Lightbringer said:

What! I'm outraged! Well, maybe you're right ... a little bit....

In terms of the square-cube thing, I'm not talking fiscal efficiency but actually possible or not. Even just a tiny bit of extra structural reinforcement on a ship 100s (or 1000s!) of metres long will quickly add up to the point where the ship can't actually move (and obviously adding an extra engine will only add to the problem, past a certain point). Thrust:Mass ratios rather than economics.

But yeah, that's boring old reality - in a universe where the ships have thousands of tons of pinnacles, gargoyles and whatnot added, I don't think that's much of a concern. Fusion drives that obviously have a higher yield than matter/antimatter conversion and field-type structural reinforcement rather than physical and it's all good, clean (well, grim) space opera! At that point, then yep - you're right (especially when you don't need to worry about not having enough crew for bigger ships, the Imperium being what it is).

Re: The Eye of Terror novel - I suspect GW would quite like nobody to have read it now. Not the greatest (IMO) but it has one thing near the beginning that sums up the Imperium better than just about anything I've read [spoiler kind of, I suppose] where the two main characters have been chatting in a bar and as they leave, a random person follows them to tell them that he'd been listening to their whole conversation and that he was concerned that they hadn't mentioned their love of the Emperor once, and that he was thinking about reporting them - awesome! One of those 'Yep, that's it!' nail-head hitting moments.

There's a reason I mentioned energy and labour costs as well as fiscal- nothing is impossible if you can afford to throw enough energy at it. Unfeasible and impractical, yes, but not quite impossible. There's a difference between being able to move, and being able to maneuver. A ship too big would be able to effect some delta-vee, but it would take a stupidly long amount of time to get under way, and at least twice as long to change course. Since we don't know the density and composition of the ships in question, we don't know how much they mass. And without that information, and without knowing their expected performance envelopes, we don't know how efficient their power sources have to be.

We do know that they take a long time to get anywhere (sources vary between a few weeks and a years to get from the primary biosphere to the jump zone, although I suspect much of that variance comes from the exact astrographic geometry at the time, or authors not working to a coherent design), and that engagements between space-going combatants usually take place at ranges of several thousand kilometers, over periods of several days. Given the descriptions of weapons batteries tend to include a large number of unguided projectile weapons which travel at distinctly sub-luminal velocities, I think it's fair to assume that rapid vector changes are not particularly likely, otherwise no-one would be able to hit anything except with lasers, lances, guided projectiles (like missiles and torpedoes) or at very (read- point blank) short range.

That argues in favor of very massive ships, potentially travelling very fast (although not at appreciable fractions of light-speed), with reasonably low acceleration rates. To me, that doesn't really suggest matter/antimatter reactions. Highly efficient fusion and/or poorly explained 'plasma reactors', yes, but not a M/AM drive.

You're certainly right about the bit in Eye of Terror though. One of my favourite moments in any 40k novel. Actually, if memory serves, the guy who comes up to them to complain was actually a Warden of the Divisio Immoralis, although not quite in the sense that DH uses the term.
On a similar reference to Eye of Terror, and in support of some of my statements above- one of the instruments on the pilot's console apparently measures the ship's speed relative to the rest of the galaxy (or possibly the local star, or the galactic core, or some other point that can be said to be 'fixed'), and has a number of dials, one in km/h, one in hundreds of km/h, on in thousands, one in fractions of light-speed, and one in multiples of c. Apparently the last two are never used outside of the warp (although how they can know their apparent realspace velocity relative to any fixed point while in the warp is quite beyond me), except in seriously unusual circumstances (such as inside the Eye itself).

Alasseo said:

Perhaps the stable point from which their relative speed is derrived/calculated in Warp is the Astronomicon ? Perhaps the navigational systems of the ship can derive a calculated value of relative speed from such a reference point, despite the crews' otherwise inability to utilize the Astronomicon in true or relative navigational calculations without the aid of a Navigator .

-=Brother Praetus=-

Brother Praetus said:

That would seem unlikely that a machine could pick up the beacon with enough clarity to judge speed (and not be able to use it for navigation). In a previous thread it seemed that gravity wells from stars stopped ships from exiting warp near them. It could be that they have enough of an effect to be a relatively stable point to calculate speed from. Of course it has to be more complicated than that as otherwise you navigate by them in the warp.

Alterntively as the warp is not actually void there could also be some way of measuring its flow past the ship but this would not really be consistant with the real world speed.

It's also possible that it is just a function of the engines power output and just gives an average value of the speed that that should theoretically get you.

But I digress.

The smallest mentioned warp capable navel vessels are destroyers (in the modern world Frigates are smaller than destroyers but I'm not sure this is the case). But for the Navy whats the point of making a vessel small enough for a navigator to operate alone.

If money is no option, and it would need to be no option you could have a ship with a crew of one person:

• A navis prima (listed as nearly priceless)
• A warp engine and geller drive (pressumable very expensive)
• A plasma engine (probably quite pricy but I guess they can make them small enough for fighters.
• Enough servitors to keep the engines working

It all depends on how small you think you can get a warp engine. The smallest thing I can think of with one is titan sized warp missile. But this only has to warp for a very short distance but it does mean that there is no real theortical minimum size (as far as ships are concerned). And of course no ship would really go to space with just servitors looking after the engines so you should probably factor in a chief engineer.

So no real information after all that but it would seem that the limiting factor is how small you want to make a ship that has a very very expensive navigation system (Navigator or Navis prima).

Face Eater said:

The thing of it is that a Navigator reads the flows and eddies of the Warp, the Astronomicon is a stable reference point within the Warp. A machine could conceivably pick up that beacon, but it takes a living and psychic mind in order to perceive the flow of the Warp.

The Warp is not stagnate; it's like traversing a river (or ocean). A river that has it's whirlpools, rapids, and waterfalls. It's flow is fast in some reaches, and slow in others. There is a real and frightening chance that a ship can become becalmed in the Warp and trapped there. The Navigator reads these changes within the Warp and compensates for them. It is perfectly reasonable to believe a machine would not be able to perform this function as well as that of a living mind in tune with both the Warp and the ship.

But, as your last line postulates, the "speedometer" may merely be giving a calculation of relative FTL speeds based off of factors; such as engine output and "general" warp conditions.

-=Brother Praetus=-

Lightbringer said:

I like this speculation actually.

Eisenhorn novels put the navigation of warp travel in the hands of slaves of servitors. There was no astropath, simply navigator servitors. Computers can mimic an astropath's innate skills, though more slowly and through brute force instead of by finesse and the Emperor's Guiding Light. Think of our modern supercomputers. They can play chess. Really, really well. But they do it through brute force, whereas a human uses something less deterministic than automatically calculating every possible move capable and the end result of every possible move. However, with the Warp, you have chaos and the chaos factor to take into account, hence why even an astropath isn't a safe bet in warp travel (but still the safest bet).

That being said, my understanding is that astropaths are the only "reliable" navigational aid. And I read somewhere (wish I could pinpoint it) that most astropaths are reserved for the Imperial Navy, the Ateres, and probably the Inquisition's black ships. Hence why charters are so important. Not only is a charter a contract allowing trade along a certain route, but it also dictates relatively stable paths through the warp to specific destinations.

Think of a charter as a nature trail. Well-beaten, but still not 100% safe. Navigators and nav computers are sort of like dead reckoning in the wilderness. You can make some educated guesses using landmarks and you are sort of kind of in the area you want to be, but god only knows what's around you. Astropaths are like having a compass and a detailed terrain map. You're best off this way, even if you're following a well beaten path, but if you're going somewhere that isn't trampled flat by many people, you're gonna need a map/astropath.

Webways, under this analogy, are like GPS and google earth on your iphone. Takes the fun out of it all.

Brother Praetus said:

Um... The Astronomicon, aka the Emperor/Golden Throne, is a psychic projection. Only the Emperor among humanity (and perhaps among all the galaxy, because I've never heard of anyone able to do this) is able to project a stable, psychic signal from Terra, which all astropaths are able to get their fix off of.

Do you have any canon sources of a machine that can detect and act upon psychic signals?

If not, I'm going to have to firmly disagree here. Any machine that might be capable of that would probably have been purged long ago by the Inquisition hard-liners.

I'm sorry TheFlatline, I'm going to have to take issue with that- first; astropath is short for astrotelepath, ie: a psyker capable of sending and receiving telepathic messages over interstellar distances. They have nothing to do with the Astronomicon, or warp travel (save as the only method of communicating). Second, the Astronomicon is not generated by the God-Emperor of Man, nor by the Golden Throne. It is generated by scores, if not hundreds, of the most powerful psykers the Imperium has, acting in choir, from underneath Mt. Everest. The Emperor apparently shapes and directs the psychic beacon they generate.

There are also a number of 'boosters' for the Astronomicon scattered around the Imperium, with smaller choirs putting out a more diffuse signal, oriented from the Astronomicon.

Navigators (always capitalised) from the Navis Nobilite are special mutants with a third eye which (among other things) lets them see the warp, and they use the Astronomicon as their fixed reference point. They don't necessarily need it, but it helps enormously (in much the same way as a compass, to use your analogy).

And there are indeed a number of canon instances of a machine able to sense, measure and act upon psychic data. Psy-trackers are auspices used (primarily) by the Ordo Hereticus to detect and track rogue psykers by the enrgies they employ, and (more pertinently) early descriptions of 'blind' warp jumps described the process, and quite clearly state that the ship in question is able to measure local warp conditions prior to entry, and uses that information to form a 'best-guess' course, which unfortunately cannot be updated after entering the warp.

And a charter wouldn't give you the route. Or rather, it would not give you the information to use the route. Imagine it as giving you permission to operate along a certain route (Scintilla to Iocanthos, for example), assuming your Charter was a route charter and not one of the other kinds (Fleet Charter, Open Charter, Free Charter, and so on, up to a Rogue Trader's Charter and Letter of Marque), but it would not give you information on conditions along that route, which heading you will need, probable warp currents you may encounter, what traffic control is like at the other end. All that information would be contained in the Navis Prima, which you may get along with the Charter, or may need to acquire separately. Think of the Navis Prima as a cross between good maps and charts and the Sailing Directions.