OK, so this is probably been talked about before but I have not come across it. This relates to:
http://www.dskelly.com/misc/aa/aasim.html
I was running some scenarios and something seemed off, so I tried something obvious and oh oh….3 Bombers against 3 subs under Spring 42 should result in no combat, no IPC lost for either side yet it is a complete win for the bombers. Change the scenario to 3 bombers versus a destroyer and 10 subs and its about a 50/50 battle, so it looks like you are attacking an 11 hit-point destroyer as the subs while not defending via dice rolls, were being taken off as hits. Obviously it does not enforce the rules requiring air power to have a destroyer present to attack subs/subs can’t be attacked or taken as hits unless attacked by air+destroyer.
Old news?
