Those are short ranged attacks.
No the real problem is that the Chaos fleet will quickly move to cover each other's rear arcs. Then the RT is pretty much boned. He can't trade blows with ships that out weigh him by this much. The Chaos fleet will also repair itself faster then the RT's fleet. Plus they're in a warp rift. If the RT's Gellar Fields go down his ship is pretty much instantly lost.
@Gavin:
Good point let me correct myself. It will be less well armed then an identically classed warship, though it may possess Arceotech surprises instead.