PDA

View Full Version : How big are Imperial Vessels?



Freefall945
06-10-2010, 11:26 PM
I'm running a Dark Heresy game for a group we have dubbed the Three Psykerteers - three psykers moving into different disciplines, with a handful of gimme-advances in out-of-career skills so that they can investigate conventionally as well.

Long story short, they're presently scurrying around on board a particularly volatile and dilapidated Black Ship.

It'd be super helpful if anyone could give me some rough dimensions of imperial vessels, particularly cruisers and battleships, and even MORE helpful if anyone knew how many decks I could expect to be on such craft.

Help a guy out!

Nabterayl
06-11-2010, 12:23 AM
According to Rogue Trader:

A Lunar class [heavy] cruiser is 5 kilometers long with a maximum beam of 0.8 km, and a crew of about 95,000;
A Dauntless class light cruiser is 4.5 kilometers long with a maximum beam of 0.5 km, and a crew of about 65,000;
A Sword class frigate is 1.6 kilometers long with a maximum beam of 0.3 km, and a crew of about 26,000.
A couple observations:

Starships in this universe are, obviously, huge.
They are also incredibly sparsely populated in terms of crew per cubic meter (do a rough comparison between a Nimitz class aircraft carrier, which is far shorter and slimmer than any 40K warp-going vessel - the Nimitz has 17 sailors or air crew per meter of length; a Sword has 16.25, a Dauntless 14.4, and a Lunar 19).
Since all of our sources depict starships as being cramped and crowded, it follows that there must be large volumes of any starship that are all but completely unpopulated - serviceways, gun batteries, magazines, engines, plasma reactors, auspex arrays ... the space in which the crew lives and works must be a relatively small fraction of the total volume of the ship itself.

We know from the Eisenhorn trilogy that the term "Black Ship" can refer to cruiser-weight vessels (I don't think anybody ever says, but my suspicion is that "Black Ship" simply means a starship of any class that officially belongs to the Inquisition), so you could have a Black Ship at least as big as a Lunar class cruiser (which is the prototypical cruiser of the Imperial Navy) - it might even be a Lunar class vessel.

As for how many decks you'd find on a ship like that ... roughly speaking Imperial vessels are as "tall" as their maximum beam (anybody with a BFG collection care to nuance that)? That means that a typical frigate would be approximately 300 meters tall, a typical light cruiser would be about 500 meters tall, and a typical cruiser would be about 800 meters tall. If we assume that most decks have only about four meter ceilings (13 feet), that means we're talking about 75, 125, and 200 decks respectively.

Of course, we shouldn't assume that all decks run the whole length of the ship (well, obviously - if you look at any Imperial vessels they all have very pronounced superstructures, but even besides that). We know that ships have big vaulted spaces such as shipboard chapels (more like cathedrals) and the bridge that are much bigger than four meters, and of course the magazines and gun decks are likely to be much bigger than that too, as would hangar bays, the reactor rooms, etc. So you'd have these big spaces that chop up the actual deck layout quite a bit, I imagine.

Freefall945
06-11-2010, 12:34 AM
Thanks, Nabterayl! Extremely helpful.

Old_Paladin
06-11-2010, 06:43 AM
merzo.net
has to-scale images of starships for different sci-fi series.
Imperial ships don't even show up until the -10 size grouping.

They are huge; Destroyer class escorts are the same size as a Star Destroyer from starwars.

Just_Me
06-11-2010, 02:30 PM
As an avid Battlefleet Gothic fan and collector, all I can say is that Nabterayl is quite correct, I really can't add anything to his excellent summary and breakdown of details.

One might speculate that the comparatively low crew density on Imperial ships is due to a combination of factors including the vast space requirements of their reactors and primary armament and otherwise general spacial inefficiency of Imperial technology (while impressively compact tech is clearly within their grasp, it is very much the exception rather than the rule), and the need for embarked stores to feed supply their crews for possibly decades of operation without access to resupply (though of course, smaller ships would have more limited operational ranges). It has also been implied that some of the largest vessels have limited production capabilities to replace munitions and losses of combat craft, and most capital ships also seem to be intended to serve as troop transports in at least a limited capacity. I would surmise that the core and primary weapons decks of most Imperial ships are largely uninhabited space, with most of the crew housed in the superstructure and "waist" of the vessel.

Enterprising individuals with sufficient clout and inclination (such as Rogue Traders, the Mechanicus, or the Inquisition) could most likely take advantage of this and greatly expand the capabilities of their vessels with the addition of more advanced and space efficient components. Meaning that even the smallest of ships could house not inconsiderable storage capacity or supplementary components (e.g. prisons, labs, advanced production capabilites, etc.), this fact is rather well represented by the Rogue Trader ship building rules in fact.

KittenOfDeath
06-11-2010, 05:19 PM
http://img819.imageshack.us/img819/3749/1274059971811.jpg

Size comparison with 40k and everyone else, also known as 40k and some dots.

Faultie
06-11-2010, 05:25 PM
If you want a better idea of the size, goto Merzo.net (www.merzo.net), and goto the -2x page. That shows a Cobra (a small torpedo frigate) next to some other famous SciFi warships. At -10x, it has a Retribution Battleship.

Quite simply, the scale is pretty large for Scifi (compare them to Star Destroyers and StarTrek ships, etc.)

Check out the website in Internet Explorer, and you can actually drag the pictures of the ships around to do one-on-one comparisons.

Nabterayl
06-11-2010, 05:55 PM
As a side note, purely as a matter of academic interest, the masses we have are almost certainly wrong. If a Lunar class cruiser, which can be approximated as a rectangle 5,000m x 800m x 800m, has a mass of a mere 28,000,000,000 kg, then its overall density is about 8.75 kg per cubic meter, less than 1% the density of water and only seven times the density of air. Even with much more conservative numbers (e.g., 5,000x600x600), these things are so light it kind of defies belief. Which is neither here nor there in a Dark Heresy context, but you may find interesting.

krispy
06-12-2010, 12:12 PM
interesting topic here - i have a question though - the numbers of crew - 26k up to 95k for the different ship sizes - does this include servitors? or are they not counted as crew seeing as they arent entirely alive?
/k

Nabterayl
06-12-2010, 02:53 PM
I don't think servitors are considered crew, no. In the BFG sourcebooks and on Andy Chambers' personal website, for instance, space marine vessels are said to have very small crews because most of the work is done by servitors.