing to handle breakbulk as well as containerized cargo, and of course the volatiles-hauling tankers; and finally, picking up irregular and speculative trade and filling in the gaps, the thousand different classes of free traders (and their somewhat more combative overlapping variants beloved of smugglers and irregular commerce-raiding privateers, the blockade runner and corsair.)  For routine transportation of volatiles, ore, and other such bulk and fungible cargo, fully automated slowhaulers often take up the task.

For passenger transport, likewise, we begin with the luxurious highliners and liners – analogous to the megahaulers and haulers in size and usage upon routes, and their express cousins the fastliners.  And then, for those travelling off the regular routes or seeking a more unique experience, a great many free traders are just as happy to carry passengers as they are to carry anything else.  Of course, the relatively wealthy and privacy-desiring have the option to travel in their private yachts, as ever, and at the other end of the scale, steerage-class transport is available to the relatively indigent on any number of iceliners, ships – often used as colonization transports – designed for the specialized task of transporting bodies in cryostasis or nanostasis, and minds recorded on data substrate.

In more specialized uses, dedicated classes abound: when messengers, mail, and packets need to get there really fast, within the stargate plexus at least, engine-heavy couriers are on the job; wrecks, debris, and flotsam are salvaged by debris recovery vehicles; hospital ships provide medical services (and reinstantiation services) to military fleets and disaster or epidemic-struck regions; logistics ships provide repair and construction services wherever they’re needed; oilers and tenders provide fuel, supplies, and other necessities to other starships; science, research, and exploration are done in the ubiquitous, customizable service/operations vehicles; smelterships render down asteroids into usable metal and other elements; and tugs and their larger cousins, the antimatter-torch equipped superlifters, move ships, modules, materiel – and in the case of the latter, entire habitats, asteroids, and even small moons – to where they’re needed to be…

…and if we’re willing to classify flying cities that are as much drift-habitats as starships, then we must include the civilization-backup ships, preserving archives, museums, and mind-states in the far reaches, ready to flee news of existential disasters; All Good Things, ICC, spreading the good word of commerce to underdeveloped regions with its skymalls; the empire ships, massive floating conferences/exhibitions/showpieces/parties flying endless loops around the Imperial Core and its many distant exclaves keeping population, culture, and knowledge well-distributed; and the embassy ships, similar exhibitions paying diplomatic calls on foreign polities and recently contacted worlds, bringing religiosity to the fuzzy-wuzzies and suchlike.

For local transport, small craft abound.  For freight, lighters scurry about transporting cargo ship-to-ship, ship-to-station, and ship-to-ground; for passengers, pinnaces provide the same service, and in moving about between local stations or habitats in a cluster, the automated commutersphere provides rapid transport. Skydivers skim gas giants for fuel; maintenance and construction are carried out by the ubiquitous workpod; and other myriad local functions are served by the flexible, customizable cutter.

All of these, of course, exist within the framework of the stargate plexus.  Outside that, a different type of ship entirely is required – lighthuggers need much more powerful engines (antimatter torch drives, for the most part) to reach the high fractions of c that make interstellar travel practical, sophisticated particle shielding to survive it, etc., etc.  Let us leave aside for the moment the shardcruisers (not true lighthuggers, but hybrid ships built to service outposts in the outer cometary cloud of star systems, whose longest-range examples fade into slow, short-range luggers); and also the starwisps, ultra-light – a matter of pounds – light-sail vessels propelled by lasers at their point of origin, carrying information, tangle, or the smallest probes across interstellar space.

These then divide into clippers – high-acceleration, relatively low-mass vessels carrying premium cargo and passengers at the highest possible speeds, including, in the limiting case, the private staryachts of the very wealthiest; and luggers, their relatively low-acceleration higher mass vessels carrying passengers and freight in larger quantity.  Specialized classes of lugger include the shiphauler (designed to transport docked starships rather than cargo directly; the military fleet carrier is an example of this type); the seedship (carrying ecopoesis packages and a startup colony); and the linelayer (transporting one half of a stargate pair to its destination system).