WH40K - Space Fleet

[Mr. Oragahn]

For once, I decided to take a look at a source, albeit a very old one, without establishing a comparison between my observations and those of members of SDN, particularly Connor, who in my opinion tends to display a habit for choosing higher estimates when it is not necessary.
Well, that was before I found that he had already gone through a source containing approximately the same data I was about to analyze on my own. The plan has not changed, but since I found Connor's posts, I'll give the links here and let you go read his and compare what we both understood.
I find it fascinating how our conclusions are so often diverging. His principal issue being that once he had decided that his very first batch of over the top interpretations were what the canon meant, then any calculation or interpretation had to fit his own original codex because that was the way to go, because it was right.
I also noticed that there were some bits he didn't pick up, which is something that has already happened before, but it may be due to the incomplete old data source he used, which seems to have gone down.
Strangely, or perhaps not, those missed elements tend to provide a more moderate vision of the universe in question. Still, considering the difficulty of getting our hands on the original material, it's possibly due to mistakes from the author.

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Interpretations he reused in a SW vs WH40K thread:
http://bbs.stardestroyer.net/viewtopic. ... 7#p1425297

Now, what about the source itself, Space Fleet?
First and foremost, since it was short timed game, and an old one at that, it's obviously hard to obtain a complete copy of the rules and the material nowadays. However, considering the citations are supposedly taken from the real source, and happen to be also present in the two almost identical documents below, I consider those two following sources reliable.

The first source is a website which, among others things, maintains a small archive of more or less old Warhammer 40000 background material, such as Rogue Traders (wherein we have a confirmation that one of the best power production technologies, taken from the STC, at least for civilians, stems from "full-scale nuclear power-grids and fission processors", obviously besting mere combustion plants).
As the source focuses on the background material, the fluff, it leaves out large sections of the game rules.
http://members.fortunecity.com/pangolin ... efleet.htm

The second source is, I suppose, Space Fleet as well, but with apparently ALL game rules coming along, and some differences in the topics that are detailed.
http://www.snapdrive.net/files/349593/B ... 0Rules.pdf
As you can see, it's considered to be a document about the 1st edition Battlefleet Gothic rules. The document itself has been edited between 1997 and 1998.
Some of the most interesting pages begin at index 14 of 77, and deals with weapons, and they're a copycat of the chapters provided in the first source.
This second source appears to lack a large amount of background information, so it's better used as a confirmation that the data provided in the first source can be considered genuine. But it also incorporates lots of details associated to the game rules, so the best thing to do, thus far, is to pay attention to the background archived in the first source, and later on analyze anything that seems new, found in the second source.

Finally, for anyone who has already read a fraction of the BFG rulebooks, it will be abundantly clear that large swathes of the background from Space Fleet has been copied and pasted into the Battlefleet Gothic rulebooks in the bluntest way possible.

Going through all of this will take some time, surely. So let's be patient.

Sidenote: Perhaps of interest, this page has plenty of shots of old miniature figurines, including Epic and Space Fleet. They'd prove useful to get an idea of the size of some of the weapons mounted on the spaceships, especially when you start comparing firepower to volume.

Edit: repaired a broken link.

[Mr. Oragahn]

Space Fleet by Jervis Johnson, Andy Jones, Simon Forrest & Rick Priestley (White Dwarf 139 &140)

SPACE FLEET

Detailed background information.

WORLDS OF THE GALAXY

...

THE IMPERIUM

Stellar empires cannot really be reckoned in terms of the spatial areas they occupy, but only in terms of the star systems under their control. The Imperium is the largest such empire in the galaxy. The million or more worlds that lie under its dominion are spread throughout the entire galaxy with the exception of the Eastern Fringe.

This one source put the number of worlds controlled by the Empire at a million, and only a fraction of them would be populated.

THE EASTERN FRINGE

The Eastern Fringe lies beyond the Astronomican and so beyond the easy reach of Imperial forces.

Outside the influence of the Astronomican, travel is most difficult.

TYRANIDS

The Tyranid hive mind is an alien entity, a great creature that is formed from countless billions of creatures, a mind that is many linked minds.

Billions of Tyranids, all sizes assumed.

The Tyranids have travelled to the Imperium in a hive fleet from an unimaginably distant galaxy. The hive fleet is a great dark swarm of many millions of individual spacecraft, each a gigantic living thing, a creature fashioned from organic tissue by means of sophisticated genetic manipulation of which the Tyranids are masters.

In reference to newer sources, it's important to remember this large amount of ships.

The Tyranid hive mind hungers for fresh gene-stocks that can be used to create new bio-construct creatures and organic machines. Their own galaxy is exhausted, its creatures long- since absorbed into the hive mind, their flesh turned to machine-like purposes or discarded as useless.

Considering the harvesting methods of the Tyranids, their own galaxy has likely been entirely scoured. It is untold if this galaxy was large or not.
The fleet in question may only be the equivalent of a colonization fleet.

The Imperium, with its countless billions of humans and other creatures, offers the Tyranids an almost inexhaustible supply of flesh and genes which will invigorate the hive mind and enable it to embody itself in new forms.

Then, the Imperium counted billions of humans. The "billions" is still present in the introduction of many most recent sources and fictions.

The hive fleet has reached the outer part of the Imperium and the entire south-eastern spiral arm of the galaxy now lies under its dominion. A thousand human worlds have already fallen to the invader, their populations consumed or enslaved by the Tyranids.

Now the Imperium prepares for war. The weapon shops of Mars turn out ever-more potent machineries of death, new spaceships sail from the shipyards of Necromunda, Space Marine chapters muster their fleets and begin the long battle to counter the hive fleet, the vast resources of the Imperial Guard gradually swing into action as millions of men prepare to embark on a war for humanity's very survival.

The Tyranid fleet of that time had taken a thousand worlds, which may explain its small size. The IoM could only dedicate millions of men for this war against the creatures.

[Mr. Oragahn]

INTERSTELLAR TRAVEL

THE PRINCIPLE OF WARP TRAVEL

A spacecraft drops into the warp by activating its warp engines. As a ship leaves the material universe it enters a corresponding point in warpspace. The ship is then carried along by the tides and currents of the warp.

After traveling in this fashion for an appropriate time, the ship uses its warp engines to drop back into real space. Because the material universe and the warp move relative to each other, the ship reappears in a new position several light years from its starting point. This process is called a jump or hop and the process of entering or leaving warpspace is known as a drop or shift.

Journeys are undertaken in short jumps of up to 4 or 5 light years. Longer jumps are unpredictable and dangerous. The tides of warpspace move in complex and inconsistent patterns and ships attempting longer hops often end up wildly off course.

That's the default travel distance through warp, without "psychic" guidance, merely computers as I get it.

Were this limitation to apply to all warp travel then humanity would not have spread throughout the galaxy as it has. It is possible to make long jumps of many light years by steering a ship within the warp itself - sensing, responding to and exploiting its currents and thereby directing the craft towards a corresponding point in the material universe. Only the strange human mutants known as Navigators can pilot a craft through the warp in this way.
...
Navigators are powerful psykers of a specialised kind who can use their powers to steer spacecraft in the warp.

That's a part of the guidance.

THE ASTRONOMICAN AND THE WARP

The Astronomican is a psychic homing signal centred upon the Earth. It is powered by the continuous mental concentration of thousands of psykers. The Astronomican cannot be detected in the real universe but only in the warp. It is by means of this signal that Navigators can steer their spaceships over long distances.

The Astronomican's signal is strongest close to Earth and gets increasingly weaker further away. It extends over a spherical area with a diameter of about 50 thousand light years. Because the Earth is situated in the galactic west, the Astronomican does not cover the extreme eastern part of the galaxy. Nor is the extent or strength of the signal constant - it can sometimes be blocked by localised activity within the warp itself. Such activity may be compared to the hurricanes or storms of a terrestrial weather system and is known as a warpstorm. Warpstorms may be so bad, and so long-lasting, that entire star systems are isolated for hundreds of years at a lime.

A warpstorm not only obscures the signal of the Astronomican, it is also dangerous for spacecraft travelling nearby. No spacecraft can venture within a warpstorm and expect to survive, although there are tales of miraculous escapes and of ships being thrown tens of thousands of light years off course.

An interesting element being that the signal gets weaker, therefore would logically render long trips towards the border of the Imperium more difficult, even within the sphere of influence of the Astronomican.

TIME DISPLACEMENT

The time differences between real space and warpspace are quite drastic. Not only does time pass at different rates in both kinds of space, but it also passes at very variable rates. Until a ship finishes its jump, it is impossible for a ship's crew to know exactly how long their journey has taken. Time passing in real space is referred to as real time. Time passing on board a spacecraft is referred to as warp time. The relationship between real time and warp time is shown on the chart below.



So, for example, a 100 light year jump will seem to take from 2.5 to 9.5 hours to a spaceship's crew, but between 3 days and 3 weeks will have passed in real space.

There's an error in the original table. The second column should be about "Maximum Warp Time". I took the liberty to correct this error in the image above.

Basically, as far as the real time is concerned, it takes between 1 to 6 months to cover 1,000 LY. Numbers increase or decrease linearly. So to cover 10,000 LY, it takes between 10 to 60 months.
But time is slowed down, so the crews experience a much shorter lapse.

These times do not include journey times out to and from jump points on the edge of the star systems. It takes from days to weeks of travel at sub-light speeds to reach a drop from the spaceship's starting planet, and a similar time to re-enter the destination system.

Back then, it was already established that the ships couldn't jump in-system, and it's a fact that still proves true.
Not only that, but their sub-light speeds were extremely limited.
These STL values appear to have been revisited, but again, it's also up to some interpretations. From what I read at SBC, notably some of L33telboi's posts, some sources may suggest accelerations in the one digit gees, while others are in the high hundreds or even thousands gees.

The Imperium is approximately 75 thousand light years from edge to edge. A journey of this length would take between 75 and 300 days in warp time, and between 6 years and 40 years real time.

Another indicator of FTL speeds.
The highest speed being 12,500 c, the lowest 1,875 c.

The other information being that the Imperium is 75,000 LY wide. Considering Earth's distance from the galactic core, and the Astronomican's range, that works rather well.

WARP NAVIGATION

Once a spacecraft activates its warp drives it is plunged into a dimension very different from our universe. It is convenient to imagine warpspace as consisting of a relatively dense, almost liquid, energy which is devoid of stars, light and life as we know it.

Perhaps plasma? That at least would match the descriptions of ships exiting the warp from newer books, decades later.

Once within warpspace a ship may move by means of its main warp drives, following powerful eddies and currents in the warp, eventually reaching a point in the warp corresponding to a destination in real space. The most difficult aspect of warp travel is that it is impossible to detect the movement of warpspace once a ship is in the warp. The ship can only blindly carry on, its crew trusting that it is going in the right direction. The longer a ship remains in warpspace the greater the chances of encountering some unexpected current that can turn it unknowingly off-course.

And again, another problem with warp travel. The longer you linger in the warp, the greater your chances of getting lost.

Navigation of warpspace can be achieved in two ways: the calculated jump and the piloted jump.

All warp-drives incorporate navigational mechanisms. When the ship is in real space, these monitor the ever shifting movements of the part of the warp corresponding to the ship's current position. By observing these movements in the warp it is possible to calculate a course, corrective manoeuvres, and approximate journey time to a proposed destination. Calculation relies on the assumption that the warp-currents observed from real space don't change significantly during flight. This method is known as a calculated jump. It is not safe to make a calculated jump of more than four or five light years at one go. The longer the jump, the greater the chances of a significant change in warp current movement.

That is again for ships using the warp, but being unable to rely on psyker for travel.

The second, and more efficient, form of warp-navigation is the piloted jump. This method relies upon two factors: the human mutants known as Navigators and the psychic beacon called the Astronomican. The Astronomican is centred on Earth and is not only controlled by, but is directed by, the psychic power of the Emperor himself. The Astronomican is a beacon that, because it is psychic, penetrates into warpspace. A Navigator on board a ship in the warp is able to pick up these signals and can steer a spaceship through warpspace, compensating for current changes as he does so. A piloted jump can safely cover a far greater distance than a calculated jump. 5,000 light years would be the normal maximum jump, but longer jumps have been made.

For some reason, a jump of 5,000 LY is the maximum. The logical consequence of this is that the Navigator has to pull the ship out of warp, and likely observe the currents to assert a relative position and an expected destination.
This forced departure from warp means that an enemy group would have an opportunity to detect it.

[Mr. Oragahn]

The section below is largely missing from Connor's post. It contains crucial data about fleet sizes though, and leads to a number at least an order of magnitude below his estimation.

IMPERIAL SPACESHIPS

The whole structure of the Imperium is founded upon the craft that transport its armies and officials across the galaxy. It is the fleets that carry vital food to the starving hive-worlds, and which bring technology and equipment to the agricultural planets. Without its fleets the Imperium would soon collapse and humanity would perish in many parts of the galaxy.

Interstellar craft may be privately owned but most operate on behalf of one of the Imperial organisations. Of these, the Imperial Fleet is the largest, numbering tens of thousands of warships and hundreds of thousands of cargo vessels of varying sizes.

As clear as crystal. The Imperial warfleet numbers less than 100,000 FTL capable warships. The low end is 20,000 warships. All sizes. The number of cargo ships ranges from 100,000 to near a million.
Bombers, fighters and other carried small transports are likely excluded.

One would say that fixed fleets (sub-stellar) matter a lot, but it doesn't really fit with the emphasis put on the arrival of an Imperial warship.

So vast is the Imperium that the Fleet is divided into five main sections, each functioning as an independent administrative unit (although they cooperate whenever it's necessary).
The Priesthood also maintains a small number of its own ships. Some of these reside permanently on the Imperial planet, whilst others are scattered throughout the galaxy, transporting Imperial servants on missions of the greatest importance or secrecy. A further corps of ships lies under the direct control of the Adeptus Arbites, the Judges, to be used for transportation and war.

Some extra STL and FTL capable ships, but obviously shadowed by the Imperial Navy.

The Space Marines have their own interstellar transports and battlefleets. Although not large in numbers these arc manned by the most ferocious and highly-trained warriors in the galaxy.

Less than tens of thousands of warships. Other fresher sources help put that number around a couple thousands anyway.

Other interstellar craft form a minority. The small exploratory fleets of the Rogue Traders may number as many as two hundred ships at one time, but are scattered beyond the fringes of human space. Other Imperial organisations, such as the Officio Assassinorum, also have access to interstellar craft, but the details of these ships are well-guarded secrets.

Around 200 ships for the Rogue Traders.

THE MERCHANT FLEETS

The combined merchant fleets comprise almost 90% of all interstellar spacecraft in the Imperium.

Pick the Navy, and multiply by 9 to get the merchant fleet size. That would fall under 900,000 merchant ships tops. The low end being 180,000 ships.
I do not know how the more recent sources treated this figure.

CIVIL FLEETS

Although the vast majority of interstellar spacecraft are part of the merchant fleets, there are several thousand ships registered to individuals, families or trading cartels. All privately-owned interstellar craft operate along routes licensed to them by the fleet authorities responsible for shipping within that Segementum. These route licences must be bought, and must be renewed after a fixed time, usually a hundred years. This means few privately-owned ships like to risk the effects of time dilation on long journeys. A licence may run out before the ship has completed its journey!

Civil fleets vary in size from a single vessel to several dozen. One of the largest is that of the Navigator family Redondo, numbering 47 registered interstellar ships. Most ship owners have only a single vessel.

Confirmation of the slowliness of FTL travel, and we see that civilian ships, outside of merchants', number in the thousands tops. That's not necessarily surprising. Civilians, outside of an economical activity, would have very little reasons to move from a planet to another, notably due to the problems of warp and most civilians simply not having a Navigator to count on I suppose. Those registered ships would probably belong, in a large quantity, to some aristocrats.

WARFLEETS

Each of the five warfleets serves within one of the Segmentae Majoris and is responsible for protecting shipping within it.

...

BATTLEFLEETS

Imperial space is so vast, with so many star systems and areas of Wilderness Space to be patrolled, that even the many thousands of spaceships in the warfleets must be spread thin, with individual ships and squadrons set out on their own assignments.

Considering that earlier on, the author bothered giving a scale indication in "tens of thousands", we can safely understand here that many thousands can go from 6000 to 9000 warships per warfleet only. The highest number would still fall below 50,000 warships in total for the whole Imperial Navy.

For the note, Connor obtains figures in the tens of thousands of warships, which brings him, from an earlier comment, to a hundred thousand warships, or more.
That's certainly not what the source was going for back then though.

The Imperium cannot maintain permanent fleets ready to respond to invasion or rebellion. Nor would it make sense to do so - it would take so long for a fleet to get from its base to the war zone that the enemy would surely have moved on by the time it arrived.

Instead, temporary battlefleets are gathered together whenever they are needed. Warships within a relatively small area are summoned to join the battlefleet. It is rare for ships more than 50 light years from the battle zone to be included in the fleet and more commonly only those within 10 or 20 light years are summoned. Even with ships this close to the battle, it will take at least days and more often weeks for them to arrive.

Considerable strategic limitations.

Only during the very largest of wars, lasting for many decades, does the lmperium bring battleflects together and dispatch them en masse to a warzone. Such a war is currently underway in the galaxy's south-eastern spiral arm. Here the Tyranid Hive Fleet Kraken is inexorably advancing, conquering and consuming the planets in its path. A massive campaign involving millions of men, thousands of ships and whole chapters of Space Marines is being fought against the Tyranid invasion. Fleets are being mustered in all the Segmentae to begin the long journey to the warzone. The journey will take decades in some cases and many of the crew will never see the battles they are heading towards - but the Imperium knows all too well that in mere decades the Tyranid threat will be as strong as ever.

A summary of the war against the Tyranid fleet Kraken.

[Mr. Oragahn]

Some selections of my own...

SPACESHIPS OF THE IMPERIUM

Most spaceships are old - open space, the most hostile environment to man, preserves the plastics and metals that spacecraft are made from.

...

The Imperial fleets number many thousands of ships, the majority of which are at least a thousand years old. Some are as old as the Imperium itself, a full ten thousand years. A very few claim a pre-Imperial origin. It is difficult for those born under the claustrophobic sky of a planet to appreciate the great dignity which is inherent in all old spacecraft.

...

The spaceships of the Imperium are vast constructions that take many decades to build. Each craft represents a huge investment of time and resources. But once completed, fitted out, armed and commissioned, a spaceship continues in service for centuries, even millennia. After that, it may be refitted, modernised, reconstructed and live on practically indefinitely. Barring a major accident or destruction in battle, a ship is immortal like a great city, its population and fabric existing in a constant state of decay and renewal.

Old, many thousands of them, takes many decades to build.

Connor minimizes the third paragraph:
"Starship construction implied in the 'decades'. Unknown whether this applies to escorts, cruisers, or battleships."

The text speaks of vast constructions. It's rather clear that we're not just talking about the smaller ones here. And it's not just decades, but many decades, again.

Interstellar spaceships are powered by plasma and warp drives. Plasma drives are used to move through star systems at sub-light speeds. They burn with the fierce energy of a star, converting their fuel into a super-heated gas plasma to create the immense thrust needed to propel these gargantuan crafts through space. As a large interstellar spaceship moves out of orbit towards the edge of a star system ready to jump into the warp, the fiery arc it traces across the night sky can clearly be seen from the planet it's leaving. It appears to be a great comet streaking through the heavens - on many worlds, the arrival or departure of' a spaceship is read as an omen, a divine harbinger of joy or doom.

Here we go with those "they burn with the fierce energy of a star" things. While some would take this literally in order to have big numbers to pin to the wall next to Miss Arkansas 2006, chanting the marvels of millions of petawatts of power and more, others would simply remember that those same ships' sublight engines couldn't do better than get ships into star systems within days or weeks.

Never mind, Connor already thinks there is an "implied stellar scale output."

Warp drives are altogether more esoteric and terrifying, understood by few even among a spaceship's crew. When the spaceship reaches the jump point at the edge of the star system it's leaving, its plasma drives are turned off and its warp drives engaged. These hurl the spaceship out of real space and into warpspace, propelling it through the warp to a destination light years away. If a spaceship's warp drives were switched on while it was still within a star system, the huge rent in the very fabric of space that they create would be catastrophic for the population and planets of the system. The spaceship itself would be torn apart as the massive pull of the star's gravity reacted unpredictably with the energies released by the warp drives.

Bye bye the ship. Somehow, the effect would be a considerable threat to the planets of the system.
Effects seem weird and random though, and considering the times involved in the construction of ships, it's relatively normal that the Imperium doesn't build ships merely dedicated to blowing up in systems.

Fully one-third of a spaceship can be taken up by its engines with their huge thruster ports, cavernous combustion chambers, generators surrounded by massive protective cladding and the miles of pipes, tunnels, corridors and ducts needed for the control mechanisms, fuel supply and access by service crews.

This ratio (1/3) has not changed much. BFG has a similar reference, iirc.

Although it's possible the ships were a couple of kilometers long, Connor considers that "'miles of pipes' is suggestive of multi-km lengths for starships (especially given the indication that 1/3 of a spaceship can be taken up by engines alone!)", which is like a terrible non sequitur. He'd probably be impressed by the length of his own intestines though. :)

The living areas of a spaceship contain the thousands, often tens of thousands, of men that serve aboard. These areas are often built up from the ship's hull into huge domes and spires that rise hundreds of metres into space. On some ships, they seem like the heart of a mighty city, immense towers rising to touch the stars, their sides glittering with lights, bridges spanning the void between them. On others they resemble a gigantic cathedral, the towers colonnaded and sculpted. Vast carved figures of legendary heroes recede into the darkness of space - huge homed gargoyles leap and leer from the highest pinnacles in mockery of the terrors of warpspace - golden domes blaze with the light of stars.

Oh basically people live in skyscrappers built outside of the ship's bulk. They stick out, waiting to be shot down or hit by debris. :/

Connor focuses on the implications regarding size only.

On freighters and merchant vessels, the rest of the ship is taken up by holds containing the ship's precious cargo. On warships this space is filled by the colossal power generators that drive their weapon systems. These towering structures hum and crackle with the monstrous energies bounded inside. They are housed within deep shafts which disappear from view into a darkness that is broken only by the crackling blue arcs of lightning which leap from the generators. When a laser battery is fired with a titanic unleashing of energy, its power well is filled with a furious roar. In battle, a warship echoes with the thunder of its weapons, its decks shuddering with the recoil of their furious discharges.

If you remember the calcs Wong did for the 30 meters wide Millennium Falcon getting rocked by supposedly some megatons of firepower, titled Kinematics Analysis of Millenium Falcon Turbolaser Impact, then I don't think we need to reach for higher orders of magnitude here, if the cannons are of the same size or mass as the MF. The displacement that affected the MF was clearly violent, in opposition to the quivering described in the text above.
Obtaining the energy of the bolt of photons (we know they're not just photons and don't behave like photons but never mind) from the angular displacement, he obtained 7290 TJ. Then counting for the angle of impact, he obtained 14,580 TJ, or 3.485 megatons.
That is just for the quick overview. Remember that contrary to the Millennium Falcon case, we're dealing with strict linear recoil here, as the laser weapon bore slides backward.
Not to say that this kind of displacements is not even necessary to send vibrations across the decks. Gigajoule chemical explosions can be felt kilometers away. Figure out that it's a chemical explosion, now imagine that this is repeated over an entire second instead of a microsecond, and you still get terajoules.
Everything here doesn't require the firepower to be pegged as anywhere higher than terajoules. A petajoule figure would obviously be a generous interpretation.

Now, a bit more specific details about the various weapons.

WEAPONS

LASER BATTERIES

Ranked batteries of powerful laser cannon are the most common armament on the spaceships of the Imperium. Mounted in huge turrets, the lasers are powered by immense generators deep within the spaceships. They release their energy in deadly bolts of light with the power to punch through the massive hulls of spaceships. They are brought to bear in a single broadside that rakes a line of devastation across an enemy spaceship.

FUSION CANNON

The fusion cannon is powered by the awesome energy released as atoms are brought together in a nuclear furnace and fused into new matter. At short range, the effects of a fusion cannon are devastating but they drop off quickly at longer ranges.

PROW LASER

The prow laser is a single bank of laser cannon firing from the front of the spaceship. Although not as powerful as a laser broadside, it's forward position gives it a good arc of fire to attack incoming ships. It is often used to soften up the enemy as the spaceship prepares to ram.

VORTEX TORPEDO

A vortex torpedo creates a vast vortex held when it explodes. The vortex field disrupts the very fabric of the universe as the raw energy of the warp is pulled through into real space with terrifyingly destructive effects, even to something as large as a spaceship.

PLASMA TORPEDO

The plasma torpedo explodes in a burst of super-heated energy that literally burns its way through a spaceship's hull as the craft is engulfed in a ball of white-hot flame thousands of metres across.

Lots of a'some and huge and else... what we can notice is that a fusion based weapon like the Fusion Cannon is devastating when it hits a ship with nearly maximum power (power decreases over distance, rather rapidly apparently).
Connor doesn't think the Fusion Cannon's reliance on fusion matches the power outputs for bigger guns, so goes to assume that they're light weapons or point defense systems. I wonder if he bothered reading the quote though, because "devastating" doesn't imply a water-cannon level firepower. It's even more amusing since the description is followed by the Prow Laser, which is identified as a weaker weapon.
Yet, it's a prow weapon used to soften up a ship before being rammed squarely. Once again, ramming also largely implies moderate accelerations for both ships, attacker and attacked.
Vortex Torpedoes are like warp drives gone bonkers, but obviously they don't threaten the star system in which the battle is fought.
The Plasma Torpedo, I'm afraid, is the Hollywood weapon in the lot. Unless it's understood that said fireball would only remain fractions of a second and expand very quickly, unless for some reason the plasma had lost a lot of its expansion speed and would still shine at much lower temperatures.
That or it's a technobabble weapon that spends some efforts maintaining a fireball, like a burning nagging spot you couldn't shake off your hull. Say, like a sticky giant lightning ball that would work in vacuum.

[Mr. Oragahn]

SPACESHIPS

ANNIHILATOR BATTLESHIP

On the Annihilator battleship, the usual laser broadsides of Imperial battleships have been abandoned in favour of two huge turret-mounted cannon. Known as Annihilator cannon, these massive weapons fire huge shells armed with powerful explosive warheads. The shells are fired at high velocity and then accelerated even further under propulsion from fast-burning plasma rockets. When they hit their target, their sheer speed and mass is enough to tear through even the armoured hull of an interstellar warship. A fraction of a second later their warheads explode and inflict devastating damage.

In essence, two huge mass drivers that fire missiles. You can see for yourself here. Once fired at high speeds, they burn some more fuel to increase their speed further.
Most interesting is that their speed gives them the power to "tear through even the armoured hull of an interstellar warship."
Yet, "a fraction of a second later their warheads explode and inflict devastating damage", which clearly indicates that the projectile survives the impact well enough for the explosive warhead to deal damage.
The projectile's own engine could either be a fission or fusion drive, or simply running on the super charged plasma the Goliath collects.

Here's an example of a futuristic plasma engine, the Mini-Helicon, running on nitrogen, producing contained plasma and channeling it out for propulsion.
http://nextbigfuture.com/2009/02/mit-mi ... space.html
http://www.wired.com/wiredscience/2009/ ... mathruster
http://www.sciencedaily.com/releases/20 ... 221524.htm

Now, about the warhead.
No matter what's inside, the projectile itself is not flying anywhere near relativistic speeds, otherwise no projectile could penetrate any hull only to detonate fractions of a second later.
It also stretches the limits of hypervelocity impacts. A sudden impact would vaporize the projectile without giving it a chance to penetrate the hull under the form of a perfectly working ticking bomb.
The impact is akin to an immense deceleration, and it would require insanely strong materials to support the stress. Obviously variants of tungstens would be completely vaporized with low fractions of such speeds.

A velocity of 10 km/s would be a good guess, and perhaps already too high.
Still, a thousand tonnes projectile travelling at 10 km/s would have a kinetic energy of 5 terajoules. That may be a tad low, but the main goal of the projectile is not to explode on the hull, but actually go through it.
With around 1 e8 kg.m/s of momentum, that's nothing to scoff at anyway.
A speed of 100 km/s would provide a KE of 5 PJ, but I just don't see how the hell the projectile is supposed to survive the impact to explode inside the ship, unless the armour is ridiculously thin.

Still, here be an interesting paper about earth-penetrating weapons, rods and hypervelocities.
I'd quote a bit here:

It is straightforward to show, however, that the maximum penetration depth is severely limited if the missile casing is to remain intact. One can make reasonably accurate estimates of the penetration depth based on the well-developed theory of "long-rod penetration." The fundamental parameter R is the ratio of the projectile ram pressure to the yield strength of the material. The target material yields, and penetration occurs, when R is greater than one. For a steel rod to penetrate concrete, the minimum velocities for penetration is about one half a kilometer per second (1100 miles per hour). For ductile materials, the kinetic energy lost from the penetrator can deform the target and dig out a penetration crater.

Fundamentally, however, the depth of penetration is limited by the yield strength of the penetrator — in this case, the missile casing. Even for the strongest materials, impact velocities greater than a few kilometers per second will substantially deform and even melt the impactor.

An earth-penetrating nuclear weapon must protect the warhead and its associated electronics while it burrows into the ground. This severely limits the missile to impact velocities of less than about three kilometers per second for missile cases made from the very hardest steels. From the theory of "long-rod penetration," in this limit the maximum possible depth D of penetration is proportional to the length and density of the penetrator and inversely proportional to the density of the target. The maximum depth of penetration depends only weakly on the yield strength of the penetrator. For typical values for steel and concrete, we expect an upper bound to the penetration depth to be roughly 10 times the missile length, or about 100 feet for a 10 foot missile. In actual practice the impact velocity and penetration depth must be well below this to ensure the missile and its contents are not severely damaged.

That said, the bore is large, so the projectile is not going to be small either. It may be the equivalent of a small ship ramming into a bigger one. Technically, enough of the missile's mass at the front could melt before the warhead, is located in the rear, would be threatened by the heat. Then the tail of the missile would enter the hole its head put into the target's superstructure.
Actually, considering the size of the ships and the size of the cannons, there's little reason to believe that the plating is thicker than the missile is longer.
This could mean the projectile could easily pierce it, or even perhaps go through its entire superstructure.

The turret mounting allows the Annihilator captain to bring his weapons to bear on all sides - only ships directly behind the Annihilator are safe from attack. The cannon can also be fired as the turret is being rotated - where a laser broadside has to concentrate its fire, the Annihilator cannon can pick out separate targets for attack. This is especially effective against smaller ships when a single shot from an Annihilator cannon can destroy the target.

Smaller ships targeted by one of these massive cannons are destroyed in one hit. When you look at the picture, notably the Stalwart ships, it's not surprising at all: An annihilator barrel is longer than an escort ship!
This would give an idea of the strength of said ships.

Another thing to point out is the recoil. The Annihilator couldn't count on its main engines to counter act the sudden recoil of the guns if they were to fire at an angle from the ship's length axis.
The source doesn't address this.

CASTELLAN SHIELD SHIP

The Castellan is a battlefleet support ship. Its role is to provide other warships with the vital defence they need to be able to close with the enemy and bring their weapons to bear.

The Castellan shield ship is built around a single huge shield generator. Most warships have a number of shield generators each projecting a short-range field in one direction. The Castellan shield emanates from the ship in every direction and is powerful enough to extend its protection to any spaceship close to the Castellan.

When the Castellan shield is hit by enemy attacks, the shield generator absorbs the energy of the attacks, preventing them from damaging their targets. This causes a gradual build-up of power in the shield generator and only the close attention of its Adeptus Mechanicus custodians prevents it from exploding.

Eventually, however, the power build-up becomes so great that unless the generator is shut down it overloads and ruptures in an almighty explosion that literally rips the Castellan apart from the inside. This sends out a vast fireball which engulfs the area that was under the shield's protection and can destroy the spaceships which were accompanying the Castellan for its protection.

In battle, the Castellan's Captain must constantly assess the dangers of leaving the shield running or shutting it down to dissipate the energy build-up. If he shuts the shield down too often, he fails to benefit the other ships around him with the Castellan's protection. If he waits too long, he jeopardises those very ships he's meant to be defending.

Odd that no one thought about mounting a Big Gun on this baby. When you can blast nearby ships when 'sploding, you'd probably like to channel that energy into a tube pointed at your enemy. Dunno, that seems rather obvious, really.
It is a rather original design, where the shield exclusively absorbs the energy instead of deflecting it, and must be shut off for said energy to be vented out rapidly, somehow, because it otherwise keeps it, and clearly the system doesn't have the capacity to swap input and output at a whim. This means even for a structure dedicated to shielding only, a low radiation (the output to get rid of the pied up energy) when the device is turned on.

One would logically think that a system that's based on the absorption of nasty energy is supposed to be some exclusive and rather exceptional (as rare) tactical gain.

COBRA DESTROYERS

Cobra Destroyers usually act in support of battleship squadrons. When a Gothic battleship, for example, arrives in a system, its supporting Cobra squadrons are deployed to patrol the individual planets and moons. Their speed and mobility make them ideal craft to pursue and engage the sub-stellar spaceships of pirates, smugglers and rebels. For although they are small in comparison to the mighty battleships they accompany, Cobra Destroyers still vastly overawe and outgun all but the very largest of sub-stellar spaceships.

That's said and fixed. Cobra destroyers completely overclass even the heaviest sub-stellar combat ships, which would have had the ability to trade FTL engines for more reactor room or weapons.
This would imply that even the bigger ones are very, very small in comparison.
It fits with my point earlier on, about the awe that strikes inhabitants of planets when an Imperial warship arrives.

Cobra Destroyers are among the fastest warships in the Imperial Fleet. In battle, they operate in large squadrons, moving in tight formation into close contact with the enemy before firing their lasers or their destructive vortex torpedoes.

Even in large formations, Cobra squadrons can make tight turns, allowing them to sweep around an enemy's flank or move directly through his fleet, turn and launch a second wave of attacks from the rear. If the enemy turns to face the Cobras, he runs the very real risk of leaving himself open to attack from the rest of the battlefleet.

Cobras outmaneuver the heavier ships, fast enough to harass them and make targeting choices hard.

DICTATOR BATTLESHIP

The Dictator is probably the most unusual battleship to be built at the great Jovian shipyards. It is designed specifically for close assault and is used to board, and often dismember, enemy spaceships.

The gigantic power claws of a Dictator can move with frightening speed to grab an enemy spaceship and rip it out of formation. Even if they fail to take hold, the massive force of the Dictator's claws can severely damage an enemy ship, tearing through its hull and crushing or pulling off huge sections of a ship's superstructure, engines or weapons.

An enemy ship that is firmly grabbed by the Dictator's claws is dragged onto the Dictator's huge boarding drill that bites deep into the unfortunate ship's innards. Once the drill has crunched through an enemy's hull and torn its path of destruction deep into the interior of the ship, hundreds of vast reinforced hatches swing open and the Dictator's crack assault teams pour out and take the battle into the very heart of the enemy ship.

If the first assault of the boarding action isn't successful and the enemy resistance appears to be strong, the Dictator captain may order his troops back to their own ship. He'll then use the Dictator's mighty power claws to twist and tear and crush the enemy ship. Smaller ships may be literally torn in two by the Dictator - larger ships may be disembowelled by the terrible saw-toothed drill.

Sometimes a ship will manage to break free, firing its engines at maximum power to loose itself from the Dictator's iron grip. But this is a desperate manoeuvre, often crippling the escaping ship as huge sections of its hull are torn off in the attempt.

The design is really nice and funny. I can imagine what it would have been to use it in-game.
That said, I'm not sure about the "battleship" part, safe perhaps a reference to a massive amount of armour. After all, it's a very close range ship, and there are practical limits to how far its claws can extend, so it has to be very well defended and armoured to get close to another enemy ship.

All in all, it gives a weird idea of the ranges at play. Eventually, the Dictator (a concept entirely ditched in BFG, becoming a Lunar-class) would need to complete, essentially, a ramming maneuver.

Minus the speed.

It has to close on its enemy, but must come in slow enough not to crash into it. This does mean the targeted ship cannot evade. The Dictator would be an idiotic concept if your average warship could pull accelerations up in the hundred gees at least.
Eventually, this monster of an issue would be tamed with the suggestion that exceptionally powerful tractor beams are used here. Unfortunately, they are not mentioned, and the concept itself belongs to Space Fleet.

DOMINATOR BATTLESHIP

The Dominator comes from the same family of ships as the Tyrant and Emperor. It is armed with the awesome inferno cannon. This massive cannon is mounted along the entire length of the Dominator's hull. The huge shells are loaded at the rear of the ship in a cavernous chamber positioned above the roaring fury of the Dominator's plasma drives.

Each inferno cannon shell is the size of a tall building, its warhead packed with explosive. The shells are moved from the ship's magazine on great tracked transport vehicles that crawl along echoing tunnels down the length of the ship. The shells are loaded by powerful winches, guided by an army of engineers whose prayers ring through the chambers. As the huge breech closes, the gun crews leave the chamber - no man could withstand at short range the awesome concussion produced as the shell is fired.

The shell accelerates down the long barrel of the cannon, reaching a searing velocity that hurls it out into space. The whole ship shudders with the recoil of the cannon - indeed, it is constructed with massively reinforced bulkheads and hull supports to withstand the powerful shockwaves.

When the shell detonates it releases a ball of radioactive fire that forms a sphere of destruction kilometres across. Not only the cannon's target, but any ship close to it receives a deadly blast of intense heat, energised particles and huge jagged shards of shrapnel larger than most sub-stellar spaceships.

The inferno cannon is affectionately known as the Planet Buster by a Dominator's crew because it is often used in planetary assaults to rain fire down on enemy cities. A single shell is powerful enough to destroy all but the largest cities, leaving only flattened ruins around a crater many hundreds of metres deep. When an enemy planet learns that a Dominator has entered the star system, it is rare for a complete and unconditional surrender not to follow swiftly.

Truly, the ship is the most powerful of all, but the procedure to load a shell and the way it has to be aimed means it's best used as a sniping ship against the enemy's main warships. A look at the game rules shall reveal if this cannon is intended to one shot any enemy ship or not.

This massive cannon is mounted along the entire length of the Dominator's hull. <- huge, lengthy, accelerator. The ship probably uses the engines to compensate for the acceleration. You can appreciate the immense size of the cannon.

Each inferno cannon shell is the size of a tall building, its warhead packed with explosive. <- it's probably several tens of meters long, and it uses explosives, but later we're told it produces "radioactive fire." Go figure. Fizzling out near-fission materials?
Interestingly, this may also imply a ship size of a kilometer, more or less.
I must say that the sentence finishing with "explosive" alone seems odd. You'd expect explosive firepower, or explosives, with an s you know. The meaning could change a lot.

As the huge breech closes, the gun crews leave the chamber - no man could withstand at short range the awesome concussion produced as the shell is fired. <- crew dies if they remain anywhere close to the section where they loaded the shell. What a curious thing. It would suggest the recoil system is not fully encased, and the sudden compression of air can reach lethal psi overpressures.

The shell accelerates down the long barrel of the cannon, reaching a searing velocity that hurls it out into space. <- clearly became the Nova cannon later on, but at this time, with no hint of near to c ejection speed. And what about the searing velocity? Does it imply that the metal, due to the stress or friction, is brought close to the heat of fusion of its respective elements?

And the rest...

The "sphere of destruction kilometres across" either is another exotic containment system, or refers to the atmospheric effect. It's a planetary assault weapon, so we could go with the scientifically accurate option, but then it presents a vacuum context, with nearby space ships.

Now, it is a shell filled with explosive material, fired at a high speed at a planet. Basically, it is suggested that it will penetrate the ground before exploding. This could mean the crater is gouged by the explosion of the reactants, starting somewhere beneath the surface, which increases the craterization. However that's almost pointless, considering the speed and the fact that the major cratering factor will be the mass of the shell itself, as the momentum would provide a greater penetration into the ground.
The design wouldn't make sense if the mass and speed alone would be more destructive than the "warhead packed with explosive", which we would understand as the speed is not so awesome after all.

What about the effects on the ground?
Asteroid impacts generally remain the better method for the making of large craters, on bodies with a noticeable gravity.
So let's use this simulator.

We'll take a not too large asteroid (60 meters wide), but pick some high density (20 tons per cubic meter, slightly more than depleted uranium) and assume an impact at 90° degrees. Purely vertical.
The biggest problem is the speed, but once again, it's a weapon packed with explosives, and that turns out to be absolutely pointless at speeds where asteroid vaporize themselves when hitting the ground.

Code: Select all

Your Inputs:
    Distance from Impact: 1.00 km = 0.62 miles 
    Projectile Diameter: 60.00 m = 196.80 ft = 0.04 miles 
    Projectile Density: 20000 kg/m³ 
    Impact Velocity: 10.00 km/s = 6.21 miles/s 
    Impact Angle: 90 degrees 
    Target Density: 2500 kg/m³
    Target Type: Sedimentary Rock 

Energy:
    Energy before atmospheric entry: 1.13 x 10^17 Joules = 27 MegaTons TNT
    The average interval between impacts of this size somewhere on Earth during the last 4 billion years is 1.4 x 10^3 years

Atmospheric Entry:
    The projectile lands intact, with a velocity 9.9 km/s = 6.15 miles/s.
    The energy lost in the atmosphere is 2.24 x 10^15 Joules = 0.53 MegaTons.

Major Global Changes:
    The Earth is not strongly disturbed by the impact and loses negligible mass.
    The impact does not make a noticeable change in the Earth's rotation period or the tilt of its axis.
    The impact does not shift the Earth's orbit noticeably.

Crater Dimensions:

    Transient Crater Diameter: 1.96 km = 1.22 miles
    Transient Crater Depth: 0.694 km = 0.431 miles

    Final Crater Diameter: 2.45 km = 1.52 miles
    Final Crater Depth: 0.523 km = 0.325 miles

    The crater formed is a simple crater 

    The floor of the crater is underlain by a lens of broken rock debris (breccia) with a maximum thickness of 243 m = 796 ft.
    At this impact velocity ( < 12 km/s), little shock melting of the target occurs.

With a speed of 10 km/s, we get a depth of 523 meters. So we have several hundred meters there. The source doesn't say tens of hundreds of meters deep, or alternatively thousands of meters deep. This would be within acceptable parameters, and don't forget that the projectiles wouldn't be round, but lengthy. The KE would therefore be multiplied a few times, and penetration would likely be increased, if the article about hypervelocity rods is anything to go by.
Changes of speed don't add many meters to the depth.

Meanwhile, in space, the weapon clearly suffers from the same problem as the Nova Cannon, although there is no implied relativistic speed: the "fireball" (or blast in BFG) would overshoot a target, especially since it's packed with explosive and that there are limits to how fast the expanding matter can move. There would not be any "sphere" to speak of.

That said, let's be clear here. The Inferno Cannon was the most conventional in mechanics, and yet an awesome weapon the Imperium could mount on its mightiest ships. But it was truly enormous.
In the end, we are still far from the glittering super numbers touted as facts and conservative, supposedly from indisputable interpretations of other random pieces taken from modern 40K literature.

[The Dude]

Gawd, I wish the fluff masters at GW would make more distinction between weapons. When I see "Inferno Cannon" I think of the weapon mounted on the Hellhound or Titans; a big-ass flamethrower.

[Mr. Oragahn]

Gawd, I wish the fluff masters at GW would make more distinction between weapons. When I see "Inferno Cannon" I think of the weapon mounted on the Hellhound or Titans; a big-ass flamethrower.

It's an older source material though. Any change they made back then, is more or less consistent by now.
I suppose.

[Dabat]

Oragahn was taking figured and fluff from older sources, much of which has been ret-coned since.

most of your numbers sound right, as I don't have any of my books here with me at work, but there are a few questions/nitpicks I have.

This one source put the number of worlds controlled by the Empire at a million, and only a fraction of them would be populated.

Source on this? I could be wrong, but most of the sources I recall reading stated that a million (or around a million) is the number of inhabited worlds the IoM controls. Not including the possible hundreds of thousands of human worlds they do not control, or likely even know about (This is, of course, nothing but conjecture on my part, due to the vast tracts of space between sectors the IoM does not even explore, let alone control)

As clear as crystal. The Imperial warfleet numbers less than 100,000 FTL capable warships. The low end is 20,000 warships. All sizes. The number of cargo ships ranges from 100,000 to near a million.
Bombers, fighters and other carried small transports are likely excluded.

This number has been officially ret-conned, though the new number is never stated. With 50-75 capitol ships per sector*, an assumed 2-3 times that in warp capable escorts, and between 1,000-10,000 sectors (Though i am inclined to side to the lower number rather than the higher). We come out with a number quite a bit higher than 100,000. Still likely less than 1 million though.

*In some places the 50-75 number says 'war ships', in others it has called them 'capitol ships'. circumstantial evidence seems to point to this number referring to capitol ships as the Battlefleet Gothic rulebook states the names 35 capitol ships serving with Battlefleet Gothic at the outset of the war, and makes mention of several others. The rulebook also never states that Battlefleet Gothic is abnormally large.

A velocity of 10 km/s would be a good guess, and perhaps already too high.

Jervis has said that every turn of Battlefleet Gothic represents a period of time between 10-20 minutes, with each cm on table representing 1,000 km. In a single turn torpedos will move 60,000 km, assuming the average of 15 minutes in a turn, that gives up 240,000 km/hr, or 67 km/s.

I also swear I have read that torpedos do not use a conventional warhead, instead they use the energy of impact to kick off the chain fusion of their reaction mass, which is also their fuel. God if I remember where though.

<- clearly became the Nova cannon later on, but at this time, with no hint of near to c ejection speed

The Nova Cannon shell has to be able to travel 168,000 km (the maximum a shell can go, after scatter) before the fastest unit in the game, fighters and torpedos (at 240,000 km/h, each), can travel 1,000 km. Which means it has to be able to cover 168,000 km in fifteen seconds. Which means they travel no less than 11,200 km/s, which translates out to just over 40 million km/h, just about 4% of c. This is the absolute lowest speed it can be and still fit within the parameters of a (relatively) riged game.

[Mr. Oragahn]

Oragahn was taking figured and fluff from older sources, much of which has been ret-coned since.

most of your numbers sound right, as I don't have any of my books here with me at work, but there are a few questions/nitpicks I have.

This one source put the number of worlds controlled by the Empire at a million, and only a fraction of them would be populated.

Source on this? I could be wrong, but most of the sources I recall reading stated that a million (or around a million) is the number of inhabited worlds the IoM controls. Not including the possible hundreds of thousands of human worlds they do not control, or likely even know about (This is, of course, nothing but conjecture on my part, due to the vast tracts of space between sectors the IoM does not even explore, let alone control)

What I meant is solely based on the observations made from the same material, not newer ones. I have observed some retcons here and there, but I can't recall the details right now.
Why I said a fraction is based on the point I detail later in the other posts. I should have probably pointed out how I came to this suggestion. That's based on the fleet numbers, the calculations, the number of sectors, the number of stars that comprise them, and how many uninhabited worlds there would be per system. That said I have no reason to be against the greater retcon, and it's also possible that small colonies were installed on the formerly unpopulated worlds of systems which had already counted at least one populated world.

As clear as crystal. The Imperial warfleet numbers less than 100,000 FTL capable warships. The low end is 20,000 warships. All sizes. The number of cargo ships ranges from 100,000 to near a million.
Bombers, fighters and other carried small transports are likely excluded.

This number has been officially ret-conned, though the new number is never stated.

From my observations in the other threads, notably the critics of Connor's 1st to 4th and plus editions, the numbers don't really need to be considerably greater. Certain estimations don't even differ.

With 50-75 capitol ships per sector*, an assumed 2-3 times that in warp capable escorts, and between 1,000-10,000 sectors (Though i am inclined to side to the lower number rather than the higher). We come out with a number quite a bit higher than 100,000. Still likely less than 1 million though.

*In some places the 50-75 number says 'war ships', in others it has called them 'capitol ships'. circumstantial evidence seems to point to this number referring to capitol ships as the Battlefleet Gothic rulebook states the names 35 capitol ships serving with Battlefleet Gothic at the outset of the war, and makes mention of several others. The rulebook also never states that Battlefleet Gothic is abnormally large.

But if I recall correctly, the Gothic sector is one of those which are the most populated, concentrated and prestigious, as noted here. Notice though that some of my observations are generally solely relevant to those old sources.

A velocity of 10 km/s would be a good guess, and perhaps already too high.

Jervis has said that every turn of Battlefleet Gothic represents a period of time between 10-20 minutes, with each cm on table representing 1,000 km. In a single turn torpedos will move 60,000 km, assuming the average of 15 minutes in a turn, that gives up 240,000 km/hr, or 67 km/s.

Interesting, although I'm not sure about the merging and inclusion of game mechanics, it's always a risky thing to do. That said 67 km would work fine. We get 121 megatons of KE, a transient crater that's 1600 meters deep, and a final one that's near 500 meters deep. When the speed gets higher, the projectile breaks apart and looses some of its capacity to focus its energy onto a single point.

I also swear I have read that torpedos do not use a conventional warhead, instead they use the energy of impact to kick off the chain fusion of their reaction mass, which is also their fuel. God if I remember where though.

Assuming it's very cleverly done, the sheer pressure at the moment of impact might bring the elements close enough to each to allow a fusion chain reaction, although I don't know if at this point, the sheer speed needed for this would make the use of any warhead pointless. Probably someone else could check that out.

<- clearly became the Nova cannon later on, but at this time, with no hint of near to c ejection speed

The Nova Cannon shell has to be able to travel 168,000 km (the maximum a shell can go, after scatter) before the fastest unit in the game, fighters and torpedos (at 240,000 km/h, each), can travel 1,000 km. Which means it has to be able to cover 168,000 km in fifteen seconds. Which means they travel no less than 11,200 km/s, which translates out to just over 40 million km/h, just about 4% of c. This is the absolute lowest speed it can be and still fit within the parameters of a (relatively) riged game.

The BFG rulebook says it travels at near c. See here (CTRL+F: "nova"). It unleashes a force more potent than a dozen plasma bombs, and yet plasma bombs are not particularly that impressive, as one of the type used against spacecrafts can only melt a city-block.

As I highlighted, the Nova cannon's mechanics is rather problematic. In the game, the explosion of the projectile creates a perfectly radial area of damage. It's a nice circle on the board, and thus a sphere in space, and a description in "Shadow Point", notably one where such a weapon is used against an Ork fleet, supports the near lightspeed velocity. I even get the impression that sources imply that the explosion may even linger a bit.

All of which is simply impossible on both accounts with the speed and momentum in play here.
People tend to solely focus on the speed and mass of the projectile and that's all.

I tried to solve this with mass lightening (a device that would much likely rape conservation of momentum like in many SF universes), so much that once the system that maintains an artificial low effective mass is destroyed, it instantly recovers its true mass, and as energy is conserved, only speed can decrease.
Now, it would make the Nova shell a rather super STC type of weapon, a rarity in itself, since I don't know about any mass lightening tech used by the Imperium.
But to borrow Sarli's argument regarding SW, if a force has access to tractor breams that manipulate gravity (spacetime), then it comes to logic that they can manipulate to some degree that manipulation of other spacetime related forces and elements can be achieved.

[Mr. Oragahn]

EMPEROR CAPITAL SHIP

...

The firepower of these vast ships is terrifying indeed. From orbit a single broadside can incinerate a whole city or reduce a mountain range to rubble - moons can be atomised - enemy spaceships seared with pious fire.

There is a great disparity between the effects on a city, and those on the mountain range or the moon.

Broadside cannons can cover an entire city with megaton shots to engulf it in flames, that's not much of a problem at all.

Now, blasting mountains, that is something hard to find data for, some relevant empirical set of figures.

The good points are that, first, a laser is a focused weapon. So is a mass driver. But the lasers are the heaviest weapon in general. The second good point is that with a mountain, to destroy one top down, you don't really need to lift the mater out of a crater, but "merely" shove it sideways. Blasting anywhere near the tip and going on deeper would logically help making gravity less relevant until the beam really reached deep into the mountain.

That said, when talking about mountains, you don't need to look at behemoths either.
http://en.wikipedia.org/wiki/Mountain
The wiki page even has pictures, at the bottom, showing small ranges. A definition pegs the lower height at 1000 feet, 300 meters.

Turning a mountain range to rubble, that's different, although not necessarily impossible to achieve with low megatons. As a basenote, the St. Helens blast was 24 megatons, but with only 7 megatons contributing to the blast apparently (which is what counts here), and removed a portion of whatever remained of the volcano's summit. A lot of the energy was actually wasted, since the major matter removal occured with the landslide, along a 5.1 magnitude earthquake, which would be less than 200 terajoules.
Notice that the blast was "powered" by molten rock and steam. This shall be less efficient than the focused and advanced weapons of a warship.

St. Helens was a large volcanic structure. This shall be a good start, although it's a mount that is quite above the minimal height of a mountain though.
The beam would continuously deposit energy down, and blowing the hundreds of meters high tip would require focused energy in the kiloton range.
The delivery method is important. Lasers have the advantage of being able to deliver their energy over a certain time. Even a handful seconds would happen to allow the beams to strike at the core of the mountains, by removing matter away until the last joule of the beam reaches deeper.
If you carved a crater on the side of the mountain, the rest of the rock (that would be fragmented beyond the crater's volume) would topple.

A NTI article on a Lybian chemical facility may prove helpful:

Pharma 300 (Tarhunah)

With the operations at the Rabta complex severely hampered in 1991 because of its exposure as a CW plant, Qadhdhafi resolved to build an entirely new, underground CW production complex near the town of Tarhunah, 50 miles southeast of Tripoli. This facility was intended to supplant the Rabta plant. As with the other two plants, the Libyan government has claimed at various times that Tarhunah was a petrochemical complex or that the facility's tunnels were part of the Great Man-Made River Project to funnel water from Libya's southern aquifers to its coastal cities. The Tarhunah facility, extending over six square miles, was reportedly a labyrinth of tunnels carved into the side of a hollowed-out mountain.

The entrance to Tarhunah was located in the middle of a long, narrow valley between two mountain peaks, making it difficult for spy-satellites to view the factory or for fighter aircraft to destroy it. The plant was considered virtually impregnable to conventional air attack because of three 450-foot-long tunnels, protected above by 100 feet of sandstone and several feet of reinforced concrete. To make the plant even more difficult to attack, Libya reportedly obtained blueprints used by the former Soviet Union to build underground bomb shelters. Apparently, only a direct hit on the top of the mountain with a nuclear warhead would be capable of destroying the facility. Former U.S. Central Intelligence Agency Director John Deutch called Tarhunah "the world's largest underground chemical-weapons plant."
. . .
To construct the Tarhunah plant and purchase the necessary equipment to manufacture CW, Qadhdhafi reportedly established a purchasing network operating through front companies and middlemen around the world. At the top of this purchasing network is the state-owned Jowfe Corporation.
. . .
Jowfe also obtained technical specifications for the construction of 150-meter-long underground tunnels, commonly used in secret military installations, from the Sauer engineering company of Salzburg, Austria. German and Austrian companies also provided construction personnel and equipment to help build the tunnels at Tarhunah.

Working through a Thai middleman, Libya purchased 60-ton rotary boring machines used to tunnel into the mountain from the German company Westfalia-Becorit. Subsequently, the German government ordered the company to cease supplying spare parts for the boring machines, so as to render them useless.

Further evidence for the intended military use of the Tarhunah complex was provided by Libya's purchase of chemical reactors and piping, whose inner walls are coated with Teflon to make them resistant to corrosive toxic substances.

There are several mountains around Tarhuna/Tarhoona, they're only 350~500 meters high, but after looking at the overall topography of the region, that's approximatively the height of all the terrain around them. They're quite already leveled.

We may also look at the destruction of Near Earth Objects with single nuclear surface impacts to know how much firepower would be needed by using nukes.
But without getting there, we can already pay attention to known ranges on Earth.

• Appalachian Mountains
  • White Mountains Range
    • Franconia Range
    • Presidential Range
    • Sandwich Range (these people had fun naming them)
    • Eastern White Mountains Range
      • Carter-Moriah Range (okay, no jokes here, thank you) (alt link)
      • Baldface Range
    • Western White Mountains Range
      • Kinsman Range
    • Pilot Range
    • Mahoosuc Range
  • Blue Ridge Mountains
    • Western Blue Ridge Range
      • NE Tennessee Range
      • Roan-Unaka Mountains
    • Central Blue Ridge Range
      • Black Mountains
      • Great Craggy Mountains

I didn't list the entire tree, but that's more than enough to get the point: a range can encompass a number of small ranges, themselves also being groups of even smaller ranges.
Most of them are between 1 and 1.5 km high. You'll find a good number of those smaller ranges which extents fit between 15 and 45 km, with an average extent around 30 km.
The Baldface Range is a rather small one, with an area of 172 km².
The ten most important mountains of that range are:

Code: Select all

Rank    Peak Name                    ft	         m           Range6
1.         North Baldface              3600+     1097+      Baldface Range
2.         South Baldface             3560+     1085+      Baldface Range
3.         Sable Mountain             3519       1073        Baldface Range
4.         West Royce Mountain    3200+      975+       Baldface Range
5.         East Royce Mountain     3114        949         Baldface Range
6.         Baldface Knob              3025        922         Baldface Range
7.         Eagle Crag                   3020+      920+       Baldface Range
8.         Eastman Mountain         2939        896         Baldface Range
9.         Mount Meader              2782        848         Baldface Range
10.       Mount Hastings             2167        661         Baldface Range

Notice that only the first three reach above 1 km.
You also have the Cascade Range, comprises separated volcanoes or mountains.
Based on the data we got from St. Helens, clearly a couple of megatons fired right into a 1.5 km mountain would largely blast it apart.
Multiply this by the number of mountains you want to turn to rubble, and you would probably not need more than a total of a couple hundred megatons of focused fire tops to gouge the mountains of a larger range such as the Cascade one.

As for atomising a moon, notice that it is unknown how we should understand "atomise".
In one of the several plausible interpretations, we're concentrating the firepower on a single target instead of spreading it over a mountain range. In theory, you could deposit the energy on a single point. A moon can be as small as 1 km, so it's not easy to tell. Conservative calcs would be base on a couple of kilometers wide moons, and the high end ones would look at the biggest moons, like Ganymede (5268 km). However, the energies needed to blast such moons, and just blast them, are so ridiculously high that it simply doesn't fit with any of the other statements.

Connor claimed a high end of e29 J. SDN being SDN, no one flinched.
Gigatons starts at 4.184 e18 J, for the reminder.
Then again the descriptions are not sufficiently detailed. Without enough details on the real effects, and with words which can be understood in various ways (atomize, for example), at best this can give an idea of the firepower at play here.

FIRESTORM CRUISER

Firestorm Cruisers are often used on long-range incursions and patrols and as the first line of defence against alien attack. In the inhabited parts of human space, they jump from system to system, maintaining regular contact and reaffirming the ever-watchful presence of the Imperium.

Even with frequent patrols, the sheer size of the galaxy and the number of inhabited planets may mean decades pass before a system is revisited. Whole generations live and die between patrols and many of the Imperium's citizens never experience the passionate excitement of the arrival of a squadron of these mighty warships.

That's reminescent of the very similar reference in BFG, but with something I don't think was present in the newer source. "Whole generations live and die", that's several of them. A generation is 25 years, generally. Therefore we're looking at 50, perhaps 75 years before a planet sees a ship again.

Although the FTL speeds are low, my estimations of tens of thousands of ships was based on a time lapse of 20 years.

GALAXY TROOP SHIP

The Galaxy is a fleet support ship used to transport regiments of the Imperial Guard from one star system to another. The Galaxy itself is not a proper warship although it will often operate as part of a battlefleet, supplying troops for planetary landings.

Depending on if these ships are treated as warships, they could represent another slice of that fleet's numbers. With millions of troopers here and there, you could easily have several thousands of such transports in the fleet.

[Mith]

Um...post snipped.

[Mr. Oragahn]

This is thread is entirely dedicated to the older Space Fleet fluff. I dealt with BFG material in the "misc numbers" thread.
I'd rather you post this into the other thread. I've already addressed those btw, and it's clear that according to BFG, the ship counts do not ignore escort ships and smaller tonnages (contrary to what Captain Hat may have said).

[Mith]

This is thread is entirely dedicated to the older Space Fleet fluff. I dealt with BFG material in the "misc numbers" thread.
I'd rather you post this into the other thread. I've already addressed those btw, and it's clear that according to BFG, the ship counts do not ignore escort ships and smaller tonnages (contrary to what Captain Hat may have said).

Doh.

[Mr. Oragahn]

Here is the piece of fluff Connor picked a reference for his misc numbers thread. A minuscule extract that speaks of fuel used by the Imperium being a thousand times better than fusion.
As you'll see, it is interesting, if only to read the entirety of it. Bear with me, it's a bit messy.

GOLlATH FACTORY SHIP

The Goliath factory ship is a vast interstellar refinery and fuel transporter. Its role is to supply fuel to energy-hungry industrial and hive worlds. It transports its cargo from star systems rich in mineral resources across vast interstellar distances to worlds which have already depleted their own natural resources.

It arrives at a mining planet and takes aboard millions of tons of unrefined rare ores - for, of course, only rare and valuable ores are worth the expense of interstellar transportation. En route, the Goliath's huge refineries extract all the precious minerals from the ores. Working at immense pressures and temperatures, these minerals are then converted into plasma fuels that are incredibly energy-rich.

The Goliath itself needs a vast quantity of energy. Each ton of enriched plasma fuel uses many times more energy in the making than it will ever provide. To power its processes, the Goliath makes use of resources not available to cities and planetary factories - the raw power of the stars themselves. The Goliath skims close to the surface of stars, sucking in the energy that is burning off them by means of power fields that funnel the energy through to the Goliath's reactors.

At the end of its long voyage, a Goliath will have produced several million tons of super-energised plasma fuel. Every ton of this fuel is a thousand times more powerful than conventional nuclear fuels. And any explosion aboard a Goliath produces an incinerating fireball a thousand times more powerful than a conventional nuclear explosion.

So let's go through this again, but at a slow pace.

• It arrives at a mining planet and takes aboard millions of tons of unrefined rare ores - for, of course, only rare and valuable ores are worth the expense of interstellar transportation. En route, the Goliath's huge refineries extract all the precious minerals from the raw samples. Working at immense pressures and temperatures, these minerals are then converted into plasma fuels that are incredibly energy-rich. <- plasma fuel is not something obtained from random ores. It may be found on some planets though, but certainly not on the industrial and hive worlds, which largely are decrepit places.
• The Goliath itself needs a vast quantity of energy. Each ton of enriched plasma fuel uses many times more energy in the making than it will ever provide. <- would have been possible to calc if we knew how long the ship stayed close to a star, and how much power it gathered.
• To power its processes, the Goliath makes use of resources not available to cities and planetary factories - the raw power of the stars themselves. The Goliath skims close to the surface of stars, sucking in the energy that is burning off them by means of power fields that funnel the energy through to the Goliath's reactors. <- cities and planetary factories don't have access to the raw power the Goliath has access to by skimming the photosphere and using those radiation scoop/funneling fields. The intensity of a star like Sol is 2.009 e7 W/m². We don't know the area of those fields, but we already know that, first, the Goliath must use an enormous amount of energy to protect itself and even more to orbit the star. Secondly, the fields themselves, collecting radiations, must not be expensive, power wise, otherwise the concept of the Goliath would not be necessary, and power would be produced differently, far from any star.
  So whatever happens there, there has to be a net gain at first, even if it is completely expended to produce the fuel, with a reaction that's far from perfect since the fuel will only contain a fraction of the energy needed to produce it.
  Most logically, we can suppose that the Goliath does barely try to protect itself, as it would immediately start routing the collected radiations into force fields from the moment it would get close to the star, to start the operation as soon as possible. It may, eventually, need to power up some shields once the fuel tanks are full and no more energy can be spent into powering the special ionized ores.
  It seems to imply that the Imperium is condemned to rely on such ships otherwise it couldn't hope obtain energy densities worth of stellar fusion.
  
  It is a surprising design which is not mimicked by mundane warships, since those crafts' defenses don't seem to funnel any energy into a special capacitor for later use. This makes the Goliath an oddity and almost unique, along a few other designs.
  It is also unknown how much energy is put into one kilogram of the plasma fuel. There obviously are limits to that.
  There's another question, which is how the plasma is contained during the trip back, and served to planets and ships, without losing heat. I don't think the Imperium has demonstrated any technology that allows for near perfect insulation, and perhaps something as wonky as cold plasma that just begs to release fantastic energies would be the solution.
  
  Now, technically, skimming a star is not efficient at all. There's just too much energy being spent against the very massive star and its radiations, in order to obtain fusionable gases which offer little more than the cold gasses of gas giants.
  So as suggested above, since in this source, skimming a star and tapping its power is a definitive source of energy for later use as fuel once stored, it's quite obvious here that the Goliath is a very unique design which can collect a large amount of free energy that's already released. Albeit being a silly metaphor, the Goliath would be like a giant vacuum cleaner, gathering radiations, plasma and yet to react hydrogen particles. If you still don't get it, try that.
• Every ton of this fuel is a thousand times more powerful than conventional nuclear fuels. <- there it is, the famous quote. It's quite a bit more complicated than what it sounded like out of context. Considering the value of the technology of fission power production (STC and all that), there's enough of a margin of maneuver before we start looking at the proof of exotic fuels. JediMasterSpock made an interesting point about this in the WH40K - 40K misc numbers thread.
  
  We can understand the comparison this way:
  
  energy of 1 ton of plasma fuel = 1000 x energy of 1 ton of conventional nuclear fuel
  
  It is a plasma fuel, produced by using the power of fusion over an extended time to charge specific elements with greater energy. It's obviously going to be capped by what is achievable with matter annihilation: it would remain within the boundaries of what's possible, since we do not reach the maximum output of perfect annihilation, that is, the maximum energy any matter we know could ever release.
  Therefore, for similar fuel masses and consumption rates (a ton of plasma fuel would last quite some time anyway, considering the energies involved), a plasma fuel power plant could output several terawatts.
  We can take a look at the burnup as well. With a low tech burnup of 40 GWd/MTU (the total energy of 40 Gigajoules per second, over a full day), we have a total of 3,456 TJ per ton.
• And any explosion aboard a Goliath produces an incinerating fireball a thousand times more powerful than a conventional nuclear explosion. <- while plasma fuel is a thousand times better than conventional nuclear fuel, an explosion aboard a Goliath, and therefore the release of the energy of fuel since it's already supercharged plasma, would be a thousand times more powerful than a conventional nuclear explosion.
  We need to clarify this.
  
  1. Let's say that we're speaking of a nuclear weapon, and the Goliath has completed its harvest, with millions of tonnes of super-energised plasma fuel. Say 2 millions, which is going to provide the highest energy density for the fuel. Then;
     
     energy of a Goliath's fuel stock explosion = 1000 x energy of a conventional nuclear device explosion
     energy of 2 e6 tons of plasma fuel = 1000 x energy of a conventional nuclear device explosion
     energy of 2 e3 tons of plasma fuel = energy of a conventional nuclear device explosion
     
     Note: there would be strict practical limits to how far you could charge up plasma. Also, considering that one tonne of fuel is a thousand times more powerful than conventional nuclear fuel, the factor would be largely smaller when compared to weapon grade nuclear reactants, since they are enriched.
     
     Now, if we assume the comparison is based on a yardstick of one tonne of weapon grade nuclear reactant (the bomb's tonne of nuclear fuel fully reacts, which we know is not going to happen but still, let's pretend it does);
     
     energy of 2 e3 tons of plasma fuel = energy of 1 ton of weapon grade nuclear reactant
     
     Going with the energy figure of what can, at best, be obtained via absolute fusion, 800 PJ per ton (I use the number given by JMS for the moment, although wikipedia points to 630 PJ/tonne);
     
     energy of 2 e3 tons of plasma fuel = 800 PJ
     energy of 1 ton of plasma fuel = 400 TJ
     
     This method is obviously not the right one. We obtain 400 TJ for one ton of plasma fuel, while a Generation II reactor can get 3,456 TJ per ton. In other words, plasma fuel would have an inferior energy density, one worth of the Magnox tech, while it's supposed to be a thousand times better, tonne for tonne. Obviously, it doesn't work.
     You can still take a look at this document though. The Magnox barely reached 5 GWd/MTU.
  2. So what else could we try?
     The other interpretation is that when the ship blows up entirely, the yield of that explosion is worth a thousand times the yield of some conventional nuclear bomb.
     
     Let's work from the fuel ratio we got earlier on:
     
     energy of 1 ton of plasma fuel = 1000 x energy of 1 ton of conventional nuclear fuel
     energy of 2 e6 tons of plasma fuel = 2 e6 x 1000 x energy of 1 ton of conventional nuclear fuel
     
     Replacing the the last term from above with the last one from the line below:
     
     energy of 2 e6 tons of plasma fuel = 1000 x energy of a conventional nuclear explosion
     
     ... we get:
     
     2 e9 x energy of 1 ton of conventional nuclear fuel = 1000 x energy of a conventional nuclear explosion
     2 e6 x energy of 1 ton of conventional nuclear fuel = energy of a conventional nuclear explosion
     
     Even based on low burnups which orbit 1 megaton of energy, it would mean a conventional nuclear explosion would release several teratons of energy.
     Oh sure, I know some would love to trout this very sketchy methodology as fact, but it just doesn't fit with anything established by Space Fleet.
     The methodology is just as random as the former one, and the ratio "energy density of nuclear fuel / energy density of weapon grade nuclear reactants" breaks physics. A nuclear fuel doesn't get a million times more powerful because it's been enriched to weapon grade quality.
     
     
     In order to obtain more accurate, logical and likely numbers, we could use the first method again, but since it resulted in impossibly low energy densities, we would have to work around this issue.
     One way of doing that is to assume much less fuel goes up during one of the ship's internal explosions.
     This is possible because the text says "any explosion aboard a Goliath produces an incinerating fireball a thousand times more powerful than a conventional nuclear explosion."
     It is an explosion. This does not mean the Goliath goes up entirely, but that an internal explosion occurs, that one of the tens if not hundreds of fuel tanks explodes.
     If we assume the ship has x fuel tanks, then an explosion could be the explosion of one leaking fuel tank. Then, if it ever were to happen, the total destruction of all tanks, and thus of the whole ship, would release millions of megatons of energy.