Hi Guys,
If I understand the rules correctly, SDB versus BatRon combat would look like this...
Squadron 154 is the Battle Rider squadron from THE SPINWARD MARCHES CAMPAIGN. Its attack factor in the Game is 6-2-8 (Attack/Bomb/Defense factor). Assuming that you are using Cronor as the example, it has 150 SDB factors.
(For purposes of this example, I will use rolls of 4 to represent the expected avarage result for both Imperial BatRon and SDB)
Roll 1d6 (getting a 4) and subtract 1/2 the TL of the SDB's. In this case, it would be a -6. Final roll is 4-6 or a -2 result (oddly enough, the game rules use a TL 13 example). This results in 20% loss rates for the SDB factors. 20% of 150 is 30.
Roll 1d6 (getting a 4) and adding Zero (TL 13 gets no bonus), final result is a 4. This is the minimum number of Defense factors the Imperium player must lose. As it just so happens, the 154th has a Defense factor of 8, and its reverse side is 4. The New counter (flipped over) looks like this: 3-1-4
Thus, for taking on a 150 Factor SDB fleet, the expected losses are 50% to the Imperial Squadron versus 20%. If the Imperial Fleet were to continue fighting to the death - it would inflict another 20% damage to the SDB fleet - and the SDB fleet would wipe the Imperial out entirely. (Turns out, that the Imperial fleet combat factor is 2 - which is half way between the 1 column and the 3 Column. As a result, it must use the 1 column in fighting the SDB's. The SDB's on the other hand, start at 150. Their attach column is listed as being 120 (same problem the Imperials have - too much combat factor that is midway between the next highest column and the one I used for the example). Both sides get to roll on the same initial combat chart for round two as they did for round 1.
Total casualties expected for the 150 factor SDB fleet is 40%. Total casualties expected for the Iperium Squadron is 100%. (hopefully I did this right)