Light fleets NOT attaking subs

[Badbonez]

Why is it that sometimes my light fleets cannot engage subs? They're in supply when they move to the sea zone with the sub but when they get there the General Combat button is grayed out. Even if I move supplies to that zone. What gives?

Thanks.

[pyrhic]

i think that happens when your unit cannot mathematically hit the other unit.

[Badbonez]

OK that makes sense. But here's my situation: It's early in the game and the German subs have 6 defense (evasion 2, durability 3). My light fleets are throwing only 1 die. In addition, I have given the computer a +1 die roll advantage. OK, fine, that FIRST light fleet cannot hit the sub. However, that sub gets a -2 for the next time it is attacked. So yeah, my first one cannot mathmatically hit the sub, but the subsequent attacks can. So I need that first attack to go through, even if it is impossible. I guess the solution is to attack with two fleets at the same time but I shouldn't have to.