Luctius said:
Correct, but during a turn there are two ordnance phases. One for you and one for the opposition. During each of those all ordnance moves, while a normal ship only moves during the movement phase of your own turn.
Edit:
At page 27 of the Basic rules pdf (I'm at work so don't have the original copy with me).
I agree that it doesn't state it very clear(on this page atleast I will check later If I can find a more clear reference).
It does however hint at it when it says that both players can move their ordnance during the same ordnance phase.
Ah, I suspected that was what you meant.
However I think this has more to do with game design and the breakdown of a game turn in BFG. But I don't think it would be that reliable to just assume that since torpedoes move in every ordnance phase, it means that they have twice the speed listed on their stats.
I'd assume the reason why torpedoes move during every Ordnance phase is because players don't move individual ships during every turn but preform actions with every ship in their fleet.
In Rogue Trader the ships don't act at the same time as in BFG since the ship who gets to act first is determined by their initiative roll, and when the ship with the best initiative has moved, the ship with the next highest acts and so on. Meaning that BFG use a more abstract way of describing in which order ships move in comparison to Rogue Trader.
If the situation was real, then both ships would have moved in real time, but since it would be kind of chaotic to keep track of that both games have to divide the action into turns. One could say that the system which Rogue Trader use is more close to Real Time than the system that BFG use. And the reason why torpedoes always move in both players Ordnance phases is implemented in order for all Ordnance to be able to keep up with the game flow (and possibly to insure that players don't forget to move pieces of Ordnance already released on the table top).
To prove my point, imagine if BFG was converted to a system more akin to Rogue Trader. Meaning that ships of different fleets acted in order according to each ships initiative rather than acting at the same time during each players turn. If the game turn still went on as normal it would mean that each additional ship on the board would provide the game flow with additional Ordnance phases. Meaning that the more ships there are on the board, the faster each piece of Ordnance would be. And that wouldn't really make a lot of sense, would it? I mean, why on earth would torpedoes suddenly be able to reach light speed just because there are hundreds of ships locked in combat when they would have moved a lot slower if there were fewer ships close by?
So to summarize: I don't think interprating the speed of objects in BFG should be based too much on the game flow of BFG, but rather trying to convert different stats used in BFG to Rogue Trader. Rogue Trader's system for starship combat might be an extrapolation on the rules used in BFG (since some game mechanics are quite effective and also helps provide the correct sense of scale), but the gameflow in BFG is drastically different from the game flow of starship combat as it is described in Rogue Trader. Don't you agree?