There is one Problem: neither scale nor timeframe in ANY Games workshop game is linear. Miniatures, Markers and Terrain don't even share the same scale.
E.G. some Areas have a Planet and a Moon of this Planet on the Table - something that is close to impossible as long as you asume a scale of 1cm=1000km and don't play on a gaming table of 4 metres or more! (the minimal distance beteween earth and moon is 363.000km!).
In other games it is the same: in 40k 12" weapon range isn't even the same than, say 12" movement. Horizontal distance is not the same as vertical distance. A Space Marine miniature is ~3,5cm high, representing a ~2,5m high Space Marine. So 1cm is ~0,7m. A Bolter has a maximum range of 24"(61cm). Does anybody believe that it can fire only over 43 metres?
A "gameturn" doesn't represent the same timeframe: while over long range Artillery-battles it represents a longer time up to an hour or so in close combat it only means some seconds/minutes. And so on...
There even was some statement in an old WD about this.
There is no real "scale" in this games and this is why you can't take data from them except the most basic like "a sword has higher maximum speed than a Lunar".
No, I hate to say it, but the stats for a Navy Lunar Class cruiser are given in the adventure Whispers on the Storm.
If you use my weapon/Range conversion formula it comes out EXACTLY it's stats in BFG, as long as you remember that the weapon ranges that are not exactly on the 15cm mark all round up to the next higher 15cm band.
I tried it again with the Murder from Edge of the Abyss, same result.
To get a cruiser's weapon and speed stats to convert from BFG to RT: divide the str of the wb/lances by the number of batteries the mini uses on a given broadside. It's range in VU will be in the the equivalent band in RT, using the str 6 macrocannon broadside as a ruler.
You can reduce a battery's str by 1 to give it +10 to ballistics tests. This is due to WB str also including accuracy. Otherwise it converts directly. A Dominator is a str 12 broadside in both games. A lunar is a str 6 wb str 2 lance in both games.
A single point of armor in BFG is 4 points of armor in Rogue Trader, for warships. (this does not convert for civilian ships such as freighters, which have a lower armor in RT then BFG, or for ships smaller then frigates, such as the cobra. However, there are also ways to add additional armor, so Navy ships may simply be equipped with this extra armor. The speed reduction they cause would explain why some ships that have a faster base speed have a lower armor then they do in BFG.)
As to why I've spent time proving this point:
Weapon stats in BFG are not exact. When one says WB Firepower, the value is just representative of how strong it is. It is very much different from 40k weaponry. You can't even directly convert the ranges much less the strength between both game systems. RT which might come close still has a different game mechanic and so still can't be directly converted.
This is incorrect. There are whole PDFs online from people that have converted ships from BFG to RT using this formula. I only handled some BoN and Dark Eldar.
