I've just downloaded the preview, and it makes me really happy to see where things are going, I'm looking forward to integrating Rogue Trader stuff in with Dark Heresy, as well as hopefully launching brave boarding actions, power cutlass in hand!

I also can't express how awesome the artwork is I've seen so far, I'm a sucker for pretty pictures, particularly of space craft.

Rules wise, I'm hesitant to comment without full context for obvious reasons, but my first thought after a quick look was where are the shields ?

It might be the BFGer in me talking here, but shields are rather important, even for normal activity in space.  I'm also left wondering about how the weapons capacity system is going to work.   The Sword Class has two dorsal hardpoints,  which the picture on the page shows is fairly...um, not exactly accurate, but I've noticed no actual axial or broadside notations, so I'm wondering is this some sort of catchall hardpoint , or are generic broadside armaments considered "as standard" ?

I'd also have to agree that the acceleration figures made me wince a little,  its very difficult to accelerate up to 75% of lightspeed, or indeed slow down from such a speed, in any useful time frame when you've got a measly 4.5 gees to play with.   (I'm assumign this was the Flight of the Eisenstein number someone referenced , since I can't think of anything else from the novel)

In fact, generally speaking,  combat velocities in 40k fiction tend change rapidly enough that we are looking at thousands of gees to rationalise it.

Mass is also an issue, 6 million tonnes sounds a lot, until you are talking about a 1.5km long starship, made up of dense, heavy armour plating and bulkheads.  Given that 40k starships appear to propel themselves by belching out vast plumes of accelerated plasma (i.e. a giant reaction engine), there is a requirement for a significant mass of fuel as well!

@ Kaihlik: I could see that. A supplement detailing ships or the Imperial Navy could cover Cobra Destroyers.

@ Thrudd: The masses could be unloaded (including fuel).  Fuel (loaded or not) could be treated seperately from cargo capicity too. We'll see.

Kaihlik said:

Flight of the Eisenstien doesn't directly produce a number, but it has a very handy example of having a mobile space fortrress undergo a velocity change of .75C over the distance between Earth and Pluto.  Now the exact distance is unknown (because the alignment of Earth and Pluto isn't), so we have a range of comparatively close numbers between maximum and minimum distance (because the biggest number by far is getting from Pluto to the inner system).  The numbers are in hundreds of gees.  To repeat, that's a space fortress pulling those gees, not a destroyer.

And it's not a outlyer.  Execution Hour has a hundred plus gee acceleration for the Planet Killer of all things, Sabbat Martyr has ships crossing multiple AUs fairly quickly and still being able to maneuver (which would require massive accelerations),  there's instances in the Grey Knights books as ships crossing systems in hours and pulling into orbit (again massive accelerations required to brake into orbit against those speeds), and so on.

As for the speeds of ships in the older fluff sublight travel is a lot slower - in Imperial Armour III it takes 3 days to reach the system's sun (approx 1AU); in Execution Hour it takes Imperial ships days to reach the safe distance for warp entry.

With so much contradictory information out there it will be very interesting to see what the RT figures are.

DW  

I'm steering well clear of this "G-acceleration" debate, as my scientific skills are so feeble that I'm ill placed to comment.

However, this preview is really really exciting, in my view. FFG have used a similar system for their ship design to White Wolf's Chantry design for Mage: the Ascension and FASA's magical group design system. I thought they might use a system like this, and I'm pleased to see it executed so elegantly.

 First off, it's clear that the vessels we're talking about here are not the same scale as top-level Imperial Battlefleet ships. The Sword class Frigate is the second smallest Imperial fleet vessel mentioned in Battlefleet Gothic, and it's in the medium size range of vessels presented here. (People have already commented on the missing Cobra Destroyer: perhaps it crops up beyond page 3 of this chapter. Personally, I would have thought that it wouldn't make a great rogue trader vessel, as its storage space is probably fairly limited.) This size range and displacement seems absolutely spot on for RPG play: players vessels will be well equipped and powerful, but not able to go toe-to-toe with hardened battlefleets of any race. However, they can dominate primitive worlds, take on pirates, travel the galaxy, transport armies...

Secondly, I love the little details here. I loved Battlefleet Gothic, but the trainspotter in me was always a little disappointed that GW never set out the specific SIZES of Imperial vessels. I was constantly shouted down on Black Libray's forums for mentioning this niggle, on the basis that it was enough to bombastically rave on about how huuuuuge Imperial ships were rather than constrict the fan's imagination. My view was...what's the HARM in presenting this stuff? It's fun, it adds colour and detail...and clearly FFG agree. Though they may now be regretting presenting their views about G-acceleration to all the other trainspotters out there! 

I think the size of these vessels has been really well thought out. A lot of effort's been put into this. This is (apart from a couple of contradictory references in BL books, with apologetic clarifications from authors on the BL forums) the first time that anyone has ever attempted to set out the size of Imperial ships. And the scales seem spot on to me: huge, but not so huge as to be ridiculous.

I REALLY like the fact that the Sword Frigate - as I say, one of the smallest vessels in the Imperial fleet - is exactly the same size as a Star Wars Imperial Star Destroyer. A sneaky little dig at the Star Wars universe, I reckon: "Anything you can do, we can do better..." 

The crew sizes also seem large, but not gigantic. Someone's already pointed out that the crew sizes produce quite a lot of space for each crewman: looking at my BFG Sword class frigate right now, I reckon both the prow and engine compartment would be largely empty, with most of the crew in the central gun chamber and control tower. The "civilian" ships of a rogue trader fleet probably wouldn't be as heavily manned as Battlefleet ships. I base this on the old "Aubrey/Maturin golden age of sail" contrast between the hugely overmanned and crowded royal naval vessels and the comparatively empty whalers and East India Co. ships of the era. Military vessels need a huge crew to be able to operate broadsides in two directions and soak up casualties for the hours a battle may take to win. I think given the design of Imperial ships, the crew sizes presented here would produce a vessel that's extremely crowded in places, but with many echoing corridors, mysterious empty holds and vast cathedral like engine rooms.   

Very very good stuff, the most exciting stuff I've seen for this game so far!

 It's also possible that the figures for the Gs pulled could be 'gravities of acceleration experienced after inertial dampening'. Of course, if that is the case, we'd have a serious problem trying to find out what the efficiency of the dampers is, and whether that is a (relative) constant across all ships, or whether 'military' drives have more powerful inertiics than 'civilian' drives. I'd be tempted to say (purely for matters of storytelling convenience) that all the ships listed have inertial dampers of roughly equal power, which reduce experienced acceleration to 1/10th of its actual force, and that the numbers given are for sustained thrust.

As for the shields- my guess is that shields are one of the 'essential' components that get fitted after choosing your hull.

I cant even remember that part of Flight of the Eisenstien. I always cringe when the type of examples you gave show up because it always seemed to me to contradict everything I thought I knew about 40k space combat. Of course there is always the problem that Sci Fi Writers Have No Sense of Scale, I wish they had put some more concrete numbers in the BFG rulebook because not having any has lead to the situation that because the writers dont know how the ships should be working they improvise and give really contradictory views. The example in Flight of the Eisenstien may have been due to some freaky tech from Mars. Its just too hard to say what is meant to be the true numbers because there is zero consistancy in the fluff.

@Santiago - There is a list of ship classes at the start which doesn't include destroyers which is what a Cobra is, it might fit in the Frigate section but I would have expected to see it before the Sword and not after. They seen to only be giving a couple of hulls from each class of ship so I wouldn't expext to see the cobra as there is already two frigate hulls.

Kaihlik

The concept of player designed ships is a fun one. However, it should have an impact on the type of missions the players can persue. So if you are aiming to include published adventures, I'd imagine it would be good to look a few over before you let the players go off in some random tangent. Or give them an idea of the things that might be useful in upcoming adventures before they spend all their points on weapons and armor and nothing on cargo capacity or crew skill.

The crew skill mechanic looks interesting. I'm wondering how easy that will be to change in play. Will min/maxers go with poorly trained crews, to afford more hardware, then spend time developing the crew during the campaign?

As far as the gees listed for the ships, they seem right to me. Dark Heresy and, by extension I imagine, Rogue Trader subscribe to a more age of sales feel with space travel and, as such, it tends to take weeks and months as opposed to hours and days to get places.

If a ship were to travel from Earth to Pluto, the average distance would be about 39 AU's (all dependent on planetary alignment and all seeing as how these damned rocks never sit still). If a ship were to preform a full acceleration burn for half the trip (19.5 AU's), flip, and then preform a full deceleration burn for the second half (so it actually stops at it's destination as opposed to flying past it at some mind boggling speed), the Jericho Pilgrim Ship will take about 14 days, the Hazeroth Privateer will take about 5 days, and a Planet Killer with an acceleration in the hundreds (we'll go with 200 for this) will take about a day.

Given the feel that DH and, we can assume, RT is going for, the acceleration numbers seem good to me. Perhaps the numbers in BG or other sources were a bit high, especially considering that with such high accelerations, reaching the light-speed barrier would actually be doable assuming that the ship is able to carry more then 6 months worth of fuel for continuous burning.

The gees listed also can't be without dampeners as a few ships pull gees in excess of 5. Without some form of counter measures, the human body can only withstand such pressures for a few seconds before blacking out due to drastic changes in blood pressure.

Traveller61 said:

The older fluff  specifically mentions accelerations of 50 gravities on a merchant ship (Genestealer game).  40k fluff info has overwhelming shown double and triple digit gravities acceleration. There are some lower outliers but there are also higher outliers as well.

For  those less science minded folks, a gravity refers to the force acting on an object on Earth, which is to say an acceleration of 9.8 meters per second squared.  That's how fast things fall on Earth.  It's a common way of measuring acceleration in science fiction settings.

[quote]

Given the feel that DH and, we can assume, RT is going for, the acceleration numbers seem good to me. Perhaps the numbers in BG or other sources were a bit high, especially considering that with such high accelerations, reaching the light-speed barrier would actually be doable assuming that the ship is able to carry more then 6 months worth of fuel for continuous burning.

[/QUOTE]

At high velocities, relativity makes you its bitch and the approximations of classical mechanics become grossly erroneously (Newtonian mechancis isn't actually how the universe works, they're just a very good approximation as long as you're travelling no where close to the speed of light).  Approaching the speed of light requires a ridiculous amount of energy and actually reaching the speed of light is impossible.

Unless you're a Necron and make the laws of physics your bitch.

Graver said:

Sounds reasonable - the ones listed in the preview are, afterall, freighter, pilgrim and ex-service military craft, rather than top-of-the-line marvels of the Omnissiah's blessed technology like the strike cruisers of the Grey Knights, the highly sophisticated pre-Imperial technology of the Imperial Fists fortress monastery (the Phalanx, which would be the station mentioned in Flight of the Eisenstein), or blasphemous nature-defying constructions like the Planet Killer (which was, amongst other things, partially constructed in the Warp and thus not entirely beholden to natural law).

There's room for a wide range of ability when it comes to the construction of ships in 40k, even if you only consider those of the Imperium. A tramp freighter or a retired (in the sense that it's no longer serving in the Imperial Navy) Sword-class Frigate will rarely be as quick through space as an Astartes cruiser or something similar.

Further... we've seen three pages of the starship rules, detailing only the hulls. It seems entirely likely that there'll be the option to give your ship more effective engines to replace the low-end baseline ones listed in the hull entry.

Well since I'm underqualified to comment on 40k physics (although I agree with the statement that sci-fi writers have no sense of scale...)  Yeah, this looks pretty good, fairly reasonable compared to what I've seen in the Traveller system and fairly in line with a universe where tanks become landbased battleships and post-human warriors run around like medieval knights.  Ships are less trawler or yacht and more ocean liner in scale, all I should say is that the folks at FFG might want to double-check their math to make sure everything makes sense.  Other then that... yeah, I'm done.

Cynical Cat said:

Well, I was using slightly sipmlified Einsteinian physics, not Newtonian and, granted, I ignored mass and what would happen to it as it's speed increased and assumed that it would be able to maintain the acceleration rate despite it's increasing mass... but still, gees in the tripple digits might be a bit much.  Crossing a decent sized solar system in under a month seems good (and amazingly fast to boot... solar systems are BIG) to me.

Cynical Cat said:

I'd have to say that warp travel in general is making the laws of physics your bitch.

"Aww, shucks reality prevents us from reaching a destination in space at the speed of light or faster. That really cramps our style!"

"What if we just simply reject the reality and drive our vessel through an extra dimensional realm of UN-reality?"

"That's not a bad idea mate! Screw the laws of physics! We'll just leave this reality for a while and simply plop out at the other end of the extra dimensional wormhole! All we have to do is manage to dodge the malicious entities in that other dimension where making the laws of physics your bitch is possible."

Then again, the Necrons have made it possible to make the laws of physics their bitch in the material realm, which is a feat in itself...